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General Discussion => Q&A Section => Topic started by: NSF Webmaster on 06/12/2009 11:12 pm

Title: Shuttle Q&A Part 5
Post by: NSF Webmaster on 06/12/2009 11:12 pm
(http://www.nasaspaceflight.com/_docs/sqa.jpg)

To keep everything at readable proportions, this is part 5 of the highly informative thread. Below are the links to previous parts. Please use the search (http://forum.nasaspaceflight.com/index.php?action=search") function to see if your question has been answered before. Have Fun!

Shuttle Q&A Part 1 (http://forum.nasaspaceflight.com/index.php?topic=625)
Shuttle Q&A Part 2 (http://forum.nasaspaceflight.com/index.php?topic=2030)
Shuttle Q&A Part 3 (http://forum.nasaspaceflight.com/index.php?topic=6156)
Shuttle Q&A Part 4 (http://forum.nasaspaceflight.com/index.php?topic=10600.0)
Shuttle Q&A Part 5 (http://forum.nasaspaceflight.com/index.php?topic=17437.0)
Title: Re: Shuttle Q&A Part 5
Post by: NSF Webmaster on 06/12/2009 11:15 pm
And to repeat the last post in Part 4 :

Banjul, also no longer used, is Yundum International Airport. NASA built a dedicated building at each of those locations.

STS-125 was told "negative Moron, select Banjul." Wouldn't that imply it's still used?
In a big emergency they might land there (edit -- probably only considered for low-inclination flights, which are now concluded), but the execute packages for 125 noted that Banjul was "politically not recommended."
Title: Re: Shuttle Q&A Part 5
Post by: Spacenick on 06/13/2009 06:28 pm
Is Groom Lake a possible landing location of the Space Shuttle?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/13/2009 06:39 pm
Is Groom Lake a possible landing location of the Space Shuttle?

In the sense of "the runway is big enough and is equipped with the proper navaids", yes.

In the sense of "would NASA ever land there", no. Groom Lake is not on the ELS list. There are other air force bases in that area of Nevada (e.g. Nellis) that are also suitable for the shuttle and aren't nearly as classified. There is no conceivable circumstance where the shuttle would be able to land at Groom Lake but not one of these other fields. Therefore it will never, ever happen.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/13/2009 11:45 pm
What are the tanks I've circled? Nitrogen or Helium? I assume they are gaseous tanks? What function do the contents serve? Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: vt_hokie on 06/14/2009 12:25 am
Forgive me if I missed this elsewhere on the forum, but can someone point me to an explanation of the "beta angle cutout" and the thermal constraints that prevent launch of STS-127 after June 20?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 06/14/2009 12:31 am
If you Google and add " site:nasaspaceflight.com" it will restrict the searches to here, where it'll be easier to find.

http://www.google.com/search?q=beta+angle+cutout+site%3Anasaspaceflight.com&sourceid=ie7&rls=com.microsoft:en-us:IE-SearchBox&ie=&oe=

has several discussions here that explain it in detail.
Title: Re: Shuttle Q&A Part 5
Post by: vt_hokie on 06/14/2009 12:35 am
Thanks, appreciate it!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/14/2009 03:16 am
What are the tanks I've circled? Nitrogen or Helium? I assume they are gaseous tanks? What function do the contents serve? Thanks.

high pressure storage for purges
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 06/14/2009 03:47 am
They're all helium, no?  The Air Liquide GN2 line is kept at 6-7 ksi.  No real need for a plenum.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 06/14/2009 03:11 pm
I have some questions about some aspects of the Space Shuttle's ascent procedures:

1. When had the OMS assist burn during ascent (on Direct Insertion) been introduced for the first time?
2. Which missions used the OMS assist burn during ascent? Is there a list available somewhere?
3. To me, it seems like all ISS missions used it, is that correct? What about other missions (e.g. Mir missions and others)? On the Ascent checklists that are available on the web, I noticed that the Hubble missions did not have an OMS assist burn, as well as STS-400.
4. What are the reasons that determine, if an OMS assist is needed during ascent? Is it only the ET reentry footprint on certain inclinations? Does it also depend on the total weight of the orbiter (incl. payload)? Other factors?

5. When had the Roll to Heads Up been introduced for the first time?
6. Which missions had performed the Roll to Heads Up? Is there a list available?
7. I have read that the reason for the introduction of Roll to Heads Up was, to establish the comm link with a TDRS satellite during ascent, which in turn made a tracking station on the Bermudas obsolete. So, I assume that after a certain point in the history of the Shuttle program all missions performed the Roll to Heads Up. Is this correct?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/14/2009 08:12 pm
I have some questions about some aspects of the Space Shuttle's ascent procedures:

1. When had the OMS assist burn during ascent (on Direct Insertion) been introduced for the first time?

STS-90, 1998.

Quote
2. Which missions used the OMS assist burn during ascent? Is there a list available somewhere?

Don't know of a list. Most flights have used it.

Quote
3. To me, it seems like all ISS missions used it, is that correct? What about other missions (e.g. Mir missions and others)? On the Ascent checklists that are available on the web, I noticed that the Hubble missions did not have an OMS assist burn, as well as STS-400.

There was only one Mir mission after STS-90 (STS-91). Don't know if it used OMS assist but it probably did. HST missions do not use OMS assist because they need all their OMS prop for in-mission usage. Roughly speaking, they burn half the tanks getting up to HST and the other half for deorbit.

Quote
4. What are the reasons that determine, if an OMS assist is needed during ascent? Is it only the ET reentry footprint on certain inclinations? Does it also depend on the total weight of the orbiter (incl. payload)? Other factors?

Reentry footprint doesn't have anything to do with it. OMS assist is performed if 1) the OMS prop required for the mission itself does not require full tanks and 2) the mission could benefit from the additional payload capacity gained by filling the OMS tanks full and burning the difference as OMS assist (IIRC it's roughly 200 lb payload for 4000 lb OMS prop). CG location is a secondary consideration on the amount loaded.

Quote
5. When had the Roll to Heads Up been introduced for the first time?

Don't remember for sure, think it was STS-86. (If it wasn't, it was another flight that year, 1997).

Quote
6. Which missions had performed the Roll to Heads Up? Is there a list available?

No public list I'm aware of.

Quote
7. I have read that the reason for the introduction of Roll to Heads Up was, to establish the comm link with a TDRS satellite during ascent, which in turn made a tracking station on the Bermudas obsolete. So, I assume that after a certain point in the history of the Shuttle program all missions performed the Roll to Heads Up. Is this correct?

Think so. RTHU does cost some performance so there were a handful of performance critical missions, after introduction of RTHU but before closure of Bermuda, that did not perform it. Off the top of my head I think STS-97 and 98 didn't but I'm not sure.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/14/2009 08:12 pm
I have some questions about some aspects of the Space Shuttle's ascent procedures:

1. When had the OMS assist burn during ascent (on Direct Insertion) been introduced for the first time?
2. Which missions used the OMS assist burn during ascent? Is there a list available somewhere?
3. To me, it seems like all ISS missions used it, is that correct? What about other missions (e.g. Mir missions and others)? On the Ascent checklists that are available on the web, I noticed that the Hubble missions did not have an OMS assist burn, as well as STS-400.
4. What are the reasons that determine, if an OMS assist is needed during ascent? Is it only the ET reentry footprint on certain inclinations? Does it also depend on the total weight of the orbiter (incl. payload)? Other factors?

5. When had the Roll to Heads Up been introduced for the first time?
6. Which missions had performed the Roll to Heads Up? Is there a list available?
7. I have read that the reason for the introduction of Roll to Heads Up was, to establish the comm link with a TDRS satellite during ascent, which in turn made a tracking station on the Bermudas obsolete. So, I assume that after a certain point in the history of the Shuttle program all missions performed the Roll to Heads Up. Is this correct?

Roll to Heads up started with STS-87 and was standard after that.  It was initiated by the program because of the expected closing of Bermuda.

OMS Assist capability was implemented with the OI-26 software, I will have to check which flight did it first.  From a quick search it looks like it was STS-90 but I seem to remember being in the simulator with John Young (yes name dropping) the night before STS-92 because of cg concerns he had with the OMS assist and subsequent aborts - I thought that was the first flight but I will have to double check I just don't remember but wiki is saying STS-90. STS-90 might have tested the concept prior to an actual heavy station mission.

Mark Kirkman

P.S.

Yep, I checked my notes and it was indeed a test objective on STS-90 which was the neurolab flight and not a station mission.
Title: Re: Shuttle Q&A Part 5
Post by: Bladerunner on 06/15/2009 02:13 am
ok i dont understand. by "range" im assuming NASA means the entire sky right? maybe a certain radius of it anyway? since the sky is all open and just "there" I dont get what this conflict is about? so what if numerous ships have a launch schedule close together, launch one, say at 10am, then launch another at 1030am---so what?  why does the range only allow a certain vessel at a time to only launch at a certain period? the sky is the sky. Once something launches and clears, why cant another go right after it? even a day later, why is it still closed off?
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 06/15/2009 02:43 am
ok i dont understand. by "range" im assuming NASA means the entire sky right? maybe a certain radius of it anyway? since the sky is all open and just "there" I dont get what this conflict is about? so what if numerous ships have a launch schedule close together, launch one, say at 10am, then launch another at 1030am---so what?  why does the range only allow a certain vessel at a time to only launch at a certain period? the sky is the sky. Once something launches and clears, why cant another go right after it? even a day later, why is it still closed off?

The antennas need to be reconfigured for the LVs trajectory heading. They don't cover the entire sky at once - they're directional dishes, not simple radio aerials.
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 06/15/2009 03:24 am
ok i dont understand. by "range" im assuming NASA means the entire sky right?

The sky is only a tiny part of the "range".

Mostly when they say "the range" they are referring to the dishes that allow telemetry from the rockets to be fed to the mission control centers. The dishes also track the rocket's path through the sky to make certain it doesn't go off course and threaten civilian populations. They also allow the flight control officer to destruct the rocket if it does go off course.

And yes, the shuttle (specifically the SRBs) has a flight termination system.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/15/2009 04:24 am
Sorry if I steped on Jorge's answers earlier but they weren't visible when I typed mine.

As for RTHU, after STS-87 I think ALL flights performed the roll because it was implemented based on the performance enhancement certifications. Flight Procedures Handbook states it is REQUIRED for low inclination flights for that reason alone.  FPH also states that roll costs about 35 lbs in performance.

I have the STS-97 checklist Jorge referred to in my files so I can look that up to confirm.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 06/15/2009 05:12 am
Jorge and Mark,
Thanks a lot for your detailed answers!

I have a few more questions, just for clarification:

OMS Assist capability was implemented with the OI-26 software, I will have to check which flight did it first.  From a quick search it looks like it was STS-90 but I seem to remember being in the simulator with John Young (yes name dropping) the night before STS-92 because of cg concerns he had with the OMS assist and subsequent aborts - I thought that was the first flight but I will have to double check I just don't remember but wiki is saying STS-90. STS-90 might have tested the concept prior to an actual heavy station mission.

Mark Kirkman

P.S.

Yep, I checked my notes and it was indeed a test objective on STS-90 which was the neurolab flight and not a station mission.

Have there been any other tests after the first one on STS-90, or was this the only one?
After the test(s), what was the first mission that used OMS Assist?
Since then, which missions have used OMS assist (or which have not, apart from the HST missions)?
Would a LON mission to the ISS also use OMS assist, or would this not be necessary, as there would be no payload on board?
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/15/2009 07:32 am
Hi folks:

I am using a Quote from Jorge near the bottom of page one.

"OMS assist is performed if 1) the OMS prop required for the mission itself does not require full tanks and 2) the mission could benefit from the additional payload capacity gained by filling the OMS tanks full and burning the difference as OMS assist (IIRC it's roughly 200 lb payload for 4000 lb OMS prop). CG location is a secondary consideration on the amount"

I thought OMS assist was used if payload was -TOO heavy-, otherwise it seems to me that it would be a waste of money too -just burn off- the OMS prop like that?

Sincerely
Oxford750 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/15/2009 09:34 am
I still don't really understand why they don't just not fill the amount of OMS that they'd burn off on the ascent anyway.

Am I missing something? Do the tanks HAVE to be full on launch?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/15/2009 11:41 am
Do the tanks HAVE to be full on launch?

It makes ground ops and flight ops planning easier.
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 06/15/2009 12:38 pm
I don't understand why they don't do the OMS burn after ET sep, e.g. after staging, call it OMS-0. Would be more efficient without the ET mass.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 06/15/2009 12:57 pm
Could be because that gain would be smaller than increased gravity losses of a heavier orbiter earlier in the ascent.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/15/2009 01:37 pm
Posting from Part 4:

Secondly, watch this video, if you would be so kind :)

http://www.youtube.com/watch?v=_vLl3K8yzOk

While "boundary" is self explanatory as an abort boundary, can anyone tell me what the crew mean when they mention "window"
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/15/2009 01:38 pm
Posting from Part 4:



While "boundary" is self explanatory as an abort boundary, can anyone tell me what the crew mean when they mention "window"

At what time is "window" said?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/15/2009 01:47 pm
Apologies Jim, I'll go through it now. Should have thought about doing that.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/15/2009 01:51 pm
ok i dont understand. by "range" im assuming NASA means the entire sky right? maybe a certain radius of it anyway? since the sky is all open and just "there" I dont get what this conflict is about? so what if numerous ships have a launch schedule close together, launch one, say at 10am, then launch another at 1030am---so what?  why does the range only allow a certain vessel at a time to only launch at a certain period? the sky is the sky. Once something launches and clears, why cant another go right after it? even a day later, why is it still closed off?

"Range" is the Eastern Range formerly the Eastern Test Range which is managed by the 45th Space Wing.   The "Range" include comm, telemetry, tracking, photo/video, range safety systems, weather forecasting systems, and security assets located on KSC, CCAFS, JDMTA, Antigua, and Ascension Island.  The configuration of these assets is different for each launch vehicle type.   For example,  the launch trajectory information to allow for telemetry and tracking antenna pointing has to be distributed, loaded  and verified.   Same goes for the abort limits for range safety computers and displays.  Comm channels have to be reconfigured, tracking camera moved and aligned.  Road blocks moved and established. There is a finite amount of time required to do this work from one launch to another.

Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/15/2009 01:59 pm
Window is mentioned at 3m58 seconds at the first instance, and then periodically during the ascent.

Edit: 5m15 too
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 06/15/2009 02:20 pm
Could be because that gain would be smaller than increased gravity losses of a heavier orbiter earlier in the ascent.

Could be. But I doubt it. Do ~60kN (OMSs) out of ~6,000kN (SSMEs) really make such a difference with respect to gravity losses? I still think having to push a 30mt ET or not would be the bigger difference.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 06/15/2009 02:24 pm
Note I said *heavier* orbiter. I didn't mean the OMS engines provided extra oomph as much as consumed extra weight early on, thus giving SSMEs less mass to push.

edit: wow, mixing weight and mass... a physicist could have me shot  :D
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/15/2009 02:56 pm
Hi folks:

I am using a Quote from Jorge near the bottom of page one.

"OMS assist is performed if 1) the OMS prop required for the mission itself does not require full tanks and 2) the mission could benefit from the additional payload capacity gained by filling the OMS tanks full and burning the difference as OMS assist (IIRC it's roughly 200 lb payload for 4000 lb OMS prop). CG location is a secondary consideration on the amount"

I thought OMS assist was used if payload was -TOO heavy-


Same thing, read 2) more carefully.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/15/2009 02:58 pm
I still don't really understand why they don't just not fill the amount of OMS that they'd burn off on the ascent anyway.

Am I missing something?

You're missing the part where I said that burning it off during ascent allows additional payload.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/15/2009 03:48 pm
I guess what I'm wondering is what gives the greater benefit, loading those OMS tanks with fuel and then burning them, or not filling the amount that would be burned.

I assume from your answer that it's the former.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/15/2009 04:29 pm
I guess what I'm wondering is what gives the greater benefit, loading those OMS tanks with fuel and then burning them, or not filling the amount that would be burned.

I assume from your answer that it's the former.

That is correct, and that is why OMS assist is done.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/15/2009 05:02 pm
Sorry if I steped on Jorge's answers earlier but they weren't visible when I typed mine.

As for RTHU, after STS-87 I think ALL flights performed the roll because it was implemented based on the performance enhancement certifications. Flight Procedures Handbook states it is REQUIRED for low inclination flights for that reason alone.  FPH also states that roll costs about 35 lbs in performance.

I have the STS-97 checklist Jorge referred to in my files so I can look that up to confirm.

Mark Kirkman

This is what the STS-97 FLT cycle FOP minutes had to say about it:

Quote
The Program Office has recently approved a change in design to remove the Roll-to-Heads-Up from the ascent profile as a performance enhancement of ~50 to 100 lbs. The Flight Design community deems this change as undesirable to STS-97 because it requires a change to ascent design procedures and internal software verification tools before implementation. The time required to incorporate these changes may not be adequate to ensure all procedures and off-line software tools are implemented properly. However, ADFD management felt that the risk to implement the No RTHU on this flight was acceptable when weighted against the very low APM and future APM threats. The ADFD flight team will work to mitigate any risks due to this change by aggressively communicating details through the design community and carefully implementing any changes associated with a No RTHU maneuver. As a result, the SSP directed Flight Design not to perform the Roll-To-Heads-Up maneuver for STS-97 Flight Cycle in order to realize the APM gain. The STS-97 CDR asked if the Engineering Cycle load could be updated to include this change in training. This is being investigated and will be updated is possible.

So at one point no-RTHU was the baseline for STS-97. If STS-97 did fly RTHU, it must have been restored after the FLT cycle.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/15/2009 05:21 pm
So at one point no-RTHU was the baseline for STS-97. If STS-97 did fly RTHU, it must have been restored after the FLT cycle.
FWIW, it's hardly definitive, but I don't hear any mention of a roll to heads up in the public broadcast of STS-97.  On STS-98, Ken Cockrell added "and we're rollin'" when acknowledging the 'Press to MECO' call...
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/15/2009 08:39 pm
Thanks Jorge.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 06/15/2009 09:59 pm
I guess what I'm wondering is what gives the greater benefit, loading those OMS tanks with fuel and then burning them, or not filling the amount that would be burned.

I assume from your answer that it's the former.

That is correct, and that is why OMS assist is done.

IIRC, the OMS tanks have to be filled completely (or as close to full as possible) because there is no sensor gage to tell you how much prop is in them.  They have to fill OMS tanks completely to know with a high degree of certainty how much prop is in them at launch.  Then, you burn what you don't need for the miss during ascent -- OMS assists -- and use calculations once on orbit to approximate how much OMS prop is left in the tanks after each firing of the OMS engines.

Am I remember incorrectly?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/15/2009 10:27 pm
IIRC, the OMS tanks have to be filled completely (or as close to full as possible) because there is no sensor gage to tell you how much prop is in them.  They have to fill OMS tanks completely to know with a high degree of certainty how much prop is in them at launch.  Then, you burn what you don't need for the miss during ascent -- OMS assists -- and use calculations once on orbit to approximate how much OMS prop is left in the tanks after each firing of the OMS engines.

Am I remember incorrectly?
The OMS/RCS load may work this way, too, but you may be thinking of Steve Payne answering a question during a recent countdown briefing about PRSD offload and why it takes an extra shift or half-shift to do that.  (His answer sounds similar to what you're describing.)
Title: Re: Shuttle Q&A Part 5
Post by: DansSLK on 06/15/2009 10:58 pm

IIRC, the OMS tanks have to be filled completely (or as close to full as possible) because there is no sensor gage to tell you how much prop is in them.  They have to fill OMS tanks completely to know with a high degree of certainty how much prop is in them at launch.  Then, you burn what you don't need for the miss during ascent -- OMS assists -- and use calculations once on orbit to approximate how much OMS prop is left in the tanks after each firing of the OMS engines.

Am I remember incorrectly?

They do have level sensors in them but if they are used during fill i don't know.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/16/2009 01:18 am
 With regard to OMS assist, I thought I read some where that the OMS engine could only work in the vaccum(spel) of space, or am I getting RCS thusters and OMS engine mixed up?

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/16/2009 01:56 am
With regard to OMS assist, I thought I read some where that the OMS engine could only work in the vaccum(spel) of space, or am I getting RCS thusters and OMS engine mixed up?

The OMS does have a minimum altitude, but IIRC it's 70,000 ft. OMS assist occurs after staging, which is around 150,000 ft.

The question does come up a lot but usually in the context of "can you fire the OMS on the ground"...
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/16/2009 01:58 am
I guess what I'm wondering is what gives the greater benefit, loading those OMS tanks with fuel and then burning them, or not filling the amount that would be burned.

I assume from your answer that it's the former.

That is correct, and that is why OMS assist is done.

IIRC, the OMS tanks have to be filled completely (or as close to full as possible) because there is no sensor gage to tell you how much prop is in them.  They have to fill OMS tanks completely to know with a high degree of certainty how much prop is in them at launch.  Then, you burn what you don't need for the miss during ascent -- OMS assists -- and use calculations once on orbit to approximate how much OMS prop is left in the tanks after each firing of the OMS engines.

Am I remember incorrectly?

You're remembering incorrectly. While I don't know the details of OMS fill on the ground, I do know that the OMS tanks do have quantity gauges. The gauges require the propellant to be "settled" at the rear of the tanks in order to work - which is true on the ground, or during powered flight.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/16/2009 03:14 am
Thanks Jorge.


Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/16/2009 07:02 am
They're all helium, no?  The Air Liquide GN2 line is kept at 6-7 ksi.  No real need for a plenum.

It's been a while since I was out there, but my foggy memory is that the tanks contain, not just helium, but also nitrogen and breathing air (for SCAPE operations and possibly crew cabin supply). But I could be wrong (happened once or twice before)......

Thanks for the replies, guys.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 06/16/2009 08:12 am
Thanks Philip and Jorge.  I think Philip is correct, I'm thinking PRSD.

After some many days of dealing with GUCP and range schedules I guess my Orbiter propellant tank knowledge slipped a little.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/16/2009 01:45 pm
Padrat, you got to be up close and personal with it the last couple days or so. What is the large black rectangle to the left of the GUCP? It looks to be about 5 ft high, maybe 6 ft across?

(not exactly singling you out. anyone can answer :) )

thanks
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/16/2009 02:06 pm
Nice. Thanks for the quick replies. Struck me odd to see a garage door (or hiding spot for lesser motivated employees) up so high.
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 06/16/2009 05:34 pm
Banjul, also no longer used, is Yundum International Airport. NASA built a dedicated building at each of those locations.

STS-125 was told "negative Moron, select Banjul." Wouldn't that imply it's still used?

Selecting Banjul onboard would cause onboard guidance to steer toward that site in the event a TAL abort were declared.  The more likely actual landing site in that case would be Amilcar, Cape Verde, which is a little "short" of the Gambian coast but along the same trajectory.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 06/16/2009 06:18 pm
Thanks for clarifying - that makes more sense.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/17/2009 12:31 am
Can the shuttle launch in rain (not thunderstorms)? And does it go through mach 5 before 60,000 ft or above it?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/17/2009 12:35 am
Can the shuttle launch in rain (not thunderstorms)?
No.  Flight through precip is a violation of weather rules.  (In fact, they won't even ferry an orbiter through rain if they can avoid it.)
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 06/17/2009 12:35 am
Can the shuttle launch in rain (not thunderstorms)? And does it go through mach 5 before 60,000 ft or above it?

No.  Way above.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/17/2009 12:40 am
Can the shuttle launch in rain (not thunderstorms)? And does it go through mach 5 before 60,000 ft or above it?

rain on tiles is like water on sugar cubes
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/17/2009 12:41 am
I wasn't sure about rain during launch, due to the weatherproofing on the tiles. Thanks gentlemen.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 06/17/2009 12:42 am
Can the shuttle launch in rain (not thunderstorms)? And does it go through mach 5 before 60,000 ft or above it?

rain on tiles is like water on sugar cubes

I thought the orbiter regularly gets soaked at the pad and the tiles are waterproofed during each OPF flow.  I also thought the issue was *high velocity* rain drops causing mechanical (as opposed to chemical like water dissolving sugar) damage to the TPS.  Am I wrong?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/17/2009 12:44 am
I wasn't sure about rain during launch, due to the weatherproofing on the tiles. Thanks gentlemen.

Waterproofing is to keep them from absorbing water while on the ground.  The internal water would turn to steam during ascent and entry and pop off parts of the tiles
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 06/17/2009 01:17 am
Thanks for the explanation Jim. I didn't think the heat got between the tiles enough to cause steam.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/17/2009 02:02 am
Hi folks:

I am sitting sitting here in Vancouver, Canada watching launch prep for STS-127 -hope she goes- and some questions came to mind.

1) How do they chill the lines for tanking (I didn't think you could put anything in the lines prior to tanking as they go to the LH2, LOX tanks)?
2) Why does the GUPC vent line come off at ignition and not when the "beanie cap" comes off as I assume both tanks need to be repressurized?
3)  What is the difference between fast fill and slow fill?
4) Why are the LH2 tank and LOX tank filled at different times?

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/17/2009 02:07 am
Hi folks:

I am sitting sitting here in Vancouver, Canada watching launch prep for STS-127 -hope she goes- and some questions came to mind.

1) How do they chill the lines for tanking (I didn't think you could put anything in the lines prior to tanking as they go to the LH2, LOX tanks)?
2) Why does the GUPC vent line come off at ignition and not when the "beanie cap" comes off as I assume both tanks need to be repressurized?
3)  What is the difference between fast fill and slow fill?
4) Why are the LH2 tank and LOX tank filled at different times?

1.  by slowly running the propellants through them
2.  GH2 is flammable and you don't want it venting around the pad.  If there is a scrub, the vent line still needs to be in place
3.  Flow rates
4.  Safety.  Just keeping the hazard level as low as possible
Title: Re: Shuttle Q&A Part 5
Post by: duane on 06/17/2009 06:41 pm
I kept reading about the shuttle not flying till the leak was found, and after a  "Thermal Blackout Period"   What is this blackout period ?

Thanks
Duane
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 06/17/2009 06:45 pm
I kept reading about the shuttle not flying till the leak was found, and after a  "Thermal Blackout Period"   What is this blackout period ?

Thanks
Duane

It's called the "beta angle cutout" and here is a link that provides some good information.  Google is your friend.
http://sci.tech-archive.net/Archive/sci.space.shuttle/2006-08/msg00226.html

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/17/2009 07:45 pm
I kept reading about the shuttle not flying till the leak was found, and after a  "Thermal Blackout Period"   What is this blackout period ?

Thanks
Duane

Seach shuttle Q&A thread 4, it has been answered multiple times
Title: Re: Shuttle Q&A Part 5
Post by: duane on 06/17/2009 07:55 pm
I kept reading about the shuttle not flying till the leak was found, and after a  "Thermal Blackout Period"   What is this blackout period ?

Thanks
Duane

Seach shuttle Q&A thread 4, it has been answered multiple times
Thanks Jim for the info. I'll go dig there also.  Actually did a little digging and found the video clip of the news conf where "beta cutoff" was used. Did some digging, and found it explained on alternate news sites. Just not the lousy mainstream media for the masses sites.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/18/2009 01:38 am
Thanks Jim.



Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 06/18/2009 05:30 pm
It's called the "beta angle cutout" and here is a link that provides some good information.  Google is your friend.
http://sci.tech-archive.net/Archive/sci.space.shuttle/2006-08/msg00226.html

Among Space Shuttle flight controllers, beta angle cutouts are also known as "a good time to schedule a vacation."  Otherwise, as Murphy dictates, the next launch will invariably slip into the long awaited trip for which you purchased non-refundable tickets!  ;)
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 06/19/2009 08:15 pm
Please excuse me for digging up my post from page 2 once again, but after mkirk's (and Jorge's) informative and interesting answers, I had a few more questions, which I would like to repeat here.
(It seems like my original post sort of drowned in the posts that followed. ;) )

OMS Assist capability was implemented with the OI-26 software, I will have to check which flight did it first.  From a quick search it looks like it was STS-90 but I seem to remember being in the simulator with John Young (yes name dropping) the night before STS-92 because of cg concerns he had with the OMS assist and subsequent aborts - I thought that was the first flight but I will have to double check I just don't remember but wiki is saying STS-90. STS-90 might have tested the concept prior to an actual heavy station mission.

Mark Kirkman

P.S.

Yep, I checked my notes and it was indeed a test objective on STS-90 which was the neurolab flight and not a station mission.

Have there been any other tests after the first one on STS-90, or was this the only one?
After the test(s), what was the first mission that used OMS Assist?
Since then, which missions have used OMS assist (or which have not, apart from the HST missions)?
Would a LON mission to the ISS also use OMS assist, or would this not be necessary, as there would be no payload on board?
Title: Re: Shuttle Q&A Part 5
Post by: rpj on 06/23/2009 02:59 pm
What is the mechanical component that allows the shuttle, ET and SRB's to complete the "roll over" technique during launch. I would assume that it is the elevon/ailerons or tail of the orbiter.
Title: Re: Shuttle Q&A Part 5
Post by: Crispy on 06/23/2009 03:12 pm
The SRB nozzles are gimballed to provide roll control during this phase of ascent.
Title: Re: Shuttle Q&A Part 5
Post by: zerm on 06/24/2009 01:22 am
Seeing the photos of the OAA being removed from LC39B, and looking at the shape of the arm it looks as if it is made up mostly of swing arm #9 from the Apollo LUT. Is that so? can anyone who knows advise?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/24/2009 01:44 am
What is the mechanical component that allows the shuttle, ET and SRB's to complete the "roll over" technique during launch. I would assume that it is the elevon/ailerons or tail of the orbiter.

Primarily the SRB gimbals, secondarily the SSME gimbals.

The aerosurfaces are not used for ascent maneuvers at all. To the extent that they are deflected at all, it is only for load relief.
Title: Re: Shuttle Q&A Part 5
Post by: Nephi on 06/24/2009 10:18 am
Hi guys, a question about DPS :
The DPS seems to allow switching between some of the major modes (OPS 201 and 202 for example), but apparently it seems impossible to revert back from some modes to the previous one. For example it seems impossible (if you have a look at the DPS dictionnary for instance) to revert back to OPS 303 once OPS 304 was entered.

So three questions in one :
1) is it possible to go back from OPS 304 to OPS 303 for example (and all the other similar configurations) ?
2) if yes how ?
3) if no : how would they do if someone entered OPS 304 too early by mistake ?

Thanks in advance
Nephi
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/24/2009 11:48 am
I would imagine that it's impossible to go from, for example, OPS 302 to OPS 304, so that's not a problem.

Edit: I've just realised who you are. Hi :)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/24/2009 10:56 pm
I have researched this question (curious myself):
#1  STS-1 (102) days on Pad
#2  STS-122 (89) days on Pad (Eco Sensor issue)
#3  STS-127 (85) days (if launched on 7/11)

Note: STS-35 had (109) "non-continuous" days split between Pad-A/B but briefly rolled back to VAB (hydrogen leaks).
Going through some old threads and wanted to add some additional trivia.

I think STS-6 has the record (and probably will keep it) for a continuous pad stay.  Jenkins (http://www.amazon.com/Space-Shuttle-National-Transportation-Missions/dp/0963397451) has the stay at Pad A as 126 days...rollout was 30 November 1982, launch was 4 April 1983.  This included two FRFs and removal/reinstallation of all the main engines at the pad.  (And removal/reinstallation of the TDRS-A payload, too.)

STS-26 was out on Pad B for 88 days.  (Rollout 4 July 1988, launch 29 September 1988.)

As with the STS-35 vehicle, the STS-38 vehicle also spent a long time out on the pad, with a orbiter destack in between.

For STS-35, it was originally rolled out to Pad A on 22 April 1990 during the second STS-31 countdown.  After 50 days which included a launch attempt and additional tankings, it was rolled back to the VAB on 13 June.  It was then rolled back out to Pad A on 9 August 1990, where additional attempts to launch were made in September.  On 8 October, it was rolled around from Pad A to Pad B, and then the next day rolled back to the VAB to avoid a tropical storm.  That covers the 109 days, but doesn't include the additional 48 days for the last pad stay -- rollout to Pad B on 14 October for another tanking test prior to launch on 2 December 1990.  So there were ~157 days on the pad for that vehicle (with the rollbacks and rollaround mixed in) between late April and early December that year.

The STS-38 vehicle only had one rollback...first rollout on 18 June 1990 for 52 days at Pad A, rolling back on 9 August 1990 (in the well-remembered two-step fashion).  It was then rolled out to Pad A on 12 October 1990 and launched on 15 November.  That vehicle ended up with ~86 days on the pad with the rollback and destacking in between.

(The STS-114 "vehicles" were out on the pad in a similar fashion in 2005.)

The STS-127 vehicle of course has also had a rollaround, with approximately one shift where it was in-between pads.  So the possible 85 days would be split into ~43 days on Pad B and ~42 days on Pad A.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 06/25/2009 02:46 am
It's called the "beta angle cutout" and here is a link that provides some good information.  Google is your friend.
http://sci.tech-archive.net/Archive/sci.space.shuttle/2006-08/msg00226.html

Among Space Shuttle flight controllers, beta angle cutouts are also known as "a good time to schedule a vacation."  Otherwise, as Murphy dictates, the next launch will invariably slip into the long awaited trip for which you purchased non-refundable tickets!  ;)

Hey... that's me for any launch in July!!!!!!! Non-refundable tickets... vacation... and now a potential Shuttle launch!
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 06/26/2009 01:56 pm
It's called the "beta angle cutout" and here is a link that provides some good information.  Google is your friend.
http://sci.tech-archive.net/Archive/sci.space.shuttle/2006-08/msg00226.html

Among Space Shuttle flight controllers, beta angle cutouts are also known as "a good time to schedule a vacation."  Otherwise, as Murphy dictates, the next launch will invariably slip into the long awaited trip for which you purchased non-refundable tickets!  ;)

Hey... that's me for any launch in July!!!!!!! Non-refundable tickets... vacation... and now a potential Shuttle launch!

Ah yes, proof that even Murphy obeys Newton's 3rd law of motion.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/26/2009 05:14 pm
Hi guys, a question about DPS :
The DPS seems to allow switching between some of the major modes (OPS 201 and 202 for example), but apparently it seems impossible to revert back from some modes to the previous one. For example it seems impossible (if you have a look at the DPS dictionnary for instance) to revert back to OPS 303 once OPS 304 was entered.

So three questions in one :
1) is it possible to go back from OPS 304 to OPS 303 for example (and all the other similar configurations) ?
2) if yes how ?
3) if no : how would they do if someone entered OPS 304 too early by mistake ?

Thanks in advance
Nephi

Yes, some OPS are a oneway street.  I have been out the training business for a while, so don't trust what I say 100%.

On going to 304 by mistake, I am assuming you haven't done the deorbit burn yet.  I think you could somehow take your time and if nothing else go back to OPS 2.  BFS engage could be an option if it didn't also go over.  I don't remember if BFS does what is called a DK listen to the command to PASS to go the 304, or if the crew has to take if over separately. 

Please forgive me if this is all lies.  Even in my prime, I wasn't a DPS instructor.  But I used to know this stuff pretty good as a control/prop instructor.

I do know going in and out of the OPS 2 mode to do an orbit burn is two way.  I can't remember the number of the modes.  I think it is 201 and 202.

Danny Deger

Where did you get a DPS dictionary.  Make sure it is on L2.  I bet Chris would trade you some L2 time for a DPS dictionary if he doesn't already have on.

Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/26/2009 05:34 pm
Hi guys, a question about DPS :
The DPS seems to allow switching between some of the major modes (OPS 201 and 202 for example), but apparently it seems impossible to revert back from some modes to the previous one. For example it seems impossible (if you have a look at the DPS dictionnary for instance) to revert back to OPS 303 once OPS 304 was entered.

So three questions in one :
1) is it possible to go back from OPS 304 to OPS 303 for example (and all the other similar configurations) ?
2) if yes how ?
3) if no : how would they do if someone entered OPS 304 too early by mistake ?

Thanks in advance
Nephi

Yes, some OPS are a oneway street.  I have been out the training business for a while, so don't trust what I say 100%.

On going to 304 by mistake, I am assuming you haven't done the deorbit burn yet.  I think you could somehow take your time and if nothing else go back to OPS 2.  BFS engage could be an option if it didn't also go over.  I don't remember if BFS does what is called a DK listen to the command to PASS to go the 304, or if the crew has to take if over separately. 

Please forgive me if this is all lies.  Even in my prime, I wasn't a DPS instructor.  But I used to know this stuff pretty good as a control/prop instructor.

I do know going in and out of the OPS 2 mode to do an orbit burn is two way.  I can't remember the number of the modes.  I think it is 201 and 202.

Danny Deger

Where did you get a DPS dictionary.  Make sure it is on L2.  I bet Chris would trade you some L2 time for a DPS dictionary if he doesn't already have on.

There was a very old DPS dictionary somewhere on the public internet, dated 1997. It was the first one I ever got. Can't remember where though.

As for OPS 201 <-> OPS 202 this is indeed two-way. 201 is for burns, 202 is for payload bay doors.

If you went into the wrong mode on orbit, then with a long process you could reload another mode. I imagine you couldn't do something like 301 -> 303, because you'd get an ILLEGAL ENTRY on the CRT I guess?

I don't have time to check right now, but there's a reason that you have to enter commands then check them before you PRO or EXEC. Slowly does it! :)
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/26/2009 05:48 pm
Where did you get a DPS dictionary.  Make sure it is on L2.  I bet Chris would trade you some L2 time for a DPS dictionary if he doesn't already have on.

Danny,

A copy of the DPS Dictionary - Generic Rev K PCN-8 (Oct 8, 2008) is available on L2.  For those with access the link is:
http://forum.nasaspaceflight.com/index.php?topic=14971.0
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/26/2009 07:11 pm

As for OPS 201 <-> OPS 202 this is indeed two-way. 201 is for burns, 202 is for payload bay doors.

Not quite. You're describing two different major functions. Burns fall under the GNC major function (and it's 202, not 201), and PL bay doors fall under the SM major function.

GNC OPS 201 - orbit coast
GNC OPS 202 - orbit burns
SM OPS 201 - normal orbit ops
SM OPS 202 - PL bay doors

You can transition both ways (201<->202) *within* a major function, but not *across* major functions.

In PASS, GNC OPS 2 and SM OPS 2 are different memory configs (i.e. they can't run on the same GPC at the same time). Typically during orbit ops GPCs 1, 2, and 3 are loaded with PASS GNC OPS 2 and GPC 4 is loaded with PASS SM OPS 2. GPC 5 is loaded with BFS, but the BFS does not have OPS 2, of course...
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 06/26/2009 07:13 pm
In PASS, GNC OPS 2 and SM OPS 2 are different memory configs (i.e. they can't run on the same GPC at the same time). Typically during orbit ops GPCs 1, 2, and 3 are loaded with PASS GNC OPS 2 and GPC 4 is loaded with PASS SM OPS 2. GPC 5 is loaded with BFS, but the BFS does not have OPS 2, of course...

Flares and sideburns are strictly optional.  ;)
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/26/2009 07:37 pm

As for OPS 201 <-> OPS 202 this is indeed two-way. 201 is for burns, 202 is for payload bay doors.

Not quite. You're describing two different major functions. Burns fall under the GNC major function (and it's 202, not 201), and PL bay doors fall under the SM major function.

GNC OPS 201 - orbit coast
GNC OPS 202 - orbit burns
SM OPS 201 - normal orbit ops
SM OPS 202 - PL bay doors

You can transition both ways (201<->202) *within* a major function, but not *across* major functions.

In PASS, GNC OPS 2 and SM OPS 2 are different memory configs (i.e. they can't run on the same GPC at the same time). Typically during orbit ops GPCs 1, 2, and 3 are loaded with PASS GNC OPS 2 and GPC 4 is loaded with PASS SM OPS 2. GPC 5 is loaded with BFS, but the BFS does not have OPS 2, of course...


That's a horrendously bad schoolboy error on my part, thanks for making me look stupid :)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/26/2009 10:16 pm
snip

That's a horrendously bad schoolboy error on my part, thanks for making me look stupid :)

I have done a lot worse in front of a class full of astronauts.  They don't let errors like this get past them.  Something about dying if they are trained wrong motivates them to point out such errors  :o

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/27/2009 09:55 am
The annoying thing is that I pride myself on getting stuff like that right, and I've played a lot of SSM2007 lately :p

Maybe that's a good idea for a thread. Most embarrassing moment in training. Or just a general "funny things that happened to me in the spaceflight business" thread.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/27/2009 12:57 pm
The annoying thing is that I pride myself on getting stuff like that right, and I've played a lot of SSM2007 lately :p

Maybe that's a good idea for a thread. Most embarrassing moment in training. Or just a general "funny things that happened to me in the spaceflight business" thread.

The Ole days thread has some posts like that
Title: Re: Shuttle Q&A Part 5
Post by: Nephi on 06/29/2009 10:44 am
Thanks for all the replies, but we got carried away to OPS 201/202 which are pretty easy to deal with and were absolutely not my primary concern I must admit :)
So any idea how we could get out of OPS 304 if getting to it too quickly from OPS 303 for example (or if the CDR brutally gets nuts  :D) ?

@Danny : if you are in OPS 303 and get to 304 it means that on the contrary, the deorbit burn has indeed been done (OPS 302 normally). So I'm not sure if you could get back to OPS 2 anyhow ?!
The problem is that there seems to be only a one way arrow from 303 to 304 on the DPS dictionnary OPS synthesis.

The problem is that OPS 303 is used to dump a few things (among other activities) and that you cannot do it from OPS 304 (entry traj). So if you went to 304 before dumping the right stuff, how do you get back to doing it before entry interface ? Hence my question about going back from 304 to 303 :) I believe that there should be a procedure somewhere.

(edit : oh and : Hi elmarko :) Pretty not surprised and pretty happy to see you here as it's the best place for all shuttle lovers :))
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/29/2009 01:11 pm
Essentially, the situation (to simplify your words) is this:

If there's a one way arrow between modes, you cant go backwards because the system won't let you (ILLEGAL ENTRY?), so by my reckoning the only way would be to manually load into memory the program you want. Which, I understand, is time consuming.

As for your point about not being able to go back to OPS 2 because the deorbit burn was already done, I'm sure it could be done manually, there'd just be little use for OPS 2 at that point.

Can someone help me out here, I'm wondering how badly I'm understanding this. DPS is a little sketchy for me so this is a learning curve.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/29/2009 01:21 pm
snip
@Danny : if you are in OPS 303 and get to 304 it means that on the contrary, the deorbit burn has indeed been done (OPS 302 normally). So I'm not sure if you could get back to OPS 2 anyhow ?!
The problem is that there seems to be only a one way arrow from 303 to 304 on the DPS dictionnary OPS synthesis.

The problem is that OPS 303 is used to dump a few things (among other activities) and that you cannot do it from OPS 304 (entry traj). So if you went to 304 before dumping the right stuff, how do you get back to doing it before entry interface ? Hence my question about going back from 304 to 303 :) I believe that there should be a procedure somewhere.

snip

If I was in the shuttle post deorbit burn and someone wanted to get back to 303 to do a dump, I would put them in the airlock for the rest of the entry so they wouldn't come up with any other "good" ideas  >:(

And I can't see of anyway to do it quick enough to get back to 304 before entry interface.  I know there must be some way to reload OPS 2 then OPS 3 but in the post burn situation there is not enough time.

It sounds like you are playing with a shuttle simulator of some type.  Is this correct?

And you are correct the DPS dictionary is not an easy way to learn DPS.  It is a reference, not a training manual.  Call JSC information 281-483-0123 and ask for the DPS training department and see if you can get someone to mail you a copy of the DPS training manual.  They might do this for you.  When I was there, they were a very nice bunch of guys and gals.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/29/2009 01:32 pm
Danny, I definately see your point about time. That was my point, really. You COULD do it by manually loading it in, but there wouldn't be enough time to do it.

And I'm pretty sure Nephi's not trying to use the Dictionary as a training manual. It already is a headbender as it is! :)

Also, re your last paragraph. Shame I'm in the UK... maybe some other nice soul wants to ring up and find us a new document for L2...

PS, we're playing Space Shuttle Mission 2007 but it's by no means a complete copy of the STS system. The DPS is very cut down in places.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/29/2009 01:37 pm
Danny, I definately see your point about time. That was my point, really. You COULD do it by manually loading it in, but there wouldn't be enough time to do it.

And I'm pretty sure Nephi's not trying to use the Dictionary as a training manual. It already is a headbender as it is! :)

Also, re your last paragraph. Shame I'm in the UK... maybe some other nice soul wants to ring up and find us a new document for L2...

PS, we're playing Space Shuttle Mission 2007 but it's by no means a complete copy of the STS system. The DPS is very cut down in places.

Being in the UK would be a problem.  We wouldn't want you Imperialist Swines to use the data to build ICBMs that could take us down.

Getting a set of training manuals for L2 is a great idea.  I think I will look into this.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/29/2009 02:29 pm
That would be amazing, thanks Danny.

It's cool, we have such a lot of documents on there, but there seems to be a few areas missing, and training books are one of them. We have lots of reference materials, but some people like to really get into how things work :)

Not that we're not thankful for what we get already, of course. We all are.

I'd definitely be interested in what you can find, as would everyone else!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/29/2009 08:18 pm
Essentially, the situation (to simplify your words) is this:

If there's a one way arrow between modes, you cant go backwards because the system won't let you (ILLEGAL ENTRY?), so by my reckoning the only way would be to manually load into memory the program you want. Which, I understand, is time consuming.

As for your point about not being able to go back to OPS 2 because the deorbit burn was already done, I'm sure it could be done manually, there'd just be little use for OPS 2 at that point.

Can someone help me out here, I'm wondering how badly I'm understanding this. DPS is a little sketchy for me so this is a learning curve.

You can get just about anywhere from OPS 0, but OPS 000 PRO is not a legal transition from 304.

However, you can force a GPC to OPS 0 by taking the GPC MODE switch to STBY and back to RUN.

So... you take GPCs 1-4 to STBY, then back to RUN, one at a time. Once you have done this, you will have a GPC common set in OPS 0. The vehicle will not be controllable at this point! Check memory config 3 (ITEM 1+3), should be fine since you used it earlier to transition to OPS 3 the first time around, then invoke the NBAT with OPS 301 PRO. Now the vehicle is under control again.

May need to clean up the BFS afterward. I never certified DPS so not my specialty.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 06/30/2009 02:11 am
I get the sense that neglecting a necessary dump before deorbit burn would be considered a contingency situation, and the solution may be manual intervention rather than jumping backwards in software routines.

I don't know specifically what kinds of dumps are in question.  I know that the potable water system can be dumped through the flash evaporator system down to 100,000 ft altitude during reentry by switching the freon loop radiator out temp to hi.

Other fluids might also be dumped in a contingency situation by manually operating valves via switch and breaker panels.  This might be more practical in a time-critical emergency than changing OPS modes.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/30/2009 02:18 am
I get the sense that neglecting a necessary dump before deorbit burn would be considered a contingency situation, and the solution may be manual intervention rather than jumping backwards in software routines.

I don't know specifically what kinds of dumps are in question.  I know that the potable water system can be dumped through the flash evaporator system down to 100,000 ft altitude during reentry by switching the freon loop radiator out temp to hi.

I don't know if there's any software functionality for that, but if there is, it would be in the SM major function, not GNC; therefore, for OPS 3 it would be in the BFS, not PASS.

Quote
Other fluids might also be dumped in a contingency situation by manually operating valves via switch and breaker panels.  This might be more practical in a time-critical emergency than changing OPS modes.

The FRCS dump cannot be controlled by switches/breakers, and can only be performed in MM 301-303 (the only other way of dumping the FRCS would be a long manual -X translation using the THC, but that would perturb the entry trajectory quite badly... and I don't think the THC is polled in MM 304/305 anyway).
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/30/2009 02:00 pm
Here are a couple of the astronaut training workbooks for the space shuttle's data processing system (DPS) - I don't have the more recent versions in an electronic format, however, for all practical purposes these are still valid - at least for the purposes of this most recent discussion.

These were current when I was there and since they have been circulated on the internet in the past I have no problem posting them in this public thread.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/30/2009 03:44 pm
Thanks a lot Mark. Going to direct some people to that post so they can read the files.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/30/2009 03:59 pm
Here are a couple of the astronaut training workbooks for the space shuttle's data processing system (DPS) - I don't have the more recent versions in an electronic format, however, for all practical purposes these are still valid - at least for the purposes of this most recent discussion.

These were current when I was there and since they have been circulated on the internet in the past I have no problem posting them in this public thread.

Mark Kirkman

Thanks Mark,

Can you grab a scanned copy of the Entry Guidance Workbook?  I know this crowd will like it.  It is written in plain English with lots of humor.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/30/2009 04:57 pm
According to the crew interface workbook, the PASS can only drive three CRTs. If the BFS is taken offline during on-orbit operations then what does the fourth CRT display? Just a cross as it has been deassigned? Or powered off?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/30/2009 06:10 pm
According to the crew interface workbook, the PASS can only drive three CRTs. If the BFS is taken offline during on-orbit operations then what does the fourth CRT display? Just a cross as it has been deassigned? Or powered off?

Yes. If the fourth CRT is left powered on it will display the big "X"/"POLL FAIL". But normally it is powered off.

Standard ops is for CRT3 to be powered down on orbit. Some CDRs like to deassign CRT4 and bring up CRT3 for OMS burns.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 06/30/2009 06:12 pm
Question re: STS-91.  According to the mission press kit, the SPACEHAB carried "Cosmonaut Return Packages" up to Mir.  Does anyone know what these packages specifically contained?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/30/2009 06:36 pm
Question re: STS-91.  According to the mission press kit, the SPACEHAB carried "Cosmonaut Return Packages" up to Mir.  Does anyone know what these packages specifically contained?  Thanks!

I would have packed them onboard the SPACEHAB module.  I don't quite remember Return Packages. 

We did fly "Cosmonaut Family Packages" and "Cosmonaut Psychological Support Packages.

All were sealed in semi opaque bags.   The family packages is self describing and the other had "magazines" in it and liquid containers.

Edit:  Now I remember, Return packages weren't launched on board, they came back on the flight and were like the shuttle official flight kit/crew personal preference kit (trinkets/memorabilia). 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 06/30/2009 11:27 pm
Standard ops is for CRT3 to be powered down on orbit. Some CDRs like to deassign CRT4 and bring up CRT3 for OMS burns.

Displaying what? Pages for monitoring the OMS/RCS/Whatever?

Edit: Should say thanks for your previous answer too, these past 2 pages have been great.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/30/2009 11:56 pm
Standard ops is for CRT3 to be powered down on orbit. Some CDRs like to deassign CRT4 and bring up CRT3 for OMS burns.

Displaying what? Pages for monitoring the OMS/RCS/Whatever?

Right. With two CRTs they normally have MNVR EXEC on 1 and SYS SUMM 2 on 2. With three they can also view SYS SUMM 1. Makes for quicker recognition of malfunctions.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/01/2009 03:31 am
Here are a couple of the astronaut training workbooks for the space shuttle's data processing system (DPS) - I don't have the more recent versions in an electronic format, however, for all practical purposes these are still valid - at least for the purposes of this most recent discussion.

These were current when I was there and since they have been circulated on the internet in the past I have no problem posting them in this public thread.

Mark Kirkman

Thanks Mark,

Can you grab a scanned copy of the Entry Guidance Workbook?  I know this crowd will like it.  It is written in plain English with lots of humor.

Danny Deger

I don't have that in an electronic format but it is good workbook and I see no reason it can't be posted - so give me some time (about a week or so since I will be on the road) and I will scan it.

Hmmm, I wonder who wrote the version I have - it says some clown named Danny prepared it - doesn't ring a bell.  ;)

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/01/2009 06:51 am
I don't have that in an electronic format but it is good workbook and I see no reason it can't be posted - so give me some time (about a week or so since I will be on the road) and I will scan it.

Hmmm, I wonder who wrote the version I have - it says some clown named Danny prepared it - doesn't ring a bell.  ;)

Mark Kirkman

Ahaha, so THAT'S why he wants it :p

It would be really amazing if we could make a thread on L2 specifically for training workbooks. I know we've had some already posted, but us Shuttle nuts love to feel as close to the action as we can. If you'd like to consider this a polite request to obtain some more, I know a lot of people would be very grateful.

I really love the way the workbooks are written, they seem to explain things in a very easy-to-understand manner, which I guess is the point.

Especially seen as we got those training catalogs, they really whet my appetite.

Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 07/01/2009 01:52 pm
Question re: STS-91.  According to the mission press kit, the SPACEHAB carried "Cosmonaut Return Packages" up to Mir.  Does anyone know what these packages specifically contained?  Thanks!

I would have packed them onboard the SPACEHAB module.  I don't quite remember Return Packages. 

We did fly "Cosmonaut Family Packages" and "Cosmonaut Psychological Support Packages.

All were sealed in semi opaque bags.   The family packages is self describing and the other had "magazines" in it and liquid containers.

Edit:  Now I remember, Return packages weren't launched on board, they came back on the flight and were like the shuttle official flight kit/crew personal preference kit (trinkets/memorabilia). 

Thanks Jim!!!!
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/01/2009 01:59 pm
snip

I don't have that in an electronic format but it is good workbook and I see no reason it can't be posted - so give me some time (about a week or so since I will be on the road) and I will scan it.

Hmmm, I wonder who wrote the version I have - it says some clown named Danny prepared it - doesn't ring a bell.  ;)

Mark Kirkman

Don't give me any flak on that book.  The astronauts gave me a Silver Snoopy for it.  I think they were trying to send a signal that they would like the other books to not be good cures for insomnia when read for more than 10 minutes  :-\

I had to get my branch chief to call the editors to let my "inappropriate" writing style into the book.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/01/2009 03:12 pm
snip

I don't have that in an electronic format but it is good workbook and I see no reason it can't be posted - so give me some time (about a week or so since I will be on the road) and I will scan it.

Hmmm, I wonder who wrote the version I have - it says some clown named Danny prepared it - doesn't ring a bell.  ;)

Mark Kirkman

Don't give me any flak on that book.  The astronauts gave me a Silver Snoopy for it.  I think they were trying to send a signal that they would like the other books to not be good cures for insomnia when read for more than 10 minutes  :-\

I had to get my branch chief to call the editors to let my "inappropriate" writing style into the book.

Danny Deger

Yeah I admit I liked reading it there very first time I picked it up and thought to myself that it was very different in tone than most all of the other training docs. 

Since we were space shuttle & space station “Crew Training”, I liked the fact that it stayed focused on what I (and ultimately the students – astronauts) needed to know to get the job done from the perspective of the cockpit.  Just look at the ASCENT GUIDANCE or ENTRY DAP workbooks to see how quickly you can go to sleep – it has great information but is NOT written for a pilot.  Granted MS’s are not all pilots but for the shuttle training flow, and in flight, they need to be trained to have some of the pilot mentality – thankfully they get much of that from flying in the T-38’s and in the Shuttle Sim.

The only other training book that seemed to have a similar tone was the MPS MAL USERS GUIDE – it was great about pointing out how to identify the problem, what needs to happen, and the bottom line/consequences – direct and to the point (even some subtle humor thrown in like your book).  I noticed that some of that approach made it into the latest versions of the MPS Workbook (section 4) which was originally written in the typical MOD format.

I would say that your version of the Entry Guidance Book is written for pilots by a pilot (or at least a flyer of some sort).  Not to say that you have to be a pilot to do the job – but I did notice a very adversarial relationship in MOD between pilots and engineers, much like you see in books/movies of the Apollo era.  It seems that both sides were overly sensitive to insinuations from the other side that they didn’t have the right background/experience to understand certain issues when obviously both perspectives are important and need to be merged. 

Just my opinion/observation!

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/01/2009 03:32 pm
You're really whetting my appetite now. Is there any chance at all we can get some more Workbooks, then? Even older versions would be cool.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/01/2009 03:36 pm
elmarko - it's being worked on...
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/01/2009 03:40 pm
My guess is Chris will give free L2 for life to anyone who shows up with a pdf of a training manual  :)

A complete set of training manuals would make a great addition to L2.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/01/2009 04:11 pm
Well like I've said, we have had some workbooks already on specific subjects. The prospect of getting some more excites me :)
Title: Re: Shuttle Q&A Part 5
Post by: Davidgojr on 07/02/2009 09:15 am
I've noticed after seeing a shuttle launch in person and from many launch videos that one does not hear sonic booms during liftoff.  Launch vehicles clearly break the sound barrier while they are still in the lower atmosphere but why is no boom heard on the ground?
Title: Re: Shuttle Q&A Part 5
Post by: Davidgojr on 07/02/2009 09:19 am
During NASA TV broadcasts of shuttle launches there is a periodic hissing sound that can be heard before liftoff.  These sounds seem to pulse in a regular rhythmic pattern.  Can someone explain what the cause of these sounds are?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/02/2009 10:09 am
Gases venting from the shuttle and after T-5 minutes, it is the exhaust from the APU's. 

There is a Shuttle Q&A thread for question like this
Title: Re: Shuttle Q&A Part 5
Post by: haywoodfloyd on 07/02/2009 11:33 am
Because the vehicle has to pass by you to hear the boom.   When the shuttle was going to launch from VAFB, it would have passed over the Channel Islands and a boom would have heard.  Since the islands were the home of many pinnipeds (seals), there was concern that during the breeding season, a boom would have made the mothers rush for the water causing the pups to be crushed.

 

Did they have the same concerns about thunderstorms?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/02/2009 11:38 am
Because the vehicle has to pass by you to hear the boom.   When the shuttle was going to launch from VAFB, it would have passed over the Channel Islands and a boom would have heard.  Since the islands were the home of many pinnipeds (seals), there was concern that during the breeding season, a boom would have made the mothers rush for the water causing the pups to be crushed.

 

Did they have the same concerns about thunderstorms?

I believe they are rare out there, also most thunderstorm build up and not have an "out of the blue" boom

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/02/2009 11:38 am
During NASA TV broadcasts of shuttle launches there is a periodic hissing sound that can be heard before liftoff.  These sounds seem to pulse in a regular rhythmic pattern.  Can someone explain what the cause of these sounds are?

Because the vehicle has to pass by you to hear the boom.   When the shuttle was going to launch from VAFB, it would have passed over the Channel Islands and a boom would have heard.  Since the islands were the home of many pinnipeds (seals), there was concern that during the breeding season, a boom would have made the mothers rush for the water causing the pups to be crushed.
Title: Re: Shuttle Q&A Part 5
Post by: haywoodfloyd on 07/02/2009 11:46 am
Because the vehicle has to pass by you to hear the boom.   When the shuttle was going to launch from VAFB, it would have passed over the Channel Islands and a boom would have heard.  Since the islands were the home of many pinnipeds (seals), there was concern that during the breeding season, a boom would have made the mothers rush for the water causing the pups to be crushed.

 

Did they have the same concerns about thunderstorms?

I believe they are rare out there, also most thunderstorm build up and not have an "out of the blue" boom


A "near-by" lightning strike can, in the right atmospheric conditions, produce a clap of thunder in the 120 dB range.
I doubt that the Orbiter at 60,000 feet can hit that level.
I could be wrong.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/02/2009 03:28 pm
Essentially, the situation (to simplify your words) is this:

If there's a one way arrow between modes, you cant go backwards because the system won't let you (ILLEGAL ENTRY?), so by my reckoning the only way would be to manually load into memory the program you want. Which, I understand, is time consuming.

As for your point about not being able to go back to OPS 2 because the deorbit burn was already done, I'm sure it could be done manually, there'd just be little use for OPS 2 at that point.

Can someone help me out here, I'm wondering how badly I'm understanding this. DPS is a little sketchy for me so this is a learning curve.

You can get just about anywhere from OPS 0, but OPS 000 PRO is not a legal transition from 304.

However, you can force a GPC to OPS 0 by taking the GPC MODE switch to STBY and back to RUN.

So... you take GPCs 1-4 to STBY, then back to RUN, one at a time. Once you have done this, you will have a GPC common set in OPS 0. The vehicle will not be controllable at this point! Check memory config 3 (ITEM 1+3), should be fine since you used it earlier to transition to OPS 3 the first time around, then invoke the NBAT with OPS 301 PRO. Now the vehicle is under control again.

May need to clean up the BFS afterward. I never certified DPS so not my specialty.

Tried this in the NGSMS this morning... worked. In the middle, I did get paranoid about losing PASS CRT interface and worked around it by taking the CRT1 major function switch to PL, then using one of the remaining PASS GPCs to hard-assign GPC1 to CRT1. (Then of course I had to remember to take CRT1 back to GNC before doing the OPS 301 PRO). As expected, the BFS went standalone when the PASS set went away. Probably broke every one of the "good DPS habits" in the process, but I did get back to 301.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 07/03/2009 01:42 am
With all the focus on the ET/GUCP these days, I was wondering about the power reactant storage and distribution system (PRSD), which stores LH2 and LOX in tanks underneath the payload bay floor for delivery to the fuel cells and cabin atmosphere (and indirectly to the potable water system).

Have there been issues in the past with power reactant loading?

Does the orbiter have a dedicated GH2 vent umbilical for PRSD?

Is the same pad storage/pumping infrastructure used for ET and PRSD?

Why does power reactant loading take place 48 hours before launch?

Are there separate teams of "pad rats" for ET and PRSD cryo ops?
Title: Re: Shuttle Q&A Part 5
Post by: blazotron on 07/03/2009 02:10 am
During NASA TV broadcasts of shuttle launches there is a periodic hissing sound that can be heard before liftoff.  These sounds seem to pulse in a regular rhythmic pattern.  Can someone explain what the cause of these sounds are?

Because the vehicle has to pass by you to hear the boom.   When the shuttle was going to launch from VAFB, it would have passed over the Channel Islands and a boom would have heard.  Since the islands were the home of many pinnipeds (seals), there was concern that during the breeding season, a boom would have made the mothers rush for the water causing the pups to be crushed.

Jim, I think you mistakenly copied over the text from the other thread you merged.  I believe he is referring to the APU system exhaust.

<edit> Jim answered on the previous page separately
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/03/2009 06:20 am


1.  Have there been issues in the past with power reactant loading?

2.  Does the orbiter have a dedicated GH2 vent umbilical for PRSD?

3.  Is the same pad storage/pumping infrastructure used for ET and PRSD?

4.  Why does power reactant loading take place 48 hours before launch?

5.  Are there separate teams of "pad rats" for ET and PRSD cryo ops?

2.  no, the amount of GH2 is very small.   The  PRSD tanks are super insulated.  (there is a vent but no umbilical)

3.  No, different tankers are brought in with the LH2 and LO2 for the PDRS.  It is a higher quality than the ET prop

4.  It is done via an umbilical (OMBUU) in the RSS

5,  there are no pad rats for ET loading, it is done from the LCC
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/04/2009 10:27 am
You can get just about anywhere from OPS 0, but OPS 000 PRO is not a legal transition from 304.

However, you can force a GPC to OPS 0 by taking the GPC MODE switch to STBY and back to RUN.

So... you take GPCs 1-4 to STBY, then back to RUN, one at a time. Once you have done this, you will have a GPC common set in OPS 0. The vehicle will not be controllable at this point! Check memory config 3 (ITEM 1+3), should be fine since you used it earlier to transition to OPS 3 the first time around, then invoke the NBAT with OPS 301 PRO. Now the vehicle is under control again.

May need to clean up the BFS afterward. I never certified DPS so not my specialty.

Tried this in the NGSMS this morning... worked. In the middle, I did get paranoid about losing PASS CRT interface and worked around it by taking the CRT1 major function switch to PL, then using one of the remaining PASS GPCs to hard-assign GPC1 to CRT1. (Then of course I had to remember to take CRT1 back to GNC before doing the OPS 301 PRO). As expected, the BFS went standalone when the PASS set went away. Probably broke every one of the "good DPS habits" in the process, but I did get back to 301.

Thanks for trying this, I hope you didn't spend too much time off the back of someone's forum query.

Why would you lose the interface? And what would taking the major function switch to PL do to resolve that? After reading the workbook I saw that taking the switch to PL keeps it in the current major function, but switches to SPEC 0 (I think?) - was that just so you could work on GPC MEMORY?
Title: Re: Shuttle Q&A Part 5
Post by: wizard on 07/04/2009 04:02 pm
On Bill Harwood's ascent timeline, what does the 23K line mean?
Quote
7:47:20 PM...T+07:47...LAST 1E PRE-MECO TAL ZARAGOZA ([email protected]%)......15,342
7:47:25 PM...T+07:52...23K...........................................15,683
7:47:25 PM...T+07:52...LAST 3E PRE-MECO TAL ZARAGOZA (67%)...........15,683
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 07/04/2009 05:13 pm
On Bill Harwood's ascent timeline, what does the 23K line mean?
Quote
7:47:20 PM...T+07:47...LAST 1E PRE-MECO TAL ZARAGOZA ([email protected]%)......15,342
7:47:25 PM...T+07:52...23K...........................................15,683
7:47:25 PM...T+07:52...LAST 3E PRE-MECO TAL ZARAGOZA (67%)...........15,683

That's 23000 feet per second. It's about 30 seconds before MECO with 3 SSMEs.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/04/2009 06:01 pm
You can get just about anywhere from OPS 0, but OPS 000 PRO is not a legal transition from 304.

However, you can force a GPC to OPS 0 by taking the GPC MODE switch to STBY and back to RUN.

So... you take GPCs 1-4 to STBY, then back to RUN, one at a time. Once you have done this, you will have a GPC common set in OPS 0. The vehicle will not be controllable at this point! Check memory config 3 (ITEM 1+3), should be fine since you used it earlier to transition to OPS 3 the first time around, then invoke the NBAT with OPS 301 PRO. Now the vehicle is under control again.

May need to clean up the BFS afterward. I never certified DPS so not my specialty.

Tried this in the NGSMS this morning... worked. In the middle, I did get paranoid about losing PASS CRT interface and worked around it by taking the CRT1 major function switch to PL, then using one of the remaining PASS GPCs to hard-assign GPC1 to CRT1. (Then of course I had to remember to take CRT1 back to GNC before doing the OPS 301 PRO). As expected, the BFS went standalone when the PASS set went away. Probably broke every one of the "good DPS habits" in the process, but I did get back to 301.

Thanks for trying this, I hope you didn't spend too much time off the back of someone's forum query.

Nah. Had a student no-show for a class (and brain fart, it was in the NGSST, not the NGSMS, but the software is the same...) so I had the time and the facility was set up... took about five minutes.

Quote
Why would you lose the interface?

When you take a GPC driving a CRT to STBY, you get the Big X/Poll fail on that CRT and you can no longer type to it. After I'd done that to GPCs 1 and 2, I started getting paranoid about what would happen after I took GPCs 3 and 4 down.

Quote
And what would taking the major function switch to PL do to resolve that? After reading the workbook I saw that taking the switch to PL keeps it in the current major function, but switches to SPEC 0 (I think?) - was that just so you could work on GPC MEMORY?

Because I vaguely recalled (again, not a DPS specialist) that PL is how you signal that you want to type to an OPS 0 GPC. That didn't get rid of the Big X/Poll fail, but the hard-assign did.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 07/04/2009 06:09 pm
From what I've seen you guys say and from what I've seen in online documentation, the Shuttle flight software UI is very, very primitive. This is perfectly understandable given its age, but I was wondering: is it considered to be difficult to upgrade the flight software or is it just something you wouldn't want to do given the amount of work needed for validation and verification and given that it would mean throwing away the flight record? Have you ever had the opportunity to look at the source code? What does it look like?
Title: Re: Shuttle Q&A Part 5
Post by: vertical on 07/04/2009 06:49 pm
From what I've seen you guys say and from what I've seen in online documentation, the Shuttle flight software UI is very, very primitive. This is perfectly understandable given its age, but I was wondering: is it considered to be difficult to upgrade the flight software or is it just something you wouldn't want to do given the amount of work needed for validation and verification and given that it would mean throwing away the flight record?
I think it's a matter of if it ain't broke... Reliability and the least amount of question marks has always been the priority in software used in human spaceflight.  Besides, even if there was a will to upgrade already working software, probably wasn't much of a budget for it.

I believe for docking, the crew heavily relies on laptops.  Do any of these actually interface directly with on board shuttle systems?  Or is the crew just acting as the end of the guidance loop and manually maneuvering the orbiter in response to what they see on the laptops?

I wonder what the software on Orion will look like.  Will it be a purpose built language or an "off the shelf" commercial language?  Significant parts of the Mars Rover use C++ IIRC.

vertical
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/04/2009 06:59 pm
From what I've seen you guys say and from what I've seen in online documentation, the Shuttle flight software UI is very, very primitive. This is perfectly understandable given its age, but I was wondering: is it considered to be difficult to upgrade the flight software or is it just something you wouldn't want to do given the amount of work needed for validation and verification and given that it would mean throwing away the flight record?
I think it's a matter of if it ain't broke... Reliability and the least amount of question marks has always been the priority in software used in human spaceflight.  Besides, even if there was a will to upgrade already working software, probably wasn't much of a budget for it.

I believe for docking, the crew heavily relies on laptops.  Do any of these actually interface directly with on board shuttle systems?

They receive data from shuttle systems via the PCMMU. They cannot send commands to the orbiter.

Quote
  Or is the crew just acting as the end of the guidance loop and manually maneuvering the orbiter in response to what they see on the laptops?

Yes.

Quote
I wonder what the software on Orion will look like.  Will it be a purpose built language or an "off the shelf" commercial language?  Significant parts of the Mars Rover use C++ IIRC.

Largely Matlab, machine-translated into C.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/04/2009 07:13 pm
From what I've seen you guys say and from what I've seen in online documentation, the Shuttle flight software UI is very, very primitive. This is perfectly understandable given its age, but I was wondering: is it considered to be difficult to upgrade the flight software or is it just something you wouldn't want to do given the amount of work needed for validation and verification and given that it would mean throwing away the flight record? Have you ever had the opportunity to look at the source code? What does it look like?

There is a large part of "if it ain't broke, don't fix it" involved, as Vertical stated. The software testing process is extensive (and expensive); you don't go through that pain unless you need to.

There are also the limitations of the platform. The AP-101S has the equivalent of 1MB memory (actually 256K 32-bit words). The development platform is an IBM System/360 (AP-101S is binary-compatible with it). The development tools are primitive; the skills required to use it, very specialized. Not a whole lot of room to add more code, either. Upgrading shuttle software requires an attention to code size and speed that is no longer a factor in commercial development. Not exactly IT skills that can be hired off the street.

The user interface could be improved by moving development off the GPCs. That was the idea behind the Cockpit Avionics Upgrade (CAU), in which the MEDS "glass cockpit" IDPs would be replaced with CDPs containing more computing capability and a more modern development platform. The GPCs would send data to the CDPs that would be used to draw more modern displays. However, CAU was cancelled after the retirement of the shuttle was announced.

The shuttle flight software is coded in HAL/S, which is somewhat similar in syntax to Fortran. Google around and you'll see some code samples.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/05/2009 09:06 am
To tie in my Centaur questions from here: http://forum.nasaspaceflight.com/index.php?topic=6479.msg430687#msg430687:

Does anyone have any photos of the Centaur mod work done on OV-099 and OV-103 at KSC? OV-104 came delivered from Palmdale with the Centaur supporting capability.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/05/2009 04:13 pm
Quote
Why would you lose the interface?

When you take a GPC driving a CRT to STBY, you get the Big X/Poll fail on that CRT and you can no longer type to it. After I'd done that to GPCs 1 and 2, I started getting paranoid about what would happen after I took GPCs 3 and 4 down.

Quote
And what would taking the major function switch to PL do to resolve that? After reading the workbook I saw that taking the switch to PL keeps it in the current major function, but switches to SPEC 0 (I think?) - was that just so you could work on GPC MEMORY?

Because I vaguely recalled (again, not a DPS specialist) that PL is how you signal that you want to type to an OPS 0 GPC. That didn't get rid of the Big X/Poll fail, but the hard-assign did.

I presume you did this on CRT3 by switching one of the keypads over to it?

This is really fascinating, I wish I had a nice big simulator to try things on.
Title: Re: Shuttle Q&A Part 5
Post by: robertross on 07/05/2009 04:38 pm
Question: all the costs incurred with GUCP, FCV & other similar issues. Are these part of the shuttle funding budget, or does these result in a budget shortfall which means deleted something, deffering until later, or requesting additional funds in a future budget to make up the losses?

I know they can't run a deficit, so the 'losses' have to be made up from somewhere.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/05/2009 07:04 pm
Quote
Why would you lose the interface?

When you take a GPC driving a CRT to STBY, you get the Big X/Poll fail on that CRT and you can no longer type to it. After I'd done that to GPCs 1 and 2, I started getting paranoid about what would happen after I took GPCs 3 and 4 down.

Quote
And what would taking the major function switch to PL do to resolve that? After reading the workbook I saw that taking the switch to PL keeps it in the current major function, but switches to SPEC 0 (I think?) - was that just so you could work on GPC MEMORY?

Because I vaguely recalled (again, not a DPS specialist) that PL is how you signal that you want to type to an OPS 0 GPC. That didn't get rid of the Big X/Poll fail, but the hard-assign did.

I presume you did this on CRT3 by switching one of the keypads over to it?

Yes, then switching CRT3 to PASS (it had previously been displaying BFS).
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/11/2009 02:09 pm
This may have been asked before, but how long can they leave the external tank full?

After the SSMEs light, about 8.5 minutes  ;D

Time on the pad is limited by crew time on their backs.  But this is an ISS mission, so the launch window will close first.

Danny Deger

Please accept my apologies in advance for the dripping sarcasm.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/11/2009 03:05 pm
Hi folks,

Are there any photos of the OMBUU as I would like to know what it is, and what it does?

thanks
Carl 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/11/2009 04:12 pm
Hi folks,

Are there any photos of the OMBUU as I would like to know what it is, and what it does?

thanks
Carl 

http://forum.nasaspaceflight.com/index.php?topic=15330.0
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/11/2009 06:13 pm
Thanks for the quick response Jim, but it seems to be in L2 which I am not a member of.

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/11/2009 06:18 pm
Thanks for the quick response Jim, but it seems to be in L2 which I am not a member of.

Thanks
Oxford750

It is uses to fill the reactants (LH2 and LO2) for the fuel cells, days before launch.  The name describes the rest
Title: Re: Shuttle Q&A Part 5
Post by: butters on 07/11/2009 06:32 pm
It may also be helpful to know that the LH2 and LOX tanks for the fuel cells are located underneath the floor of the payload bay, in the midbody.

I have a question: what are SRB water baggies?  Chris mentioned them this morning, but google wasn't doing it for me.  Sound suppression?
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/11/2009 07:37 pm
Thanks folks.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/11/2009 08:24 pm

I have a question: what are SRB water baggies?  Chris mentioned them this morning, but google wasn't doing it for me.  Sound suppression?

Yes.
http://www-pao.ksc.nasa.gov/nasafact/count4ssws.htm
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/11/2009 08:49 pm
Hi folks,

Here to ask more questions.

1) Does anyone know how "dirty" the "white room" gets after a launch?

2) I was reading NASA Facts on launch Complex 39. pads A & B, and noticed that in one photo of "the stack" at the pad, you could see the flame trench, and I remembered once that someone told me, there is a metal inverted "v" in the trench that deflects flames from the SRB's one way, and flames from the SSME's the other.  That is why the "steam" from the SSME's goes one way and the smoke from the SRB's goes the other way

My question is: why is that deflector there?

3)  How are some valves recycled?   ie: ET/GUCP valve.  My understanding is either a valve is open or closed and if there is a leak around it, it won't change the situation till you tighten the valve physicaly(spel) and/or replace it.


Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/11/2009 09:00 pm

2) I was reading NASA Facts on launch Complex 39. pads A & B, and noticed that in one photo of "the stack" at the pad, you could see the flame trench, and I remembered once that someone told me, there is a metal inverted "v" in the trench that deflects flames from the SRB's one way, and flames from the SSME's the other.  That is why the "steam" from the SSME's goes one way and the smoke from the SRB's goes the other way

My question is: why is that deflector there?


To divert the exhaust away from the stack.  Flames and energy (noise) would bounce back if there was only flat surface.
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 07/12/2009 01:52 am
Who exactly is on the Mission Management Team?  What positions?  Do the same people comprise the pre-launch MMT at the Cape as the in-flight MMT in Houston?
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/12/2009 02:11 am
Thanks Jim.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 07/12/2009 05:30 pm
Hi folks,

Here to ask more questions.

1) Does anyone know how "dirty" the "white room" gets after a launch?


3)  How are some valves recycled?   ie: ET/GUCP valve.  My understanding is either a valve is open or closed and if there is a leak around it, it won't change the situation till you tighten the valve physicaly(spel) and/or replace it.


Thanks
Oxford750

1) You can see on some launch footage from inside the white room that it gets covered quite a bit with booster dust. It's basically open to the atmosphere during launch.


3) I'm not sure about the valve in the ET, but the vent valve on the GSE side just downstream from the GUCP (along with a few other valves in our system) is a pneumatically operated butterfly valve. When it's open for a long period of time with supercold hydrogen flowing through it, they have a tendency to stiffen up and not close completely. so occasionally you have to cycle it open then closed again to get it to seal. I imagine the valve in the ET is the same way. I'm just not sure what type of valve it is. I want to say it's a type of poppet or piston valve. maybe someone else knows for sure. I"ll ask our engineer when I get in to work later this afternoon.
Title: Re: Shuttle Q&A Part 5
Post by: hygoex on 07/12/2009 10:38 pm
What will happen to the RSS from Pad 39B and 39A for that matter?    Is there going to be a plan to preserve parts of it for public display?
Title: Re: Shuttle Q&A Part 5
Post by: Jones36 on 07/13/2009 12:29 am
OK this one is off the wall, saw it on the NasaKSC Facebook.


Would VAFB launches to ISS been feasible?
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/13/2009 12:51 am
Thanks Padrat.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/13/2009 01:07 am
OK this one is off the wall, saw it on the NasaKSC Facebook.


Would VAFB launches to ISS been feasible?

No,The shuttle can't get to 51.8 degrees from there
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/13/2009 01:12 am
OK this one is off the wall, saw it on the NasaKSC Facebook.


Would VAFB launches to ISS been feasible?

No,The shuttle can't get to 51.8 degrees from there

It probably could if you don't mind putting the SRBs someplace they shouldn't be :-)

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: hygoex on 07/13/2009 11:26 am
When the White Room is disassembled, how much of a gap is it between the orbiter hatch opening and the white room floor?   If the astronauts had to get out quickly, wouldn't that pose a safety risk in itself, considering the White room personnel have to be harnessed after disassembling the White Room?
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 07/13/2009 11:41 am
I somewhat understand that NASA has to calculate the launch time based on where the ISS is in orbit to determine launch time, but, why is this window so critical?

What sort of an impact would launching 30 or so minutes before a given launch time, such as STS-127's 7:13 time this past Sunday.  If they could have launched 30 minutes earlier, the weather might have been a GO for launch.

Would the shuttle not have been able to catch up with the station properly if launched a few minutes before or after the given window?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/13/2009 11:46 am
I somewhat understand that NASA has to calculate the launch time based on where the ISS is in orbit to determine launch time, but, why is this window so critical?

What sort of an impact would launching 30 or so minutes before a given launch time, such as STS-127's 7:13 time this past Sunday.  If they could have launched 30 minutes earlier, the weather might have been a GO for launch.

Would the shuttle not have been able to catch up with the station properly if launched a few minutes before or after the given window?

Thanks.

The shuttle would be in the wrong plane if it launched earlier or later than the window.   The window size is determined by the shuttle's ability to steer into the right plane,  which is very limited.

This has been answered in the shuttle Q&A thread
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 07/13/2009 11:48 am
There are certain times in the launch window when ISS orbital plane intersects the launch site. That's one of the considerations. If you launch too early or late, Earth's rotation shifts you too far away from that plane so the Shuttle cannot rendezvous with ISS anymore, it doesn't have the fuel to get into the correct orbital plane during launch and especially during on orbit operations.

Plane change maneuvers are very expensive in terms of delta-V, not like raising/lowering the orbit by tens of kilometers.

EDIT: yeah, what Jim said.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 07/13/2009 12:00 pm
When the White Room is disassembled, how much of a gap is it between the orbiter hatch opening and the white room floor?   If the astronauts had to get out quickly, wouldn't that pose a safety risk in itself, considering the White room personnel have to be harnessed after disassembling the White Room?

I know there's an "egress pole" designed to guide escaping crew clear of the wing leading edge when bailing out in flight.  I think it's deployed as a part of the pyrotechnic sequence that blows the hatch.  I wonder if that also plays a role in helping the crew escape a pad emergency?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/13/2009 12:17 pm
When the White Room is disassembled, how much of a gap is it between the orbiter hatch opening and the white room floor?   If the astronauts had to get out quickly, wouldn't that pose a safety risk in itself, considering the White room personnel have to be harnessed after disassembling the White Room?

I know there's an "egress pole" designed to guide escaping crew clear of the wing leading edge when bailing out in flight.  I think it's deployed as a part of the pyrotechnic sequence that blows the hatch.  I wonder if that also plays a role in helping the crew escape a pad emergency?

Pole is not used on the ground.

The gap is only a few inches and not a concern for crew.

The closeout crew wears a harness because the left wall of the white room is opened up during close out.  It is to allow for the white room to swing into place in case the hatch is already open during an emergency egress.
Title: Re: Shuttle Q&A Part 5
Post by: Jones36 on 07/13/2009 02:23 pm
That's what I thought, just wanted to double check.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/14/2009 10:43 am
If the crew has to be so carefull when they enter the shuttle, how fast can they exit,if the need arises?

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: wizard on 07/14/2009 02:01 pm
OK this one is off the wall, saw it on the NasaKSC Facebook.


Would VAFB launches to ISS been feasible?

No,The shuttle can't get to 51.8 degrees from there

The shuttle can't get there, but some LVs can access that orbit from VAFB.

Edit: disregard my question, I just realized the SRBs and ET impact points would likely be the problem for a VAFB launch to ISS. Coffee hasn't kicked in yet this morning  :)
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 07/14/2009 07:09 pm
Reguarding the tyvek covers, are they disposed of as the shuttle reaches orbit, or what happens to them during a launch?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/14/2009 07:11 pm
Reguarding the tyvek covers, are they disposed of as the shuttle reaches orbit, or what happens to them during a launch?

fall off or burn off.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/14/2009 08:11 pm
Hi folks:

What are the objects I have circled, in these pictures?

Where can I find out more about the launch/entry suits the astronauts wear?  (i.e.  What is the white wheel hanging from the neck)

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/14/2009 08:15 pm
Hi folks:

What are the objects I have circled, in these pictures?
First image: The GOX Vent Hood maintenance access platform.

Second image: One of the vernier FRCS jets.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/14/2009 08:16 pm
1.  is the access platform to work on the GOX vent hood while it is retracted

2.  is vernier thruster

3.  The wheel with the strap keeps the neck ring from rising up while the suit is under pressure.
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 07/14/2009 08:16 pm
Reguarding the tyvek covers, are they disposed of as the shuttle reaches orbit, or what happens to them during a launch?

fall off or burn off.

Thanks for the answer! As a follow up question, has there ever been a case where one of the covers did not come off???

Also what are they made out of, lightweight material of some type I'd imagine and how are they attatched?? (sorry for the boat load of questions)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/14/2009 08:18 pm
Reguarding the tyvek covers, are they disposed of as the shuttle reaches orbit, or what happens to them during a launch?

fall off or burn off.

Thanks for the answer! As a follow up question, has there ever been a case where one of the covers did not come off???

Also what are they made out of, lightweight material of some type I'd imagine and how are they attatched?? (sorry for the boat load of questions)

It burns off from the thruster firing

They are attached by RTV.

They are made of tyvek

There is an article about the covers
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 07/14/2009 10:49 pm
How accurately is the Shuttle launch mass known and how is it determined?
What limits the accuracy of this figure? Maybe ice build up or... ?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/14/2009 11:54 pm
MDMoery: The propellant in the storages spheres isn't sufficient to keep replenishing what boils off every second for those 24 hrs. And going too low isn't a good thing. It's only something you would do during a major pad mod period.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 07/15/2009 01:36 am
From what I've been told our storage tanks in LH2 have never been completely drained since they were first chilled during Apollo. Now over on LOX, there was the flexhose rupture that drained the tank and damaged it as well.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/15/2009 01:41 am
How accurately is the Shuttle launch mass known and how is it determined?
What limits the accuracy of this figure? Maybe ice build up or... ?


The orbiter is weighed.  Not all the other components are (like SRB's).  But pieces parts are weighed.  The amount of propellants in the ET is known.  Knowing the weight of the whole stack within .1% (not saying that this is the accuracy) means that they could be off by 6000 lbs.   Most of this is going to be in the SRB's so it doesn't affect payload to orbit by that much (around 12 to 1 ratio or so)
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/15/2009 01:43 am
I think I know where he might be coming from.

On a 24 hour turnaround, it seems like they get the tank drained and then fill it again just a few hours later.  Why not keep the External Tank fueled and just keep it in stable replenish for the next attempt the next day?

Ice accumulation is probably a part of it too.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/15/2009 02:02 am
Thanks Dave and Jim.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 07/15/2009 05:35 am
How accurately is the Shuttle launch mass known and how is it determined?
What limits the accuracy of this figure? Maybe ice build up or... ?


The orbiter is weighed.  Not all the other components are (like SRB's).  But pieces parts are weighed.  The amount of propellants in the ET is known.  Knowing the weight of the whole stack within .1% (not saying that this is the accuracy) means that they could be off by 6000 lbs.   Most of this is going to be in the SRB's so it doesn't affect payload to orbit by that much (around 12 to 1 ratio or so)

Most interesting. Thanks a bunch!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/15/2009 01:31 pm
Is there a certain percentage of "no-go" for weather where they do not even try to launch? Because Tuesday there was a 60% change no-go. With the open Tyvek cover in mind, wouldn't it have been wiser to immediatly put the launch to Wednesday and repair the tyvek cover on Tuesday? I'm a newbie, so just kick me if I'm wrong.

No percentage. Have you ever been to Florida? Weather changes often by the minute there. They have launched on 90% no-go days before.

Analyst
Point taken -- especially in the summer time -- but can't think of a launch with a 90% WX violation forecast going into tanking.  I believe they have tanked with that forecast and scrubbed.  And they have launched with a 70% chance of violation going in (I believe STS-116 was the most recent example).  Not sure about launches with a 80% chance of violation at tanking.

Analyst pointed me to STS-94, which launched with a 90% forecast going into tanking -- even with a 2 hour, 30 minute launch window; reference:
http://www-pao.ksc.nasa.gov/kscpao/status/stsstat/1997/jun/6-30-97s.htm

It's also worth noting that in that situation (Spacelab mission), they were able to move the targeted T-0 up by one hour to improve their chances.

The launch ended up being delayed for about 12 minutes due to a shower in the RTLS radius:
http://www-pao.ksc.nasa.gov/kscpao/status/stsstat/1997/jul/7-01-97t.htm
Title: Re: Shuttle Q&A Part 5
Post by: Frankfordewinne on 07/15/2009 05:15 pm
Why does the SRB on the left have a black ribbon around the top? Is it to indicate which SRB (left or right side) it is?


Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/15/2009 05:16 pm
Yes
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/15/2009 05:43 pm
In plotting my radar over the KSC complex, I realized the SLF runway source I have is not NW/SE but more N/S and not near the actual observation site. Leads me to believe the lat/long coordinates of the runway ends are not correct.

Any source of the actual coordinates of each end of the SLF runway?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/15/2009 05:56 pm
According to Google Earth which I've found to be surprisingly accurate in the past:

N end:  28°37'57.95"N  80°42'21.94"W
S end:  28°35'49.26"N  80°40'57.81"W
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 07/15/2009 06:36 pm
Can anyone direct me to a list of exactly who comprises the MMT?  Is the MMT at the Cape different from the MMT in Houston?
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 07/15/2009 06:38 pm
Is this black marking permanent or is the same SRB sometimes used as the left SRB and sometimes as the right SRB? Are they symmetrical or are they mirror images?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/15/2009 06:40 pm
Is this black marking permanent or is the same SRB sometimes used as the left SRB and sometimes as the right SRB? Are they symmetrical or are they mirror images?

The paint is removed during refurb
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 07/15/2009 06:47 pm
Does anyone know of a link for NASA TV or at least the audio that streams on an iPhone (I'm not even sure if the iPhone is capable of streaming media, but it's all I have today)? 
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 07/15/2009 07:46 pm
According to Google Earth which I've found to be surprisingly accurate in the past:

N end:  28°37'57.95"N  80°42'21.94"W
S end:  28°35'49.26"N  80°40'57.81"W

Pretty darn close...maybe off by a pixel or two.  ;)  Here's what actually get's used:

KSC15:  28°37'57.85"N  80°42'21.83"W
KSC33:  28°35'49.23"N  80°40'57.66"W
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/15/2009 07:47 pm
Here' s the audio stream link:
http://www.nasa.gov/178952main_Mission_Audio_UP.asx

Here's the media channel link:
http://www.nasa.gov/145590main_Digital_Media.asx

Here's the public channel link:
http://www.nasa.gov/qtl/151335main_NASA_TV_QT.qtl

Hopefully, one of these will work for you. The audio quality seems to be best on the media channel.

Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/15/2009 07:51 pm
I was watching Failure is not an Option Part II and noticed in the video from Columbia's last fight, the front windows appeared to have some sort of interior covers. It was this final footage as they began to interface with the atmosphere.

Was this just an illusion, or are the front windows covered during initial phase of reentry?
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 07/15/2009 08:06 pm
Here' s the audio stream link:
http://www.nasa.gov/178952main_Mission_Audio_UP.asx (http://www.nasa.gov/178952main_Mission_Audio_UP.asx)

Here's the media channel link:
http://www.nasa.gov/145590main_Digital_Media.asx (http://www.nasa.gov/145590main_Digital_Media.asx)

Here's the public channel link:
http://www.nasa.gov/qtl/151335main_NASA_TV_QT.qtl (http://www.nasa.gov/qtl/151335main_NASA_TV_QT.qtl)

Hopefully, one of these will work for you. The audio quality seems to be best on the media channel.



These work fine for me on the PC, but not on the iPhone.  I'm new to the iPhone so it could be lack of capability or some kind of plug-in I need. 
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/15/2009 08:07 pm
Thanks much! The Rwy33 side was fine but the northwest end was angled too far to the north on the numbers I had.

If by chance you can give exacts for VAB / 39A / 39B it'd be appreciated.

 - Rob
Title: Re: Shuttle Q&A Part 5
Post by: kermit on 07/15/2009 08:15 pm
Does anyone know of a link for NASA TV or at least the audio that streams on an iPhone (I'm not even sure if the iPhone is capable of streaming media, but it's all I have today)? 

Try this: iphone.akamai.com

touch the NASA TV button

Works on my ipod touch 1G with a good wifi connection.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/15/2009 08:37 pm
They do have radar but aircraft radar is very limited, it's more to keep them oriented with respect to the storms instead of a full interrogation. Their goal is to fly through the stuff that the ground sees on the ground radar.
Title: Re: Shuttle Q&A Part 5
Post by: tva on 07/15/2009 09:08 pm

If by chance you can give exacts for VAB / 39A / 39B it'd be appreciated.


VAB
28° 35' 11"N  80° 39' 03"W

LC-39A
28° 36' 30"N  80° 36' 15"W

LC-39B
28° 37' 36"N  80° 37' 15"W
Title: Re: Shuttle Q&A Part 5
Post by: fcmadrid on 07/15/2009 09:10 pm
Hello!

I am very interesting about this happening about space shuttle and its mission and million of data, etc. I have a few questions about it.
I calculate that space shuttle needs to break the sound barrier from lift of to sound barrier=10.7sec. Is this correct or does anyone have some other data about this. I really wanna know how much time does it take that space shuttle breaks the sound barrier.
My second question: where can I get this dialogue of a man. I really want to have the text of his speech from lift off and on. When he talk how much is an altitude of space shuttle and other data.

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 07/15/2009 09:16 pm
Thanks much! The Rwy33 side was fine but the northwest end was angled too far to the north on the numbers I had.

If by chance you can give exacts for VAB / 39A / 39B it'd be appreciated.

 - Rob

VAB*:  28°35'09.84" N 80°39'04.26" W
39A:    28°36'30.32" N 80°36'14.73" W
39B:    28°37'37.97" N 80°37'14.87" W

*I didn't have exact coordinates for the VAB so I lifted them from Google Maps.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 07/15/2009 09:59 pm
Did I see the left SSME twitch pretty hard during APU prestart/start?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/15/2009 10:02 pm
Did I see the left SSME twitch pretty hard during APU prestart/start?
Saw that, too, but have seen it on other counts.
Title: Re: Shuttle Q&A Part 5
Post by: Zephon907 on 07/15/2009 10:54 pm
These surely have been asked before, but...

A few seconds after liftoff, the shuttle rolls to a position where it is basically hanging underneath the external tanks, why?

Second question, the huge clamps that clamp onto the wings, holding the craft in place on the pad...how do those not damage the wings?  I assume a lot of force must be used to do the work needed.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/15/2009 10:59 pm
Second question, the huge clamps that clamp onto the wings, holding the craft in place on the pad...how do those not damage the wings?  I assume a lot of force must be used to do the work needed.
Those aren't clamps and they don't touch the wings.  They are tail service masts and are only connected to the orbiter via a plate on each side of the aft fuselage, through which electrical and fluid connections are made (they are called T-0 umbilicals because they separate from the vehicle at liftoff).  The vehicle is only held to the pad by the four bolts in each SRB aft skirt (for a total of eight).
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/15/2009 10:59 pm
These surely have been asked before, but...

A few seconds after liftoff, the shuttle rolls to a position where it is basically hanging underneath the external tanks, why?

Simplifies guidance and makes it easier to maintain negative angle of attack during first stage.

Quote
Second question, the huge clamps that clamp onto the wings, holding the craft in place on the pad...how do those not damage the wings?

There are no clamps holding the wings.

The stack is held to the pad using eight bolts on the SRB aft skirts. The Tail Service Masts (TSMs are in front of the wings but do not "clamp" them. The only connection between the TSMs and the orbiter is at the T-0 umbilicals that attach to the side of the aft fuselage. These are not load-bearing connections.
Title: Re: Shuttle Q&A Part 5
Post by: Zephon907 on 07/15/2009 11:56 pm
Hey, thanks guys for the quick answers.  I enjoy watching the launches and mission coverage on NASA TV, but there are a lot of things I don't have a clue about.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 07/16/2009 10:13 am
I calculate that space shuttle needs to break the sound barrier from lift of to sound barrier=10.7sec. Is this correct or does anyone have some other data about this. I really wanna know how much time does it take that space shuttle breaks the sound barrier.

42 sec
http://www.cbsnews.com/network/news/space/127/127ascentdata.html (http://www.cbsnews.com/network/news/space/127/127ascentdata.html)


p.s. 42 as in The Hitchhiker's Guide to the Galaxy  ;)
http://en.wikipedia.org/wiki/Phrases_from_The_Hitchhiker's_Guide_to_the_Galaxy (http://en.wikipedia.org/wiki/Phrases_from_The_Hitchhiker's_Guide_to_the_Galaxy)
Title: Re: Shuttle Q&A Part 5
Post by: patmamu on 07/16/2009 02:28 pm
Out of curiosity, I was reading a report on L2 about the fuel cell and was wondering what type of redundancies the orbiter has for a Fuel Cell loss. Would it have any impact on mission and if so what would that be? Thanks in advance.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/16/2009 03:46 pm
Out of curiosity, I was reading a report on L2 about the fuel cell and was wondering what type of redundancies the orbiter has for a Fuel Cell loss. Would it have any impact on mission and if so what would that be? Thanks in advance.

There are 3 fuels cells and loss of one would be minimum duration mission, loss of two would be immediate return
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 07/16/2009 04:48 pm
Mike Moses with Candrea Thomas:

Water cycled through the fuel cell, then we can transfer for drinking water (which we do).  If we don't drain the water, it'll build up, of course.  Too much water would let the electrolyte compound into the fuel cell.  It would end up drying out the fuel cell.  Worst case would be the fuel cell getting way too hot, way too fast.  We monitor the temps, the trend on the past few launch attempts have been that the temps are creeping up a bit.  We can't monitor the KOH (electrolyte compound) on orbit, but we can on ground.  When we run the SSPTS system, it takes off a lot of the load from the fuel cells.  That means, we don't dry the fuel cells out enough, and the temps increase.  If we can't, then we can't take as much power from the SSPTS, then we lose some mission durations.  Preliminary calculations show a normal mission, not anything currently big enough to knock off mission duration.  We'll ask JSC again today just to check.

Copied this from the Launch/FD1 thread because it is an excellent explanation of "Why (power-wise) can't the shuttle stay docked forever with the SSPTS on?"
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 07/16/2009 07:53 pm
Why does the SRB on the left have a black ribbon around the top? Is it to indicate which SRB (left or right side) it is?




It is also referred to lovingly as the "wedding ring."
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 07/17/2009 12:32 pm
OK this is one of those pessimistic "what ifs...", but what is the contingency if there is a significant loss of cabin pressure while on orbit but not docked to ISS, from looking at the reference manuals the ACES suits cant withstand pressures lower than 100K ft and only have 10 minutes of O2 so that doesn't seem like an option.

Would they just immediately deorbit and land/egress wherever they ended up? Any links to documents about this would be greatly appreciated
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/17/2009 01:08 pm

Would they just immediately deorbit and land/egress wherever they ended up? Any links to documents about this would be greatly appreciated

No,  Not enough time to prep for deorbit.  Have to close payload bay doors, attach seats, etc.  Your scenario is not survivable.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 07/17/2009 01:49 pm
Copied this from the Launch/FD1 thread because it is an excellent explanation of "Why (power-wise) can't the shuttle stay docked forever with the SSPTS on?"

I can think of a bunch of potential reasons, but why can't the fuel cells be shut down while the orbiter is docked to the ISS?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/17/2009 01:52 pm
I can think of a bunch of potential reasons, but why can't the fuel cells be shut down while the orbiter is docked to the ISS?

1.  restarting is hard and risky
2.  LH2 is boiling off so why not use it to produce power
Title: Re: Shuttle Q&A Part 5
Post by: Maty on 07/17/2009 01:53 pm
Was doing some thinking today....

During the RPM, photographs are taken using 800mm and 400mm lens.  Now they are some hefty super-tele lenses and, at least down here, would require some effort to maintain them stable to get a decent shot.  Does anyone know how things go in zero-g?  Without gravity it probably becomes a lot easier to handle the lenses, requiring little effort to move and therefore not requiring much input to stablise.  Would the photographers just be in free drift near the window or is there a system in place to maintain the lenses steady?
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 07/17/2009 04:11 pm
What exactly is the "big loop?"  Is it merely joining together A/G1 and S/G1?  Or is there something more complex involved? 
Title: Re: Shuttle Q&A Part 5
Post by: mjcrsmith on 07/17/2009 05:13 pm
If I recall correctly the only thing behind the RCC panels is the airframe.

If this is the case, would filling in the back of the RCC's with tile material provided any measure of structural reinforcement and thermal redundancy?

Granted there would be a weight penalty.

Thanks,
Roger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/17/2009 06:08 pm
What exactly is the "big loop?"  Is it merely joining together A/G1 and S/G1?  Or is there something more complex involved? 

Yes, pretty much. If I remember correctly, The Big Loop will connect the ISS, Orbiter, MCC for the shuttle, and MCC for the ISS all on one loop.

Would appreciate any correction, though.
Title: Re: Shuttle Q&A Part 5
Post by: janmb on 07/17/2009 08:29 pm
Sorry if covered, but unable to find anything through searching...

Approximately during which time window of the total ascent is foam debris considered a potential threat to the vehicle?

(Asking about numbers here, not the principles determining this)
Title: Re: Shuttle Q&A Part 5
Post by: mark147 on 07/18/2009 09:29 pm
Sorry if covered, but unable to find anything through searching...

Approximately during which time window of the total ascent is foam debris considered a potential threat to the vehicle?

This has been asked a few times recently. First 2 mins 15 secs.
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 07/21/2009 01:02 am
Is there any documentation regarding the deployment of the Centaur or PAM assisted payloads from the Shuttle?

In particular I'm trying to find out what sort of range those payloads had to have from the Orbiter before the engines were ever ignited.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/21/2009 01:10 am
Is there any documentation regarding the deployment of the Centaur or PAM assisted payloads from the Shuttle?

In particular I'm trying to find out what sort of range those payloads had to have from the Orbiter before the engines were ever ignited.

Ross.

When there were 3 PAM spacecraft, they were deployed one per day.
IUS and Centaur were to be deployed 6-8 hours after launch.

The IUS and PAM's fired 40 minutes or so after deployment. 

Title: Re: Shuttle Q&A Part 5
Post by: yinzer on 07/21/2009 01:28 am
The IUS planners guide here says SRM arm happened after the IUS was at least 10 miles away from the orbiter.

I dug some more and found some documentation for STS-93.  OMS-2 left Columbia in a 144.7x153.7 nmi orbit.  After deploying Chandra, Columbia performed a separation maneuver using one OMS engine for 34.0 seconds, applying a delta-V of 30 ft/sec and ending up in a 153x163 nm orbit.  IUS ignition took place one hour later.  It should be fairly simple to calculate the distance between the IUS and Columbia given this information.

Further edited: a press release stated Columbia was about 30 miles from Chandra at the time of IUS ignition.
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 07/22/2009 01:49 am
I did not know exactly what to search on to find an answer to this question, but, I have always be highly curious as to exactly how the shuttle is mated to the ET stack.

I see these V shaped rods attached to the ET and they come together at the bottom of the V and attach to the shuttle.

I suppose there is some sort of bolt and nut at the shuttle connection that explosively separates at ET separation.

So, just exactly how is this done?  I know it has to be robust to handle the weight of the shuttle, the power of the thrust of the main engines during ascent and such. When ET SEP occurs, there appears to be no evidence whatsoever that there was ever an ET attached.

Thanks for any help with this question.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/22/2009 01:55 am
http://forum.nasaspaceflight.com/index.php?topic=10600.msg331064#msg331064
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 07/22/2009 03:47 am
http://forum.nasaspaceflight.com/index.php?topic=10600.msg331064#msg331064

Okay, this really does not answer my question. I'm asking exactly _how_ the shuttle is mated to the ET.

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/22/2009 03:49 am
http://forum.nasaspaceflight.com/index.php?topic=10600.msg331064#msg331064

Okay, this really does not answer my question. I'm asking exactly _how_ the shuttle is mated to the ET.

Thanks!

The bipod at the front doesn't take the weight or thrust load, the aft struts do.  They're all connected with explosive bolts.

EDIT:  specifics:  http://forum.nasaspaceflight.com/index.php?topic=625.msg9752#msg9752
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 07/22/2009 04:16 am
Does anyone know who the female PAO is that sort of sounds like a southern cheerleader? She covered the mission after the -127 launch, and mentioned the ISS being "200 ft above the ocean" so I was curious who she was. For that matter any of the PAO's aside from Mr. Diller. Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 07/22/2009 05:07 am
and mentioned the ISS being "200 ft above the ocean"

Let's hope it's more than 200 ft above the ocean! :)

Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 07/22/2009 05:42 am
oh, it's in night glider config. ;)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/22/2009 11:08 am
Does anyone know who the female PAO is that sort of sounds like a southern cheerleader? She covered the mission after the -127 launch, and mentioned the ISS being "200 ft above the ocean" so I was curious who she was. For that matter any of the PAO's aside from Mr. Diller. Thanks.
Brandi Dean.  She's the Shuttle Orbit 2 Orbit 1 PAO for this mission:
http://www.cbsnews.com/network/news/space/127/127personnel.html

Edit -- thanks, Mach 25 -- my mistake on the shift.
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 07/22/2009 04:35 pm
http://forum.nasaspaceflight.com/index.php?topic=10600.msg331064#msg331064

Okay, this really does not answer my question. I'm asking exactly _how_ the shuttle is mated to the ET.

Thanks!

The bipod at the front doesn't take the weight or thrust load, the aft struts do.  They're all connected with explosive bolts.

EDIT:  specifics:  http://forum.nasaspaceflight.com/index.php?topic=625.msg9752#msg9752

Are these explosive bolts attached from inside the shuttle? If so, how do they gain access to this area?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/22/2009 05:32 pm

Are these explosive bolts attached from inside the shuttle? If so, how do they gain access to this area?

No, the bolts are accessible from the outside
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 07/23/2009 06:37 am
Does anyone know who the female PAO is that sort of sounds like a southern cheerleader? She covered the mission after the -127 launch, and mentioned the ISS being "200 ft above the ocean" so I was curious who she was. For that matter any of the PAO's aside from Mr. Diller. Thanks.
Brandi Dean.  She's the Shuttle Orbit 2 PAO for this mission:
http://www.cbsnews.com/network/news/space/127/127personnel.html


Brandi is working Orbit 1 for this flight.
Title: Re: Shuttle Q&A Part 5
Post by: Finn on 07/23/2009 09:53 am
The STS-127 crew has a sleep shift of 2.5 hours so far (12.03 GMT on FD2, 9.33 GMT on FD9). Is this normal, or does STS-127 have any special reason to sleep shift a lot?
Title: Re: Shuttle Q&A Part 5
Post by: dcbecker on 07/23/2009 01:12 pm
In the STS-127 FD 09 execute package at
http://www.nasa.gov/pdf/372278main_fd09_exec_pkg.pdf
on page 17 of pdf (or 3-97), there is an entry at 22:00 MET titled
"LOW BACK PAIN QUEST (ASSY OPS, PAYLOADS)". also found on pg 16, at ~22:50

is that real, or is that supposed to be a gag? what is it referring to?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/23/2009 06:48 pm
is that real, or is that supposed to be a gag? what is it referring to?

Real.  Due to the lack of gravity, the disks in the spine expand and the astronaut grows a couple of inches.  This expansion puts some strain on some back muscles and cause pain.  The questionnaire is part of a study into alleviating the pain.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 07/23/2009 10:09 pm
looking at old landing video (sts-2, 41-d, etc, etc)....why does the shuttle appear to no longer use the RCS above mach 1.  it always left contrails in the sky as quick puffs of white smoke.....i never see them anymore....has something changed?

thanks!
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 07/23/2009 10:10 pm
what was the reason for changing the color of the little "flapper doors" over the elevon hinge line from black to white?  was this a thermal issue?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/24/2009 01:36 pm
looking at old landing video (sts-2, 41-d, etc, etc)....why does the shuttle appear to no longer use the RCS above mach 1.  it always left contrails in the sky as quick puffs of white smoke.....i never see them anymore....has something changed?

thanks!

I believe those were OMS pulses and I further believe it was used to help the T-38's visually acquire the shuttle.

They weren't OMS and they weren't to help the T-38. 

They were yaw thrusters.  As far as not seeing them now days is just a coincidence, atmospheric conditions weren't conducive for seeing the pulses.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/24/2009 01:44 pm
More info already posted in previous Q&A threads:
http://forum.nasaspaceflight.com/index.php?topic=2030.msg97528#msg97528

Can think of at least one later instance than mentioned:
http://forum.nasaspaceflight.com/index.php?topic=10600.msg219529#msg219529
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 07/24/2009 11:47 pm
Figured I'd post this here rather than in the processing thread but few questions on the pull tests for the ET (not there isn't an ET QnA that I missed right?)

How often are the pull tests done?
With so many being done, couldn't that pose a hazard risk of some type, such as failure of the foam in the area, no resealing properly, etc? (sorry, messing with the ET brings lots of safety questions to my mind)
And what is the difference between NCFl foam and the BX manual spray? Does the spray work just as well as the foam?


Sorry if this is in the wrong area...

Sarah.
Title: Re: Shuttle Q&A Part 5
Post by: Davidgojr on 07/25/2009 03:16 am
Thanks for the answers to my earlier questions.  I do have a couple of others. 

How are the liquid hydrogen and oxygen generated for the shuttle? 

How are the gases generated and then subsequently cooled to cryogenic temperatures? 

Are they generated on site or transported in? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/25/2009 01:06 pm
Thanks for the answers to my earlier questions.  I do have a couple of others. 

How are the liquid hydrogen and oxygen generated for the shuttle? 

How are the gases generated and then subsequently cooled to cryogenic temperatures? 

Are they generated on site or transported in? 


There is a liquid Oxygen plant in nearby Mims FL.  It is trucked from there to the pad.  The LH2 is produced from methane in a plant in Louisana.

I would google to get the answers on the production processes.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/25/2009 06:57 pm
Can someone email me some shuttle first stage trajectory data?  I have built a tool to model how an abort system will get away from the SRB debris.

I need velocity (x and y) and altitude.  The ascent cue card doesn't have velocity  >:(

Danny Deger

Edit: Can someone point me to the SODB?  I know it is on L2 somewhere, but "search" doesn't find it.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/25/2009 07:15 pm
Probably not what you need but can you get anything from Bill Harwood's spreadsheets that he does every mission for CBS/Spaceflight Now?
Title: Re: Shuttle Q&A Part 5
Post by: tva on 07/25/2009 07:55 pm
Can someone email me some shuttle first stage trajectory data?

Check out my post !
http://forum.nasaspaceflight.com/index.php?topic=10600.msg395844#msg395844

There is a file attached with data compiled by Bill Harwood.
Title: Re: Shuttle Q&A Part 5
Post by: STS-Chris on 07/25/2009 08:37 pm
Hello!
My question is:
Why are there no more Space Shuttle Processing Status Reports on the NASA website?
The last one is from Feb. 1, 2008.
http://www.nasa.gov/centers/kennedy/shuttleoperations/status/2008/index.html
Title: Re: Shuttle Q&A Part 5
Post by: unintelligible on 07/26/2009 01:48 am
http://www.nasa.gov/home/hqnews/2009/apr/HQ_09-080_Orion_Heat_Shield.html

This press release in regards to the chosen Orion heat shield material (Avcoat ablator) states that the material was used during Apollo and "on select regions of the space shuttle orbiter in its earliest flights. "

I had never heard of this... is it true? If so, where exactly was it used and for what purpose (i.e. why weren't the usual silica tiles or thermal blankets used)?

Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/26/2009 07:13 am
Hi,
 

Hope this is in the right section.


I thought a "progres" was not allowed to dock with ISS while shuttle still there (progress 34 docking)?

Thanks
Oxford750

Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/26/2009 08:07 am
AFAIK, Progress 34 is scheduled to dock on Wednesday, one day after shuttle departs. Progress will be loitering until then.

Recall that STS-127's mission had to be modified in order to allow for the weather-delayed departure. They were originally scheduled to stay attached to ISS one day longer, but shifted some things to after departure in order to accommodate the Progress docking.
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 12:47 pm
I would be interested in the reasons why:

1) the Progress launch could not have been delayed a day or two, and, more generally
2) why it can't dock while a Shuttle is present?

With all the vehicles visiting ISS, and with all the delays they have here and there, this situation will come up again and again. Watch for STS-128 and HTV.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2009 01:04 pm

2) why it can't dock while a Shuttle is present?


Because one hit  MIR
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 01:33 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2009 01:39 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

Analyst

And post launch tile inspections are ...........

Rules like this are made when you are risk adverse.

Progress have had other instances of control problems.  But then again, the whole ISS is at risk
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 01:47 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

Analyst

1) And post launch tile inspections are ...........

2) Rules like this are made when you are risk adverse.

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

1) Correct. Because every significant damage can been seen before docking. Same for late inspections. Same for LON.

2) Yup, so it all begins. I would say extremely risk averse.

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: JosephB on 07/26/2009 03:35 pm
Why doesn't the shuttle bring up a free flying camera and/or imax to film the station/shuttle stack? The pictures would be phenomenal. Bring one up & leave it attached to the truss for servicing by arm or EVA.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2009 04:34 pm
Why doesn't the shuttle bring up a free flying camera and/or imax to film the station/shuttle stack? The pictures would be phenomenal. Bring one up & leave it attached to the truss for servicing by arm or EVA.

IMAX camera only holds 7 mins of film
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 04:38 pm
Good idea. Likely because of cost (and upmass).

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/26/2009 06:01 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

No, it's perfectly consistent. Shuttle is more fault-tolerant and has a human crew controlling it, so its approach is safer than Progress. Period.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/26/2009 06:46 pm
IMAX camera only holds 7 mins of film
IIRC, the STS-125 crew only shot 4 "reels" (28 min.) of Hubble. If I had to guess, I'd say another IMAX will be going up before shuttle retirement to capture the completed station during the traditional post-docking 'flyaround'. I sure hope so.

What would *really* be cool would be a mini-satellite with a Hi-Def video camera that could be used for maintenance views of areas not covered by any of the fixed cameras. It could also produce some great gee-wiz shots of the entire station. When not in use, the satellite could simply be 'parked' nearby, or retrieved via the Kibo hatch for battery changeouts. Wait -- of course! Make that two cameras for 3D.

Sorry... just dreaming a bit.
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 07/26/2009 07:19 pm
May be a crazy question but has the shuttle fleet ever been photographed together? Would be more of a PR picture than nessessity, but I thought it would be interesting to see if there was a picture out there.  I googled for it and nothing came up.

If not, upon shuttle retirement, it'd be nice to see the three side by side for a picture.

Sorry if the question in far fetched and the suggestion crazy (cost money, not needed, etc) just thinking out loud of pictures I'd like to see and possibly have to frame.
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 07:31 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

No, it's perfectly consistent. Shuttle is more fault-tolerant and has a human crew controlling it, so its approach is safer than Progress. Period.

No. You completely misunderstood. This has nothing to do with a Shuttle docking. This is about Progress being allowed to dock with ISS only when a Shuttle is not present.

So Progress is is safe enough (redundancy etc.) to dock with ISS, worth tens of billions of dollars, with 6 folks on board. But it is not safe enough to dock when a Shuttle is present at the very same ISS. This is inconsistent. Eighter it is safe enough in both situation or in none. Period. Period.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: tva on 07/26/2009 07:39 pm
Because one hit MIR

If a visiting vehicle hits the docked shuttle, she would be very likely unable to reenter (and bring home its crew wich is more than half of the astronauts present on the station). The same accident might as well demage the PMA and station as well...

So you have at least 13 stranded people with 2 soyuz and limited time and resources. Not a desirable situation ???
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/26/2009 07:41 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

No, it's perfectly consistent. Shuttle is more fault-tolerant and has a human crew controlling it, so its approach is safer than Progress. Period.

No. You completely misunderstood. This has nothing to do with a Shuttle docking. This is about Progress being allowed to dock with ISS only when a Shuttle is not present.

So Progress is is safe enough (redundancy etc.) to dock with ISS, worth tens of billions of dollars, with 6 folks on board. But it is not safe enough to dock when a Shuttle is present at the very same ISS. This is inconsistent. Eighter it is safe enough in both situation or in none. Period. Period.

Incorrect, Analyst. I have explained this before. The auto-abort function in Kurs is designed to protect the station. It does not and cannot account for the presence of a docked shuttle. If Kurs detects a fault condition and auto-aborts, there is no guarantee it will not auto-abort in the direction of the shuttle, and there may be insufficient time or comm for the ISS crew to take over with TORU and avert a collision.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/26/2009 07:52 pm
Progress can be manually docked (with KURS deactivated), but to consider this while shuttle is docked would certainly be off-nominal. The only reason I can imagine this scenario might ever be considered is if the current Progress were carrying a supply or component that suddenly became critical due to some sort of failure. For example, someone accidentally flushed the last packet of hot sauce down the toilet :'(
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/26/2009 08:25 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

No, it's perfectly consistent. Shuttle is more fault-tolerant and has a human crew controlling it, so its approach is safer than Progress. Period.

No. You completely misunderstood. This has nothing to do with a Shuttle docking. This is about Progress being allowed to dock with ISS only when a Shuttle is not present.

So Progress is is safe enough (redundancy etc.) to dock with ISS, worth tens of billions of dollars, with 6 folks on board. But it is not safe enough to dock when a Shuttle is present at the very same ISS. This is inconsistent. Eighter it is safe enough in both situation or in none. Period. Period.

Incorrect, Analyst. I have explained this before. The auto-abort function in Kurs is designed to protect the station. It does not and cannot account for the presence of a docked shuttle.

Sounds like an excuse to me. This system can abort safely from the ever growing station (100m by 70m or so), but can't when the station is yet a little bigger because of a present Shuttle? Or to put it differently: Progress would barely miss PMA-2, or a solar array, but hit the Shuttle if present?

Wouldn't it be much easier if this system assumes the station is a little bigger? Would ease operations.

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/26/2009 08:43 pm
Very stupid (non) reason. (I talk about the reason, not about your answer.)

3) Progress have had other instances of control problems.  But then again, the whole ISS is at risk

3) Yes, the whole ISS is at risk and this is o.k., but not for Shuttle. Inconsistent. Shouldn't we stop all docking operations with ISS (Progress and all other vehicles)? Would be safer.

No, it's perfectly consistent. Shuttle is more fault-tolerant and has a human crew controlling it, so its approach is safer than Progress. Period.

No. You completely misunderstood. This has nothing to do with a Shuttle docking. This is about Progress being allowed to dock with ISS only when a Shuttle is not present.

So Progress is is safe enough (redundancy etc.) to dock with ISS, worth tens of billions of dollars, with 6 folks on board. But it is not safe enough to dock when a Shuttle is present at the very same ISS. This is inconsistent. Eighter it is safe enough in both situation or in none. Period. Period.

Incorrect, Analyst. I have explained this before. The auto-abort function in Kurs is designed to protect the station. It does not and cannot account for the presence of a docked shuttle.

Sounds like an excuse to me.

Sounds like ignorance to me.

Quote
This system can abort safely from the ever growing station (100m by 70m or so), but can't when the station is yet a little bigger because of a present Shuttle? Or to put it differently: Progress would barely miss PMA-2, or a solar array, but hit the Shuttle if present?

Quote
Wouldn't it be much easier if this system assumes the station is a little bigger? Would ease operations.

It is not a matter of size as much as arrangement. The station is mostly "in front of" the Progress, while the shuttle "breaks the plane".
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/27/2009 01:33 am
Thanks for the correction folks, I missed that.


"For example, someone accidentally flushed the last packet of hot sauce down the toilet" 


That is FUNNY


Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Ron Carlson on 07/27/2009 01:55 pm

Edit: Can someone point me to the SODB?  I know it is on L2 somewhere, but "search" doesn't find it.

Will these do?

http://spaceflight.nasa.gov/shuttle/reference/sodb/


Shuttle Operational Data Book

These pages are in Portable Document Format (.PDF). You must have the Adobe Acrobat Reader software installed on your computer to view them.

# Left side of the Orbiter

    * Moldline penetrations/access panels/markings (296K)
    * Exterior finish/external insulation - OV102, Columbia - TBS (144K)
    * Exterior finish/external insulation - OV103 (Discovery), OV104 (Atlantis) and OV105 (Endeavour) (176K)
    * Structure (288K)
    * Structure - pg (248K)
    * Structure - sc (200K)
    * Component/system location (256K)

# Right side of the Orbiter

    * Moldline penetrations/access panels/markings (272K)
    * Exterior finish/external insulation - OV102, Columbia - TBS (240K)
    * Exterior finish/external insulation - OV103 (Discovery), OV104 (Atlantis), OV105 (Endeavour) (176K)
    * Structure (160K)
    * Structure - alt (248K)
    * Component/system location (280K)

# Top view of the Orbiter

    * Moldline penetrations/access panels/markings (176K)
    * Exterior finish/external insulation - OV102, Columbia - TBS (440K)
    * Exterior finish/external insulation - OV103 (Discovery), OV104 (Atlantis), OV105 (Endeavour) (360K)
    * Structure (248K)
    * Component/system location (152K)

# Bottom view of the Orbiter

    * Moldline penetrations/access panels (128K)
    * Exterior finish/external insulation - all vehicles (344K)
    * Structure (208K)
    * Component/system location (264K)

# Aft view of the Orbiter

    * Moldline penetrations/access panels (96K)
    * Exterior finish/external insulation - all vehicles< (104K)

# Orbiter structure (512K)
# Wiring locator

    * Forward fuselage (584K)
    * Mid- and aft fuselage (208K)
    * Mid- and aft fuselage - bw (176K)

# Electrical power system component/line locator

    * Electrical power system component/line locator (272K)
    * Electrical power system component/line locator - cl (312K)

# Environmental control and life support system component/line locator

    * Purge/conditioning/air revitalization systems ducting (360K)
    * Forward fuselage coolant/air revitalization components (264K)
    * Forward fuselage coolant/air revitalization components1 - alt (256K)
    * Mid- and aft fuselage coolant system (400K)
    * Mid- and aft fuselage coolant system - alt (472K)

# Hydraulic system component/line locator

    * Hydraulic system component/line locator (336K)
    * Hydraulic system component/line locator - bw (296K)

# Auxiliary power system component/line locator

    * Auxiliary power system component/line locator (408K)
    * Auxiliary power system component/line locator - bw (304K)

# Reaction control subsystem component/line locator

    * Forward reaction control subsystem (896K)
    * Forward reaction control subsystem - bw (720K)
    * Forward reaction control subsystem - cl (896K)
    * Aft reaction control subystem (504K)
    * Aft reaction control subystem - bw (392K)
    * Aft reaction control subystem - cl (512K)

# Orbital maneuvering system component/line locator

    * OMS components/lines (344K)
    * OMS components/lines - cl (352K)
    * OMS crossfeed (152K)
    * OMS crossfeed - bw (144K)
    * OMS crossfeed - cl (160K)

# Main propulsion system component/line locator

    * Main propulsion system component/line locator (616K)
    * Main propulsion system component/line locator - bw (568K)
    * Main propulsion system component/line locator - cl (624K)



Ron Carlson
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/27/2009 11:45 pm
Hi folks:

1)What is METOX?

2) why were two coverings taken off parts of pieces, then jettisoned into space?   Where they dropped?
I mean they could have been brought in and put with the other "space junk.


Thanks
Oxford570
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/28/2009 08:16 am
Hi folks:

Why is an astronaut always on capcom, I mean they all speak english don't they?

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 07/28/2009 12:23 pm

On a similar line - what happened to Aercam (Sprint).


Try your search again - you might have spelled it wrong or something? Boatloads of threads came back when I just tried it using "aercam"

http://forum.nasaspaceflight.com/index.php?topic=3696.0
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 07/28/2009 01:26 pm
I would really like to look at a diagram showing how did Columbia's Crew Cabin got open in case the ejection seats were used... I just find so hard to imagine how a pressurized, space-worth and TPS-covered cabin could just open a hole in the upper part of the assembly... A photo, an image, a diagram will be appreciated!! Thanks a lot!!
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 07/28/2009 01:51 pm
Don't think this has been answered yet so here is my question.
Challenger had the major malfunction during its launch. I heard that it was "Blown Up" to keep the debris farther away from the audience or something. Is that true or was the entire explosion just from the O-Ring seal problem?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/28/2009 02:01 pm
Don't think this has been answered yet so here is my question.
Challenger had the major malfunction during its launch. I heard that it was "Blown Up" to keep the debris farther away from the audience or something. Is that true or was the entire explosion just from the O-Ring seal problem?

Thanks

Range safety sent the destruct signals
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/28/2009 02:12 pm
Don't think this has been answered yet so here is my question.
Challenger had the major malfunction during its launch. I heard that it was "Blown Up" to keep the debris farther away from the audience or something. Is that true or was the entire explosion just from the O-Ring seal problem?

Thanks

The explosion was just from the O-ring seal problem. The SRBs were destroyed almost 40 seconds later by RSO.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/28/2009 02:27 pm
Hi folks:

Why is an astronaut always on capcom, I mean they all speak english don't they?

Others have mentioned why it is desirable to centralize comm at one individual on the ground. CAPCOM and FD ensure that comm is properly prioritized and is presented using consistent terminology the crew understands.

Not all ISS capcoms are astronauts; for off-shifts and weekends ISS training leads serve as capcoms. Shuttle CAPCOMs are always astronauts.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/28/2009 02:31 pm
Don't think this has been answered yet so here is my question.
Challenger had the major malfunction during its launch. I heard that it was "Blown Up" to keep the debris farther away from the audience or something. Is that true or was the entire explosion just from the O-Ring seal problem?

Thanks

The explosion was just from the O-ring seal problem. The SRBs were destroyed almost 40 seconds later by RSO.
No explosion whatsoever. What looks like an explosion cloud is nothing other than burning gases from the destroyed ET.

No shock waves or any other effects associated with an explosion was present. The orbiter broke up due to aerodynamic stresses on the airframe exceeding the capabilities of the airframe.

The SRBs did not show any effects of any explosions. They were intact and continued to burn until the RSO sent the destruct commands. Only then, the SRBs stopped burning.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/28/2009 04:22 pm
Don't think this has been answered yet so here is my question.
Challenger had the major malfunction during its launch. I heard that it was "Blown Up" to keep the debris farther away from the audience or something. Is that true or was the entire explosion just from the O-Ring seal problem?

Thanks

The explosion was just from the O-ring seal problem. The SRBs were destroyed almost 40 seconds later by RSO.
No explosion whatsoever. What looks like an explosion cloud is nothing other than burning gases from the destroyed ET.

Yes, a deflagration.

Quote
No shock waves or any other effects associated with an explosion was present.

Shock waves are associated with detonations.

The term "explosion" is colloquially applied to both deflagrations and detonations. It is therefore proper to use the term when communicating with non-technical people, as I did here, and will continue to do.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 07/28/2009 04:28 pm
Is a shockwave impossible with LOX/LH2 or did it just not happen in the case of Challenger? I was under the impression that the old hypergolic launchers didn't need escape rockets because they couldn't detonate because the propellant couldn't mix properly and would only burn at the two dimensional interface.
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 07/28/2009 04:41 pm
Technically, you can get a detonation with H2/O2 if it's well-mixed and an ignition source is present after they mix. What happened with Challenger is the LOX tank at the top and LH2 tank at the bottom kept the propellants separated, tanks failed at roughly the same time and H2 got ignited fast, before good mixing could occur.

That's one of the reasons why it's hard to predict what a total destructive power of a catastrophic vehicle explosion would be. Saturn V carried some 3000 tons of propellants, a good bit of that was high energy LH2 and yet the estimated explosive power if it got unleashed was estimated at around 0.5 kilotons TNT equivalent. Even though LH2/LOX combo alone has more energy per kg than TNT, IIRC.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/28/2009 05:10 pm
Is a shockwave impossible with LOX/LH2 or did it just not happen in the case of Challenger? I was under the impression that the old hypergolic launchers didn't need escape rockets because they couldn't detonate because the propellant couldn't mix properly and would only burn at the two dimensional interface.

Tests have shown hydrogen can give you a blast because it can mix then go off.  Worst case it probably about 4% will go off in a blast.  The Apollo 8 upperstage went off on a test stand an blew everything into little pieces.  Good thing it didn't happen on the flight.  I looked for photos of the remains of the stage and test stand, but I couldn't find any. 

Hypergolics will never mix first.  They always ignite at first contact.  Gemini did not protect the crew from blast, that is why they could use ejection seats instead of a tower.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 07/28/2009 06:12 pm
That's one of the reasons why it's hard to predict what a total destructive power of a catastrophic vehicle explosion would be.

The best is for radioactive (RTG) launches.  They assume a full-stack, inverted powered flight into the ground.  NFW it would ever happen, but they do it anyway.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/29/2009 12:45 am
1)What is METOX?

Metal Oxide == refers to the technology used for recyclable CO2 scrubbing canisters. The crew bakes them in a special oven to release the CO2 to the station's atmosphere, which is then removed by one of the central scrubbers.

Quote
2) why were two coverings taken off parts of pieces, then jettisoned into space?   Where they dropped? I mean they could have been brought in and put with the other "space junk.

This question came up in one of the briefings. Those that weren't needed were thrown overboard to save the time/hassle of trying to wiggle them into a storage bag. Because of their low mass, they will reenter in a matter of days, IIRC, rather than becoming a long-term debris risk.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/29/2009 12:57 am
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 07/29/2009 01:39 am

Tests have shown hydrogen can give you a blast because it can mix then go off. 

in about 90% of the jobs that we do one of the first steps we do before we open the system is to verify that the system is at less than 1% H2 and less than 1% O2. Then while the system is open it is purged with GN2/GHe to prevent air intrusion. The reason is to prevent what is called an "in-line detonation" which can, if severe enough, damage or destroy equipment. I've seen photos of one such detonation that occured in a vent line at Stennis. Every 90 degree turn in the line was split or blown out from the shockwave traveling through the line, since the shockwave resists sharp turns. Earlier this year we actually had a detonation for the first time that anyone could remember. We were between waves during tankers and got shut down for weather. It was an extremely windy day (at least 30 knot sustained winds) with a hot (H2 rich) vent line since we vent to the flare stack during tankers. We were in the shop and kept hearing this weird noise that sounded like something hitting the side of the shop, about every 15 mins or so, but couldn't figure out what it was. What was happening was that due to the low pressure in the line from no flow the wind was blowing out the flame and actually blowing air back into the line. It would mix, then the pressure would finally build enough to push the mixture out of the line, where it would ignite when it hit the propane igniters. We finally got the all clear to continue so we went back out and continued tanker offload. When tankers were done flow slowed again, but with an enriched line the wind blew it out again. This time when it lit it sounded like a bomb going off. It actually knocked all of the frost off the line all the way back to the storage area. Definately got our attention. There was alot of leak checking and inspections after that to make sure nothing was damaged.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/29/2009 01:44 am
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

Just to clarify, *ISS* CAPCOMs during shuttle missions are often members of the ISS backup crew. Shuttle missions themselves do not have backup crews.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/29/2009 02:40 am

Tests have shown hydrogen can give you a blast because it can mix then go off. 

in about 90% of the jobs that we do one of the first steps we do before we open the system is to verify that the system is at less than 1% H2 and less than 1% O2. Then while the system is open it is purged with GN2/GHe to prevent air intrusion. The reason is to prevent what is called an "in-line detonation" which can, if severe enough, damage or destroy equipment. I've seen photos of one such detonation that occured in a vent line at Stennis. Every 90 degree turn in the line was split or blown out from the shockwave traveling through the line, since the shockwave resists sharp turns. Earlier this year we actually had a detonation for the first time that anyone could remember. We were between waves during tankers and got shut down for weather. It was an extremely windy day (at least 30 knot sustained winds) with a hot (H2 rich) vent line since we vent to the flare stack during tankers. We were in the shop and kept hearing this weird noise that sounded like something hitting the side of the shop, about every 15 mins or so, but couldn't figure out what it was. What was happening was that due to the low pressure in the line from no flow the wind was blowing out the flame and actually blowing air back into the line. It would mix, then the pressure would finally build enough to push the mixture out of the line, where it would ignite when it hit the propane igniters. We finally got the all clear to continue so we went back out and continued tanker offload. When tankers were done flow slowed again, but with an enriched line the wind blew it out again. This time when it lit it sounded like a bomb going off. It actually knocked all of the frost off the line all the way back to the storage area. Definately got our attention. There was alot of leak checking and inspections after that to make sure nothing was damaged.

And some people think we will be putting this stuff in cars at gas stations someday.  I think not. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/29/2009 02:53 am
1)What is METOX?

Metal Oxide == refers to the technology used for recyclable CO2 scrubbing canisters. The crew bakes them in a special oven to release the CO2 to the station's atmosphere, which is then removed by one of the central scrubbers.

Quote
2) why were two coverings taken off parts of pieces, then jettisoned into space?   Where they dropped? I mean they could have been brought in and put with the other "space junk.

This question came up in one of the briefings. Those that weren't needed were thrown overboard to save the time/hassle of trying to wiggle them into a storage bag. Because of their low mass, they will reenter in a matter of days, IIRC, rather than becoming a long-term debris risk.

Thanks for answering my questions ginahoy.

As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Makes no sense to me, if that is the case.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/29/2009 03:07 am
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.

Thanks again ginahoy.

I just thought that "anybody" at mission control in Houston that works on the specific mission (i.e. STS-127) can speak to the astronauts as  most of MCC-H know the mission "like the back of tere hand",but you had good answer to things I never thought of.


oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/29/2009 03:42 am
Why is an astronaut always on capcom, I mean they all speak english don't they?

Not sure who you mean by "they", but astronauts are uniquely qualified to serve as the communications liaison between the on-orbit crew and the flight control team. They're not just reading a script. During shuttle missions, they are often members of the back-up crew, so they will be familiar with all aspects of the mission.

It is my observation that capcoms during shuttle missions are always astronauts while ISS stage operations sometimes have non-astronaut  capcoms. That's probably just a function of the large number of hours during stage operations.

Thanks again ginahoy.

I just thought that "anybody" at mission control in Houston that works on the specific mission (i.e. STS-127) can speak to the astronauts as  most of MCC-H know the mission "like the back of tere hand",but you had good answer to things I never thought of.

Flight controllers are trained as specialists. Astronauts are generalists. A flight controller will not necessarily have any training in systems outside their particular console position. They know their systems like the backs of their hands, and they know how their system fits into the big picture of the mission, but that does not grant them particular insight into other systems nor to communicate those insights to the crew.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/29/2009 03:49 am
snip

Flight controllers are trained as specialists. Astronauts are generalists. A flight controller will not necessarily have any training in systems outside their particular console position. They know their systems like the backs of their hands, and they know how their system fits into the big picture of the mission, but that does not grant them particular insight into other systems nor to communicate those insights to the crew.

Why don't we just pump the flight loop up to the crew and let them sort that mess out  :o

Just kidding.  It takes years of training to learn to listen to that chatter. 

An experienced instructor might make a better capcom than an experienced flight controller.  At least the instructor speaks the language of the flight crews.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/29/2009 05:43 am
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/29/2009 06:08 am
Why is thr ISS "red".

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/29/2009 06:35 am
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.


So are you saying that two idenical cases in orbit, -one lighter than the other-,  that the lighter one will fall faster.

OR


something that is round and flat (ie a cover or blanket) will fall faster because of its shape?

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/29/2009 07:20 am
As for question 2: Am I to assume then that something that is bigger and has a higher mass will stay in orbit longer?

Lightweight objects loose energy quicker due to atmospheric drag. Remember, there's enough atmosphere still present at 220 miles to cause the space station to require periodic reboost.


So are you saying that two idenical cases in orbit, -one lighter than the other-,  that the lighter one will fall faster.

OR


something that is round and flat (ie a cover or blanket) will fall faster because of its shape?

Oxford750

It is a combination of size, shape, and weight.  But for the most part, small objects slow down at a faster rate.  Having said this, a 100 pound object the size of a school bus will probably slow down faster than a 10 pound metal sphere.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/29/2009 11:15 am
Why is thr ISS "red".

Oxford750

I could be wrong but I think that means the system isn't pulling in any data for range and rate?
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 07/29/2009 02:05 pm
As for falling out of orbit, look up ballistic coefficient or ballistic number.

http://en.wikipedia.org/wiki/Ballistic_coefficient
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 07/29/2009 02:15 pm

And some people think we will be putting this stuff in cars at gas stations someday.  I think not. 

Danny Deger

Well, I wouldn't necessarily say that. I'm one all for a hydrogen society. It will just take a learning and education process like it was for gasoline way back when. We will develop processes and safety guidelines, develop new specialized hardware and safety equipment. I'm sure there will be accidents and we will learn from them. It's just that, here, we work for a government entity that has it's own safety regulations, industry-wide safety regulations, and we are dealing with a much, much larger amount of commodity that most of the public will ever have to at one time.
Title: Re: Shuttle Q&A Part 5
Post by: kenny008 on 07/29/2009 05:24 pm
A quick question on astronaut training:

When using the Shuttle Mission Simulator, does the crew periodically wear their ACES suits?  I'm sure they don't wear them for every session, but I'm curious to know whether they often get the chance to practice reacting to anomalies while wearing the full flight suit.  It seems like this can make quite a difference in their learned automatic responses if they practice in the simulator differently than when in actual flight.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/29/2009 05:49 pm
A quick question on astronaut training:

When using the Shuttle Mission Simulator, does the crew periodically wear their ACES suits?

Yes.
Title: Re: Shuttle Q&A Part 5
Post by: darren1 on 07/29/2009 10:32 pm
Ok, apologies for this but I HAVE looked (as much as I will at bed time :) ) , but when was STS-134 announced???  I thought the schedule went to STS-133 but the NASA site is showing an additional flight for launch on Sept 16th.  Cant believe I'm the 1st to see this but can not see a thread?????

Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 07/29/2009 10:42 pm
Darren1,

Officially, about a year ago. It started out as the LON mission for STS-133 before being confirmed via an Act of Congress which mandated the delivery of AMS-2 to the ISS.  STS-134 is currently scheduled to launch BEFORE STS-133 in July 2010 on Endeavour with STS-133 on Discovery following in September 2010.   STS-335 (on Atlantis) is scheduled to be the LON flight for STS-133 now.
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 07/29/2009 11:03 pm
Ok, apologies for this but I HAVE looked (as much as I will at bed time :) ) , but when was STS-134 announced???  I thought the schedule went to STS-133 but the NASA site is showing an additional flight for launch on Sept 16th.  Cant believe I'm the 1st to see this but can not see a thread?????



http://www.nasaspaceflight.com/tag/sts-134
http://www.nasaspaceflight.com/tag/sts-133

Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 07/30/2009 05:04 pm
I have two shuttle-related questions:
1) To what extent if any was the orbiter weight constrained by the 747 ferry requirement when the sts was being designed?
2) In an emergency, could an astronaut make a brief spacewalk in the current ACES, being that it's a full-pressure suit?
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 07/30/2009 05:37 pm
Has there ever been a shuttle landing at KSC while a shuttle rollout was in progress?
Title: Re: Shuttle Q&A Part 5
Post by: Analyst on 07/30/2009 06:37 pm
Well, there have been many shuttle landings a split of a second before the shuttle rolling out, but ... this is not your question. ;)

Analyst
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/30/2009 07:37 pm
I have two shuttle-related questions:
1) To what extent if any was the orbiter weight constrained by the 747 ferry requirement when the sts was being designed?
2) In an emergency, could an astronaut make a brief spacewalk in the current ACES, being that it's a full-pressure suit?

1. no. 

2.  no. 
Title: Re: Shuttle Q&A Part 5
Post by: butters on 07/30/2009 11:58 pm
How does the orbiter's onboard flight simulator work? For example, when they practice entry and landing before deorbit, do they throw switches on the flight deck control panels?  How is the simulation environment isolated from the flight environment?  Is it just a GPC video game that temporarily takes over the rotational hand controller?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/31/2009 12:13 am
How does the orbiter's onboard flight simulator work? For example, when they practice entry and landing before deorbit, do they throw switches on the flight deck control panels?  How is the simulation environment isolated from the flight environment?  Is it just a GPC video game that temporarily takes over the rotational hand controller?

separate laptop with separate handcontroller
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/31/2009 12:35 am

And some people think we will be putting this stuff in cars at gas stations someday.  I think not. 

Danny Deger

Well, I wouldn't necessarily say that. I'm one all for a hydrogen society. It will just take a learning and education process like it was for gasoline way back when. We will develop processes and safety guidelines, develop new specialized hardware and safety equipment. I'm sure there will be accidents and we will learn from them. It's just that, here, we work for a government entity that has it's own safety regulations, industry-wide safety regulations, and we are dealing with a much, much larger amount of commodity that most of the public will ever have to at one time.

You are the expert on this stuff, so you give me a ray of hope.  Is the goal liquid or compressed gas.  I understand there some prototype stations working today.

But, I don't recall there ever being that big of an issue in handling gasoline into cars.  Heck, we don't even ground our cars like we do planes.  It takes about 5 seconds to teach someone to gas up a car.  If there is a big spill (which there are), it doesn't quickly boil into an explosive cloud.  Detonating a cloud is really, really bad.  Probably a gallon turning into vapor will level a whole gas station when it goes off.

I can't imagine my ex ever gassing up her car with liquid hydrogen  :o

In my opinion, even liquid propane is something that shouldn't be taken lightly. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: jiehrlich on 07/31/2009 04:38 am
Here's a question before it gets busy:

Are there any photos online of the egress process?   Since the hatch opens on the left side when the orbiter is on the pad, I presume that it opens downward on the runway.   There must be some interesting hardware to accommodate that...
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/31/2009 05:40 am
Is there an article (for the layman like me) that explains in which direction each thruster fires, and which way it would make the shuttle move?

I know what the OMS engines do, but what about the others?

If one OMS engine failed for any reason, would firing just one for a "longer" period be enough or would that induce a yaw as the other one can't compensate?

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/31/2009 08:38 am
Is there an article (for the layman like me) that explains in which direction each thruster fires, and which way it would make the shuttle move?

I know what the OMS engines do, but what about the others?

If one OMS engine failed for any reason, would firing just one for a "longer" period be enough or would that induce a yaw as the other one can't compensate?

Thanks
Oxford750

Attaching a diagram from the Shuttle Crew Operations Manual which should explain things.


Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 07/31/2009 10:07 am
Here's a question before it gets busy:

Are there any photos online of the egress process?   Since the hatch opens on the left side when the orbiter is on the pad, I presume that it opens downward on the runway.   There must be some interesting hardware to accommodate that...
I'm not sure that's ever been documented, even as far back as the Enterprise landing tests (where they exited via a mostly regular airline mobile stairway).
From STS-1-on, the hatch area has been covered and I can't recall ever seeing any pics of the hatch being opened. or of any crew exiting after a mission.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/31/2009 12:25 pm

1.  If one OMS engine failed for any reason, would firing just one for a "longer" period be enough or

2. would that induce a yaw as the other one can't compensate?


1. yes

2.  The nozzle can be gimbaled to avoid yaw.  Also there many times where only one engine is needed
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/31/2009 12:32 pm
Here's a question before it gets busy:

Are there any photos online of the egress process?   Since the hatch opens on the left side when the orbiter is on the pad, I presume that it opens downward on the runway.   There must be some interesting hardware to accommodate that...
I'm not sure that's ever been documented, even as far back as the Enterprise landing tests (where they exited via a mostly regular airline mobile stairway).
From STS-1-on, the hatch area has been covered and I can't recall ever seeing any pics of the hatch being opened. or of any crew exiting after a mission.


It isn't anything complex.  The top platform of the stairway has an compartment for the hatch.   The cover of the compartment serves at the platform where the workers and crew walk on.

The hatch, when open, fits inside the compartment and then it is covered by the platform
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/31/2009 12:42 pm
Thanks Jim.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/31/2009 01:37 pm
Is there an article (for the layman like me) that explains in which direction each thruster fires, and which way it would make the shuttle move?

I know what the OMS engines do, but what about the others?

If one OMS engine failed for any reason, would firing just one for a "longer" period be enough or would that induce a yaw as the other one can't compensate?

Thanks
Oxford750

If one fails the other can very easily take up the job with a longer burn.  The system was designed to do this.  With a single engine OMS burn the single engine is fired through the center of gravity, which creates no yawing or pitching moments.  IIRC, RCS roll jets are used to correct for any roll that might creep in.

For a two engine burn, both engines are put parallel to the body (not through the c.g.).  This is OK, but they counter each other and no yaw results.  For roll control, one goes up, and one goes down. 

If things get really bad, the OMS propellant can be piped to the RCS jets and they can be used.  Not as efficient though.  For one thing they are NOT perfectly through the c.g. and when they are burned, some pitch jet firing is always needed to take care of pitch control.
They will not give the same delta V for the same propellant load. 

I don't remember if the rules require there always be enough prop to do an RCS burn if needed.  I think they do.  This gets complex fast, because you can do things like get by with a lesser burn and compensate by hitting the atmosphere at 90 degrees of bank instead of the typical wings level.  I think this saves about 800 pounds of propellant.  I actually put in a cost saving suggestion once to start doing this nominally to increase ascent performance.   I was a new instructor.  This action, did not make the flight controller happy with me.  There was a lot of undue concern that "pre-bank" would increase shuttle heating.  The story of this confusion, has to wait for another day.  It is fairly long and complex, and I have to watch David Wolf  and his team get back home.

Danny Deger

P.S.  I think the good SODB is on L2 somewhere.  I can't find it.  I don't mean the cheesy one on the internet that is basically a bunch of pictures.  I mean the one that reads like an owners manual for the shuttle.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/31/2009 04:49 pm
Would love to hear the rest of that story, Danny. So you were advocating the use of prebank as a nominal procedure? What happens then if you underburn? :)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/31/2009 05:28 pm
Would love to hear the rest of that story, Danny. So you were advocating the use of prebank as a nominal procedure? What happens then if you underburn? :)

I was advocating nominal prebank entry.  Response to an underburn was one of the problems.  Underburn prebank was not an official reserve for OMS problems, but it was considered a hip pocket reserve.  I argued it should be put in the rules if it was used as such. 

On the heating confusion, if a prebank is required as the result of an underburn, the orbiter is own a high energy profile.  This results in a high temp entry.  Because we often did under burn prebank cases in training, the world got to have a one on one association with prebanks and overtemps.  This is what I was taught.

Nominal prebanks were not in the card deck, so we didn't see them.  They were allowed in the flight rules for OMS propellant failures, but never trained because the case was and is much harder to get in the simulator.  It is also pretty much a long sim run, that isn't done much. 

I was told the inventor of Entry Guidance, Jon Harpold, would never even think of nominal prebanks.  At the time he was head of MOD, so picking up the phone and calling him was not to be taken lightly.  I finally did and he basically said, "Not really a problem now.  Early in the program, I wanted a wings level entry because it was steeper and more tolerant to any errors in the system.  Now that we have flown many times, I don't think coming in with 90 degrees of bank would be a problem.  We know enough about all the errors, the shallower entries would be OK.  And you are correct a planned perbank entry has the same temperatures"

Shortly after this conversation, I wrote the cost saving suggestion which basically got thrown back into my face.  I realize just writing the suggestion, was not good for my career.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 07/31/2009 05:51 pm
http://www.spacetransportnews.com/ (http://www.spacetransportnews.com/) had a link today to an MIT Open Courseware video course (http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/index.htm) on the Space Shuttle with lots of prominent designers who were involved with the design of the shuttle. Lecture #9 is about the OMS, RCS, APU and hydraulics and it briefly discusses using RCS for the deorbit burn. It's a great course, highly recommended.

There's also a great document (http://www.shuttlepresskit.com/scom/218.pdf) on Shuttle OMS and RCS on http://www.shuttlepresskit.com/ (http://www.shuttlepresskit.com/).
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/31/2009 06:20 pm
That document you linked is from the SCOM, the full version of which is on L2.

Thanks for the lecture though, looks great!
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/31/2009 06:21 pm
Thanks for the write up, Danny. What was your plan for any underburn, then? If an engine quits before the targets are met, then you can't prebank anymore.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 07/31/2009 06:26 pm
That document you linked is from the SCOM, the full version of which is on L2.

Thanks for that!
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 07/31/2009 06:35 pm
Has there ever been a shuttle landing at KSC while a shuttle rollout was in progress?

I do not believe an orbiter has ever landed while another Shuttle vehicle was rolling out to the pad.  However, there was an instance where one Orbiter landed while the next Shuttle's crew was in their vehicle conducting their TCDT.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 07/31/2009 10:49 pm
Is there an article (for the layman like me) that explains in which direction each thruster fires, and which way it would make the shuttle move?

I know what the OMS engines do, but what about the others?

If one OMS engine failed for any reason, would firing just one for a "longer" period be enough or would that induce a yaw as the other one can't compensate?

Thanks
Oxford750

Attaching a diagram from the Shuttle Crew Operations Manual which should explain things.





Thanks elmarko.

Would't  the body flap negate the momentum of the plumes of thrusters: R4D,R2D,R3d,L4D,L2D,L3D or can the body flap move down 90 degrees, or is it there just to protect the engines

Thanks

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/31/2009 11:22 pm

Would't  the body flap negate the momentum of the plumes of thrusters: R4D,R2D,R3d,L4D,L2D,L3D or can the body flap move down 90 degrees, or is it there just to protect the engines

The body flap is there for entry control. It happens to protect the main engines but that is not what it's there for.

The left and right down-firing thrusters you listed are canted outward. Body flap impingement does cancel some of their thrust, but not enough to be a problem.

Body flap impingement is more noticeable on the down-firing aft vernier thrusters (L5D, R5D) since they point straight down rather than being canted to the sides. They lose almost 40% of their thrust. Still not a problem, though.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 08/01/2009 01:39 am

You are the expert on this stuff, so you give me a ray of hope.  Is the goal liquid or compressed gas.  I understand there some prototype stations working today.

But, I don't recall there ever being that big of an issue in handling gasoline into cars.  Heck, we don't even ground our cars like we do planes.  It takes about 5 seconds to teach someone to gas up a car.  If there is a big spill (which there are), it doesn't quickly boil into an explosive cloud.  Detonating a cloud is really, really bad.  Probably a gallon turning into vapor will level a whole gas station when it goes off.

I can't imagine my ex ever gassing up her car with liquid hydrogen  :o

In my opinion, even liquid propane is something that shouldn't be taken lightly. 

Danny Deger

Most of the concepts I've seen deal with compressed gas. Would probably be similar to gassing a vehicle with propane or LNG nowadays.

One other thing to keep in mind is that hydrogen dissipates much faster than gasoline does. The liquid boils so fast you would probably never see it, just vapor. The biggest concern is if it is in an enclosed space or covered area, so it accumilates more and won't disperse as quickly. Then you may have quite a safety hazard. But for the most part, most experts say that hydrogen is overall safer than gasoline. Biggest concern is the large flammability range (4-74%).

BTW, if anyone is interested, there's a website I've found to be very informative on hydrogen and related topics (hydrogen cars, etc.)

http://www.hydrogenassociation.org
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/01/2009 07:26 pm
Thanks for the write up, Danny. What was your plan for any underburn, then? If an engine quits before the targets are met, then you can't prebank anymore.

I'm not sure I completely understand your question's context, by definition the enigne quiting early would result in an underburn.  Which engine are you talking about - an OMS engine?  In that case you down-mode to other options such as RCS Completeion, Recovery Pre-bank & Landing Site Redesignation(for ex: can't make KSC then maybe redes to Gander or Shannon).

Entry Flight Procedures Handbook explains much of this in section 4.  Chris has a semi current version although it is not accurate about the KSC re-des options since those procedures are relatively new.

Mark Kirkman

 
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/01/2009 07:57 pm

You are the expert on this stuff, so you give me a ray of hope.  Is the goal liquid or compressed gas.  I understand there some prototype stations working today.

But, I don't recall there ever being that big of an issue in handling gasoline into cars.  Heck, we don't even ground our cars like we do planes.  It takes about 5 seconds to teach someone to gas up a car.  If there is a big spill (which there are), it doesn't quickly boil into an explosive cloud.  Detonating a cloud is really, really bad.  Probably a gallon turning into vapor will level a whole gas station when it goes off.

I can't imagine my ex ever gassing up her car with liquid hydrogen  :o

In my opinion, even liquid propane is something that shouldn't be taken lightly. 

Danny Deger

Most of the concepts I've seen deal with compressed gas. Would probably be similar to gassing a vehicle with propane or LNG nowadays.

One other thing to keep in mind is that hydrogen dissipates much faster than gasoline does. The liquid boils so fast you would probably never see it, just vapor. The biggest concern is if it is in an enclosed space or covered area, so it accumilates more and won't disperse as quickly. Then you may have quite a safety hazard. But for the most part, most experts say that hydrogen is overall safer than gasoline. Biggest concern is the large flammability range (4-74%).

BTW, if anyone is interested, there's a website I've found to be very informative on hydrogen and related topics (hydrogen cars, etc.)

http://www.hydrogenassociation.org

OK last post for me on this thread on this. 

Most gas stations are covered :o

I am not even sure cover is needed.  As you said the boil off is so fast an explosive cloud may form.  If we go to refueling cars with liquid hydrogen, many people a year will die from REALLY big explosions.  Fuel air bombs are more effective than a regular bombs in crushing a concrete bunker. 

My guess is compressed gas hydrogen cars will not have enough range to be viable.   I will look at the link.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/01/2009 11:02 pm
Thanks for the write up, Danny. What was your plan for any underburn, then? If an engine quits before the targets are met, then you can't prebank anymore.

I'm not sure I completely understand your question's context, by definition the enigne quiting early would result in an underburn.  Which engine are you talking about - an OMS engine?  In that case you down-mode to other options such as RCS Completeion, Recovery Pre-bank & Landing Site Redesignation(for ex: can't make KSC then maybe redes to Gander or Shannon).

Entry Flight Procedures Handbook explains much of this in section 4.  Chris has a semi current version although it is not accurate about the KSC re-des options since those procedures are relatively new.

Mark Kirkman

 

Thanks Mark, but you're misunderstanding me. Danny was advocating a nominal entry with a prebank. Ergo, less fuel required for the deorbit burn, I guess. But then, if you're targetting for that, and then the engines quit, you're already planning to prebank, so you might not be able to prebank anymore (if you were targetting for a 90deg prebank, for instance).
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/02/2009 03:07 am
snip

Thanks Mark, but you're misunderstanding me. Danny was advocating a nominal entry with a prebank. Ergo, less fuel required for the deorbit burn, I guess. But then, if you're targetting for that, and then the engines quit, you're already planning to prebank, so you might not be able to prebank anymore (if you were targetting for a 90deg prebank, for instance).

Even if both engines fail, you can use the RCS.  The problem is a failure of the propellant system itself.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/02/2009 09:19 am
Yeah, I do understand that. I was just trying to account for every eventuality, I guess.

This is a fun topic, though :)
Title: Re: Shuttle Q&A Part 5
Post by: rsmath on 08/02/2009 10:48 am
I'm sorry if these have been answered before, but a couple things got my curiosity going the last few days:

1) I saw a pic of the SLF and noticed for the first time there is a canal around the runway (broken up by a few roads/access points).

Is that to try to limit wildlife other than alligators from easily accessing the SLF or does it serve some other purpose?

2) If an orbiter was to land in Europe or Africa, how would they return it to KSC?  Put it on a ship or does the SCA have the ability to be refueled in-flight?

 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/02/2009 11:14 am
2) It would be ferried with quite a few stops on the way. An orbiter has been carried to and from Europe before.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 08/02/2009 11:15 am
If only one engine fails, could you use RCS and the remaining engine simultaneously?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/02/2009 11:41 am
You'd have to reorientate to an attitude that would account for the difference in thrust level. Which would probably then be hideously unefficient. Most likely they'd kill the other engine and complete the entire burn in RCS, I guess?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/02/2009 11:41 am
2) It would be ferried with quite a few stops on the way. An orbiter has been carried to and from Europe before.
That was Enterprise(OV-101). I believe she was a fair bit lighter than an operational OV would be for a TAL abort ferry.

I believe in order to make the trip viable they would have to undertake some major operations like removing the payloads, SSMEs and completely draining the OMS/RCS and APU prop.

Quite possible that they would need to remove any liquids onboard that could freeze, to make it possible for the SCA to attain the highest altitude possible to extend the range.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/02/2009 12:06 pm
All of that seems reasonable enough, but a huge task. Blimey.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/02/2009 12:14 pm

1) I saw a pic of the SLF and noticed for the first time there is a canal around the runway (broken up by a few roads/access points).

Is that to try to limit wildlife other than alligators from easily accessing the SLF or does it serve some other purpose?


the rain has to drain some where
Title: Re: Shuttle Q&A Part 5
Post by: randomly on 08/02/2009 12:39 pm
You are the expert on this stuff, so you give me a ray of hope.  Is the goal liquid or compressed gas.  I understand there some prototype stations working today.
My guess is compressed gas hydrogen cars will not have enough range to be viable.   I will look at the link.

You can get sufficient range out of compressed hydrogen systems for passenger cars when coupled with efficient low weight designs (think prius). However many engineers no longer think a Hydrogen economy is viable because of the costs and inefficiencies.

Major problems -

Storage - Liquid hydrogen is right out, it costs you 30% of the energy in the hydrogen to liquify it and you have boil-off issues. Compressed gas is the most viable at 5000-10,000 psi, but it still cost you 12% of your energy. All the adsorption materials like palladium glom on to the hydogen so aggressively that it takes considerable energy to get the hydrogen back out again, the higher the capacity the material the more energy it takes to release the hydrogen.

Transport - Transport is difficult and energy intensive. You cannot use any existing pipelines because of hydrogen embrittlement, you have to lay all new pipe. The pumping energy for pipeline transport is high because of the very low density which is a further drain on your over all energy efficiency. A very busy gas station can be refueled by a single tanker truck a day, to deliver an equivalent mileage of hydrogen fuel would require about 20 tanker trucks a day and the associated impacts and costs of that. Transporting the energy to a hydrogen station by electricity would require all new transmission lines to handle the load, and since electrolyzers are only about 50% efficient you lose half your energy turning it into hydrogen. You also need to dissipate the other 50% of your energy as heat at the station.

Sources of Hydrogen - The only currently economical source of hydrogen is from reforming natural gas, which is quite efficient at about 80% of the original energy in the natural gas. But this doesn't get you away from fossil fuels nor reduce your carbon footprint. The fuel cells are only about 50% efficient and there does not appear yet any way to make them substantially more efficient, especially under the high current densities required for an automotive system. An MIT study found that even with projected improvements in hydrogen fuel cells that by 2020 a simple diesel hybrid car would still be more efficient Well to Wheels than a Hydrogen fuel cell vehicle. Worse yet is production of hydrogen by electrolysis which is only about 50% efficient. If you have any source of electricity the cost of that power in the vehicle is 4x since you lose half in electrolysis and half in the fuel cell for overall efficiency of 25%. This is only 1/3-1/4 as efficient as a battery system which is about 90% efficient for energy storage and return. In short until you have eliminated all your fossil fuel based electrical power generation there will better places to use your electrical power than for hydrogen production.
The only economical source of hydrogen in the future would be from Very High Temperature Nuclear Reactors using a Sulfur-Iodine cycle. That's at least 20-30 years out.
This is before you even get to problems of the very high cost and fragility of fuel cell systems, poisoning of the catalyst by carbon monoxide and other compounds, limited membrane lifetimes etc.

I once had high hopes for hydrogen, but unfortunately given the current and forseeable technology I think it's highly unlikely that a hydrogen economy will arise in the next 50 years, if ever.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/02/2009 07:00 pm
If only one engine fails, could you use RCS and the remaining engine simultaneously?

No. As long as one OMS engine is firing you are in the TVC DAP and cannot use the THC to perform an RCS translation. In the TVC DAP with a single engine RCS is nominally used only for roll control.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/02/2009 07:00 pm
You'd have to reorientate to an attitude that would account for the difference in thrust level. Which would probably then be hideously unefficient. Most likely they'd kill the other engine and complete the entire burn in RCS, I guess?

Nope, as long as you have a single engine, you will continue to use it. It is more efficient than downmoding to RCS.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/03/2009 09:12 am
You'd have to reorientate to an attitude that would account for the difference in thrust level. Which would probably then be hideously unefficient. Most likely they'd kill the other engine and complete the entire burn in RCS, I guess?

Nope, as long as you have a single engine, you will continue to use it. It is more efficient than downmoding to RCS.

So if a single engine on one side is still firing, the RCS will fire to keep the attitude where it's needed?

PS: You're really killing my confidence with these corrections  :D
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/03/2009 11:46 am
You'd have to reorientate to an attitude that would account for the difference in thrust level. Which would probably then be hideously unefficient. Most likely they'd kill the other engine and complete the entire burn in RCS, I guess?

Nope, as long as you have a single engine, you will continue to use it. It is more efficient than downmoding to RCS.

So if a single engine on one side is still firing, the RCS will fire to keep the attitude where it's needed?

The remaining OMS engine will gimbal to point through the c.g. RCS control for roll attitude, OMS gimballing for pitch and yaw.
Title: Re: Shuttle Q&A Part 5
Post by: cgrunska on 08/05/2009 06:56 pm
Is there any plan for the centrifugal module going up to the ISS if the shuttle is extended? Wasn't it completed, just waiting for a ride? I seem to remember reading something like that, but now I can't remember.
Title: Re: Shuttle Q&A Part 5
Post by: Orbiter on 08/05/2009 07:01 pm
Was wondering, what was the lightest / Heaviest Shuttle Launch/Landing ever?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/05/2009 07:07 pm
Is there any plan for the centrifugal module going up to the ISS if the shuttle is extended? Wasn't it completed, just waiting for a ride? I seem to remember reading something like that, but now I can't remember.

search this site. You will find it is in a parking lot.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/05/2009 07:07 pm
Is there any plan for the centrifugal module going up to the ISS if the shuttle is extended? Wasn't it completed, just waiting for a ride? I seem to remember reading something like that, but now I can't remember.

No. There are no plans to reinstate the CAM if shuttle is extended because there is nothing left to reinstate. The pressure hull was completed but not the rotor. The pressure hull has been sitting outdoors in a parking lot in Tsukuba for a couple of years. It is no longer flight worthy. All work was stopped on the rotor.
Title: Re: Shuttle Q&A Part 5
Post by: cgrunska on 08/05/2009 08:51 pm
So what are nasa's plans on figuring out microgravity effects on biological creatures prior to moon/mars/neo missions, if they threw away the "artificial gravity" maker?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 08/05/2009 08:56 pm
what are nasa's plans on figuring out microgravity effects on biological creatures prior to moon/mars/neo missions, if they threw away the "artificial gravity" maker?

That's not part of the space shuttle... You might try a research thread.
Title: Re: Shuttle Q&A Part 5
Post by: cgrunska on 08/05/2009 09:06 pm
true, i'll take that elsewhere. Thanks guys!
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/05/2009 10:51 pm
just a quickie whilst its on my mind but where do the sound suppression system's water tanks get their water supply from? is it sea water thats treated at a plant in KSC?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/06/2009 12:35 am
just a quickie whilst its on my mind but where do the sound suppression system's water tanks get their water supply from? is it sea water thats treated at a plant in KSC?

City of Cocoa water

There is no sea water treatment plant or water plant at KSC or CCAFS. 

Seawater water would be corrosive
Title: Re: Shuttle Q&A Part 5
Post by: Stefan0875 on 08/06/2009 08:14 pm
Hello

perhaps anyone can help me with a question about the SRB:

have a look at this photo:

(http://www.mallitsj.de/98089760_ae75Apax__MG_1744.jpg)

What are these rings (red arrows) for and what kind of material is it?

Thanks fpr your help

Regards
Stefan
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/06/2009 08:19 pm
This goes to the shuttle Q&A thread

That is foam protecting the strengthening rings on the lower segment.  The strengthening ring prevent the casing from crushing when the aft skirt punches a hole in the water and the water collapses back.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 08/06/2009 09:09 pm
Hereis a question I have often wondered since they started showing SRB camera footage of SRB Seperation.

I notice that the underside of the ET (Very bottom) always seems burnt black looking and even sometimes as if its glowing, Does the heat from the Shuttles Main Engines darken this area or is this marks left from the SRB's during liftoff or more from when they jettison away?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/06/2009 09:12 pm
Hereis a question I have often wondered since they started showing SRB camera footage of SRB Seperation.

I notice that the underside of the ET (Very bottom) always seems burnt black looking and even sometimes as if its glowing, Does the heat from the Shuttles Main Engines darken this area or is this marks left from the SRB's during liftoff or more from when they jettison away?

The scorching is caused by plume recirculation from both the SRBs and the SSMEs.
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 08/07/2009 07:45 am
This video shows that recirculation prominently starting at 1:55 into the clip:

http://www.youtube.com/watch?v=vQ7LCK8AE_g
Title: Re: Shuttle Q&A Part 5
Post by: LMSenus on 08/07/2009 01:58 pm
Please forgive me if this has been asked before, but what is the protocol for flying the shuttle flags?  Are the flags flown only when the shuttle is on orbit, or once the stack is rolled out?
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 08/07/2009 02:38 pm
Hereis a question I have often wondered since they started showing SRB camera footage of SRB Seperation.

I notice that the underside of the ET (Very bottom) always seems burnt black looking and even sometimes as if its glowing, Does the heat from the Shuttles Main Engines darken this area or is this marks left from the SRB's during liftoff or more from when they jettison away?

The scorching is caused by plume recirculation from both the SRBs and the SSMEs.

Gotcha, so is the tank coated there with something to keep the heat from blowingt hrough the tank and or heating the fuel inside?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/07/2009 02:40 pm

Gotcha, so is the tank coated there with something to keep the heat from blowingt hrough the tank and or heating the fuel inside?

The orange foam.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 08/07/2009 02:47 pm
LOL, I know that, But I was wondering if its coated extra there or something so the heat doesnt scortch through
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 08/07/2009 04:30 pm
Hey I have a question about the OBSS Inspection. As far as I know the OBSS inspection does not inspect the belly. It only inspects the RCC and nose and the OMS pods. Am I mistaken. The OBSS video on L2 shows only that but there is a diagram i saw from somebody that showed them scanning like the whole belly. Is there a video like the one on L2 that I can show somebody on the SSM forum. Thanks :)

Here is the pic.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/07/2009 05:27 pm
LOL, I know that, But I was wondering if its coated extra there or something so the heat doesnt scortch through

Just the appropriate thickness of foam.  It works both ways, it ablates and insulates.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/07/2009 05:34 pm
Hey I have a question about the OBSS Inspection. As far as I know the OBSS inspection does not inspect the belly. It only inspects the RCC and nose and the OMS pods. Am I mistaken. The OBSS video on L2 shows only that but there is a diagram i saw from somebody that showed them scanning like the whole belly. Is there a video like the one on L2 that I can show somebody on the SSM forum. Thanks :)

Here is the pic.

You are mistaken.  For ISS flights, the OBSS only looks at the RCC WLE and Nose Cap. But for STS-125 -- which is the image you posted -- they didn't have the ability to do the RPM at the ISS so they used the OBSS to thoroughly scan the Orbiter's underbelly. 

Check the L2 section on 125. There are many, many, many presentations there.  Also, refer to the multitude of articles published before 125 in July/August/September 2008 and March/April/May 2009.  They should be sufficient.  Other than that, search videos for "125."
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/07/2009 05:46 pm
Please forgive me if this has been asked before, but what is the protocol for flying the shuttle flags?  Are the flags flown only when the shuttle is on orbit, or once the stack is rolled out?

Are you taking about these flags?

If so, then they are flown when the specific vehicle they represent is at the pad or on orbit.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 08/07/2009 05:48 pm
Thanks Chris. That is actually exactly what I thought. What it is is on SSM-2007 it has you put the end of the arm under the belly for a short inspection.(Full inspection not yet here)  and I was telling them on the forum that I didn't think it was right.So I was actually correct because I f I understand you than all flights carrying the OBSS except for STS-125 don't scan the under belly. Let me know Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 08/07/2009 06:26 pm
Just an off question from the most recent NSF article... IF there is a roll back, what happens to the payload, taken out of the shuttle of course but does the canister come back out to get it, or does it sit at the RSS (hopefully not during hurricane season)? If so, doesn't this pose a higher risk of getting the payload "dirty" (not sure if contamination is the correct term)?

Second question, I googled the payload room at the RSS and I noticed in pictures everyone is in full protective garb but THEY AREN'T wearing gloves!!! Why???? (I would post pictures but I'm at work atm and they frown upon us saving pictures)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/07/2009 06:40 pm
IF there is a roll back, what happens to the payload, taken out of the shuttle of course

1.   but does the canister come back out to get it, or

2.  does it sit at the RSS (hopefully not during hurricane season)?

3.    If so, doesn't this pose a higher risk of getting the payload "dirty" (not sure if contamination is the correct term)?

4.  Second question, I googled the payload room at the RSS and I noticed in pictures everyone is in full protective garb but THEY AREN'T wearing gloves!!! Why???? (I would post pictures but I'm at work atm and they frown upon us saving pictures)

1.  That is an option

2.  can do that too.  It depends on a lot of factors.

3.  no more than any other facility

4.  They aren't touching the payload so no need for gloves.  Also not a payloads have the same sensitivity to contamination.  Especially, ISS payloads, they aren't like spacecraft with optical surfaces.
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 08/07/2009 06:52 pm
Thanks for the answers Jim... if you don't mind a few more silly questions; how do they determine which option to do? You mentioned it depends on a lot of factors, is the type of payload one of them?

Also could you explain what you mean by optical, I'm not to sure how it is used in context with the space shuttle, but when I hear it I think lens type sensitivity.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 08/07/2009 06:57 pm
Thanks for the answers Jim... if you don't mind a few more silly questions; how do they determine which option to do? You mentioned it depends on a lot of factors, is the type of payload one of them?

Also could you explain what you mean by optical, I'm not to sure how it is used in context with the space shuttle, but when I hear it I think lens type sensitivity.
I think optical means like equipment for Hubble or anything for a telescope or maybe even a satellite. Hubble payload always goes under extreme clean room.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/07/2009 07:46 pm
Thanks for the answers Jim... if you don't mind a few more silly questions; how do they determine which option to do? You mentioned it depends on a lot of factors, is the type of payload one of them?

Also could you explain what you mean by optical, I'm not to sure how it is used in context with the space shuttle, but when I hear it I think lens type sensitivity.

The payload drives the requirements.  Solar arrays, radiators, sun sensors, star trackers, mirrors, thermal surfaces, sensors, etc all have varying optical properties and are susceptible to particle fallout and NVR
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/07/2009 09:24 pm
Thanks Chris. That is actually exactly what I thought. What it is is on SSM-2007 it has you put the end of the arm under the belly for a short inspection.(Full inspection not yet here)  and I was telling them on the forum that I didn't think it was right.So I was actually correct because I f I understand you than all flights carrying the OBSS except for STS-125 don't scan the under belly. Let me know Thanks!

Correct. All flights to the ISS (since STS-114) do not scan the TPS underbelly as part of their normal inspection routine.  However, they all have the ability to scan the underbelly in case of Focused Inspection -- as was seen on STS-118.
Title: Re: Shuttle Q&A Part 5
Post by: LMSenus on 08/08/2009 07:27 pm
Please forgive me if this has been asked before, but what is the protocol for flying the shuttle flags?  Are the flags flown only when the shuttle is on orbit, or once the stack is rolled out?

Are you taking about these flags?

If so, then they are flown when the specific vehicle they represent is at the pad or on orbit.

Yes, Chris, those are the flags.  I have small versions for my office, and I have been displaying the appropriate flag while the vehicle was on orbit.  Then I realized they might also be flown while the vehicle is at the pad, and I didn't want to be incorrect in my use of the flags.  I'll need to put out my Discovery flag when I get into the office on Monday.  ;D  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: BenB5150 on 08/10/2009 12:44 am
Please forgive me if this has been asked before, but what is the protocol for flying the shuttle flags?  Are the flags flown only when the shuttle is on orbit, or once the stack is rolled out?

Are you taking about these flags?

If so, then they are flown when the specific vehicle they represent is at the pad or on orbit.

Yes, Chris, those are the flags.  I have small versions for my office, and I have been displaying the appropriate flag while the vehicle was on orbit.  Then I realized they might also be flown while the vehicle is at the pad, and I didn't want to be incorrect in my use of the flags.  I'll need to put out my Discovery flag when I get into the office on Monday.  ;D  Thanks!

Where can you get the small versions or any version?

Thanks
Ben
Title: Re: Shuttle Q&A Part 5
Post by: LMSenus on 08/10/2009 01:30 pm
Yes, Chris, those are the flags.  I have small versions for my office, and I have been displaying the appropriate flag while the vehicle was on orbit.  Then I realized they might also be flown while the vehicle is at the pad, and I didn't want to be incorrect in my use of the flags.  I'll need to put out my Discovery flag when I get into the office on Monday.  ;D  Thanks!

Where can you get the small versions or any version?

Thanks
Ben

I found images of the flags here:  http://flagspot.net/flags/us-shut.html (http://flagspot.net/flags/us-shut.html)  The Atlantis flag I had to draw up based on photos.

I print them out as needed.  It's not ideal, but until I find actual flags, I'm stuck.  Anybody know if the shop at KSC sells them?  In any case, even with the paper version, anybody walking by my cubicle knows which vehicle is on the pad or on orbit.  I'm just doing my bit for space program awareness  ;)
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 08/10/2009 02:18 pm
The flags are flown out here when the bird rolls out until the bird is back on the ground.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 08/10/2009 02:25 pm
In response to the payload questions, We don't have to wear gloves unless you are on a J-hook or any other position where you might touch the orbiter or payload, or any flight hardware.  Also you can wear a full face hood unless you have facial hair in which you have to wear an eye hood. The only exception since I've been working here has been Hubble, where everyone in the PCR had to have gloves and eyehoods. Concerning weather, if possible they don't really like to keep the payload in the PCR during a hurricane because , even though it is a clean room, it isn't water tight and there have been instances of water getting in  there. It's much safer to just leave it in the orbiter with the doors shut. They will usually only remove the payload if they might de-stack for some reason, or if the payload contains something like batteries that requires servicing every couple days. We do have different rain covers/gutters that we install in the PCR depending on if the orbiter is at the pad or not.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/10/2009 04:11 pm
Ive looked and had no luck googling this but what design are the ROFI sparklers that are used for the shuttle, having looked at several launch vids ive noticed a whirring noise that happens about 15 seconds before launch which would lead me to suspect they have something spinning in them, perhaps an angle-grinder and friction pad thing, is this the case or are they some kind of pyrotechnic device? would anyone happen to have a schematic on these (or maybe a pad-technician document on them if such a thing exists)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/10/2009 05:01 pm
are they some kind of pyrotechnic device?

Yes and DeltA IV uses them also.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/10/2009 08:41 pm
oh ok do they need to be replaced then between firings?, seems like that could be a problem if theres an RSLS abort or something like that
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/10/2009 08:43 pm
oh ok do they need to be replaced then between firings?, seems like that could be a problem if theres an RSLS abort or something like that
They have to replaced if fired. I believe that was the main driver behind the 48 hr scrub turnaround between the first and second launch attempts of STS-93 in July 1999.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/10/2009 09:11 pm
oh ok do they need to be replaced then between firings?, seems like that could be a problem if theres an RSLS abort or something like that

Not a problem, there would be bigger issues to worry about like HPU/APU propellant and the reason for the RSLS abort.  They would be replaced as a matter of course.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/11/2009 12:09 am
are they mini solid motors with say iron/magnesium  filings added, that kind of thing of something different?
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 08/11/2009 01:18 am
Ive looked and had no luck googling this but what design are the ROFI sparklers that are used for the shuttle....

I've looked too, and found nothing. Would love to see some closeup photos of the actual hardware, not just while it is firing.

Can you imagine one, out in the middle of your yard, during a July 4th celebration?  :)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/11/2009 01:22 am
They are nothing but fountain sparklers.  No big deal.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/11/2009 01:36 am
They are nothing but fountain sparklers.  No big deal.

I'll bet NASA pays more than $4 a piece for them!   :D
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 08/11/2009 01:37 am
Ive looked and had no luck googling this but what design are the ROFI sparklers that are used for the shuttle....

I've looked too, and found nothing. Would love to see some closeup photos of the actual hardware, not just while it is firing.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890003237_1989003237.pdf has some info.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/11/2009 01:49 am
Ive looked and had no luck googling this but what design are the ROFI sparklers that are used for the shuttle....

I've looked too, and found nothing. Would love to see some closeup photos of the actual hardware, not just while it is firing.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890003237_1989003237.pdf has some info.

Nice quote:

"A ROFI is, in effect, a small rocket motor filled with zirconium pellets.  These pellents [sic] flood the area between the SSME nozzles and the duct entrance with small (550-micron), extremely hot zirconium sparklers."
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/11/2009 01:59 am
Ahhh thanks for the link, good 'ol military style zirconium filings it seems, tbh with the way NASA does things I was half expecting these to have been like a multimillion dollar ATK contract with years of testing/evalutation and pages and pages of paperwork but apparently not:)
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 08/11/2009 07:28 pm
Are there any photos from UNDER the MLP while the stack is on the pad looking UP into the SRB nozzle?  Shine a spotlight up into the booster core.  I am presuming you could see the center hole all the way up to the top of the booster, right?

There are a few SRB test videos on L2 that show the ignition from the nozzle end, and some pics around the web (including from NASA and ATK) that show views into each segment, and segment mating views.

However, there's not much to see, except for a hole all the way up to the igniter cap. With really intense lights you might see the tips of the 1st segment star-shaped propellant mold sticking out, but it would still be a pretty boring view until ignition.

Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/11/2009 08:48 pm
ok just a few questions about the whole GLS shabang:

1. What type of computer is used to run the GLS software? is it located in the console or in a huge computer bank in a backroom somewhere

secondly, and bound to have been asked before but why is the GLS console behind a glass screen (I my have this wrong and its a different console but why are the two glass screens there atall?)

From what I understand the GLS operator has to manually "activate" the RSLS/Auto sequencer, is this just a case of pressing a button or is it more involved than that, same question goes about issuing a cutoff command,

Also is it true that this is the last time a human being has do something in order for the shuttle to put itself in orbit? (assuming everything works as planned)

Are there any pictures anywhere of the GLS console as this would really help answering some of these questions

thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/11/2009 09:11 pm


1.  secondly, and bound to have been asked before but why is the GLS console behind a glass screen (I my have this wrong and its a different console but why are the two glass screens there atall?)

2.  From what I understand the GLS operator has to manually "activate" the RSLS/Auto sequencer, is this just a case of pressing a button or is it more involved than that, same question goes about issuing a cutoff command,

3. Also is it true that this is the last time a human being has do something in order for the shuttle to put itself in orbit? (assuming everything works as planned)


1.  What glass screen?

2.  Computer entry.

3.  The crew has to do some tasks.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 08/11/2009 09:11 pm
I believe the GLS is hands off after T-9, yes, but there are also cockpit switch throws the crew makes during terminal count without which the shuttle could not fly (e.g. connecting essential busses and starting APUs), so no, it's not really the last time a person has to take action.

Edit: Jim beat me.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/11/2009 09:29 pm
I would attach a picture however i cant find one to hand of firing room 4, but they are the two "greenhouse" type things at either corner of the room which seem to be sealed off from the rest of the room

Also what does the "computer entry" entail?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/11/2009 09:48 pm
I would attach a picture however i cant find one to hand of firing room 4, but they are the two "greenhouse" type things at either corner of the room which seem to be sealed off from the rest of the room

That is where the MMT and VIP's sit.  The GLS is just a regular console
Title: Re: Shuttle Q&A Part 5
Post by: Variable on 08/15/2009 06:22 pm
How many successive scrubs can the system handle?

Are these driven by the ET fill/drain cycles (limited number?)  or something else?

Is there a time constraint as well - as in the system can't stand on the pad for more than x-number of days?  If so, what drives that?  (not launch window related)

ty
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/15/2009 06:24 pm
How many successive scrubs can the system handle?

Are these driven by the ET fill/drain cycles (limited number?)  or something else?

Is there a time constraint as well - as in the system can't stand on the pad for more than x-number of days?  If so, what drives that?  (not launch window related)

The cryo tanks for the fuel cells need to be topped off periodically due to boiloff. The exact frequency depends on mission-specific cryo margins but is typically once every 3-4 scrubs.

Limit on ET fill/drain cycles is 13.
Title: Re: Shuttle Q&A Part 5
Post by: Variable on 08/15/2009 06:33 pm
Ty Jorge.

More tank cycles than I had imagined.  Is that number driven primarily by the foam? (my impression)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/15/2009 06:56 pm
How many successive scrubs can the system handle?

Are these driven by the ET fill/drain cycles (limited number?)  or something else?


2 when the ET is filled for both launch crew rest and MPS inspections.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/15/2009 08:30 pm
To me a more important question is this:  Why is the Russian program so inflexible regarding launch dates?

It seems to me that Soyuz or Progress launches are set in stone by GOD and Shuttle with all of its weather related and other challenges always has to stand down to let Soyuz or Progress "play thru".  Why can't Progress or Soyuz slip their launch a few days to let Shuttle "play thru"?

Heck, we even seriously contemplate shortening Shuttle missions so they can undock in time for a Progress or Soyuz launch.  Why does this make sense?  Slip the Russian launch a couple of days and we don't have to do this.

What am I missing here?


Well, for one thing the Shuttle launch pads are only used to launch Space Shuttles.  Russia conducts many more missions per year than we do here in the U.S. and the launch pads that launch the Progress and Soyuz vehicles are also used to launch other vehicles.  It's all about maintaining schedules and seeing what you can slip this way and delete here.

When we cut content from STS-119 (which I'm fairly certain is the first time we've ever lopped content off an ISS mission just to get it launched in a given window), it was because those activities that were cut could easily be performed by the Station crew after the Shuttle left.  They were just a part of the original mission because SSPTS allows us to stayed docked longer and it was slightly more convenient to have them done when the shuttle was there. 

STS-119 lost nothing because we took an EVA off to get the mission up before Soyuz (and by doing that we were able to preserve STS-125 in May and the opening launch attempt for STS-127 in June).

And Soyuz and Progress have slipped for Shuttle before when we've needed them to. STS-115 is great example of that. However, the simple fact is, Shuttle is more flexible than Soyuz and Progress which have constraints as to how long they can be on orbit for (Soyuz) and constraints as to how far their launches can slip because they are bringing needed food, water, and supplies to the Station crew (Progress and Soyuz).
Title: Re: Shuttle Q&A Part 5
Post by: Variable on 08/15/2009 08:54 pm
How many successive scrubs can the system handle?

Are these driven by the ET fill/drain cycles (limited number?)  or something else?


2 when the ET is filled for both launch crew rest and MPS inspections.

ty Jim
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 08/16/2009 02:23 pm
Wow I just found out today that there had been launch aborts after Main Engine ignition. I was pretty amazed. I never hear about today.

Why were they having so many problems with the Main Engines cutting off?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/16/2009 02:25 pm
Wow I just found out today that there had been launch aborts after Main Engine ignition. I was pretty amazed. I never hear about today.

Why were they having so many problems with the Main Engines cutting off?

Valves that weren't responding according to plans
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/16/2009 05:20 pm
Wow I just found out today that there had been launch aborts after Main Engine ignition. I was pretty amazed. I never hear about today.

Why were they having so many problems with the Main Engines cutting off?

Valves that weren't responding according to plans

And there have only been FIVE post-SSME ignition RSLS aborts in the 127 flight history of the Shuttle program. 

And they weren't really having "so many problems." They just encountered times when one of the three engines on each of those five flights did not perform as it should in the initial fire-up and testing period.  The system worked exactly as it should by initiating the aborts and safing the vehicle.

For what it's worth:

STS-41D (Discovery):  12th Shuttle Mission. 1st Flight OV-103 (Discovery).  Launch attempt on June 26, 1984 aborted at T-6 seconds when the GPCs detected an anomaly in the orbiter's number three main engine.  The abort marked the first time since Gemini 6A that a Manned Spacecraft experienced a shutdown of its engines just prior to launch.

STS-51F (Challenger):  STS-51F was the 50th U.S. manned spaceflight. On July 12, 1985 the countdown was halted at T-3 seconds after main engine ignition when a malfunction of number two SSME coolant valve caused shutdown of all three main engines. Launch took place at July 29, 1985 at 5:00:00 p.m. EDT. Five minutes and 45 seconds into ascent, the number one main engine shut down prematurely due to a faulty high temperature sensor. To date, this has been the only in-flight main engine failure of the shuttle program. At about the same time, a second main engine almost shut down because of a similar problem, but this was observed and inhibited by a fast acting flight controller in Houston. The failed SSME resulted in an ATO trajectory.

STS-55 (Columbia):  The launch attempt on March 22, 1993 was aborted automatically at T-3 seconds when computers detected an incomplete ignition of the number three SSME. The problem was traced to a leak in the liquid oxygen preburner check valve.

STS-51 (Discovery):  On August 12, 1993, the count reached the T−3 second mark, at which point a shutdown was then triggered because of a faulty fuel flow sensor in one of the SSMEs.

STS-68 (Endeavour):  Launch on August 18, 1994 was halted by a RSLS abort at T-1.9 seconds. The automatic abort was initiated by the onboard General Purpose Computers when the discharge temperature on MPS SSME Main Engine #3 High Pressure Oxidizer Turbopump (HPOT) exceeded its redline value. The HPOT typically operates at 28,120 rpm and boosts the liquid oxygen pressure from 422 to 4,300 psi (2.91 to 29.6 MPa). There are two sensor channels measuring temperature on the HPOT. The B channel indicated a redline condition while the other was near redline conditions. The temperature at shutdown was at 1563 degrees Rankine (868 K), while a normal HPOT discharge temperature is around 1403 °R (779 K). The readline limit to initiate a shutdown is at 1560 °R (867 K). This limit increases to 1760 °R (980 K) at T-1.3 seconds.
Title: Re: Shuttle Q&A Part 5
Post by: SpaceCat on 08/17/2009 04:36 am
When does an SRM become an SRB?
Is it a function of overall thrust percentage or a function of size of the unit... or something else?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/17/2009 05:36 am
When does an SRM become an SRB?
Is it a function of overall thrust percentage or a function of size of the unit... or something else?
Something else. SRM refers to the motor components only. SRB is the whole deal, both motor components and the non-motor components.
Title: Re: Shuttle Q&A Part 5
Post by: Longhorn John on 08/17/2009 04:06 pm
What would happen if the shuttle did not throttle down for MaxQ? LOV/C, or survivable, but part of the launch profile to ensure against problems?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/17/2009 05:21 pm
What would happen if the shuttle did not throttle down for MaxQ? LOV/C, or survivable, but part of the launch profile to ensure against problems?

What's the failure mode that could cause all three engines to fail to throttle? If just one, I think you can continue. If all three, must be due to PASS software problem so the action would be to engage BFS.

Not an ascent expert, mkirk or Danny can fill in.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/17/2009 08:39 pm
What would happen if the shuttle did not throttle down for MaxQ? LOV/C, or survivable, but part of the launch profile to ensure against problems?

The structure would be over stressed.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 08/18/2009 02:23 am
Yeah, but the wondrous FS=1.4 would solve that, right? ;)
Title: Re: Shuttle Q&A Part 5
Post by: SpaceCat on 08/18/2009 05:29 pm
Thanks, Dave

What confused the nomenclature- to me anyway- is that the 'little guys' on Deltas & Atlases are typically referred to as SRM's; while the larger stacks on Shuttle & the big Titans (until phase out) were always called SRB's.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/18/2009 08:25 pm
Thanks, Dave

What confused the nomenclature- to me anyway- is that the 'little guys' on Deltas & Atlases are typically referred to as SRM's; while the larger stacks on Shuttle & the big Titans (until phase out) were always called SRB's.

Titans used SRM's.  SRB is an incorrect term for them
Title: Re: Shuttle Q&A Part 5
Post by: edkyle99 on 08/18/2009 08:50 pm
When does an SRM become an SRB?
Is it a function of overall thrust percentage or a function of size of the unit... or something else?

"Something else" is probably the best answer!

A motor is a motor, no doubt about that, but try to find a precise definition of "booster". 

In the old days of the space age, "booster" could have meant the entire rocket!  (The "Booster" controllers at JSC were in charge of all of the Saturn propulsion stages, for example.  Atlas was a "booster" for Mercury, etc.)  Over the years, the meaning shifted toward describing the propulsive unit or units that initially lifted the rocket from the pad.  During the Shuttle era, "booster" more commonly described strap-on units, because NASA named its STS solids "Boosters". 

Calling a strap on solid motor a "motor" is always correct.  But spin-stabilized third stage solid motors are also "motors".  So are solid motors used to separate stages, etc.  "Booster" is not as clearly defined and is, as a result, only assuredly correct when the name is called out by the vehicle creator.  Space Shuttle Solid Rocket Boosters may be the only "Solid Rocket Boosters", though other solid rocket motors can be said to "boost".  The Titan Stage Zero motors were not called Boosters (upper case), but it may have been correct to call them boosters (lower case).

I have a headache now ...

 - Ed Kyle
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/18/2009 08:55 pm
The nomenclature for the shuttle is as the following:

The SRM is component that ATK produces, the motor with the nozzle.  It becomes a SRB when the aft skirt, IEA, aft attach hardware, forward attachment, recovery systems, jettison motors and nose cone are added.

Edit:  Typo fixed
Title: Re: Shuttle Q&A Part 5
Post by: jcm on 08/19/2009 04:54 am
The nomenclature for the shuttle is as the following:

The SRM is component that ATK produces, the motor with the nozzle.  It becomes a SRM when the aft skirt, IEA, aft attach hardware, forward attachment, recovery systems, jettison motors and nose cone are added

Typo there Jim - you meant to write "it becomes an SRB when...".
Title: Re: Shuttle Q&A Part 5
Post by: SpaceCat on 08/19/2009 06:50 pm
I have a headache now ...

I'm with you, Ed!  :)
See, I wouldn't have asked this if a 12-year-old had not asked me first.
Thanks, guys- I see what you're saying;
I'll pass all this along to the 12-yr-old.  :)
Title: Re: Shuttle Q&A Part 5
Post by: Longhorn John on 08/19/2009 10:04 pm
Thanks Jorge, Jim. Curveball question that seems better placed here than another thread, is John Shannon NASA or USA?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/19/2009 10:11 pm
Thanks Jorge, Jim. Curveball question that seems better placed here than another thread, is John Shannon NASA or USA?
NASA. He's a former Flight Director and the FDs have always been NASA employees and not contractor engineers. So Leroy Cain is NASA as well.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/19/2009 10:46 pm
Thanks Jorge, Jim. Curveball question that seems better placed here than another thread, is John Shannon NASA or USA?
NASA. He's a former Flight Director and the FDs have always been NASA employees and not contractor engineers. So Leroy Cain is NASA as well.

Not to mention he is currently Head of the Shuttle Program Office.  This is a very, very big Civil Servant job at NASA.  NASA is blessed to have him and Leroy working there.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 08/20/2009 04:00 pm
what's the ascent witch list performed at T-11H & hold???
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/20/2009 05:07 pm
what's the ascent witch list performed at T-11H & hold???

There are several different switch lists performed during the countdown but the Ascent Switch List is performed by the ASP/Cape Crusader folks during the T-11 Hold.  Additional Pre-Ingress Switch Verifications are performed during the T-3 Hour Hold and then the ASP will do some Post Ingress Switch adjustements after the crew is on-board in order to get some of the hard to reach switches.

To answer your question "what is it"? This checklist pretty much verifys that every switch, knob, light, & display located in the flight and mid-decks of the spacecraft are in the proper configuration for hand-over to the astronaut flight crew during ingress.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 08/20/2009 05:45 pm
ty mr kirkman!!!!!!
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/21/2009 09:03 am
This is an odd one but does anyone know where I can find a diagram of the first few orbits of an ISS flight after launch?

I have a few people on another forum asking about it, people wanted to try snagging the UHF comms with their scanners.
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 08/21/2009 09:45 am
This is an odd one but does anyone know where I can find a diagram of the first few orbits of an ISS flight after launch?

I have a few people on another forum asking about it, people wanted to try snagging the UHF comms with their scanners.

TLEs for ISS and Shuttle:
http://spaceflight.nasa.gov/realdata/elements/index.html
just look at the time and choose the right TLE data.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/21/2009 09:47 am
I wanted something that required as little work as possible, but thanks I guess :p
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 08/21/2009 09:53 am
maybe getting a satellite tracking program (orbitron comes to mind) and then update the TLEs a couple of times per day.... don't know if celestrak updates shuttle TLEs after they do a burn...
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/21/2009 09:58 am
Aye, I might have a go.

I thought maybe there were some diagrams from any books on ascent guidance or stuff like that.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/21/2009 12:34 pm
I was wondering if theres an in-depth guide or handbook pertaining to shuttle fuelling and replenishment etc anywhere? Ive been looking everywhere on NSF but have had no luck so far, sporadic Q&A posts are good but dont tend to give you the "complete" picture
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 08/21/2009 05:03 pm
What are you looking for? Which fueling? There's a few different types (Hyper, LH2/LOX, PRSD loading) On L2 a while back I made a picture thread on the GSE side of the PRSD system, which services the fuel cells. I'm thinking about making a similar thread on the LH2 system here soon. It would be on L2 of course, due to the high res pics.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/21/2009 11:51 pm
Ahh sorry that last post was pretty ambiguous looking at it now, what I was after was some detailed documentation/pictures of shuttle ET fuelling and the ground to shuttle interface(TSM, GUCP, beanie cap) so perhaps that would be the ET console handbook and also the ground cryo systems handbook (if such a document exists) mainly interested in just anything to do with the MPS LH2/LOX side of things but also anything else like hypergols etc would be really interesting too.

also having a look for those pictures now padrat..
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 08/22/2009 07:45 am
If the Apollo program could transmit live TV via S-band, why can't the Shuttle?  When Ku is unavailable, the Shuttle is limited to sequential stills.  If Apollo could send TV via S-band, what changed that the Shuttle cannot?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/22/2009 07:54 am
If the Apollo program could transmit live TV via S-band, why can't the Shuttle?  When Ku is unavailable, the Shuttle is limited to sequential stills.  If Apollo could send TV via S-band, what changed that the Shuttle cannot?

It is not S vs Ku band, it is omni vs steerable. The steerable antennas on both spacecraft provide more bandwidth. Apollo had steerable S-band plus omni S-band, shuttle has steerable Ku band and omni S-band. Neither Apollo nor the shuttle could transmit TV using the omni antennas, only the steerable ones.
Title: Re: Shuttle Q&A Part 5
Post by: Davidgojr on 08/22/2009 07:07 pm
Why are built in holds of known durations added to the countdown?  Why not simply have a countdown of longer duration that includes the holds without stopping the clock?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/22/2009 07:18 pm
Why are built in holds of known durations added to the countdown?  Why not simply have a countdown of longer duration that includes the holds without stopping the clock?

Answered previously, do a search.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2009 08:42 pm
Why are built in holds of known durations added to the countdown?  Why not simply have a countdown of longer duration that includes the holds without stopping the clock?

This is not shuttle unique but common to all launch vehicles.
Title: Re: Shuttle Q&A Part 5
Post by: dcbecker on 08/23/2009 03:41 pm
Why are built in holds of known durations added to the countdown?  Why not simply have a countdown of longer duration that includes the holds without stopping the clock?

http://forum.nasaspaceflight.com/index.php?topic=12553.msg356130#msg356130
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/23/2009 06:35 pm
Is there a place to look at time to launch assuming the holds all go as planned?  If NASA doesn't have one, it would be trivial to build and add to nasa.gov. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/23/2009 09:20 pm
Is there a place to look at time to launch assuming the holds all go as planned?  If NASA doesn't have one, it would be trivial to build and add to nasa.gov. 

Danny Deger

????

http://countdown.ksc.nasa.gov/shuttle/countdown/cdt/
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/25/2009 12:49 am
OK, can some quickly post the planned holds?

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: wizard on 08/25/2009 01:24 am
Is this what you're looking for?

9:41 pm     Countdown resumes at the T-3 hour mark
12:21 am     Countdown enters a 10-minute hold at the T-20 minute mark
12:31 am     Countdown resumes at the T-20 minute mark
12:42 am     Countdown enters an ~45-min. hold at the T-9 minute mark
1:27:05 am     Countdown resumes at the T-9 minute mark
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/25/2009 07:43 am
Is this what you're looking for?

9:41 pm     Countdown resumes at the T-3 hour mark
12:21 am     Countdown enters a 10-minute hold at the T-20 minute mark
12:31 am     Countdown resumes at the T-20 minute mark
12:42 am     Countdown enters an ~45-min. hold at the T-9 minute mark
1:27:05 am     Countdown resumes at the T-9 minute mark

Yes, thank you.  10 minute hold at T minus 20, 45 minutes at T-9.  How about the T minus 3 hour hold?  How long is it?

Danny
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 08/25/2009 07:47 am
Is this what you're looking for?

9:41 pm     Countdown resumes at the T-3 hour mark
12:21 am     Countdown enters a 10-minute hold at the T-20 minute mark
12:31 am     Countdown resumes at the T-20 minute mark
12:42 am     Countdown enters an ~45-min. hold at the T-9 minute mark
1:27:05 am     Countdown resumes at the T-9 minute mark

Yes, thank you.  10 minute hold at T minus 20, 45 minutes at T-9.  How about the T minus 3 hour hold?  How long is it?

Danny

2hr 30mins hold at T minus 3 hours.
2hr hold at T minus 6 hours (normally)

Edit: 1 hour hold at T minus 6 hours for this STS-128 24-hour scrub
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 08/25/2009 05:34 pm
During tanking/replenish is the LO2 pumped through the SSMEs and then into the tank or is it sent straight up into the tank with a "trickle" sent through the engines, if its option 2 what percentage of the total flow is sent to the engines?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/25/2009 08:08 pm
LH2 and LOX are loaded through the T0 umbilicals into the aft of the Orbiter, then up through the porpellant lines and into the respective tanks of the ET.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/25/2009 08:33 pm
During tanking/replenish is the LO2 pumped through the SSMEs and then into the tank or is it sent straight up into the tank with a "trickle" sent through the engines, if its option 2 what percentage of the total flow is sent to the engines?

As the oxygen comes in from the Tail Service Mast via the Fill & Drain Lines, it flows into the common LO2 Manifold (that all 3 engines feed from) and through the prevalves and into the engines - while it can flow through the turbo pumps it CAN NOT flow into the cumbustion chamber because the main oxidizer valves are closed at this point.  From the LO2 Manifold the flow of oxygen also goes out through the ET Feedline Disconnect and up the Downcomer (this is the 17 inch feedline you see running up the outside of the ET) and into the bottom of the oxygen portion of the external tank.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: ceepdublu on 08/26/2009 03:45 am
What does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position?  Wait a week for boiloff via flarestack?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/26/2009 03:54 am
They said in the presser that they can drain the tank through the PV13 valve... it would just take hours long than usual.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 08/26/2009 04:24 am
If the fill/drain valve issue is an instrumentation problem, what instrumentation would be involved?  Is there any instrumentation within the valve assembly that indicates position, or is valve position derived from pressure transducers in the feedline manifold, external tank, tail service mast, etc.?

Seems to me that if they know the pressures in the LH2 tank and T-0 umbilical, then they should be able to determine the position of the fill/drain valve unless there is an off-nominal leak in the circuit.  So if there's a problem with the valve instrumentation itself (if applicable) or the feedline manifold pressure transducer, then there should be alternative methods of monitoring the valve position.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 08/26/2009 11:19 am
Is there a list of the all the Criticality 1 systesms on the space shuttle? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/26/2009 11:23 am
then there should be alternative methods of monitoring the valve position.

Not viable.  How would position be know with no flow?
Title: Re: Shuttle Q&A Part 5
Post by: joncz on 08/26/2009 03:00 pm
What does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position?  Wait a week for boiloff via flarestack?

There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal  :o
Title: Re: Shuttle Q&A Part 5
Post by: ceepdublu on 08/26/2009 03:38 pm


There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal  :o
[/quote]

That was actually my initial thought before asking the question... ;)
Title: Re: Shuttle Q&A Part 5
Post by: cabbage on 08/26/2009 09:17 pm
I notice on another thread that after boiloff they have inerted the tank with helium. Is there a reason for using helium for this rather than (say) nitrogen? Is it a concern that the tank is too cold for nitrogen?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/26/2009 09:21 pm
I notice on another thread that after boiloff they have inerted the tank with helium. Is there a reason for using helium for this rather than (say) nitrogen? Is it a concern that the tank is too cold for nitrogen?

LH2 would condense the N2
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 08/27/2009 02:11 am
My apologies if this has been asked before...

After a 24-hr weather scrub, I'm trying to understand the specific reasons why the vehicle can't remain fueled and then topped off prior to crew arrival the following day. Is it due to the volatility of the liquid hydrogen? Or would it waste too much fuel via boil-off? Or would the ET turn into a huge icicle due as the insulation and tank mass loses all its embodied heat? Are there other factors?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/27/2009 04:35 am
Is it due to the volatility of the liquid hydrogen? Or would it waste too much fuel via boil-off?

Bingo
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 08/27/2009 04:39 am
What does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position?  Wait a week for boiloff via flarestack?

There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal  :o

This "8-1/2 minute rapid drain sounds like a "launch" without lighting the SRB's.  But, that is not even a consideration right? Wouldn't that require replacement of the SSME's?
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 08/27/2009 04:42 am
LH2 and LOX are loaded through the T0 umbilicals into the aft of the Orbiter, then up through the porpellant lines and into the respective tanks of the ET.

Are the T0 umbilicals those grey things that stand up from the MLP behind the wings?

If not, where are they located?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/27/2009 04:45 am
LH2 and LOX are loaded through the T0 umbilicals into the aft of the Orbiter, then up through the porpellant lines and into the respective tanks of the ET.

Are the T0 umbilicals those grey things that stand up from the MLP behind the wings?

If not, where are they located?


Those are the tail service masts, in which the T-0 umbilicals are located
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/27/2009 05:00 am
What does the scrub scenario look like if one of the LH2 fill/drain valves were to get stuck in the closed position?  Wait a week for boiloff via flarestack?

There's an 8-1/2 minute rapid-drain procedure - but it's likely a one-shot deal  :o

This "8-1/2 minute rapid drain sounds like a "launch" without lighting the SRB's.  But, that is not even a consideration right? Wouldn't that require replacement of the SSME's?


He was being facetious.
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 08/27/2009 02:40 pm
With all the references to the MMT, there is never any discussion of who is on it.  We only hear from Mike Moses at the Cape and Leroy Cain in Houston.  Who exactly is on the MMT?  Is there a different MMT pre-launch at KSC than during a mission at JSC?
Title: Re: Shuttle Q&A Part 5
Post by: iprefermuffins on 08/27/2009 07:37 pm
I've read that the aft skirts of the SRBs support the entire weight of the shuttle on the pad. However, it seems like they would be offset by quite a bit from the CG of the entire stack, considering that there's an orbiter hanging off one side and not the other. Is there any other structure providing a lateral force to keep the stack from tipping over? Or are the hold-down posts on the skirts enough to keep the stack securely upright?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/27/2009 07:46 pm
I've read that the aft skirts of the SRBs support the entire weight of the shuttle on the pad. However, it seems like they would be offset by quite a bit from the CG of the entire stack, considering that there's an orbiter hanging off one side and not the other. Is there any other structure providing a lateral force to keep the stack from tipping over? Or are the hold-down posts on the skirts enough to keep the stack securely upright?

The 8 hold-down posts do every thing
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/27/2009 07:50 pm
When the GOX vent arm is extended for ET loading, the beanie cap is lowered into position for final fit checks.  Then, the beanie cap is raised but the arm is left extended.  Why is the beanie cap raised up like this?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/27/2009 07:53 pm
I've read that the aft skirts of the SRBs support the entire weight of the shuttle on the pad. However, it seems like they would be offset by quite a bit from the CG of the entire stack, considering that there's an orbiter hanging off one side and not the other. Is there any other structure providing a lateral force to keep the stack from tipping over? Or are the hold-down posts on the skirts enough to keep the stack securely upright?

You need to realize that the orbiter only weighs on the order of 1/10th as much as two fueled SRBs, so the CG isn't offset all that much.  The moment it applies is the same regardless of the SRB mass of course, but even that moment isn't all that much - around 100 metric tons times something in range of high single-digit meters.  That's nothing for a large steel tube to take in bending (much less two of them) and the 8 bolts Jim mentioned are large and widely spaced from each other.
Title: Re: Shuttle Q&A Part 5
Post by: iprefermuffins on 08/27/2009 08:15 pm
You need to realize that the orbiter only weighs on the order of 1/10th as much as two fueled SRBs, so the CG isn't offset all that much.  The moment it applies is the same regardless of the SRB mass of course, but even that moment isn't all that much - around 100 metric tons times something in range of high single-digit meters.  That's nothing for a large steel tube to take in bending (much less two of them) and the 8 bolts Jim mentioned are large and widely spaced from each other.

Thanks (& to Jim too). The weight difference had occurred to me but I didn't know it was quite that much.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/27/2009 08:26 pm
You need to realize that the orbiter only weighs on the order of 1/10th as much as two fueled SRBs, so the CG isn't offset all that much.  The moment it applies is the same regardless of the SRB mass of course, but even that moment isn't all that much - around 100 metric tons times something in range of high single-digit meters.  That's nothing for a large steel tube to take in bending (much less two of them) and the 8 bolts Jim mentioned are large and widely spaced from each other.

Thanks (& to Jim too). The weight difference had occurred to me but I didn't know it was quite that much.

The force of the main engines during start up push the stack the opposite direction with more force than the weight of the orbiter
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/28/2009 12:08 am
Does anyone know the difference in q between a high q and low q profile?  I also need to know how much performance gain there is.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: simcosmos on 08/28/2009 09:03 pm
Does anyone know the difference in q between a high q and low q profile?  I also need to know how much performance gain there is.

Danny Deger

Maybe this old NSF article might provide the kind of info you are looking for?

http://www.nasaspaceflight.com/2006/04/low-q-option-for-sts-121/

António
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 08/28/2009 10:55 pm
Hypothetically,

If a foam strike occurs while climbing to orbit, and severe damage is very obvious (i.e. can be seen to anyone looking at the camera mounted on the ET that is usually shown on the public channel), could they do an RTLS abort based on that?

(not that I hope this ever occurs)
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/28/2009 10:57 pm
Hypothetically,

If a foam strike occurs while climbing to orbit, and severe damage is very obvious (i.e. can be seen to anyone looking at the camera mounted on the ET that is usually shown on the public channel), could they do an RTLS abort based on that?

(not that I hope this ever occurs)

No.  Ascent would continue as planned. The FD2 OBSS inspections performed, docking undertaken, and CSCS implemented if a patch of the area cannot be safely accomplished.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 08/28/2009 10:58 pm
Thanks  :)
On that note, what does qualify for an RTLS abort? Engine or two going down I would assume, but is there anything else?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/28/2009 10:59 pm
Hypothetically,

If a foam strike occurs while climbing to orbit, and severe damage is very obvious (i.e. can be seen to anyone looking at the camera mounted on the ET that is usually shown on the public channel), could they do an RTLS abort based on that?

(not that I hope this ever occurs)
Also asked and answered here before...start with this and read down:
http://forum.nasaspaceflight.com/index.php?topic=14583.msg323022#msg323022
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/28/2009 11:13 pm
Thanks  :)
On that note, what does qualify for an RTLS abort? Engine or two going down I would assume, but is there anything else?

RTLS is any system error (single engine or dual engine failure or severe cabin leak, etc....) that prevents you from either safely reaching orbit or safely executing a TAL before the moment of Negative Return (approximately T+4 mins) -- at which point the Shuttle vehicle has passed too far downrange and gained too much forward moment to safely return to KSC.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/28/2009 11:52 pm
Thanks  :)
On that note, what does qualify for an RTLS abort? Engine or two going down I would assume, but is there anything else?
RTLS is any system error (single engine or dual engine failure or severe cabin leak, etc....) that prevents you from either safely reaching orbit or safely executing a TAL before the moment of Negative Return (approximately T+4 mins) -- at which point the Shuttle vehicle has passed too far downrange and gained too much forward moment to safely return to KSC.
A dual engine failure early in ascent is probably more a contingency abort case than RTLS -- if Mark's nearby, you can ask him. :)
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/29/2009 12:04 am
Just asked Mark (he's sitting right behind me).  Duel engine failure is most likely a contingency abort.  Could be RTLS but depends on the MET failure times of the two engines (would have to be fairly let in RTLS capability zone to make it an RTLS v. contingency).

Page 2-46 of ascent cue card has the engine out abort scenarios.
Title: Re: Shuttle Q&A Part 5
Post by: glen4cindy on 08/29/2009 01:15 am
Noticed this when we were at Kennedy for STS-127, searched the Q&A but didn't find any mention of it.

At various times during the countdown, I noticed a helicopter circling the KSC complex.

Is this a security measure to make sure that there are no unauthorized persons anywhere they are not supposed to be during a launch?

It seems that it would be a rather difficult thing for anyone to actually gain access to any critical area because of things being so locked down.

Remember the movie Jumper? I would love to have his ability during a launch where I would teleport myself to the roof of the VAB for a prime view.  But, then, I would have to avoid being seen too. 

Thanks for this site.  I can't afford L2, but, there is so much great information I have learned here.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/29/2009 02:33 am
Vast majority of reason for RTLS is single engine out during something like the first 2 minutes of flight.  After that TAL.  For cabin leak and I think 2 APUs down and one failing an RTLS can be done.  Lets just put it this way, we hated RTLS so bad that as a person that use to make a living putting failures in the simulator to force an abort, making us go RTLS after TAL was available was available was very hard to do. 

Oh and I forgot the one single stuck in the throttle bucket and one failed to force a TAL.  It was a pain in the rear to time the second failure to not go contingency, or not go TAL.   I used to have so much fun trying to force a given abort.  The problem was, we would have a whole script of failures based on a given abort.   If I failed in my job to produce an RTLS and we went TAL instead, I got lots of dirty looks from my fellow instructors. 

Danny Deger

Edit: I forgot this one.  The cracked thermal window pane due to a bird strike.  The idea was to never get to high Mach numbers and avoid heating.  It was next to impossible to get this case without prebriefing the commander on this.  The abort call is made on what the command was observing.

On getting the right abort, my worst day in the world in this matter was a rare long duration integrated simulation to exercise all of NASA on a major, Columbia like, problem on orbit.  We decided to do an abort to orbit on ascent for some reason.  I was new and screwed it up and sent us back to KSC with an RTLS.  It took us 20 minutes or so to turn the sim around and get everyone synced up and going again.  I think god him self was monitoring the flight loops.  I know the administrator at the time was.  Have you ever seen the Southwest Airlines commercial "Do you want to get away?"

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/29/2009 12:45 pm

1.  Is this a security measure to make sure that there are no unauthorized persons anywhere they are not supposed to be during a launch?

2.  It seems that it would be a rather difficult thing for anyone to actually gain access to any critical area because of things being so locked down.


1.  Yes

2.  Not really.  There isn't a fence around the whole center. 
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 08/29/2009 07:45 pm
Re: security.  Eight years ago:
http://archive.newsmax.com/archives/articles/2001/7/24/202351.shtml

There are also stories of techs coming into LC39 in the morning and finding "BAM!" stickers on things, where the Navy SEALs had used the KSC beach and facilities the night before for invasion practice.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 08/30/2009 03:29 am
To Whom it may concern, this might be in the wrong section but I don't know where to put it.


I have seen the moon move across the sky over the course of 2-3 hours but why did the moon move so fast last night at the launch.

2.  Are there photos of thrusters l4d,l2d,l3d,l5d,l5l
and the same ones on the right side .  I have only seen l4l,l2l,l3l,l1l,l1a,l3a,l4u,l2u,l1u even from an SSME change photos.

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/30/2009 03:47 am
To Whom it may concern, this might be in the wrong section but I don't know where to put it.


I have seen the moon move across the sky over the course of 2-3 hours but why did the moon move so fast last night at the launch.

Narrow angle camera.

Plus, the moon's apparent motion is faster than many people realize. It moves its own diameter about every two minutes. This is not easily apparent when watching the moon at night, even with a single landmark in front of the moon, because most people have an unconscious tendency to move their heads to keep the landmark aligned with the moon. Aligning two landmarks with the moon provides a reference to keep the head steady. (Or set up binoculars on a fixed tripod, or use a telescope.)
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 08/30/2009 06:18 am
To Whom it may concern, this might be in the wrong section but I don't know where to put it.


I have seen the moon move across the sky over the course of 2-3 hours but why did the moon move so fast last night at the launch.

Narrow angle camera.

Plus, the moon's apparent motion is faster than many people realize. It moves its own diameter about every two minutes. This is not easily apparent when watching the moon at night, even with a single landmark in front of the moon, because most people have an unconscious tendency to move their heads to keep the landmark aligned with the moon. Aligning two landmarks with the moon provides a reference to keep the head steady. (Or set up binoculars on a fixed tripod, or use a telescope.)

Thanks Jorge

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 08/30/2009 04:03 pm
Here's a question that'll make Jim wince ;)

When is an orbiter's birthday? I know PAO are going on the maiden launch date - and that's cool, we'll do likewise. However, I'd of thought it would have been maybe her first powerup at Palmdale or when the orbital first arrived at KSC on the back of the SCA?

How do the Navy work this? Commission date?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/30/2009 04:48 pm
Here's a question that'll make Jim wince ;)

When is an orbiter's birthday? I know PAO are going on the maiden launch date - and that's cool, we'll do likewise. However, I'd of thought it would have been maybe her first powerup at Palmdale or when the orbital first arrived at KSC on the back of the SCA?

How do the Navy work this? Commission date?

Or when the first piece is placed in the final assembly rig, equivalent to when a ship's keel is laid.

Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/30/2009 04:55 pm
When is an orbiter's birthday? I know PAO are going on the maiden launch date - and that's cool, we'll do likewise. However, I'd of thought it would have been maybe her first powerup at Palmdale or when the orbital first arrived at KSC on the back of the SCA?
As these things go, today is definitely a big silver anniversary, but I think what it's an anniversary of is a matter of preference.  (Not a big deal one way or another.)
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/30/2009 06:11 pm
Very true, Philip.

And here's a relatively complete list of her various birthdays/milestones:

January 29, 1979             Contract Award
August 27, 1979             Start long lead fabrication of Crew Module
June 20, 1980             Start fabrication lower fuselage
November 10, 1980     Start structural assembly of aft-fuselage
December 8, 1980     Start initial system installation aft fuselage
March 2, 1981             Start fabrication/assembly of payload bay doors
October 26, 1981             Start initial system installation, crew module, Downey
January 4, 1982             Start initial system installation upper forward fuselage
March 16, 1982             Midfuselage on dock, Palmdale
March 30, 1982             Elevons on dock, Palmdale
April 30, 1982             Wings arrive at Palmdale from Grumman
April 30, 1982             Lower forward fuselage on dock, Palmdale
July 16, 1982             Upper forward fuselage on dock, Palmdale
August 5, 1982             Vertical stabilizer on dock, Palmdale
September 3, 1982     Start of Final Assembly
October 15, 1982             Body flap on dock, Palmdale
January 11, 1983             Aft fuselage on dock, Palmdale
February 25, 1983    Complete final assembly and closeout installation, Palmdale
February 28, 1983     Start initial subsystems test, power-on, Palmdale
May 13, 1983             Complete initial subsystems testing
July 26, 1983             Complete subsystems testing
August 12, 1983             Completed Final Acceptance
October 16, 1983             Rollout from Palmdale
November 5, 1983     Overland transport from Palmdale to Edwards
November 9, 1983     Delivery to Kennedy Space Center
June 2, 1984            Flight Readiness Firing
August 30, 1984            First Flight (41-D)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/30/2009 06:54 pm
Very true, Philip.

And here's a relatively complete list of her various birthdays/milestones:

January 29, 1979             Contract Award
August 27, 1979             Start long lead fabrication of Crew Module
June 20, 1980             Start fabrication lower fuselage
November 10, 1980     Start structural assembly of aft-fuselage
December 8, 1980     Start initial system installation aft fuselage
March 2, 1981             Start fabrication/assembly of payload bay doors
October 26, 1981             Start initial system installation, crew module, Downey
January 4, 1982             Start initial system installation upper forward fuselage
March 16, 1982             Midfuselage on dock, Palmdale
March 30, 1982             Elevons on dock, Palmdale
April 30, 1982             Wings arrive at Palmdale from Grumman
April 30, 1982             Lower forward fuselage on dock, Palmdale
July 16, 1982             Upper forward fuselage on dock, Palmdale
August 5, 1982             Vertical stabilizer on dock, Palmdale
September 3, 1982     Start of Final Assembly
October 15, 1982             Body flap on dock, Palmdale
January 11, 1983             Aft fuselage on dock, Palmdale
February 25, 1983    Complete final assembly and closeout installation, Palmdale
February 28, 1983     Start initial subsystems test, power-on, Palmdale
May 13, 1983             Complete initial subsystems testing
July 26, 1983             Complete subsystems testing
August 12, 1983             Completed Final Acceptance
October 16, 1983             Rollout from Palmdale
November 5, 1983     Overland transport from Palmdale to Edwards
November 9, 1983     Delivery to Kennedy Space Center
June 2, 1984            Flight Readiness Firing
August 30, 1984            First Flight (41-D)
I grew up in the L.A. area, so the rollout ceremonies and delivery to Florida were a bigger deal there.  All the orbiters got their picture in the papers when that happened.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 08/30/2009 07:40 pm
Was wondering why STS 131 is scheduled to carry 7 crew members where every other remaining mission carries 6?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/30/2009 07:46 pm
Was wondering why STS 131 is scheduled to carry 7 crew members where every other remaining mission carries 6?
Thank you.

Payload upmass requirements on the last missions require smaller crew sizes.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 08/30/2009 07:58 pm
Thanks, Chris, but wouldn't NASA want to maximize upmass on "131" as well?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/30/2009 08:04 pm
And here's a relatively complete list of her various birthdays/milestones:

January 29, 1979             Contract Award
August 27, 1979             Start long lead fabrication of Crew Module
June 20, 1980             Start fabrication lower fuselage
November 10, 1980     Start structural assembly of aft-fuselage
December 8, 1980     Start initial system installation aft fuselage
March 2, 1981             Start fabrication/assembly of payload bay doors
October 26, 1981             Start initial system installation, crew module, Downey
January 4, 1982             Start initial system installation upper forward fuselage
March 16, 1982             Midfuselage on dock, Palmdale
March 30, 1982             Elevons on dock, Palmdale
April 30, 1982             Wings arrive at Palmdale from Grumman
April 30, 1982             Lower forward fuselage on dock, Palmdale
July 16, 1982             Upper forward fuselage on dock, Palmdale
August 5, 1982             Vertical stabilizer on dock, Palmdale
September 3, 1982     Start of Final Assembly
October 15, 1982             Body flap on dock, Palmdale
January 11, 1983             Aft fuselage on dock, Palmdale
February 25, 1983    Complete final assembly and closeout installation, Palmdale
February 28, 1983     Start initial subsystems test, power-on, Palmdale
May 13, 1983             Complete initial subsystems testing
July 26, 1983             Complete subsystems testing
August 12, 1983             Completed Final Acceptance
October 16, 1983             Rollout from Palmdale
November 5, 1983     Overland transport from Palmdale to Edwards
November 9, 1983     Delivery to Kennedy Space Center
June 2, 1984            Flight Readiness Firing
August 30, 1984            First Flight (41-D)
Hope this is OK, but for grins a couple of screenshots from maybe five seconds of a local news report during STS-5; the rest I missed.  Unfortunately, this was the only tape I owned at the time and I was more focused on the mission (it was EOM day at the time).
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/30/2009 08:26 pm
Thanks, Chris, but wouldn't NASA want to maximize upmass on "131" as well?

There are three other mission after STS-131. As such, it's just not that much of a concern.

This might help explain it a little better.

http://www.nasaspaceflight.com/2009/02/sts-131-logistics-flight-baselined-by-prcb/

The mission is already deep into planning and is a very complex logistics flight (which brings up a lot of supplies and upmass to begin with).  The mission was baselined as a 12-day flight but because of everything that needs to take place on the mission they are extending it to 13-days to make sure the 7-member crew can complete all the objectives.  Reducing crew size on that mission for the sake of upmass would not be a good move.

UPDATE: Also, STS-133 (the final flight) will only carry 5 crew members, not 6.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 08/30/2009 08:37 pm
Thank you, Chris...now it makes sense.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 08/31/2009 01:04 am
Those are pretty cool stills, psloss.  If it's not available elsewhere, you might think about putting the whole video on L2 Historical.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/31/2009 02:26 am
Does anyone know if there is a plan on the books in shuttle to do a planned prebank if needed for ascent performance?  It gives about 800 pounds, IIRC, and Jon Harpold himself approved it.

I am thinking it might still be useful for some of the flights left.  It wouldn't be surprised if some of them aren't bumping up on the max ascent performance to carry stuff to station.  Even if it would allow us to carry more water up, that would be a plus. 

Station needs to be stuffed full of supplies when shuttle is retired.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/31/2009 09:45 am
Didn't we do this topic a few weeks ago? I was whining about how you'd cope with an underburn if you'd already targetted for a prebank or something like that.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 08/31/2009 10:46 pm
Sorry for the ignorance, but what's a prebank?
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 08/31/2009 11:29 pm
Prebank is a maneuver you do so you "fall faster" into the atmosphere. It's done between the D/O burn and EI, and it's just banking the orbiter so that the lift goes to the side instead of upwards... thus the orbiter falls faster... and you want to do that if you have a "D/O underburn" or in an AOA.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/31/2009 11:36 pm
Presumably that means you *plan* for a deorbit underburn thereby freeing up OMS propellant for use on ascent, thus giving you more ascent performance?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/31/2009 11:39 pm
Didn't we do this topic a few weeks ago? I was whining about how you'd cope with an underburn if you'd already targetted for a prebank or something like that.

It just came to me though it might have great utility in the remaining flights to help fill station to the brim with supplies.  I am sure it gives about 800 pounds per flight -- for free.  Why not do it? 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/01/2009 12:16 am
Thank you all for your answers as to what a prebank is.

Now, just so I'm understanding this, what you're asking Danny is why not launch with 800 additional lbs of cargo that's not provided for under standard mission rules, burn extra OMS propellant during ascent to get you to orbit -- leaving you with insificiant fuel to do a standard OMS deorbit, then, at the end fo the mission (or AOA) you intentionally perform a D/O burn with an underburn and the prebank to get the Orbiter to E/I faster?

Wouldn't that carry a lot more risks than potential benefits?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/01/2009 12:24 am
Thank you all for your answers as to what a prebank is.

Now, just so I'm understanding this, what you're asking Danny is why not launch with 800 additional lbs of cargo that's not provided for under standard mission rules, burn extra OMS propellant during ascent to get you to orbit -- leaving you with insificiant fuel to do a standard OMS deorbit, then, at the end fo the mission (or AOA) you intentionally perform a D/O burn with an underburn and the prebank to get the Orbiter to E/I faster?

Wouldn't that carry a lot more risks than potential benefits?

You just don't carry the OMS prop up in the first place.  The flight rules have lots of protection for reserves without the hip pocket reserves a planned pre-bank.  For example you would probably still cover for both OMS engines failing and having to do the deorbit with RCS.  Loss of an OMS tank while at station is probably loss of crew anyway.  The scenario that extra 800 pounds would matter is basically nil.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 09/01/2009 02:01 pm
Loss of an OMS tank while at station is probably loss of crew anyway.

Why? Sudden thrust on the shuttle tearing it from the PMA resulting in ISS/STS depressurization?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/01/2009 02:12 pm
Loss of an OMS tank while at station is probably loss of crew anyway.

Why? Sudden thrust on the shuttle tearing it from the PMA resulting in ISS/STS depressurization?

Not enough Delta V to do a survivable deoribit burn at station altitudes.  Most shuttle missions are loss of crew for loss of OMS tank.  And by loss of tank, I just mean the loss of ability to get the prop from a tank to either of the OMS engines or the 4 aft RCS jets.  The shuttle is well designed to protect for this failure.  About the only thing that could do this would be a design or manufacturing flaw in a tank weld.  Even for a leak, you would burn it retrograde before it all leaked out. 

Danny Deger

Edit, OMS tank leaks is one of the most fun things to throw at the control team during training an EVA session.  Nothing like a potential loss of crew to wake them up.  Just about everyone would get involved in the complex trade offs of when and how to burn.  It is not just fun, it is great training for the team.

BTW, a flight ready mission control team is in my opinion one of the best examples of a finally tuned, ready for anything, group of people in the history of the world.   This complement is coming from someone that use to train to fight WWIII for a living and has studied military history extensively.   I used to consider it an honor to train them to the high state of readiness they always achieved. 
Title: Re: Shuttle Q&A Part 5
Post by: D.A. on 09/01/2009 07:02 pm
Been wondering this for a while:

Does the shuttle have the largest (by dimensions) payload capacity of all launch systems in use today? Wikipedia says it's 4.6m by 18m in size, how much of that can be used for a single payload?

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/01/2009 07:10 pm
Been wondering this for a while:

Does the shuttle have the largest (by dimensions) payload capacity of all launch systems in use today? Wikipedia says it's 4.6m by 18m in size, how much of that can be used for a single payload?



No.  It is 60 feet by 15 feet in diameter.  All of it can used by a single payload.

Delta IV can have a longer fairing.  Atlas V has a wider fairing.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 09/01/2009 09:33 pm
But if STS looses an OMS tank while at ISS, the crew can remain aboard ISS until the LON arrives. No LOC, right?
Title: Re: Shuttle Q&A Part 5
Post by: nooneofconsequence on 09/01/2009 09:37 pm
Ok. Danny's been talking of 60 degree alpha entry by the Shuttle.

I assume this means a rapid deceleration, instability, and low cross range entry profile.

1. Would it have made a difference to Columbia? Downsides?

2. Earlier Shuttle concepts had high angle entry with "belly flop" manuver. What were the limits of this high drag approach on TPS that caused it to go away?

3. RCC leading edge certainly takes more thermal load than the foamed glass bricks on the underside. But what about the heat capacity/ thermal distribution? Or do we still just melt aluminum too quickly, regardless of RCC hole size?

Thank you.

edit:
Anyone? Anyone? Bueller?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/01/2009 09:39 pm
But if STS looses an OMS tank while at ISS, the crew can remain aboard ISS until the LON arrives. No LOC, right?

Not only is it not an LOC case, it is not even necessarily a CSCS/LON case. Prop fail will most likely start as a leak, not instantaneous failure of the tank. There is highly likely to be sufficient time for a joint expedited undocking/sep, followed by an orbit adjust burn using the leaking tank to lower perigee and decrease the prop cost of deorbit to within the capability of the good tank.

At least, that is how this case usually plays out when we sim it.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/01/2009 11:11 pm
Re my whining about prebanks and underburn.

My point was that you use prebank as a backup option in case of an underburn. So if you've already targeted for a prebank scenario, and then you suffer an underburn, what do you do then? You can't prebank, because you've already targetted for an prebank.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/01/2009 11:20 pm
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/01/2009 11:21 pm
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/01/2009 11:23 pm
Re my whining about prebanks and underburn.

My point was that you use prebank as a backup option in case of an underburn. So if you've already targeted for a prebank scenario, and then you suffer an underburn, what do you do then? You can't prebank, because you've already targetted for an prebank.

That's what I'm thinking too. I know Danny's question was hypothetical, but I wouldn't expect NASA to plan for a pre-bank.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/02/2009 12:16 am
Hmmm, what part of the ROFI's makes that noise?, from what I understand they are roman-candle type affairs which would be lit in the same way a model rocket would be (with a glow plug at the end of a wire), I cant see how this would make the distinct "revving" noise
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 12:29 am
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.

I think it is the SRB's Aux Power Units powering up.  And they are turbines.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/02/2009 12:32 am
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.

I think it is the SRB's Aux Power Units powering up.  And they are turbines.

Danny Deger

SRB HPU start is T-27secs with SRB nozzle steering checks at T-21secs
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 12:36 am
Re my whining about prebanks and underburn.

My point was that you use prebank as a backup option in case of an underburn. So if you've already targeted for a prebank scenario, and then you suffer an underburn, what do you do then? You can't prebank, because you've already targetted for an prebank.

That's what I'm thinking too. I know Danny's question was hypothetical, but I wouldn't expect NASA to plan for a pre-bank.

An underburn requires a failure of OMS propellant, not OMS engines.  The shuttle routinely flies without protection for OMS propellant failures. 

And if you plan for 90 and underburn, you recover with 180.  And a targeted 90, with a recovery to 180 is the same temp profile as we have today with a 90 recovery.

It is fully allowed by the current flight rules and was approved without hesitation by Mr. Entry himself, Jon Harpold.

In my opinion the almost nil risk is very much worth getting several tons of supplies up to station.  The current plan does not support ops without shuttle. 

This extra upmass might make the difference between 6 and 3 man crew in the not too distant future. 

Danny Deger

And I am not hypothetical.  I recommend it be done for all remaining flights to station to get more supplies up there.
Title: Re: Shuttle Q&A Part 5
Post by: HarryM on 09/02/2009 12:57 am
Ok. Danny's been talking of 60 degree alpha entry by the Shuttle.

I assume this means a rapid deceleration, instability, and low cross range entry profile.

1. Would it have made a difference to Columbia? Downsides?

2. Earlier Shuttle concepts had high angle entry with "belly flop" manuver. What were the limits of this high drag approach on TPS that caused it to go away?

3. RCC leading edge certainly takes more thermal load than the foamed glass bricks on the underside. But what about the heat capacity/ thermal distribution? Or do we still just melt aluminum too quickly, regardless of RCC hole size?

Thank you.

edit:
Anyone? Anyone? Bueller?

According to "The Space Shuttle Decision" it was the Air Force who really didn't like the belly-flop entry of the early Max Faget straight wing proposal, more to do with controllability than TPS.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 02:32 am
Ok. Danny's been talking of 60 degree alpha entry by the Shuttle.

I assume this means a rapid deceleration, instability, and low cross range entry profile.

1. Would it have made a difference to Columbia? Downsides?


No change in deceleration.  The shuttle would fly at a higher altitude to get the same amount of drag -- that is the whole point.  The auto pilot is fully certified to fly at 60 alpha so no stability problems.

Cross range is reduced, but easily compensated for by landing opportunity selection, especially if you have days to plan the entry.

Quote

2. Earlier Shuttle concepts had high angle entry with "belly flop" manuver. What were the limits of this high drag approach on TPS that caused it to go away?


I don't understand the question exactly, but I hope this answers your question.

Maximum Lift over Drag is best cross range.  For shuttle this is alpha 20.  But the leading edge temperature is too high at alpha 20.  Minimum heating is a maximum lift.  This is 60 for the shuttle, but lift over drag is much less at 60 than 20.  Alpha 40 is the lowest alpha to not over temp the RCC on the leading edge of the wings, so it was picked.  But the autopilot was certified to 60 just in case this high alpha was ever needed for any reason.

Quote

3. RCC leading edge certainly takes more thermal load than the foamed glass bricks on the underside. But what about the heat capacity/ thermal distribution? Or do we still just melt aluminum too quickly, regardless of RCC hole size?

 

An alpha 60 entry certainly reduces both heat rate and total heat load a lot.  But, in my opinion Columbia was probably hurt to bad to have been saved by this technique.  But remember, NASA didn't know how bad Columbia was hurt.  Given they didn't know, an alpha 60 entry should have been done in my opinion.

I learned all this when I trained astronauts how to do an approved "High Energy TAL", which is done at alpha 50.  I would put the failure in to get the correct entry condition and have the crew do the procedure.  The orbiter bug on the display showed us WAYYY past the max temp line on the entry display.  I was concerned we were actually burning up, but the sim doesn't model heating anyway.  I took a screen shot of the display and talked to the flight design guys about this.  They confirmed I put the crew where they belonged, but because they were alpha 50 instead of 40 -- all was well.  The reduction of heat at 50 was huge.  60 is even better.

As I said the shuttle is designed an certified to fly an alpha 60 entry.  It only limits your landing opportunities. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 02:37 am
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.

I think it is the SRB's Aux Power Units powering up.  And they are turbines.

Danny Deger

SRB HPU start is T-27secs with SRB nozzle steering checks at T-21secs

I thought they started at T-19.  I am certainly not a reliable source on this though, so you are probably correct.  But I do recall STS-51 "aborted" at T-19 because one didn't start.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 03:10 am
snip

The fear of going into a spin - potentially a hypersonic spin.

snip

Hypersonic delta wings actually love high alphas.  They actually go out of control due to dutch roll at low alphas and the shuttle has a lower hypersonic alpha limit for this reason.  For example, the shuttle flies a hypersonic alpha 57 on an RTLS.  Like I said, the autopilot is fully certified to alpha 60 hypersonic.  It is in the SODB that I know is in L2 here, but I can't find it.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 03:59 am

So no downsides?

Only need to look harder for a landing site.

Quote

snip
Faget's orbiter had a high drag profile pushing stability - was it due to perceived TPS limitations or fear of entering a flat spin. Also, was dynamic, adaptive profiles and aborts to other landings considered or not.


I am not familiar with this design.  Post a link here and I will take a look.


Quote
Do you have any idea of the figure of merit of how much -meaning are we talking a drastic decrease or a linear relationship?

Drastic decrease in heating.  On a high energy TAL, the orbiter bug is WAYY past the high temp line on the TRAJ display.  And, this is at alpha 50.  I think it is linear with coeficent of lift because, but I am not sure.  I derived the effect once, but it is late and I have my own spaceship to get past SDR by Sept 22.

snip

Quote
The pilot was I think aware of the issue soon into entry - too late to change profile (e.g, adaptive), although I think I heard he altered yaw and pitch to attempt to mitigate. It doesn't seem like he had much other in the way of options to mitigate.


Too late to change in the middle of the entry, but it could be done.  Rick Husband took control just before data was lost.  It is obvious he was reacting to the un-commanded roll the left.   He reacted exactly as I trained him to.

Quote

Even the theory of a crack or deformation from laminar flow on the leading edge is a significant issue for entry, so you would want to fly a profile to unstress it in a safety culture. Was the high alpha entry more likely to be distrusted because of it being untried, or simply considered ineffectual for a potential issue  -e.g. the cure being worse than the disease?

Remember the official answer was Columbia wasn't hurt.  We didn't even need to ask DOD to take pictures.  I have no doubt the people that invented high energy TAL would have figured this out if asked.  I had even seen flight controller make a call real time in a sim to increase alpha to reduce heating.  Increasing alpha to reduce heating was not a secret.  It is now though  >:(

Quote

snip

When was the commit to do the procedure? Prior to entry or during entry?


Before the entry.
snip
Quote
That's very creepy.
 

Dying in the sim was not uncommon.  That is what they are for.  I asked John Young once about him dying during training during a sim that they didn't get the LM up and running in time.  He responded he died so many times, he wouldn't have a chance to remember.
snip

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: nooneofconsequence on 09/02/2009 04:12 am
Faget's orbiter:
(http://history.nasa.gov/SP-4221/p208.jpg)
http://history.nasa.gov/SP-4221/ch5.htm#208 (http://history.nasa.gov/SP-4221/ch5.htm#208)
http://forum.nasaspaceflight.com/index.php?topic=9004.0 (http://forum.nasaspaceflight.com/index.php?topic=9004.0)
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/02/2009 04:45 am
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.

I think it is the SRB's Aux Power Units powering up.  And they are turbines.

Danny Deger

SRB HPU start is T-27secs with SRB nozzle steering checks at T-21secs

I thought they started at T-19.  I am certainly not a reliable source on this though, so you are probably correct.  But I do recall STS-51 "aborted" at T-19 because one didn't start.

Danny Deger

"There are two self-contained, independent Hydraulic Power Units (HPUs) on each SRB. Each HPU consists of an auxiliary power unit (APU), fuel supply module, hydraulic pump, hydraulic reservoir and hydraulic fluid manifold assembly. The APUs are fueled by hydrazine and generate mechanical shaft power to drive a hydraulic pump that produces hydraulic pressure for the SRB hydraulic system. The two systems operate from T-28 seconds until SRB separation from the ET."
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 05:11 am
Faget's orbiter:
(http://history.nasa.gov/SP-4221/p208.jpg)
http://history.nasa.gov/SP-4221/ch5.htm#208 (http://history.nasa.gov/SP-4221/ch5.htm#208)
http://forum.nasaspaceflight.com/index.php?topic=9004.0 (http://forum.nasaspaceflight.com/index.php?topic=9004.0)

It would have had to have done a very high alpha entry with those thin wings.  I don't know about high alpha stability of this design.  I know delta wings are OK, but then they are also good high alpha wings subsonic.

In general, shuttle has about as much wing as you can stand at Mach 25.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/02/2009 05:27 am
Faget's orbiter:
(http://history.nasa.gov/SP-4221/p208.jpg)
http://history.nasa.gov/SP-4221/ch5.htm#208 (http://history.nasa.gov/SP-4221/ch5.htm#208)
http://forum.nasaspaceflight.com/index.php?topic=9004.0 (http://forum.nasaspaceflight.com/index.php?topic=9004.0)

It would have had to have done a very high alpha entry with those thin wings.  I don't know about high alpha stability of this design.

The USAF did not think highly of its stability, especially for the "belly flop" maneuver from high-alpha entry to controlled flight. They thought it to be beyond the capability of 1970s era fly-by-wire systems.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 09/02/2009 06:40 am
What is the whirring noise heard usually at about T-15 seconds? it sounds like what you'd expect the high-pressure turbos to sound like but this is much too early for them, so I can only guess its air being forced through the pipes and out of the nozzles as water runs through the sound suppresion system?

The ROFI systems powering up.

I think it is the SRB's Aux Power Units powering up.  And they are turbines.

Danny Deger

SRB HPU start is T-27secs with SRB nozzle steering checks at T-21secs

I thought they started at T-19.  I am certainly not a reliable source on this though, so you are probably correct.  But I do recall STS-51 "aborted" at T-19 because one didn't start.

Danny Deger

"There are two self-contained, independent Hydraulic Power Units (HPUs) on each SRB. Each HPU consists of an auxiliary power unit (APU), fuel supply module, hydraulic pump, hydraulic reservoir and hydraulic fluid manifold assembly. The APUs are fueled by hydrazine and generate mechanical shaft power to drive a hydraulic pump that produces hydraulic pressure for the SRB hydraulic system. The two systems operate from T-28 seconds until SRB separation from the ET."

I thought at T-15 or so, the high pitched sound was the sound suppression system pumps kicking up, or air coming out of the waterbirds as well.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 09/02/2009 07:01 am
I apologize for inserting a new question in the midst of an interesting discussion, but...

When viewing the Shuttle MCC on NASA TV, what are the narrow amber displays on both ends of each console? The ISS MCC consoles have them as well.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/02/2009 09:26 am
They are the DVIS system, essentially the voice loops that everyone listens to. You can turn on or off various ones to listen to, and then talk on those loops if required.

Actually, that's a request for L2, potentially. Is there any kind of documentation about the DVIS system? I'd be really interested, as someone who sometimes deals with audio routing and the like (we have radio studios at my university job).
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/02/2009 09:27 am
Sorry for bringing up the prebank again, but surely a 180 degree prebank puts your TPS facing upwards, and the crew cabin directly into the face of hot burny firey danger?
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 09/02/2009 10:37 am
no it doesn't, the prebank it done BEFORE EI (not alot of heat there). And it's not a roll, but a banking. If alpha is positive, you can bank all you want and the bottom will still be facing forward.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/02/2009 11:05 am
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...

Also, I know the banking is done pre-EI, so when does it come out of the prebank after EI?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 01:32 pm
Sorry for bringing up the prebank again, but surely a 180 degree prebank puts your TPS facing upwards, and the crew cabin directly into the face of hot burny firey danger?

Not at all.  You are upside down, but still at any alpha you choose to be at.  The belly is still taking the heat, not the top. 

Take the case of flying fighter aircraft.  If I needed to go down fast, I would never just push over.  I would roll over and pull.  This way I was upside down with positive angle of attack and positive Gs.  I hated negative Gs because all of the crap on the bottom of the cockpit would float up and get in my eyes.  It is really hard to thoroughly vacuum out the cockpit of a fighter aircraft. 

On getting the voice loops here.  That would be great.  They are controlled by "Houston Voice".  They are a great bunch of guys to work with.  Someone contact them by calling JSC information 281-483-0123 and ask for Houston Voice.  My guess is they would be all for it, but others will not like the flight loop and such available to people like us.  It is even closely controlled inside the center.   Only "special people" have a flight loop speaker on their desk.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 01:46 pm
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...

Also, I know the banking is done pre-EI, so when does it come out of the prebank after EI?

The pre-bank is taken out by the crew simply selecting "auto" roll as soon as guidance wakes up as the orbiter gets in the atmosphere and the IMUs sense drag on the airframe.  Before I took over entry training, the crew manually flew out the pre-bank, but they routinely died by either not rolling at all (thus burning up) or rolling to wings level and staying there until I had to stop the sim and ask then why they wanted to back into orbit instead of completing the entry  :o

When I told the flight controllers the procedure at the time had something like a 50% mortality rate built into it, I was told we needed to continue to use it anyway to keep the roll rates down.  They didn't like it when I asked them if the auto commanded rates would result in a mortality rate greater than 50%.  I did their job for them and found a forgotten feature in the auto-pilot to limit roll rates at high Mach numbers and my change to let auto fly out the prebank finally got approved. 

And yes I was not happy that the flight controllers didn't take quick action when the Entry Training Flow Supervisor alerted them that an established and documented procedure had a 50% mortality rate due to crew error.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 09/02/2009 01:49 pm
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...

It might be facing the ground but it's still facing away from the direction of travel.  Travel is more-or-less parallel to the ground, so upside down with nose pointing down at a steep angle still puts the heat on the belly.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/02/2009 02:50 pm
Can someone get me the shuttle's Cl and Cd vs. alpha at hypersonic Mach numbers?   I want to quantify the reduction is heat load and heat rate for an alpha 60 entry.  It will not be hard with these numbers.

I am starting to think Columbia might have held together with an alpha 60 entry.  She did hang in there until something like Mach 18.  This is about the time she was starting to cool down anyway. 

There is no way the people that invented the very effective 50 alpha high energy TAL didn't look into this.  I am also very certain that these people would have instantly recommended a high alpha entry for Columbia, if they had known about the potential of TPS damage.  Enough people knew about the debris strike, such information had to get the heating guys.

I can't tell the effect in that room when I asked where the alpha 60 entry data was in looking at mitigating TPS damage.  It sucked the air right of me.  Did somebody's dissenting opinion get quashed -- once again?  I know mine did.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/02/2009 07:04 pm
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...


It is actually very easy to visualize. Take a foam orbiter toy. Shove a stick into the belly at a 40 degree angle below the nose. That is the relative wind vector. It is also the X axis of the stability axis frame. That is the key. The bank is performed about stability axes, not body axes.

Now orient the toy so that you're looking down the stick at the belly. You're seeing the orbiter from the relative wind point of view. As long as the relative wind is aligned with the stick, the proper angle of attack (alpha) of 40 and sideslip angle (beta) of zero are maintained.

Now rotate the orbiter toy about the stick so that the belly is on top and the nose is pointed 40 degrees down. That's a prebank of 180. But the relative wind is still looking at the black belly, not the white tiles.

That's the key. When you perform a "roll" during entry you are rolling about the stability axes (the stick) and not the body axes (the nose). If you rolled 180 about the body axes you'd wind up with the top (white tiles) facing the wind. But a roll about stability axes always keeps the black side facing the wind.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/02/2009 09:12 pm
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...

It might be facing the ground but it's still facing away from the direction of travel.  Travel is more-or-less parallel to the ground, so upside down with nose pointing down at a steep angle still puts the heat on the belly.

Perfect, that makes sense now. I guess I still had the idea of the flight path angle being aimed down somewhat, but of course it's not that bad.

Re the DVIS, Danny, I wasn't advocating getting access to the loops or anything, just any kind of documentation on it's use for MCC personnel, or anything that might be interesting to those of us who happen to work with audio technology.

If Chris is reading, you can consider this an L2 request, but I'll post it in there as well just to make sure. :)
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/02/2009 09:15 pm
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...


It is actually very easy to visualize.

Oh that's a great help too, thanks!
Title: Re: Shuttle Q&A Part 5
Post by: MCC Tech on 09/03/2009 12:27 am
Quote
Quote by elmarko: 
Actually, that's a request for L2, potentially. Is there any kind of documentation about the DVIS system? I'd be really interested, as someone who sometimes deals with audio routing and the like (we have radio studios at my university job).

DVIS is one of the systems I work on.   I'll see if I can find a keyset users manual tonight and get it scanned for L2.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/03/2009 08:47 am
You're wonderful, thank you so much!

Is there any kind of orientation training manual kind of thing for new users, or do they just get given the manual?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/03/2009 11:14 pm
I have quantified the effect of increased alpha on heating, but I think we should move the discussion and leave this thread for shorter Q&As.

http://forum.nasaspaceflight.com/index.php?topic=8080.msg471678#msg471678

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/04/2009 12:39 am
You're wonderful, thank you so much!

Is there any kind of orientation training manual kind of thing for new users, or do they just get given the manual?

I don't recall even getting the manual. DVIS is one of those things you learn by having a senior sit next to you and show you how to use it. It has some fancy features but 90% of what a flight controller will ever use it for can be learned in ten minutes.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/04/2009 03:16 am
You're wonderful, thank you so much!

Is there any kind of orientation training manual kind of thing for new users, or do they just get given the manual?

I don't recall even getting the manual. DVIS is one of those things you learn by having a senior sit next to you and show you how to use it. It has some fancy features but 90% of what a flight controller will ever use it for can be learned in ten minutes.

I agree.  It is well designed and has an intuitive interface.  My dishwasher on the other hand....

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 09/05/2009 01:56 am
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...


It is actually very easy to visualize. Take a foam orbiter toy. Shove a stick into the belly at a 40 degree angle below the nose. That is the relative wind vector. It is also the X axis of the stability axis frame. That is the key. The bank is performed about stability axes, not body axes.

Now orient the toy so that you're looking down the stick at the belly. You're seeing the orbiter from the relative wind point of view. As long as the relative wind is aligned with the stick, the proper angle of attack (alpha) of 40 and sideslip angle (beta) of zero are maintained.

Now rotate the orbiter toy about the stick so that the belly is on top and the nose is pointed 40 degrees down. That's a prebank of 180. But the relative wind is still looking at the black belly, not the white tiles.

That's the key. When you perform a "roll" during entry you are rolling about the stability axes (the stick) and not the body axes (the nose). If you rolled 180 about the body axes you'd wind up with the top (white tiles) facing the wind. But a roll about stability axes always keeps the black side facing the wind.

Jorge, I have read this explaianation over and over and still can't picture it.  where can I find a drawing of this?

Even stick figures will help as I am not a member of L2.

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 09/05/2009 02:19 am
To whom it may concern:

How can the (small compared to ISS) shuttle, or even the russian segment, for that matter, boost the orbit of the ISS?  I mean don't you need MORE more thrusters spread out along the truss on both sides (like the shuttle) to boost the mass of ISS.

Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/05/2009 02:20 am
It's really hard to visualise it.

I don't suppose anyone fancies a crack at drawing a diagram or something, because to me all I can think of is the orbiter banking past 90 degrees and then after 90 the white stuff is facing the ground...


It is actually very easy to visualize. Take a foam orbiter toy. Shove a stick into the belly at a 40 degree angle below the nose. That is the relative wind vector. It is also the X axis of the stability axis frame. That is the key. The bank is performed about stability axes, not body axes.

Now orient the toy so that you're looking down the stick at the belly. You're seeing the orbiter from the relative wind point of view. As long as the relative wind is aligned with the stick, the proper angle of attack (alpha) of 40 and sideslip angle (beta) of zero are maintained.

Now rotate the orbiter toy about the stick so that the belly is on top and the nose is pointed 40 degrees down. That's a prebank of 180. But the relative wind is still looking at the black belly, not the white tiles.

That's the key. When you perform a "roll" during entry you are rolling about the stability axes (the stick) and not the body axes (the nose). If you rolled 180 about the body axes you'd wind up with the top (white tiles) facing the wind. But a roll about stability axes always keeps the black side facing the wind.

Jorge, I have read this explaianation over and over and still can't picture it.  where can I find a drawing of this?

Even stick figures will help as I am not a member of L2.

Thanks
Oxford750

Here is a drawing from the Entry DAP Workbook.

Title: Re: Shuttle Q&A Part 5
Post by: AlexInOklahoma on 09/05/2009 02:26 am
Ok - stick figures it is  :-)  And I am not positive that I got this right, but I will try.  In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)

Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak.  However, notice how its the 'bottom' that is striking the 'wind'?  Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow.  Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...

I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!).  Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL!  Thanks, Jorge..seriously, it helped me more than you may realize!

Anyways, hope that helps, and I truly hope that I am showing things correctly...  not too shabby for a quick Paint sketch, 'eh?

Alex

Edit - Jorge beat me to the pic...and I like his pic much better  :-)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/05/2009 03:23 am
Ok - stick figures it is  :-)  And I am not positive that I got this right, but I will try.  In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)

Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak.  However, notice how its the 'bottom' that is striking the 'wind'?  Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow.  Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...

I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!).  Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL!  Thanks, Jorge..seriously, it helped me more than you may realize!

Anyways, hope that helps, and I truly hope that I am showing things correctly...  not too shabby for a quick Paint sketch, 'eh?

Alex

Edit - Jorge beat me to the pic...and I like his pic much better  :-)

You got it perfectly -- including the terms. 

And I like your picture better  :)

On boosting station.  I don't know the details, but you can boost with a small single thruster through the center of gravity it you burn it a long time.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 09/05/2009 04:10 am
To whom it may concern:

How can the (small compared to ISS) shuttle, or even the russian segment, for that matter, boost the orbit of the ISS?  I mean don't you need MORE more thrusters spread out along the truss on both sides (like the shuttle) to boost the mass of ISS.

Thanks
Oxford750

It's not so much the quantity or size of the thrusters as much as where they're located and how much time is needed for the burn.

Note that either the Russian segment or Progress thrusters can used for reboosts (and usually are).

Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 09/05/2009 05:56 am
Ok - stick figures it is  :-)  And I am not positive that I got this right, but I will try.  In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)

Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak.  However, notice how its the 'bottom' that is striking the 'wind'?  Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow.  Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...

I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!).  Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL!  Thanks, Jorge..seriously, it helped me more than you may realize!

Anyways, hope that helps, and I truly hope that I am showing things correctly...  not too shabby for a quick Paint sketch, 'eh?

Alex

Edit - Jorge beat me to the pic...and I like his pic much better  :-)

Wow I never knew that the shuttle did that to "bleed off speed" or do I have it wrong. After seeing that I realized that I DID have the "right" picture in my mind, I just needed a conformation.

Thanks AlexInOklahoma


















Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/05/2009 06:05 am
Ok - stick figures it is  :-)  And I am not positive that I got this right, but I will try.  In my pic, the upper Orbiter is with bottom towards ground and travelling to the 'left' of pic...arrow indicates direction of air/wind that Orbiter is 'seeing' upon its surfaces/wings. (angle0of-attack of wings is approximate but should give general idea)

Lower pic is after Orbiter 'rolls' 180 over onto its 'belly', so to speak.  However, notice how its the 'bottom' that is striking the 'wind'?  Yes, the top is facing downwards, but nothing else has changed for the most part, particularly the angle-of-attack of the wings -v- airflow.  Its a position kind of like when an airplane is about to touchdown on landing (if that helps?)...

I realize my terms are not standard, but trying to 'dumb it down' (no offense to anyone!).  Jorge's explanation got me FINALLY picturing all this in my head, and I am (used to be anyways) a licensed pilot, LOL!  Thanks, Jorge..seriously, it helped me more than you may realize!

Anyways, hope that helps, and I truly hope that I am showing things correctly...  not too shabby for a quick Paint sketch, 'eh?

Alex

Edit - Jorge beat me to the pic...and I like his pic much better  :-)

Wow I never knew that the shuttle did that to "bleed off speed" or do I have it wrong. After seeing that I realized that I DID have the "right" picture in my mind, I just needed a conformation.

Thanks AlexInOklahoma




















Well, more accurately the orbiter *could* do that if it needed to. To my knowledge, we've never done a prebank of 180. I kinda doubt it's ever gone past 90, actually.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 09/05/2009 06:09 am

Wow I never knew that the shuttle did that to "bleed off speed" or do I have it wrong. After seeing that I realized that I DID have the "right" picture in my mind, I just needed a conformation.

Thanks AlexInOklahoma

Speed is relative. What the whole reentry profile/trajectory is doing is managing/bleeding off energy all the way to the runway.

What made my lightbulb blink on years ago was changing my focus from just speed to energy - it lets you view the entire sequence from orbit to landing in a much more logical and understandable fashion - the safest way so large amount of orbital energy is dissipated during reentry.

 
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 09/05/2009 06:20 am
To whom it may concern:

How can the (small compared to ISS) shuttle, or even the russian segment, for that matter, boost the orbit of the ISS?  I mean don't you need MORE more thrusters spread out along the truss on both sides (like the shuttle) to boost the mass of ISS.

Thanks
Oxford750

It's not so much the quantity or size of the thrusters as much as where they're located and how much time is needed for the burn.

Note that either the Russian segment or Progress thrusters can used for reboosts (and usually are).



Thanks for that answer however the other problem I am having is with the center of gravity. I mean is the shuttle "not" on the "wrong" side of the stations center of gravity as opposed to Directly beneth it, (ie the thusters at the nose and the tail of the shuttle are an equall distance from the "middle" of the payload bay) therefore imparting the station to "roll" and or "yaw" and the same thing with the russain segment ?


Hope I made sense.
Thanks
Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: hop on 09/05/2009 06:56 am
Thanks for that answer however the other problem I am having is with the center of gravity. I mean is the shuttle "not" on the "wrong" side of the stations center of gravity as opposed to Directly beneth it, (ie the thusters at the nose and the tail of the shuttle are an equall distance from the "middle" of the payload bay) therefore imparting the station to "roll" and or "yaw" and the same thing with the russain segment ?
This probably belongs in ISS Q&A, but anyway... the thrust doesn't have to be exactly through the center of the stacks CG. You can counter the torques with other thrusters, it just burns some additional propellant.

Thrust a long the long axis of the station (i.e. a Progress or ATV docked on the end of Zvezda firing rearward facing engines) is pretty close to the CG, and AFAIK this is the preferred configuration to do reboosts.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 09/05/2009 08:26 am
This probably belongs in ISS Q&A, but anyway... the thrust doesn't have to be exactly through the center of the stacks CG. You can counter the torques with other thrusters, it just burns some additional propellant.

Thrust a long the long axis of the station (i.e. a Progress or ATV docked on the end of Zvezda firing rearward facing engines) is pretty close to the CG, and AFAIK this is the preferred configuration to do reboosts.

Is it not true that the stack can be re-oriented via CMGs so that the thrust is pretty close to the total CG (or is that what you're saying, with other thrusters or CMGs making up the difference to keep the stack steady)?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/05/2009 01:28 pm
snip

Well, more accurately the orbiter *could* do that if it needed to. To my knowledge, we've never done a prebank of 180. I kinda doubt it's ever gone past 90, actually.

Correct.  So far it has always entered wings level, but quickly goes to almost 90 to keep from skipping back up into the vacuum of space.

I am proposing it start coming in at 90 in the first place -- 90 degrees prebank.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 09/05/2009 03:57 pm
where can I find a drawing of this?

Here's a good wiki article, with words describing the axes (no pictures).  There are 3 books listed in the references.  I've seen Roskam's on many, many shelves.
http://en.wikipedia.org/wiki/Stability_derivatives
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 09/05/2009 04:59 pm
Thanks for that answer however the other problem I am having is with the center of gravity. I mean is the shuttle "not" on the "wrong" side of the stations center of gravity as opposed to Directly beneth it, (ie the thusters at the nose and the tail of the shuttle are an equall distance from the "middle" of the payload bay) therefore imparting the station to "roll" and or "yaw" and the same thing with the russain segment ?
This probably belongs in ISS Q&A, but anyway... the thrust doesn't have to be exactly through the center of the stacks CG. You can counter the torques with other thrusters, it just burns some additional propellant.

Thrust a long the long axis of the station (i.e. a Progress or ATV docked on the end of Zvezda firing rearward facing engines) is pretty close to the CG, and AFAIK this is the preferred configuration to do reboosts.

thanks hop
Title: Re: Shuttle Q&A Part 5
Post by: ZANL188 on 09/06/2009 09:36 pm
Which TDRS spacecraft are being used as TDRS-East & TDRS-West Now?  I had assumed it was TDRS-4 (Norad: 19883) & TDRS-7 (Norad:23613) however it appears TDRS-7 has been moved quite a bit west of its old location.  This put the ZOE over mid Pacific which I don't think is correct..

Title: Re: Shuttle Q&A Part 5
Post by: klausd on 09/07/2009 05:11 am
What is this on the discovery  ???

(http://666kb.com/i/bc65spc2ywjjeckp2.jpg)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/07/2009 05:13 am
What is this on the discovery  ???

Vents 1 and 2.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 09/07/2009 12:56 pm
I never noticed those. What do they do?
They're close to the RCS system, do they vent out the remaining RCS fuel once the shuttle is in the atmosphere and RCS is useless?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/07/2009 01:52 pm
I never noticed those. What do they do?
They're close to the RCS system, do they vent out the remaining RCS fuel once the shuttle is in the atmosphere and RCS is useless?

No, they vent the internal compartments of the orbiter during ascent and descent.  They line the orbiter going from the nose to the aft.  They are more visible on the payload bay sides. The payload bay is not air tight and all the air must go in and out.

The forward RCS "dumped" right before entry and it is done through the thrusters.
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 09/09/2009 04:10 pm
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/09/2009 04:26 pm
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)

KH-12 has propulsion systems. Hubble doesn't.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/09/2009 04:29 pm
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)

It is because Hubble is NASA and KH-12 is DOD.  DOD follows the international rules on satellite and upperstage disposal, and NASA makes up its own and any engineer that brings the international rules into a NASA meeting for discussion on the matter is considered a trouble maker and is labeled a "loose cannon" by his boss.  I have first hand experience in this matter. 

I am sure Hubble could just be allowed to enter own its own and all would be well.  This happens all the time to space assets.  Station, however, could not be allowed to have a natural decay.  It is too big and there would be too much risk to people on the ground.  The ET is also too big and it must be disposed of in a controlled manner. 

Danny Deger

Edit: Come to think about it.  Upperstage disposal hurt EELV performance a lot, even though it is clearly not needed. 

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/09/2009 04:56 pm
In which checklist are the PL Cams B/C tilt/pan angles listed for the FCS C/O?
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 09/09/2009 10:29 pm
Why are there quindar tones on UHF comm, but not on A/G1 and A/G 2?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/09/2009 10:40 pm
Why are there quindar tones on UHF comm, but not on A/G1 and A/G 2?

Bill, this has been answered many, many, many times.  Use the search function to search the Q&A forums.  :)
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 09/09/2009 10:46 pm
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)

KH-12 has propulsion systems. Hubble doesn't.

That's something I didn't know. So the question that pops up in my head is why don't Hubble have propulsion? Is it unnecessary for it's mission or would it be to heavy to launch on shuttle? What kind of propulsion does KH-12 have and how long does it last? I know this is classified but a qualified guess?
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 09/09/2009 10:48 pm
Chris, I searched and couldn't find it.  I searched again, and was directed to this current thread.  I'll keep trying, will throw out another question.  C.J. just requested a tag-up with Entry Flight on Air/Ground 3.  What is A/G3?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/09/2009 10:48 pm
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)

KH-12 has propulsion systems. Hubble doesn't.

That's something I didn't know. So the question that pops up in my head is why don't Hubble have propulsion?

Concerns over contamination of the optics.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/09/2009 11:41 pm
What kind of propulsion does KH-12 have and how long does it last? I know this is classified but a qualified guess?

Define a qualified guess.  There are many types of low orbiting NRO spacecraft, and the propulsion systems would be just varied as NASA's spacecraft.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/09/2009 11:44 pm

It is because Hubble is NASA and KH-12 is DOD.  DOD follows the international rules on satellite and upperstage disposal, and NASA makes up its own. 


Danny, you are painting NASA with a too broad of brush.  NASA follows the proper protocols for orbital debris and its requirements are more stringent than the FAA's or international laws.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/10/2009 12:08 am

It is because Hubble is NASA and KH-12 is DOD.  DOD follows the international rules on satellite and upperstage disposal, and NASA makes up its own. 


Danny, you are painting NASA with a too broad of brush.  NASA follows the proper protocols for orbital debris and its requirements are more stringent than the FAA's or international laws.

I plead guilty as charged.  I can only speak toward making the Delta and Atlas do a "guided" disposal of their upperstages for Exploration missions.  I know that this is not done for commercial satellite missions where they end up in Geo Transfer Orbit.  Does the Atlas and Delta upperstages do a deorbit burn when they go low earth orbit?  I do recall being repermanded for being a loose cannon just because I asked the question to help get the performance up.    I really did my best to save us many billions of dollars.

And Hubble has no propulsion at all.  The gyros and some type of control wheels control attitude.  I don't know about the NRO telescopes.  I could make a guess, but I know too much to do it here.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: yinzer on 09/10/2009 12:52 am
During the STS-125 mission they attached a soft docking mechanism to Hubble to de-orbit it safely. I understand that this is because they don't want it there when the gyroscopes fail and they loose control of it. But what about the KH-12 spy satellite (or the other KHs) which are about the same size and mass as Hubble, what will happen to them when there gyroscopes fail?

Or is the safe de-orbiting of Hubble just because of the big public awareness of Hubbe compare to KH-12?

(sorry if this is the wrong section, couldn't find a good one)

KH-12 has propulsion systems. Hubble doesn't.

That's something I didn't know. So the question that pops up in my head is why don't Hubble have propulsion?

Concerns over contamination of the optics.

Hubble doesn't have to be in any particular orbit, as it looks at stuff that is distributed all over the sky and that generally doesn't change.  So they put it up as high as possible, and reboost it when they service it.

The KH-12 likes to be in a particular orbit, since it looks at certain things on the ground and wants to see them at certain times.  Staying in that orbit requires propulsion.  It also sometimes wants to be in a different particular orbit from the one it happens to be in, which also requires propulsion.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 09/10/2009 04:05 am
Re: disposal orbits.  Mostly they just have to get out of the orbit of whatever they're dropping off.  Usually it's perigee lowering to facilitate entry, but it can also be an out-of-plane burn.  Once in a long while they can even do earth escape.

In any case, the key is inerting, blowing down all fluids and leaving the valves open (which makes me wonder about wet cell batteries, come to think of it).  There was a spent Ariane stage that exploded in the 90s that led to the international agreements on this.
Title: Re: Shuttle Q&A Part 5
Post by: rlloyd1 on 09/10/2009 03:35 pm
I was wondering, while shuttle is orbitting in space how long does it take to revolve around the earth?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 09/10/2009 03:43 pm
About 90 minutes.
Title: Re: Shuttle Q&A Part 5
Post by: rlloyd1 on 09/10/2009 03:45 pm
About 90 minutes.

Thanks !
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 09/10/2009 07:18 pm
Quick question, sorry if its been asked before, but POA mentioned on NASA tv last night that Discovery's crew was installing a chair for Kopra so he can adjust to gravity easier on entry. Is this the usual chair you would see on mid-deck or how does it differ?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/10/2009 07:18 pm
Quick question, sorry if its been asked before, but POA mentioned on NASA tv last night that Discovery's crew was installing a chair for Kopra so he can adjust to gravity easier on entry. Is this the usual chair you would see on mid-deck or how does it differ?

Thanks.

It's a recumbent seat, so Kopra will be lying down.
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 09/10/2009 07:25 pm


It's a recumbent seat, so Kopra will be lying down.

Thanks! If I may ask, how is it positioned, doesn't seem to be much room on mid-deck. So he will be laying down with aspect to the shuttle being horizontal, would the head be towards the nose then?

Sorry there for a minute I was picturing a seat laying down while shuttle is vertical. *face palm*
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/10/2009 07:35 pm


It's a recumbent seat, so Kopra will be lying down.

Thanks! If I may ask, how is it positioned, doesn't seem to be much room on mid-deck. So he will be laying down with aspect to the shuttle being horizontal, would the head be towards the nose then?

Sorry there for a minute I was picturing a seat laying down while shuttle is vertical. *face palm*

No, feet toward nose.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/10/2009 07:35 pm


It's a recumbent seat, so Kopra will be lying down.

Thanks! If I may ask, how is it positioned, doesn't seem to be much room on mid-deck. So he will be laying down with aspect to the shuttle being horizontal, would the head be towards the nose then?

Sorry there for a minute I was picturing a seat laying down while shuttle is vertical. *face palm*
Here's a link to a picture from STS-79:
http://spaceflight.nasa.gov/history/shuttle-mir/multimedia/sts-79-photos/79p-006.htm

For comparison, I've attached that photo along with a rotated screenshot that Ford posted during strap-in for this mission's launch that shows the typical mid-deck seats in horizontal orientation.
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 09/10/2009 07:42 pm
Thanks for posting the link psloss, very helpful.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 09/11/2009 01:58 pm
If they're expecting difficulty with afternoon weather in Florida, why not try a descending node landing?  Is the boundary layer DTO the reason?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/11/2009 02:00 pm
If they're expecting difficulty with afternoon weather in Florida, why not try a descending node landing?  Is the boundary layer DTO the reason?
The issue with noctilucent clouds is in the summer (well, northern hemisphere summer).

For a non-contingency case, there's also sleep-shift issues...the descending nodes are closer to crew sleep.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 09/11/2009 02:02 pm
If they're expecting difficulty with afternoon weather in Florida, why not try a descending node landing?  Is the boundary layer DTO the reason?

Ascending node or decending node don't really matter when the weather concerns are in and around the 30 nmi circle of KSC.  Still violates constraints.  Plus a decending node would take the vehicle over the US during the final phase of entry and that is something that is avoided as much as possible post-STS-107. 
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 09/11/2009 02:06 pm
If they're expecting difficulty with afternoon weather in Florida,

It's not just afternoon, as we've been mentioning - it's raining about all the time around KSC. Some pretty heavy rain knocking on the door right now even!
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 09/11/2009 02:09 pm
If they're expecting difficulty with afternoon weather in Florida, why not try a descending node landing?  Is the boundary layer DTO the reason?

Ascending node or decending node don't really matter when the weather concerns are in and around the 30 nmi circle of KSC.  Still violates constraints.  Plus a decending node would take the vehicle over the US during the final phase of entry and that is something that is avoided as much as possible post-STS-107. 

Descending node is 12 hours earlier so that's what I was thinking - not the route chosen.  But Rob mentioned bad weather in the mornings too, so there goes that idea!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/11/2009 02:22 pm
Descending node is 12 hours earlier so that's what I was thinking - not the route chosen.  But Rob mentioned bad weather in the mornings too, so there goes that idea!
I think generally those opportunities are more like 4-6 orbits later:
http://forum.nasaspaceflight.com/index.php?topic=6156.msg180132#msg180132
Title: Re: Shuttle Q&A Part 5
Post by: kimmern123 on 09/11/2009 02:32 pm
I've noticed that most landings at KSC lately have been at RWY15. The last one at RWY33 was STS-120. Is 15 favored due to weather?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 09/11/2009 03:02 pm
Usually the winds in Florida are blowing from the east (off the water.) I don't know if they sent any other sort of preference ahead of time, but at landing the runway is picked from weather / visibility / STA recommendations.
Title: Re: Shuttle Q&A Part 5
Post by: kimmern123 on 09/11/2009 03:29 pm
Thanks a lot! :)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/11/2009 05:11 pm
I've noticed that most landings at KSC lately have been at RWY15. The last one at RWY33 was STS-120. Is 15 favored due to weather?

I know one of the criteria is to not have a huge turn to line up on the runway.  Anything over about 300 degrees is frowned on because it become more difficult to fly these large turns for many different reasons.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Avron on 09/12/2009 02:59 pm
Dudes, I just cannot find a reference to the price of the Shuttle in todays dollar, anyone have an approx value?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/12/2009 03:17 pm
Dudes, I just cannot find a reference to the price of the Shuttle in todays dollar, anyone have an approx value?

That is a very complex question with many different answers.  First of all, do you mean a launch, or the "price" of an Orbiter.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/12/2009 05:29 pm
I've noticed that most landings at KSC lately have been at RWY15. The last one at RWY33 was STS-120. Is 15 favored due to weather?

I know one of the criteria is to not have a huge turn to line up on the runway.  Anything over about 300 degrees is frowned on because it become more difficult to fly these large turns for many different reasons.

Danny Deger

Actually, main  runway selection at KSC is generally determined (prior to the primary EOM day) by the sun angle relative to the runway.  Morning landings will generally favor Runway 33 so the final approach is flown with the sun behind and to the right of the CDR and PLT.  In this way, runway 33 would be the prime target with winds and specific weather patterns factoring into the final decision for which end of the runway to target.

Case in point: 

-- STS-114 was targeting RNWY 33 (but diverted to DFRC);
-- STS-121 targeted RNWY 33 until 10 minutes or so before landing when a shower popped up to the south.  Discovery's CDR then targeted RNWY 15.
-- STS-115 targeted and landed on RNWY 33 just before dawn in September 2006.
-- STS-120 targeted and landed on RNWY 33 in the early afternoon (with head and tail winds making the the final decision for MCC to stick with the RNWY).  Energy management of the vehicle was also a consideration in the initial selection of the RNWY 33 for this mission.
-- STS-122 initially targeted RNWY 33 for a morning landing but -- before the deorbit burn -- MMC switched to RNWY 15 at the discretion of the Steve Lindsey in the STA.
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 09/12/2009 06:27 pm
what was the white plume coming out of Discovery's wings shortly before touchdown??
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 09/12/2009 06:30 pm
what was the white plume coming out of Discovery's wings shortly before touchdown??

http://en.wikipedia.org/wiki/Wingtip_vortices
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 09/12/2009 08:00 pm
Won an auction for a piece of the shuttle and was wondering if someone could fill me in on what the numbers mean.

Tag reads TCS 2-27-2682, I know it belonged to Columbia but what was the purpose. What do the V070 numbers mean, catalog numbers I would assume?  It's a TCS Strap, has 6 snaps on it. Will post a picture if someone needs.

Sorry if this is in the wrong spot, thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/12/2009 08:12 pm
What do the V070 numbers mean, catalog numbers I would assume?  I

Drawing number, which with the dash number ends up being the part number.

V070 means it is a Rockwell drawing
Title: Re: Shuttle Q&A Part 5
Post by: fcmadrid on 09/12/2009 09:24 pm
Hello!

I really want to have a transcript of a man who comments on nasatv whether it goes for take-off or landing. Is this possible to get, if it is, where?

Thanks for your help
Title: Re: Shuttle Q&A Part 5
Post by: AlexInOklahoma on 09/13/2009 01:56 pm
@fcmadrid:  I do not know exactly how you would get this, but if you go to  http://www.nasa.gov/about/contact/index.html  I bet you could get the phone number and/or e-mail address of an Office that would get you to the right person or whatever  :-)  On the right side of webpage is a frame called 'Contact NASA' - I would start there myself...

HTH, and good luck,
ALex
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 09/13/2009 10:48 pm
what was the white plume coming out of Discovery's wings shortly before touchdown??
http://en.wikipedia.org/wiki/Wingtip_vortices

I saw some replays of 128's liftoff and you could see tip vortices during the roll just above the pad.
Title: Re: Shuttle Q&A Part 5
Post by: AlexInOklahoma on 09/13/2009 11:06 pm
I realize that 'research' would likely give me this info, but isn't the airspeed (over wings) as Shuttle clears tower and 'rolls just above pad' approximately same as landing airspeed of which C5C6 asks above?

Thanks,
Alex
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/13/2009 11:41 pm
A question on the filament wound casing SRBs intended for polar flight from SLC-6 at Vandenberg AFB:

I have managed to find one black&white image of the FWC SRM segments stacked together, and it seems like they only have field joints where each segment is stacked with the previous segment but no factory joints like on the steel segments.

Is this correct? Was this a weight-saving feature of the FWC SRM segments along with the case material change? Also, was the ET Attachment Ring built into the aft SRM segment like it was on to be the ASRM?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/13/2009 11:42 pm
A question on the filament wound casing SRBs intended for polar flight from SLC-6 at Vandenberg AFB:

I have managed to find one black&white image of the FWC SRM segments stacked together, and it seems like they only have field joints where each segment is stacked with the previous segment but no factory joints like on the steel segments.

Is this correct? Was this a weight-saving feature of the FWC SRM segments along with the case material change? Also, was the ET Attachment Ring built into the aft SRM segment like it was on to be the ASRM?

yes and no
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/14/2009 12:55 am
A question on the filament wound casing SRBs intended for polar flight from SLC-6 at Vandenberg AFB:

I have managed to find one black&white image of the FWC SRM segments stacked together, and it seems like they only have field joints where each segment is stacked with the previous segment but no factory joints like on the steel segments.

Is this correct? Was this a weight-saving feature of the FWC SRM segments along with the case material change? Also, was the ET Attachment Ring built into the aft SRM segment like it was on to be the ASRM?

yes and no
Thanks for the answers. On the ETAR: Was it a 270° ring like on the standard steel segments or was it a full 360° ring that would be used after the STS-51L accident?
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 09/14/2009 11:11 pm
Quick question, sorry if this is the wrong thread but upon shuttles retirement, for which ever shuttle goes out west (IF it happens) why land the orbiter at KSC instead of just landing at EDW and keep it there?

I realize that the OPF is only in KSC but I'm trying to think outside of the box here.  What all is going to go into preping the shuttle for displays, would any of it be able to be done out at EDW?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/14/2009 11:18 pm
Quick question, sorry if this is the wrong thread but upon shuttles retirement, for which ever shuttle goes out west (IF it happens) why land the orbiter at KSC instead of just landing at EDW and keep it there?

I realize that the OPF is only in KSC but I'm trying to think outside of the box here.  What all is going to go into preping the shuttle for displays, would any of it be able to be done out at EDW?

No, OPF is required for down loading all the hazardous commodities and passivating all the hazardous systems.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/14/2009 11:41 pm
Quick question, sorry if this is the wrong thread but upon shuttles retirement, for which ever shuttle goes out west (IF it happens) why land the orbiter at KSC instead of just landing at EDW and keep it there?

I realize that the OPF is only in KSC but I'm trying to think outside of the box here.  What all is going to go into preping the shuttle for displays, would any of it be able to be done out at EDW?

No, OPF is required for down loading all the hazardous commodities and passivating all the hazardous systems.

Just do what we do at the chemical plants down here in Houston, wait until the middle of the night, dig a big hole, drain the nasty stuff in the hole, then cover it up  ::)

If anyone asks, you have no idea why the fish in a local pond now have 3 eyes.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/15/2009 01:37 am
What do the Square root symbols (that are shown before many of the steps in the crew checklists) actually mean?

For example, this is from the ascent checklist:

√ ADI (two) – LVLH
√ H → +400 (θmax = 75°)
AT FINE COUNT:
√ Pitch Dn to α = -2°
√ MECO, ET SEP
√ Pitch Up
√ MM602
Go to RTLS ---MECO--- (FB)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/15/2009 01:38 am
What do the Square root symbols (that are shown before many of the steps in the crew checklists) actually mean?

For example, this is from the ascent checklist:

√ ADI (two) – LVLH
√ H → +400 (θmax = 75°)
AT FINE COUNT:
√ Pitch Dn to α = -2°
√ MECO, ET SEP
√ Pitch Up
√ MM602
Go to RTLS ---MECO--- (FB)

They are check marks meaning check this item
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/15/2009 01:53 am
What do the Square root symbols (that are shown before many of the steps in the crew checklists) actually mean?

For example, this is from the ascent checklist:

√ ADI (two) – LVLH
√ H → +400 (θmax = 75°)
AT FINE COUNT:
√ Pitch Dn to α = -2°
√ MECO, ET SEP
√ Pitch Up
√ MM602
Go to RTLS ---MECO--- (FB)

They are check marks meaning check this item

Wow, you mean - like a checklist or something? :)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/15/2009 03:26 am
What do the Square root symbols (that are shown before many of the steps in the crew checklists) actually mean?

For example, this is from the ascent checklist:

√ ADI (two) – LVLH
√ H → +400 (θmax = 75°)
AT FINE COUNT:
√ Pitch Dn to α = -2°
√ MECO, ET SEP
√ Pitch Up
√ MM602
Go to RTLS ---MECO--- (FB)

They are check marks meaning check this item

It has been a while, but I think a key to a checkmark is there should be no action at this step.  But if something is not correct, maybe an action is needed.

No check mark means an action (i.e. a switch throw) is needed at the step.  Maybe someone with more active brain cells and closer to training can confirm.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/15/2009 03:51 am
What do the Square root symbols (that are shown before many of the steps in the crew checklists) actually mean?

For example, this is from the ascent checklist:

√ ADI (two) – LVLH
√ H → +400 (θmax = 75°)
AT FINE COUNT:
√ Pitch Dn to α = -2°
√ MECO, ET SEP
√ Pitch Up
√ MM602
Go to RTLS ---MECO--- (FB)

They are check marks meaning check this item

It has been a while, but I think a key to a checkmark is there should be no action at this step.  But if something is not correct, maybe an action is needed.

No check mark means an action (i.e. a switch throw) is needed at the step.  Maybe someone with more active brain cells and closer to training can confirm.

Danny Deger

That's correct. The check step gives the *expected* config and if the config is as expected, no action.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/16/2009 11:27 pm
what is the job/purpose of the person sat at the FD's left during ascent and entry (and occasionally during orbit ops).

And also what does the person/s next to the Capcom do?(from watching a few of the MCC replays on youtube there always seems to be one or a couple of people sat there just staring at the big screens the whole time)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/17/2009 12:10 am
what is the job/purpose of the person sat at the FD's left during ascent and entry (and occasionally during orbit ops).

And also what does the person/s next to the Capcom do?(from watching a few of the MCC replays on youtube there always seems to be one or a couple of people sat there just staring at the big screens the whole time)


Assistant FD
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/17/2009 12:18 am
And also what does the person/s next to the Capcom do?(from watching a few of the MCC replays on youtube there always seems to be one or a couple of people sat there just staring at the big screens the whole time)


Weather CAPCOM.
Title: Re: Shuttle Q&A Part 5
Post by: Avron on 09/17/2009 02:57 am
Dudes, I just cannot find a reference to the price of the Shuttle in todays dollar, anyone have an approx value?

That is a very complex question with many different answers.  First of all, do you mean a launch, or the "price" of an Orbiter.

Danny Deger


Danny, just the Orbiter would work fine.. thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/17/2009 03:05 am
Dudes, I just cannot find a reference to the price of the Shuttle in todays dollar, anyone have an approx value?

That is a very complex question with many different answers.  First of all, do you mean a launch, or the "price" of an Orbiter.

Danny Deger


Danny, just the Orbiter would work fine.. thanks

$1.7B for Endeavour in 1987-92, but that one was assembled using previously built (and paid for) spares, and the production tooling has since been destroyed.

So count on at least twice that much in today's dollars, partially to count for inflation, partially to pay for new tooling, and partially to account for the previously-built components that weren't in Endeavour's price tag.

On second thought, make it three times, then round it to an even $5B since there's no way to know this figure past one significant digit.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/17/2009 03:16 am
snip

On second thought, make it three times, then round it to an even $5B since there's no way to know this figure past one significant digit.

You forgot to add Florida sells tax  ::)

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/17/2009 03:22 am
snip

On second thought, make it three times, then round it to an even $5B since there's no way to know this figure past one significant digit.

You forgot to add Florida sells tax  ::)

Danny Deger

Florida or California? The factory was in Palmdale. :)

Though come to think of it, the Palmdale factory has been, um, repurposed. So now they could be built anywhere. Anywhere you can build the factory, construct the tooling, and transport it out, that is.

And of course, I didn't include the cost of a new factory in the $5B...
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/17/2009 08:28 pm
This first question was asked back in the 3rd Q&A but if there was an answer, I couldn't find it.         

So, what are the radial grooves seen near the forward RCS nozzles in the picture below for?

And another question, (and vaguely related) every TPS tile on the orbiters has a small white circle which as I understand is for "instrumentation" purposes, does this mean that there is a sensor/thermocouple type thing behind every single one of them? (surely not!), Are these "white dots" holes drilled into the tile or something more superficial?
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 09/17/2009 09:27 pm
what is the job/purpose of the person sat at the FD's left during ascent and entry (and occasionally during orbit ops).

And also what does the person/s next to the Capcom do?(from watching a few of the MCC replays on youtube there always seems to be one or a couple of people sat there just staring at the big screens the whole time)


Assistant FD

He goes by "Weather Flight".
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/17/2009 09:43 pm
And another question, (and vaguely related) every TPS tile on the orbiters has a small white circle which as I understand is for "instrumentation" purposes, does this mean that there is a sensor/thermocouple type thing behind every single one of them? (surely not!), Are these "white dots" holes drilled into the tile or something more superficial?


That is where the waterproofing is injected
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 09/18/2009 05:58 am
I apologize if this has been asked/answered, but there are simply too many pages to sort through.  Node 3 was originally intended to be placed on Unity's nadir CBM, with PMA-3 being attached to the Earth-facing port of Node 3.  Was it ever NASA's intention to dock an orbiter to PMA-3 while it was on Node 3?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/18/2009 06:13 am
I apologize if this has been asked/answered, but there are simply too many pages to sort through.  Node 3 was originally intended to be placed on Unity's nadir CBM, with PMA-3 being attached to the Earth-facing port of Node 3.  Was it ever NASA's intention to dock an orbiter to PMA-3 while it was on Node 3?  Thanks!

At the time that Node-3 was slated for that location, I don't think NASA had plans to dock an Orbiter to PMA-3.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/18/2009 12:08 pm
I apologize if this has been asked/answered, but there are simply too many pages to sort through.  Node 3 was originally intended to be placed on Unity's nadir CBM, with PMA-3 being attached to the Earth-facing port of Node 3.  Was it ever NASA's intention to dock an orbiter to PMA-3 while it was on Node 3?  Thanks!

At the time that Node-3 was slated for that location, I don't think NASA had plans to dock an Orbiter to PMA-3.

That's correct. PMA-3 was used for two orbiter dockings (97/4A and 98/5A) and has been a backup since, with no plan ever to dock an orbiter there.
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 09/18/2009 03:11 pm
I did a search for 'shuttle+tail+cone' and there were no hits, so I'll ask this question in the context of what's currently going on out at Edwards.  Once a SCA carries an orbiter back to KSC and it's off-loaded for processing, the protective tail cone would then need to be returned to the west coast.  How is that done?  By truck?  By rail?  By air or by sea seems a bit over the top, but perhaps it's that way.  Anyone know?  Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 09/18/2009 03:23 pm
The tailcone breaks apart and is carried inside the SCA.
Title: Re: Shuttle Q&A Part 5
Post by: Squid.erau on 09/18/2009 05:25 pm
The tailcone breaks apart and is carried inside the SCA.

Not to nit pick, but I asked an Orbiter Handling engineer in the next cube, and the tailcones are broken down into about 6 pieces and crated.  They are then shipped by truck back to Dryden. 
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 09/18/2009 06:26 pm
The tailcone breaks apart and is carried inside the SCA.

The SCAs don't have a cargo door like a 747-F would so there is no way to get the sections inside them. They are usually shipped across country by truck, but if there were to be a TAL abort, they would be carried on a C-17 or C-5 to the landing site.
Title: Re: Shuttle Q&A Part 5
Post by: dcbecker on 09/21/2009 04:18 pm
since the STS-128 is arriving with showers all around, I would assume there is a risk of rain shortly after touchdown of the SCA. Are they not worried about getting the shuttle wet, or do they have some way to get the entire SCA and shuttle undercover quickly, since the demating and towing of the shuttle will take some time?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/21/2009 04:28 pm
since the STS-128 is arriving with showers all around, I would assume there is a risk of rain shortly after touchdown of the SCA. Are they not worried about getting the shuttle wet, or do they have some way to get the entire SCA and shuttle undercover quickly, since the demating and towing of the shuttle will take some time?
There's no complete cover at either the mate-demate device at Dryden or at the SLF.  There's concern about lots of rain, as it would take longer to dry out the blankets and tiles, but they can handle some rain on the ground.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/21/2009 07:19 pm
since the STS-128 is arriving with showers all around, I would assume there is a risk of rain shortly after touchdown of the SCA. Are they not worried about getting the shuttle wet, or do they have some way to get the entire SCA and shuttle undercover quickly, since the demating and towing of the shuttle will take some time?
There's no complete cover at either the mate-demate device at Dryden or at the SLF.  There's concern about lots of rain, as it would take longer to dry out the blankets and tiles, but they can handle some rain on the ground.


There's no concern of an Orbiter getting rained on while on the SLF/at the MDD.  STS-117/Atlantis got a pretty good soaking after her return to KSC on the SCA.  They simply dried out her blankets and tiles once she was back in OPF-1.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/21/2009 07:32 pm
How long does that take, though? Would there be a call for some sort of covering device?

Not that matters in this late stage in the program, of course, but was it ever a concern in the past before they realised it wasn't a big deal?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/21/2009 07:38 pm
There's no concern of an Orbiter getting rained on while on the SLF/at the MDD.  STS-117/Atlantis got a pretty good soaking after her return to KSC on the SCA.  They simply dried out her blankets and tiles once she was back in OPF-1.
Thanks for clarifying.  Bigger issue to have steady rain -- like we're getting in Atlanta the last few days -- out at Dryden.  At KSC, they can demate and tow her into the OPF to get out of any rain.  At Dryden, there's at least one case (STS-98) where rain at Dryden soaked some of the tiles enough that it took extra time to "bake" the moisture out with heat lamps when Atlantis got back to Florida.  And the rain there keeps the ferry from getting started, which increases the time outdoors.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/21/2009 07:47 pm
1) How long does that take, though?

2) Would there be a call for some sort of covering device?

3) Not that matters in this late stage in the program, of course, but was it ever a concern in the past before they realised it wasn't a big deal?

1) Depends on how much water is absorbed.

2) Why would there need to be a covering device when it's no problem if the vehicle gets rained on while at Dryden/on the SLF/at the MDD.

3) No.
Title: Re: Shuttle Q&A Part 5
Post by: fcmadrid on 09/21/2009 08:25 pm
Hello!

I'd like to know what are temperatures on that altitude the space shuttle fly?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 09/21/2009 08:55 pm
Hello!

I'd like to know what are temperatures on that altitude the space shuttle fly?

Thanks


While on orbit, the Shuttle's exterior temperature can fluctuate between 250° F and -250° F.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/21/2009 10:17 pm
2) Why would there need to be a covering device when it's no problem if the vehicle gets rained on while at Dryden/on the SLF/at the MDD.

I was trying to determine how much of a "non problem" it was - like, how much time it takes to dry out the blankets and tiles vs the cost and effort of covering everything.

Surely there'd be a breakpoint where you decide "Yeah, actually it is worth it..."
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/21/2009 10:27 pm
Surely there'd be a breakpoint where you decide "Yeah, actually it is worth it..."
Maybe, but it would probably be IF the landing sites were in different climates.  As noted, the orbiter is only going to be exposed at the SLF for probably a couple of shifts.  Dryden/Edwards is in the middle of a desert -- they generally don't get a lot of rain, and the humidity there is often in the teens.  (It's as dry there as it is muggy in Florida in the summer.)

Even in the extreme case (after STS-98), I'd guess that the processing crews learned from the delay to the subsequent flow (for STS-104) and were it to happen again would be able to dry out the TPS without extending an OPF stay.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/22/2009 04:36 pm
This ought to be fairly well known but I cant seem to find any info anywhere:

How much do the expendables cost on the shuttle per launch, im talking about the cryo's, ET, srb propellant, tyres etc.

Come to think of it, is there a document covering these somewhere (a budget breakdown or such)?
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 09/22/2009 10:10 pm
During STS-128's approach to Edwards, I recall Rob Navias commented that the twin sonic booms herald the shuttle's approach as it passes through the sound barrier.

I always thought the sonic shock wave is continuous throughout supersonic flight, not just at the mach 1 transition. I guess it's not surprising for a non-technical person to get this wrong, but in the STS-127 crew presentation airing today on NTV, Chris Cassidy made the following comment during the landing replay "...as we come through mach 1, if you've been there, you can hear the two sonic booms."

Now I'm wondering... do I have it wrong?
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 09/22/2009 10:21 pm
2) Why would there need to be a covering device when it's no problem if the vehicle gets rained on while at Dryden/on the SLF/at the MDD.

I was trying to determine how much of a "non problem" it was - like, how much time it takes to dry out the blankets and tiles vs the cost and effort of covering everything.

Surely there'd be a breakpoint where you decide "Yeah, actually it is worth it..."

I think it's probably been determined that the chance of rain (and quantity) around that area at Edwards is low enough that immediately covering the orbiter isn't necessary. (not to say there's an up-to-date quantity of very large sheets in storage there somewhere just in case the unexpected occurs)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/23/2009 12:55 am
During STS-128's approach to Edwards, I recall Rob Navias commented that the twin sonic booms herald the shuttle's approach as it passes through the sound barrier.

I always thought the sonic shock wave is continuous throughout supersonic flight, not just at the mach 1 transition. I guess it's not surprising for a non-technical person to get this wrong, but in the STS-127 crew presentation airing today on NTV, Chris Cassidy made the following comment during the landing replay "...as we come through mach 1, if you've been there, you can hear the two sonic booms."

Now I'm wondering... do I have it wrong?

It is continuous
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 09/23/2009 03:26 am
Yes, ginahoy, it's continuous, but some of us don't like to give a full explanation. You'd hear it from once the orbiter got into some traces of the atmosphere, at mach 20+, all the way until the point it drops under mach 1. The pressure wave/cone spreads out to roughly 60 miles or so in most directions, aside from the front.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 09/23/2009 04:28 am
You hear a sonic boom when the shock wave passes over your ears, or the microphone.  Not when it's going through Mach 1.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 09/23/2009 04:33 am
I'd like to know what are temperatures on that altitude the space shuttle fly?

I'm assuming you're talking about the atmosphere there, rather than on the orbiter itself.  I just searched for an ESTEC standard that I ran across somewhere several years ago, but I can't find it now.  Maybe you can come up with more creative Google terms than me.

Basically, the individual atoms or molecules are really hot (>1000K), but they are so far apart that it would "feel" really cold (<100K).

Edit: here's a ton of models
http://ccmc.gsfc.nasa.gov/modelweb/
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 09/23/2009 02:40 pm
On the PASS TRAJ 1 display....what does the TMECO field display in MM102?

Does it look like this TMECO XX:XX then is populated once PEG converges in MM103...or is it not present until MM102 and then appears in MM103?

Thanks in advance.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/23/2009 02:53 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 09/23/2009 02:58 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.

So thats the question really...it appears at liftoff, but does it display XX:XX...crazy values, too high values, too low values...and then once into MM103 settles down into a good value?
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 09/23/2009 04:31 pm
Any answers to the cost per launch question above?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/23/2009 08:58 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.

So thats the question really...it appears at liftoff, but does it display XX:XX...crazy values, too high values, too low values...and then once into MM103 settles down into a good value?

I imagine it has some sort of I-loaded value at liftoff, and then it doesn't change during 1st stage (because it's open loop, so there's no inputs from the system), and then during the cycles of convergence they change.

Whether that means going lower or higher would depend on the initial value, obviously.

Any insight from Jorge/Mkirk?
Title: Re: Shuttle Q&A Part 5
Post by: Mach25 on 09/23/2009 09:25 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.

So thats the question really...it appears at liftoff, but does it display XX:XX...crazy values, too high values, too low values...and then once into MM103 settles down into a good value?

I imagine it has some sort of I-loaded value at liftoff, and then it doesn't change during 1st stage (because it's open loop, so there's no inputs from the system), and then during the cycles of convergence they change.

Whether that means going lower or higher would depend on the initial value, obviously.

Any insight from Jorge/Mkirk?

Guidance doesn't compute TMECO until MM103.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 09/23/2009 10:13 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.

So thats the question really...it appears at liftoff, but does it display XX:XX...crazy values, too high values, too low values...and then once into MM103 settles down into a good value?

I imagine it has some sort of I-loaded value at liftoff, and then it doesn't change during 1st stage (because it's open loop, so there's no inputs from the system), and then during the cycles of convergence they change.

Whether that means going lower or higher would depend on the initial value, obviously.

Any insight from Jorge/Mkirk?

Guidance doesn't compute TMECO until MM103.

Okay, that much is clear. Is the TMECO field present before MM103 just with null data (like XX:XX instead of figures) or does it 'appear' once MM103 begins?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/23/2009 10:17 pm
Appears at liftoff, according to Ascent Guidance workbook. I imagine as guidance converges the prediction changes.

So thats the question really...it appears at liftoff, but does it display XX:XX...crazy values, too high values, too low values...and then once into MM103 settles down into a good value?

I imagine it has some sort of I-loaded value at liftoff, and then it doesn't change during 1st stage (because it's open loop, so there's no inputs from the system), and then during the cycles of convergence they change.

Whether that means going lower or higher would depend on the initial value, obviously.

Any insight from Jorge/Mkirk?

Guidance doesn't compute TMECO until MM103.

Mach 25 is right! 
TMECO is not even shown on the PASS or BFS ASCENT TRAJ 1 Displays (first stage, OPS 102).  It appears on PASS & BFS ASCENT TRAJ 2 (second stage OPS 103) during staging.  The crew will check that both the PASS and BFS independently come up with stable estimates for MECO within ~ 10 seconds of staging (guidance convergence).  Both of the PASS & BFS predictions should closely agree with each other. The time will be displayed as something like 08:32.

Mark Kirkman




Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 09/23/2009 10:29 pm
Mach 25 is right! 
TMECO is not even shown on the PASS or BFS ASCENT TRAJ 1 Displays (first stage, OPS 102).  It appears on PASS & BFS ASCENT TRAJ 2 (second stage OPS 103) during staging.  The crew will check that both the PASS and BFS independently come up with stable estimates for MECO within ~ 10 seconds of staging (guidance convergence).  Both of the PASS & BFS predictions should closely agree with each other. The time will be displayed as something like 08:32.

Mark Kirkman


Thanks..thats narrowed it down. So although the TRAJ display layout is basically the same there is essentially a TRAJ display for MM101,102 and 103. TMECO is not present until MM103 when it appears on the display, and (hopefully!) rapidly converges to a sensible TMECO.

Of course the BFS has two vastly different TRAJ displays (1 & 2)...and TRAJ 1 doesn't have TMECO and TRAJ 2 does.

There is no way to determine whats on the different PASS TRAJ displays and when from the DPS dictionary.

I've always thought TRAJ 1 and TRAJ 2 on the BFS seem to provide a clearer look at the ascent situation than the single PASS TRAJ. The PASS TRAJ has a lot of 'screen real-estate' taken up with RTLS stuff. Presumably on a normal ascent the crew will watch the BFS TRAJ displays more than pass (or maybe they are all equally covered in the 'instrument scan').
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/23/2009 11:03 pm
Mach 25 is right! 
TMECO is not even shown on the PASS or BFS ASCENT TRAJ 1 Displays (first stage, OPS 102).  It appears on PASS & BFS ASCENT TRAJ 2 (second stage OPS 103) during staging.  The crew will check that both the PASS and BFS independently come up with stable estimates for MECO within ~ 10 seconds of staging (guidance convergence).  Both of the PASS & BFS predictions should closely agree with each other. The time will be displayed as something like 08:32.

Mark Kirkman


Thanks..thats narrowed it down. So although the TRAJ display layout is basically the same there is essentially a TRAJ display for MM101,102 and 103. TMECO is not present until MM103 when it appears on the display, and (hopefully!) rapidly converges to a sensible TMECO.

Of course the BFS has two vastly different TRAJ displays (1 & 2)...and TRAJ 1 doesn't have TMECO and TRAJ 2 does.

There is no way to determine whats on the different PASS TRAJ displays and when from the DPS dictionary.

I've always thought TRAJ 1 and TRAJ 2 on the BFS seem to provide a clearer look at the ascent situation than the single PASS TRAJ. The PASS TRAJ has a lot of 'screen real-estate' taken up with RTLS stuff. Presumably on a normal ascent the crew will watch the BFS TRAJ displays more than pass (or maybe they are all equally covered in the 'instrument scan').

Maybe this diagram from the GNC section of the SCOM will help you visualize the first and second stage shuttle trajectory displays better.

As for the second stage PASS TRAJ Display – it was originally intended for RTLS use, so it is true that the BFS does provide better fidelity for nominal second stage flight.

Mark Kirkman

Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/24/2009 08:41 am
Well ok, the Ascent Guidance workbook says that:

* (pages 6-18 and 6-20) ASCENT TRAJ 1 and 2 are available in the BFS only (1 comes up at MM102/SSME Ignition, 2 comes up at MM103/SRB SEP)
* (page 6-22) XXX ASCENT TRAJ is available in the PASS and that it comes up automatically at SSME start (does that mean it remains on a CRT throughout the entire ascent? And if so, kneecaps original question of what the TMECO field displays before MM103 still applies).

Hence, I'm a little confused.

It seems that certain documents conflict here. My brain hurts. :)

Thanks for your answers so far, though!
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/24/2009 09:11 am
Although, re-reading, I guess it does change at MM103 to include the TMECO field that wasn't previously there during MM102. Is that right?
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 09/24/2009 12:43 pm
Okay, manifest question.  A FAWG manifest dated April 21, 2005 had STS-119/ISS 15A delivering the S-6 truss prior to the launch of Node 2 and the international partner lab modules.  We know that 119 was postponed until after those modules were delivered to the station in order to allow those labs to get up and running sooner.  When was the manifest changed, and is there any memo, press release, or other documentation availalbe re this change?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/24/2009 01:42 pm
Okay, manifest question.  A FAWG manifest dated April 21, 2005 had STS-119/ISS 15A delivering the S-6 truss prior to the launch of Node 2 and the international partner lab modules.  We know that 119 was postponed until after those modules were delivered to the station in order to allow those labs to get up and running sooner.  When was the manifest changed, and is there any memo, press release, or other documentation availalbe re this change?
Have you tried searching NSF?  I found a story on the timing by just plugging "15A site:nasaspaceflight.com" into Google.

Actually, this probably ends up being at least as much an ISS question as a shuttle question...15A was in front of 10A in the assembly sequence going back to before STS-107.

Edit: actually, it also involves RTF and VSE and probably ESAS, too.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/24/2009 04:02 pm
Well ok, the Ascent Guidance workbook says that:

* (pages 6-18 and 6-20) ASCENT TRAJ 1 and 2 are available in the BFS only (1 comes up at MM102/SSME Ignition, 2 comes up at MM103/SRB SEP)
* (page 6-22) XXX ASCENT TRAJ is available in the PASS and that it comes up automatically at SSME start (does that mean it remains on a CRT throughout the entire ascent? And if so, kneecaps original question of what the TMECO field displays before MM103 still applies).

Hence, I'm a little confused.

It seems that certain documents conflict here. My brain hurts. :)

Thanks for your answers so far, though!

I think part of the reason you might be getting confused is because the PASS TRAJ displays were recently modified (in OI-32, STS-120 I believe) – the picture I posted reflects my understanding of what the current displays look like for nominal ascent.  Originally the BFS TRAJ 1 display was primary for first stage flight because the original PASS ASCENT TRAJ was really intended for use as an abort display and wasn’t much use for Nominal Ascent (particularly first stage).  On the old PASS display the little triangle and predictors would stay all bunched up early in ascent because of the relative scaling so you relied on the BFS ASCENT TRAJ 1 predictors.

I am not very familiar with the current (new) displays – other than what I have read in training materials – and I have forgotten much of what I thought I knew about the older stuff.  Jorge or someone else who actually works in Mission Ops now is better equipped to explain all this if I have confused you.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 09/24/2009 07:02 pm
Okay, manifest question.  A FAWG manifest dated April 21, 2005 had STS-119/ISS 15A delivering the S-6 truss prior to the launch of Node 2 and the international partner lab modules.  We know that 119 was postponed until after those modules were delivered to the station in order to allow those labs to get up and running sooner.  When was the manifest changed, and is there any memo, press release, or other documentation availalbe re this change?
Have you tried searching NSF?  I found a story on the timing by just plugging "15A site:nasaspaceflight.com" into Google.

Actually, this probably ends up being at least as much an ISS question as a shuttle question...15A was in front of 10A in the assembly sequence going back to before STS-107.

Edit: actually, it also involves RTF and VSE and probably ESAS, too.


Thanks Phil!!!  I guess I was plugging the wrong phraseology into Google.  So, based on the article I found, it looks like the decision was made in 2006 to move 119 to after 126. 
Title: Re: Shuttle Q&A Part 5
Post by: anik on 09/24/2009 07:51 pm
Okay, manifest question. A FAWG manifest dated April 21, 2005 had STS-119/ISS 15A delivering the S-6 truss prior to the launch of Node 2 and the international partner lab modules. We know that 119 was postponed until after those modules were delivered to the station in order to allow those labs to get up and running sooner. When was the manifest changed, and is there any memo, press release, or other documentation available re this change?

According to FAWG Planning Manifests, STS-119 mission was postponed from "after STS-118" to "after STS-124" in February 2006.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 09/24/2009 09:26 pm
This ought to be fairly well known but I cant seem to find any info anywhere:

How much do the expendables cost on the shuttle per launch, im talking about the cryo's, ET, srb propellant, tyres etc.

Come to think of it, is there a document covering these somewhere (a budget breakdown or such)?

The only costs I've encountered is the ET LOX/LH2 cryo costs per launch (~$230,000 or so), but have never read anywhere of a complete breakdown of all the costs of gasses/fluids/propellants/expendables used for a launch.
(ref for cryo costs: http://forum.nasaspaceflight.com/index.php?topic=11374.msg233148#msg233148 )
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 09/26/2009 11:19 am
Has anyone kept a log of how much on-orbit time was spent waiting for a landing opportunity?

If not my guess is: 1000 orbits or 10.000 Astronaut hours.
That's assuming 1/3 day/mission for a crew of 7 throughout the Shuttle flight history.

Has anyone statistics or some educated guess to share?
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 09/26/2009 09:33 pm
Why was MPLM Donatello never flight certified and what made Raffaello get chosen for PLM?

One more MPLM question. Why has Leonardo been flying so much recently rather than Raffaello?

Thanks :)
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 09/26/2009 11:43 pm
1) Why was MPLM Donatello never flight certified
2) and what made Raffaello get chosen for PLM?

3) One more MPLM question. Why has Leonardo been flying so much recently rather than Raffaello?

Thanks :)

Your third question is answered by your second question. They need time to refit the MMOD panels on Raffaello and do whatever else needs to be done to convert the MPLM into the PLM.

The answer to the first question is: $$$. By forgoing flight certification for Donatello, they save money that can then be spent elsewhere. Donatello was only going to have one flight anyway (was going to be 128 I believe). 
Title: Re: Shuttle Q&A Part 5
Post by: anik on 09/27/2009 10:40 am
what made Raffaello get chosen for PLM?

It appears that PLM will be Leonardo, not Raffaello.

http://www.collectspace.com/ubb/Forum30/HTML/000371.html (September 4, 2009)

"According to ISS Program Manager Mike Suffredini just two days ago, the MPLM to be adapted as the PLM is Leonardo (currently on-orbit with STS-128), not Raffaello. Suffredini did say the plan could change, but currently, Leonardo is it."
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/27/2009 12:37 pm
what made Raffaello get chosen for PLM?

It appears that PLM will be Leonardo, not Raffaello.

http://www.collectspace.com/ubb/Forum30/HTML/000371.html (September 4, 2009)

"According to ISS Program Manager Mike Suffredini just two days ago, the MPLM to be adapted as the PLM is Leonardo (currently on-orbit with STS-128), not Raffaello. Suffredini did say the plan could change, but currently, Leonardo is it."
Interesting post.  It was Suffredini that publicly identified Raffaello (FM-2) as the flight module to become the PLM earlier this year. (Edit: corrected by anik).

Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 09/27/2009 12:53 pm
1) Why was MPLM Donatello never flight certified
2) and what made Raffaello get chosen for PLM?

3) One more MPLM question. Why has Leonardo been flying so much recently rather than Raffaello?

Thanks :)

Your third question is answered by your second question. They need time to refit the MMOD panels on Raffaello and do whatever else needs to be done to convert the MPLM into the PLM.

The answer to the first question is: $$$. By forgoing flight certification for Donatello, they save money that can then be spent elsewhere. Donatello was only going to have one flight anyway (was going to be 128 I believe). 

Donatello was planned to be used to transport "active" payloads to and from orbit. A good example of this is the MELFI freezer, they have 3 freezers that originally was planned to rotated on orbit. Since the Colombia disaster changed that they didn't have the need for Donatellos extra capability to keep continuous power.
Title: Re: Shuttle Q&A Part 5
Post by: anik on 09/27/2009 02:20 pm
Interesting post. It was Suffredini that publicly identified Raffaello (FM-2) as the flight module to become the PLM earlier this year

I doubt it was Michael Suffredini. It was Daniel Hartman, manager of Integration and Operations in ISS Program.

http://www.collectspace.com/ubb/Forum30/HTML/000371.html

"Dan Hartman, NASA's manager for the integration and operations of the International Space Station, addressed this topic today (May 6) during a press conference: "The study is back on the table so we're looking at adding what we call a 'PLM', a permanent logistics module to the International Space Station. And I believe it is 'Unit 2' and I'm not quite sure what that one [MPLM] is specifically called"
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/27/2009 02:39 pm
Interesting post. It was Suffredini that publicly identified Raffaello (FM-2) as the flight module to become the PLM earlier this year

I doubt it was Michael Suffredini. It was Daniel Hartman, manager of Integration and Operations in ISS Program.

http://www.collectspace.com/ubb/Forum30/HTML/000371.html

"Dan Hartman, NASA's manager for the integration and operations of the International Space Station, addressed this topic today (May 6) during a press conference: "The study is back on the table so we're looking at adding what we call a 'PLM', a permanent logistics module to the International Space Station. And I believe it is 'Unit 2' and I'm not quite sure what that one [MPLM] is specifically called"
You're right -- my mistake.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 09/28/2009 08:00 pm

I think part of the reason you might be getting confused is because the PASS TRAJ displays were recently modified (in OI-32, STS-120 I believe) – the picture I posted reflects my understanding of what the current displays look like for nominal ascent. 


Thanks, that explains why i've never even seen those displays! The old PASS TRAJ was very RTLS orientated. I'll try and find some docs detailing the new displays.

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Lawntonlookirs on 10/01/2009 04:39 pm
Probably a dumb question and has been answered before although I wasn't able to find it on a search.  With the SSME having LO2 and LH as fuel, when the engines are first started, is it with the Liquid or gaseous O2 and H.  I was just wondering how it is vaporized before the engines are started or is it liquid when it ignites and during the flight?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/01/2009 07:06 pm
Probably a dumb question and has been answered before although I wasn't able to find it on a search.  With the SSME having LO2 and LH as fuel, when the engines are first started, is it with the Liquid or gaseous O2 and H.  I was just wondering how it is vaporized before the engines are started or is it liquid when it ignites and during the flight?

Only liquid is fed to the engines.  The start sequency is complex and I never understood it completely.  For example in a running engine the hydrogen runs in tubes in the nozzle to cool it.  This vaporizes the hydrogen.  When I taught an MPS class, I crossed my fingers no one whould ask how the darn thing starts.  I would admit I didn't have a clue, but had the name and number of a booster flight control they could bug. 

I found saying "I don't know" was better than making up stuff.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 10/01/2009 07:31 pm

Only liquid is fed to the engines.  The start sequency is complex and I never understood it completely.  For example in a running engine the hydrogen runs in tubes in the nozzle to cool it.  This vaporizes the hydrogen.  When I taught an MPS class, I crossed my fingers no one whould ask how the darn thing starts.  I would admit I didn't have a clue, but had the name and number of a booster flight control they could bug. 

I found saying "I don't know" was better than making up stuff.

Danny Deger

I was considering giving my understanding of what happens, but thinking about it i'm not sure of some specific details. Specifically when the ASIs (Spark igniters) actually start sparking.

Apparently only liquid head pressures and the ASIs sparking is actually needed to start, but I'd love to hear an expert explain or illustrate this!
Title: Re: Shuttle Q&A Part 5
Post by: Lawntonlookirs on 10/01/2009 07:48 pm
Probably a dumb question and has been answered before although I wasn't able to find it on a search.  With the SSME having LO2 and LH as fuel, when the engines are first started, is it with the Liquid or gaseous O2 and H.  I was just wondering how it is vaporized before the engines are started or is it liquid when it ignites and during the flight?

Only liquid is fed to the engines.  The start sequency is complex and I never understood it completely.  For example in a running engine the hydrogen runs in tubes in the nozzle to cool it.  This vaporizes the hydrogen.  When I taught an MPS class, I crossed my fingers no one whould ask how the darn thing starts.  I would admit I didn't have a clue, but had the name and number of a booster flight control they could bug. 

I found saying "I don't know" was better than making up stuff.

Danny Deger

Thanks DD, so I guess it wasn't a dumb question after all.  Maybe a post on L2 would get an answer.  I checked the SSME Bible and it gives a lot of the information, but will take some time to digest for me.  "Download 2"

http://forum.nasaspaceflight.com/index.php?topic=4413.0

 
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 10/01/2009 08:02 pm

Thanks DD, so I guess it wasn't a dumb question after all.  Maybe a post on L2 would get an answer.  I checked the SSME Bible and it gives a lot of the information, but will take some time to digest for me.  "Download 2"

http://forum.nasaspaceflight.com/index.php?topic=4413.0

 

It doesn't answer the question in a succinct way (if at all).
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/01/2009 11:15 pm
snip

Apparently only liquid head pressures and the ASIs sparking is actually needed to start, but I'd love to hear an expert explain or illustrate this!


God himself spins up the turbopumps and breaths fire into the combustion chamber.  That's my story and I am sticking to it.   ;D

If someone figures out how those pumps go from zero to 100,000 hp in a couple of seconds -- please tell us all.

I think a key must be to get a fire going to blow hot gas through the turbines that drives the main pumps.  I don't think there is any kind of starter that spins the pump up.

Danny Deger

Edit: Ask more shuttle question, please.  The status of Ares I is getting old.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 10/02/2009 08:01 am

I think a key must be to get a fire going to blow hot gas through the turbines that drives the main pumps.  I don't think there is any kind of starter that spins the pump up.



One of the first things that happens is the Main Fuel Valve ramps fully open, this allows LH2 to get to the preburners. Both the Oxidizer preburner and Fuel preburner valves also ramp open (but not fully) in the same time period. I'm thinking that the requirement for head pressure to start simply forces LOX and LH2 into the preburners (and the ASIs (igniters).

Pressure has forced LOX and LH2 into the preburners. This burns which causes a small amount of hot gas, this spins the turbines which in turn causes more LOX and LH2 to reach the preburners (which causes the pumps to spin faster, pumping more to the preburners, and so on).

At some point the igniters will stop since combustion in the preburners will become self sustaining.



Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/02/2009 11:59 am
This link has been posted here before...the material there is at least historically related:
http://www.enginehistory.org/ssme.htm
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/02/2009 12:53 pm

I think a key must be to get a fire going to blow hot gas through the turbines that drives the main pumps.  I don't think there is any kind of starter that spins the pump up.



One of the first things that happens is the Main Fuel Valve ramps fully open, this allows LH2 to get to the preburners. Both the Oxidizer preburner and Fuel preburner valves also ramp open (but not fully) in the same time period. I'm thinking that the requirement for head pressure to start simply forces LOX and LH2 into the preburners (and the ASIs (igniters).

Pressure has forced LOX and LH2 into the preburners. This burns which causes a small amount of hot gas, this spins the turbines which in turn causes more LOX and LH2 to reach the preburners (which causes the pumps to spin faster, pumping more to the preburners, and so on).

At some point the igniters will stop since combustion in the preburners will become self sustaining.


OK.  I just thought of a key in starting the turbo pumps, vs. starting a gas turbine engine.  The preburner is where the fire is on the SSMEs.  There is only one way out -- across the turbine.   In a gas turbine, there is an opening at both ends and the turbine and compressor must be spun up by some means so the fire doesn't just go out the compressor.

I wish I would have thought of this while I still teaching the Main Propulsion System classes.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Lawntonlookirs on 10/02/2009 06:41 pm
This link has been posted here before...the material there is at least historically related:
http://www.enginehistory.org/ssme.htm


Thanks psloss and DD for the information.  More than I can digest, but interesting on the development of the engines.  I assume the engines still run the same way and adjust for the oscillations after the main fuel valve is opened.  It also tells about how many problems they had during the development of the engine. 

It has a spark plug in the preburner that uses a LH rich fuel for the turbo pumps and then they adjust the final fuel mixture in the Main combustion chamber.  Not sure if they have just the one spark plug for ignition or one in the preburner and one in the MCC.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 10/02/2009 09:25 pm

It has a spark plug in the preburner that uses a LH rich fuel for the turbo pumps and then they adjust the final fuel mixture in the Main combustion chamber.  Not sure if they have just the one spark plug for ignition or one in the preburner and one in the MCC.

There are six "spark plugs". ASIs, Augmented Spark Igniters. They are found in pairs (for redundancy) in both pre burners and in the main injector.

The fuel:oxidizer ratio is controlled by the fuel preburner oxidizer valve (FPOV) only and is NOT adjusted at the MCC.

The thrust level is controlled by the oxidizer preburner oxidizer valve (OPOV) and the FPOV moves to maintain the correct mixture.

I believe the MOV (Main Oxidizer Valve, lets LOX into the MCC) is open 100% during the entire mainstage.

Digest the flow paths through the engine and (it took me quite a long time), you'll have a eureka moment when it all kind of makes sense.

It's a beautifully complex but remarkably simple engine in many ways..I think 'elegant' is the better word.
Title: Re: Shuttle Q&A Part 5
Post by: Lawntonlookirs on 10/03/2009 03:28 pm

It has a spark plug in the preburner that uses a LH rich fuel for the turbo pumps and then they adjust the final fuel mixture in the Main combustion chamber.  Not sure if they have just the one spark plug for ignition or one in the preburner and one in the MCC.

There are six "spark plugs". ASIs, Augmented Spark Igniters. They are found in pairs (for redundancy) in both pre burners and in the main injector.

The fuel:oxidizer ratio is controlled by the fuel preburner oxidizer valve (FPOV) only and is NOT adjusted at the MCC.

The thrust level is controlled by the oxidizer preburner oxidizer valve (OPOV) and the FPOV moves to maintain the correct mixture.

I believe the MOV (Main Oxidizer Valve, lets LOX into the MCC) is open 100% during the entire mainstage.

Digest the flow paths through the engine and (it took me quite a long time), you'll have a eureka moment when it all kind of makes sense.

It's a beautifully complex but remarkably simple engine in many ways..I think 'elegant' is the better word.

Yes kneecap.  I am starting to understand quite a bit about it.  It is just hard to imagine the liquid H and O going from the cyrogenic temp to 6000 F instantly.  I guess one could say it is one H*** of a controled explosion.
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 10/03/2009 08:10 pm
In 28.5 degree shuttle missions, does the shuttle make a 90º counterclockwise roll program??
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/03/2009 08:24 pm
In 28.5 degree shuttle missions, does the shuttle make a 90º counterclockwise roll program??
Yes.
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 10/03/2009 09:29 pm
Okay, I'm confused.  I heard some talk about pad time on one of the prior flights, maybe it was LON for STS-125 if they needed to use one pad.. something like 25 (I'm not sure, but it's at least that many IIRC) days at the pad, with a few days turnaround before rolling out.

STS-51D (http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/archives/sts-51D.html) launched on April 12th, 1985, landed 7 days later.  STS-51B (http://www.nasa.gov/mission_pages/shuttle/shuttlemissions/archives/sts-51B.html) launched on April 29th, 1895... that's a whole 10 days after 51D landed, so that's 17 days between launches, and both were on Pad-A.

Is there a reason they flew 17 days apart, or was it just that they wanted to go as many as possible in 1985?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/03/2009 10:20 pm
Is there a reason they flew 17 days apart, or was it just that they wanted to go as many as possible in 1985?
The latter -- they were working towards a flight rate of 24 flights per year.  (This has been discussed here before.)  Since the 51-B payload was a Spacelab module (already loaded), that probably shortened the pad time a little bit.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 10/05/2009 11:49 pm

The latter -- they were working towards a flight rate of 24 flights per year.

And we look back now and think:
"Six flights a year per orbiter? They must have been nuts to even imagine that could happen!"
Title: Re: Shuttle Q&A Part 5
Post by: K466 on 10/06/2009 03:05 pm
Question regarding Ferry Flights:

Does the Shuttle's wings provide any lift during the flight, or is the orbiter just dead weight atop the SCA?
Title: Re: Shuttle Q&A Part 5
Post by: astrobrian on 10/06/2009 03:25 pm
Question regarding Ferry Flights:

Does the Shuttle's wings provide any lift during the flight, or is the orbiter just dead weight atop the SCA?
The shape of the wing provides some lift, but given the relatively slow airspeed while on the SCA it probably doesn't help a lot
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 10/06/2009 10:49 pm
Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: K466 on 10/06/2009 11:19 pm
Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.

The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.

Before they got the Orbiter Transporter System the orbiters were towed during rollover too.
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 10/07/2009 12:09 am
Thanks. That makes sense. The OTS was originally for the long tow at Vandenberg right?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/07/2009 12:47 am
Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.

The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.

Before they got the Orbiter Transporter System the orbiters were towed during rollover too.

Then why was it built in the first place.  The orbiters have wheels, why not just use them.  Just raise the gear after the orbiter gets onto the cranes in the VAB.

And, can't they get more than one landing out of a set of tires.  Do they actually go out of specs (thread thickness) in a single landing?  Why not throw on some more tread and get at least two landing before new tires are needed.

Danny Deger

Edit: OK I just read on another post the cart was built for a long tow at Vandenburg.  This almost makes sense, bearing temps or something might go out of specs for a long tow -- even then I don't see what is wrong with a long tow.  But why then move the darn thing to KSC and use it instead of just towing to the VAB for stacking.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/07/2009 01:00 am
Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.

The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.

Before they got the Orbiter Transporter System the orbiters were towed during rollover too.

You meant to say tires didn't you.  The brakes were redesigned in about 1995 to allow for multiple uses.  The old brakes broke up with a single use and tended to stick and what not.  Really, really bad brakes.  You couldn't use them, let up, then use them again.  The pads would fracture at the first use and then when released, fractured pieces of brake pad would do nasty things to the brake assembly with the second application.  They were an accident ready to happen and NASA fixed them.  They also added the drag chute for crew safety at about this time.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/07/2009 01:40 am

Edit: OK I just read on another post the cart was built for a long tow at Vandenburg.  This almost makes sense, bearing temps or something might go out of specs for a long tow -- even then I don't see what is wrong with a long tow.  But why then move the darn thing to KSC and use it instead of just towing to the VAB for stacking.

The "tow" route was hilly. Also the OTS allows for the gear to be retracted in a better facility
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/07/2009 01:58 am

Edit: OK I just read on another post the cart was built for a long tow at Vandenburg.  This almost makes sense, bearing temps or something might go out of specs for a long tow -- even then I don't see what is wrong with a long tow.  But why then move the darn thing to KSC and use it instead of just towing to the VAB for stacking.

The "tow" route was hilly. Also the OTS allows for the gear to be retracted in a better facility

I can certainly see the need for a cart on hilly terrain.  Towing on a hill is a big time no-no.  Way too much stress on the nose gear and tow bar.  Enough to maybe snap the nose gear off.

If I recall the gear goes up very nicely in the VAB.  Don't they pretty much raise them selves with pneumatic actuators in the orbiter wheel wells.  The final raising is a ceremony where a $8 push broom is used to close the nose gear doors. 

Danny Deger

Edit: Why was there a need to tow on hilly terrain at Vandie?  Sounds like a really bad place for shuttle OPS is there was not enough room to avoid hilly terrain.  Even then, we have machines called "earth moving equipment" to level a road bed.   
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/07/2009 11:24 am

Edit: Why was there a need to tow on hilly terrain at Vandie?  Sounds like a really bad place for shuttle OPS is there was not enough room to avoid hilly terrain.  Even then, we have machines called "earth moving equipment" to level a road bed.   

You haven't been to VAFB.  Launch pads were in canyons.  The tow route was more than 5 (maybe twenty) miles.  The OMCF was on the north base and SLC-6 was on the south base.
Title: Re: Shuttle Q&A Part 5
Post by: tva on 10/07/2009 12:01 pm
You haven't been to VAFB.  Launch pads were in canyons.  The tow route was more than 5 (maybe twenty) miles.  The OMCF was on the north base and SLC-6 was on the south base.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/07/2009 12:17 pm
That isn't the exact route.

I will try to find it
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/07/2009 12:36 pm

Edit: Why was there a need to tow on hilly terrain at Vandie?  Sounds like a really bad place for shuttle OPS is there was not enough room to avoid hilly terrain.  Even then, we have machines called "earth moving equipment" to level a road bed.   

You haven't been to VAFB.  Launch pads were in canyons.  The tow route was more than 5 (maybe twenty) miles.  The OMCF was on the north base and SLC-6 was on the south base.

Sounds like a place to NOT do shuttle ops.  Why in the heck did DOD buy off on this vs. Titans, etc.  NASA should not have gotten in the business of doing 100 precent of DOD and comercial launches with an unproven design.   Heck, the brakes distroyed themselves during each landing.  Hardly a design for quick turn around.  Look at how long it takes to hook the shuttle up to the launch tower.  No way for a quick turn around. 

Enough said for the Q&A thread.  Please don't reply to this here. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: K466 on 10/07/2009 06:50 pm
Why is the orbiter not placed on the Orbiter Transporter System when it is taken off of the mate/demate device at KSC? Was the MDD not designed to lower the orbiter with enough precision? Thanks.

The wheels have to be replaced anyway after a flight, it is faster to just tow it to the OPF.

Before they got the Orbiter Transporter System the orbiters were towed during rollover too.

You meant to say tires didn't you.  The brakes were redesigned in about 1995 to allow for multiple uses.  The old brakes broke up with a single use and tended to stick and what not.  Really, really bad brakes.  You couldn't use them, let up, then use them again.  The pads would fracture at the first use and then when released, fractured pieces of brake pad would do nasty things to the brake assembly with the second application.  They were an accident ready to happen and NASA fixed them.  They also added the drag chute for crew safety at about this time.

Danny Deger

Yes I meant to say tires.

The rear tires, as I understand, can only be used once, due to the high landing speeds. The front tires can be used for two landings.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 10/07/2009 08:00 pm
With the SSME having LO2 and LH as fuel, when the engines are first started, is it with the Liquid or gaseous O2 and H.  I was just wondering how it is vaporized before the engines are started or is it liquid when it ignites and during the flight?

Cryo engines have liquid down to the last wet closed valve prior to start.  When the valves start opening, all of the hardware has to quench to liquid or near liquid temperatures.  So initially there's some "hot" vapor coming out of the injectors as heat comes out of the hardware and into the propellants.  Since combustion stability is really sensitive to the thermodynamic conditions of the propellant and local mixture ratios, this is why the start sequence valve positions are often really odd.  Eventually the injectors prime and the propellant is liquid or at least supercritical up to the cold side of injector.  Almost always, propellant comes out of the injector as gas since only gases can burn.  The pressure loss across the injector vaporizes the propellant.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 10/08/2009 06:34 pm
Why does it take 1 week normally from the time the shuttle is connected to the Tank and Boosters in the VAB to roll it out? Once connected what tasks do they go through? Are there many, or just a few but are time consuming?

Also I know the fuel from the tank goes through lines at the base of the tank into the shuttle via connections to both, But does anyone have a diagram that shows how they join together? And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point? What if it failed to close?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/08/2009 07:01 pm

And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?

The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.html

Photo here:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554

Quote
What if it failed to close?

The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.

If the doors can't be closed at all, LOV/C.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/08/2009 07:16 pm
Why does it take 1 week normally from the time the shuttle is connected to the Tank and Boosters in the VAB to roll it out? Once connected what tasks do they go through? Are there many, or just a few but are time consuming?


Not only do they have to mechanically mate the orbiter to the ET but also electrical and fluid connections. Additionally, the umbilicals to the TSM's have to be mated.  The fluid connections have to be leak check and interface tests have to be done to verify all the electrical connections between the MLP and the vehicle and between the orbiter and ET.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 10/08/2009 07:21 pm

And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?

The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.html

Photo here:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554

Quote
What if it failed to close?

The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.

If the doors can't be closed at all, LOV/C.

Thank you so much for the picture of the doors, Not something I have ever seen. Thanks so much!!
Title: Re: Shuttle Q&A Part 5
Post by: Alpha Control on 10/08/2009 11:59 pm

And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?

The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.html

Photo here:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554

Quote
What if it failed to close?

The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.

If the doors can't be closed at all, LOV/C.

Jorge; two follow-ups, if I may:

(1) Regarding the manual closure of the ET umbilical doors, how is this done? Via a hand crank of some kind?

(2) Prior to the OBSS era, how would the EVA crewmember accomplish this without the extra reach provided by the boom? Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/09/2009 01:28 am

And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?

The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.html

Photo here:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554

Quote
What if it failed to close?

The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.

If the doors can't be closed at all, LOV/C.

Jorge; two follow-ups, if I may:

(1) Regarding the manual closure of the ET umbilical doors, how is this done? Via a hand crank of some kind?

There is no crank. What the crew would do depends on the failure mode. If centerline latch, open the latch manually and allow the motors to close the doors. There are two motors on each door, geared such that a jam in one motor cannot prevent the other motor from closing the door. An EVA astronaut could probably not close the door manually with a dual motor failure, but two independent failures like that is highly unlikely.

Quote
(2) Prior to the OBSS era, how would the EVA crewmember accomplish this without the extra reach provided by the boom? Thanks.

Prior to the EVA, the crew would improvise a bolo using a bag full of clothes and an EVA safety tether. The EVA crewmember would translate to the aft end of the payload bay along the EVA slidewire on the sill, secure the tether end of the bolo to the slidewire, then sling the bolo such that the bag catches in the gap between the inboard elevon and the aft fuselage (this would likely take several attempts). The EVA cremember would then attach his own safety tether to the bolo, translate down the bolo to the elevon, then pull himself over the side. The umbilical doors are reachable from the underside of the elevon.

This EVA was considered unlikely to work and consequently not taken seriously by most astronauts.

Nevertheless, there was (and maybe still is) a high-fidelity mockup of the ET umbilical doors in the highbay of JSC building 9 for EVA training.
Title: Re: Shuttle Q&A Part 5
Post by: Alpha Control on 10/09/2009 02:55 am

And when the tank seperates on orbit does the doors seal the same as landing gear doors (Do they come down) or do they slide over to cover the connection point?

The doors are hinged on the inboard side, and after ET sep they flip 180 degrees to close.

http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/sep/umbdoors.html

Photo here:

http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=43554

Quote
What if it failed to close?

The doors can be closed manually via EVA. The area around the doors is (just barely) reachable by an astronaut in a foot restraint on the tip of the OBSS at the end of the RMS.

If the doors can't be closed at all, LOV/C.

Jorge; two follow-ups, if I may:

(1) Regarding the manual closure of the ET umbilical doors, how is this done? Via a hand crank of some kind?

There is no crank. What the crew would do depends on the failure mode. If centerline latch, open the latch manually and allow the motors to close the doors. There are two motors on each door, geared such that a jam in one motor cannot prevent the other motor from closing the door. An EVA astronaut could probably not close the door manually with a dual motor failure, but two independent failures like that is highly unlikely.

Quote
(2) Prior to the OBSS era, how would the EVA crewmember accomplish this without the extra reach provided by the boom? Thanks.

Prior to the EVA, the crew would improvise a bolo using a bag full of clothes and an EVA safety tether. The EVA crewmember would translate to the aft end of the payload bay along the EVA slidewire on the sill, secure the tether end of the bolo to the slidewire, then sling the bolo such that the bag catches in the gap between the inboard elevon and the aft fuselage (this would likely take several attempts). The EVA cremember would then attach his own safety tether to the bolo, translate down the bolo to the elevon, then pull himself over the side. The umbilical doors are reachable from the underside of the elevon.

This EVA was considered unlikely to work and consequently not taken seriously by most astronauts.

Nevertheless, there was (and maybe still is) a high-fidelity mockup of the ET umbilical doors in the highbay of JSC building 9 for EVA training.

Fascinating. Thanks very much for the detailed info.
Title: Re: Shuttle Q&A Part 5
Post by: Oberon_Command on 10/13/2009 06:43 pm
Apologies in advance if this has been asked already (in which case the forum search function has failed me), but can anyone tell us why 51-L used white instead of black rings on the upper SRB segments?
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 10/17/2009 04:32 am
Following the Wikipedia ET page (http://en.wikipedia.org/wiki/Space_Shuttle_external_tank) to this Lockheed Martin page (http://www.lockheedmartin.com/ssc/michoud/ExternalTank/ByNumbers.html) I found this quote:

Quote
50 – approximate percent of the 15,000-pound shuttle performance increase necessary to fly to the International Space Station that is provided by the Super Lightweight Tank

What provides the other 50%?
Title: Re: Shuttle Q&A Part 5
Post by: spaceshuttle on 10/17/2009 06:05 am
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?

Also...

Following the Wikipedia ET page (http://en.wikipedia.org/wiki/Space_Shuttle_external_tank) to this Lockheed Martin page (http://www.lockheedmartin.com/ssc/michoud/ExternalTank/ByNumbers.html) I found this quote:

Quote
50 – approximate percent of the 15,000-pound shuttle performance increase necessary to fly to the International Space Station that is provided by the Super Lightweight Tank

What provides the other 50%?

I'd like to know this also.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/17/2009 11:03 am
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?
The covers have always been paper, never "tiles" -- they burn.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/17/2009 11:22 am
Following the Wikipedia ET page (http://en.wikipedia.org/wiki/Space_Shuttle_external_tank) to this Lockheed Martin page (http://www.lockheedmartin.com/ssc/michoud/ExternalTank/ByNumbers.html) I found this quote:

Quote
50 – approximate percent of the 15,000-pound shuttle performance increase necessary to fly to the International Space Station that is provided by the Super Lightweight Tank

What provides the other 50%?

I think it is simply the amount carried up is reduced.  I recall going to the Russian's orbit caused a lot of mission redesign for this reason.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/17/2009 11:22 am
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?
The covers have always been paper, never "tiles" -- they burn.

Besides, AFRSI is a thermal blanket material, not a tile material.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/17/2009 11:23 am
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?
The covers have always been paper, never "tiles" -- they burn.


I have heard the acoustics from SRB ignition take them off.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/17/2009 11:45 am
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?
The covers have always been paper, never "tiles" -- they burn.


I have heard the acoustics from SRB ignition take them off.

Danny Deger
They come off (mostly) when the main engines start on the pad before booster ignition.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/17/2009 10:14 pm
What causes the tyvek (previously AFRSI) covers to blow off of the aft RCS thrusters once the SSMEs ignite?
The covers have always been paper, never "tiles" -- they burn.


I have heard the acoustics from SRB ignition take them off.

Danny Deger
They come off (mostly) when the main engines start on the pad before booster ignition.


How about the ones on the forward pod?  Do they survive the main engines starting?

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/17/2009 10:49 pm
They come off (mostly) when the main engines start on the pad before booster ignition.


How about the ones on the forward pod?  Do they survive the main engines starting?
Yes.  The ones on the forward RCS were changed after STS-107 to get them to release early (and more completely) in first stage before they can become a debris risk.

For examples of what happens to the aft butcher paper covers, reference footage of most engine starts on the pad -- with a good view of the area and when the butcher paper was installed.  (Doesn't look like they were put on for some of the FRFs.)

For an example of what happens to the FRCS paper covers, reference the ET camera video footage from STS-112.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/18/2009 02:38 am
Following the Wikipedia ET page (http://en.wikipedia.org/wiki/Space_Shuttle_external_tank) to this Lockheed Martin page (http://www.lockheedmartin.com/ssc/michoud/ExternalTank/ByNumbers.html) I found this quote:

Quote
50 – approximate percent of the 15,000-pound shuttle performance increase necessary to fly to the International Space Station that is provided by the Super Lightweight Tank

What provides the other 50%?

Most of it was provided by various shuttle flight software upgrades implemented in OI-26, 26B, and 27 in the late 1990s. OMS assist provides up to ~400 lbm performance increase, for example. There were a lot of little upgrades and they all provided a little performance, which added up.
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 10/24/2009 09:18 pm
Can anyone describe (or point me to an existing description) of the process involved in ET foam removal and replacement?

I can only imagine that it is a fairly complex process, especially removing all traces of the previous foam from the underlying materials before applying the new layers, but I'm really curious whether the stripping and preparing is done by mechanical or chemical means -- or a combination of the two?

TIA,

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/25/2009 10:58 pm
In the unlikely event that the Shuttle lost both OMS thrusters could the Shuttle reenter simply by letting its orbit decay? I imagine this depends very strongly on its altitude and orientation. How soon would the Shuttle's orbit decay if it presented the maximum possible area normal to its velocity vector? Could it survive such a reentry, provided it reoriented itself in time? Could it keep the crew alive for long enough to do this?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/25/2009 11:18 pm
In the unlikely event that the Shuttle lost both OMS thrusters could the Shuttle reenter simply by letting its orbit decay? I imagine this depends very strongly on its altitude and orientation. How soon would the Shuttle's orbit decay if it presented the maximum possible area normal to its velocity vector? Could it survive such a reentry, provided it reoriented itself in time? Could it keep the crew alive for long enough to do this?

No but it could use its RCS thrusters
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/25/2009 11:26 pm
In the unlikely event that the Shuttle lost both OMS thrusters could the Shuttle reenter simply by letting its orbit decay? I imagine this depends very strongly on its altitude and orientation. How soon would the Shuttle's orbit decay if it presented the maximum possible area normal to its velocity vector? Could it survive such a reentry, provided it reoriented itself in time? Could it keep the crew alive for long enough to do this?

No but it could use its RCS thrusters
Yep. The +X RCS jets.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 10/26/2009 12:38 am
In the unlikely event that the Shuttle lost both OMS thrusters could the Shuttle reenter simply by letting its orbit decay? I imagine this depends very strongly on its altitude and orientation. How soon would the Shuttle's orbit decay if it presented the maximum possible area normal to its velocity vector? Could it survive such a reentry, provided it reoriented itself in time? Could it keep the crew alive for long enough to do this?

No but it could use its RCS thrusters
Yep. The +X RCS jets.


Doesn't have to be just the +X jets, fast flip and prebank can also contribute to getting the needed delta V.  This topic has been covered a lot here so a search might find you some more detailed answers.


Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/26/2009 01:02 am
No but it could use its RCS thrusters

Where would things go wrong if you tried the orbital decay route? Not trying to say it would be a good idea, just trying to understand.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/26/2009 03:06 am
No but it could use its RCS thrusters

Where would things go wrong if you tried the orbital decay route? Not trying to say it would be a good idea, just trying to understand.

Decay lifetime >> crew lifetime. Sometimes >>>

Simple as that.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/26/2009 12:23 pm
No but it could use its RCS thrusters

Where would things go wrong if you tried the orbital decay route? Not trying to say it would be a good idea, just trying to understand.

wrong entry angle.  Too shallow
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/26/2009 12:25 pm
wrong entry angle.  Too shallow

What happens if you enter at too shallow an angle? Do you then descend too fast and burn up? I remember from playing with Orbiter that counterintuitively, if you are descending too fast you have to dive.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/26/2009 07:14 pm
wrong entry angle.  Too shallow

What happens if you enter at too shallow an angle? Do you then descend too fast and burn up? I remember from playing with Orbiter that counterintuitively, if you are descending too fast you have to dive.

In case my previous post was too subtle...

Shuttle orbits are high enough that they will not decay naturally within the lifetime of the crew. Therefore this approach is not viable (literally!) and the discussion is moot.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/26/2009 07:16 pm
Shuttle orbits are high enough that they will not decay naturally within the lifetime of the crew. Therefore this approach is not viable (literally!) and the discussion is moot.

I know, but I'm just curious. You've explained it would take too long, which seems understandable enough. Jim said the reentry angle would be too shallow and I don't understand what's wrong with that and I'd like to know. Feel free not to answer!
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 10/27/2009 12:51 am
I know, but I'm just curious. You've explained it would take too long, which seems understandable enough. Jim said the reentry angle would be too shallow and I don't understand what's wrong with that and I'd like to know. Feel free not to answer!
I'm assuming it takes too long because the entry angle is too shallow; at that altitude it takes a long time for atmospheric resistance to significantly affect your velocity.  By descending more steeply, you reach the denser part of the atmosphere more quickly.

Of course, Jim might have had something else in mind.  I wish he would give more verbose answers. :(

EDIT: On the other hand, you have to be mindful that the heat shield is on the bottom of the shuttle, not the nose. :)
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 10/27/2009 12:53 am
It's pretty simple - if you don't have something to put brakes on the shuttle, it will stay up there for a LONG LONG time. I'm not sure what's confusing?
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/27/2009 12:55 am
I did some googling and it turns out there is something called an entry corridor which determines the range of angles suitable for reentry. Too steep and you burn up, too shallow and you skip out of the atmosphere again. I don't know if this applies to return from LEO as well as lunar returns, but I suppose it does. So what happens once you skip out? Since you would have lost some energy your orbit would still be decaying. How steep would the next angle be? Could it be that the angle gets progressively steeper with every skip until finally you burn up?
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/27/2009 12:59 am
It's pretty simple - if you don't have something to put brakes on the shuttle, it will stay up there for a LONG LONG time. I'm not sure what's confusing?

That part was clear. I know this is not a viable way to return - and I knew you could use the RCS for a deorbit burn before I asked the question since this has been discussed before.

I wondered if changing the attitude of the Shuttle could increase drag by enough to deorbit and I now know the answer is no. I wondered if the shallow reentry would be a problem and I now know it would be. What I don't understand is the details of what the correct angle for reentry is.

Again, feel free not to answer, I'm grateful for the answers I've received so far.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 10/27/2009 01:56 am
So what happens once you skip out?

On a low eccentricity orbit, such as the subject hypothesis, there would be no skip.  It would be a continuous aerodynamic decay.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 10/27/2009 10:15 am
Changing your attitude so that there's more of a cross section pointing in the direction of the velocity vector SHOULD increase drag, but probably not enough to do anything significant.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 10/27/2009 08:42 pm
What happens if you enter at too shallow an angle?

In all likelihood it will not reach an airport due to the increased uncertainty of the trajectory.

Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/27/2009 09:05 pm
On a vaguely related note, is there anything an Orbiter with a damaged heatshield can do to make reentry safer in the sense that it would get down low enough and slow enough for the crew to bail out?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 10/27/2009 09:21 pm
Only if they bail in orbit. But then they have other issues.
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 10/28/2009 10:57 am
In the unlikely event that the Shuttle lost both OMS thrusters could the Shuttle reenter simply by letting its orbit decay? I imagine this depends very strongly on its altitude and orientation. How soon would the Shuttle's orbit decay if it presented the maximum possible area normal to its velocity vector? Could it survive such a reentry, provided it reoriented itself in time? Could it keep the crew alive for long enough to do this?

No but it could use its RCS thrusters
Yep. The +X RCS jets.


Doesn't have to be just the +X jets, fast flip and prebank can also contribute to getting the needed delta V.  This topic has been covered a lot here so a search might find you some more detailed answers.


Mark Kirkman

For those on L2 there are some fab documents that cover prebank and fast flip.

Also when it comes to OMS ENGINE failures (assuming you have good prop) you can feed the aft RCS jets with the OMS tanks.

The Orbiter has many options available for a safe deorbit burn.
Title: Re: Shuttle Q&A Part 5
Post by: Hop_David on 10/28/2009 02:43 pm
I did some googling and it turns out there is something called an entry corridor which determines the range of angles suitable for reentry. Too steep and you burn up, too shallow and you skip out of the atmosphere again. I don't know if this applies to return from LEO as well as lunar returns, but I suppose it does. So what happens once you skip out? Since you would have lost some energy your orbit would still be decaying. How steep would the next angle be? Could it be that the angle gets progressively steeper with every skip until finally you burn up?

It seems to me angle of incidence would equal angle of reflection. Like a pool ball bouncing off the edge of a table or a photon bouncing off a mirror.

And since the spherical earth and elliptic orbit have a symmetry I would expect re-entry at the same angle that the craft bounced from.

Of course the ship's interaction with the atmosphere might change the bounce angle.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 10/29/2009 02:39 am
I'm assuming you're talking about the atmosphere there, rather than on the orbiter itself.  I just searched for an ESTEC standard that I ran across somewhere several years ago, but I can't find it now.  Maybe you can come up with more creative Google terms than me.

Basically, the individual atoms or molecules are really hot (>1000K), but they are so far apart that it would "feel" really cold (<100K).

Edit: here's a ton of models
http://ccmc.gsfc.nasa.gov/modelweb/
I'd like to know what are temperatures on that altitude the space shuttle fly?

Mind like a steel trap, or maybe I stumbled across it while looking for the answer to someone else's Isp question.
http://www.spenvis.oma.be/spenvis/ecss/ecss07/ecss07.html
Your answer is 699 Kelvin.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 10/29/2009 09:52 am
Great link! I thought SPENVIS only modeled the radiation environment in the van Allen belts, but it's much more extensive than that.
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 10/29/2009 03:01 pm
I recently saw some footage of slow motion MLP cameras during launch and I could see some kind of dirt covering up the cameras. I understand that is SRB exhaust. Does this 'dirt' contaminates the ocean when the SRBs fly over it??
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 10/29/2009 11:05 pm
I recently saw some footage of slow motion MLP cameras during launch and I could see some kind of dirt covering up the cameras. I understand that is SRB exhaust. Does this 'dirt' contaminates the ocean when the SRBs fly over it??

SRBs do not pollute the ocean.
Title: Re: Shuttle Q&A Part 5
Post by: C5C6 on 10/30/2009 11:07 pm
I recently saw some footage of slow motion MLP cameras during launch and I could see some kind of dirt covering up the cameras. I understand that is SRB exhaust. Does this 'dirt' contaminates the ocean when the SRBs fly over it??

SRBs do not pollute the ocean.
could you please explain it up??

is that 'dirt' covering the cameras not part of SRB exhaust?? in case they are part of it, does it fall into the ocean?? in case they fall into the ocean, is it toxic??
Title: Re: Shuttle Q&A Part 5
Post by: AlexInOklahoma on 10/31/2009 02:04 pm

is that 'dirt' covering the cameras not part of SRB exhaust?? in case they are part of it, does it fall into the ocean?? in case they fall into the ocean, is it toxic??

I could not find any quick/easy references for you, but, going from memory only, the exhaust is *not* a ~credible bio-hazard or such (imho)  I think the 'particles' are aluminum-based and not a concern at all.  Gritty and abrasive, but not 'reactive' biologically speaking  The 'worst part' of the exhaust (IMHO) is that it can cause some pH 'shifting' of the air in the area (??), but it is so very (very, very, very....) slight that it is not of any practical concern whatsoever.  It would be bad to pump out the exhaust for hours on end for months and months continuously, but at usual rates, non-issue   :)

The perchlorate(s) (look *that* part up for more info, plz) formed are present but trivial overall (!!!)  I am not explaining this any deeper as I forget the actual details and don't want to mislead by intention, but it is a non-issue environmentally speaking.  Could be debatable, but IMHO, that is calling a tiny molehill a huge mountain...

Make sense?  There is no effect from the exhaust that is meaningful.  After all, there is a 'Refuge' surrounding the launch complex there  ;)  Gebhardt just put it a lot more succinctly as it can sometimes be stretched into something it is not  ;)

More here -> http://forum.nasaspaceflight.com/index.php?topic=18447.0
and here -> http://www.epa.gov/OGWDW/contaminants/unregulated/perchlorate.html

HTH,
Alex
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/31/2009 02:21 pm
The exhaust products are aluminum oxide and hydrochloric acid.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 10/31/2009 04:13 pm
Pretty dilute, though AIUI.  Plus the standard combustion products (COx, H2O)
Title: Re: Shuttle Q&A Part 5
Post by: Gambina-GSFC on 11/09/2009 06:02 pm
Just a couple question about the shuttle assembly for a model.  I would like to be as realistic as possible

1)  What is the pitch angle of the orbiter when attached to the External Tank?
            -Other ways to answer this question

                  a) What is the offset of the orbiter at the aft of the ET and what is the offset at the bipod assembly at the forward attachment?

2)  What are the dimensions of the SRB Thrust Beam inside the Intertank?  This is the beam that connects the port and starboard SRBs at the forward attachment point.  It also accounts for the dampening of the oscillations that originate from the SRBs.

3)  I am looking for structural drawings of the orbiter itself.  Mostly for wing profile and the like, but I would like to also see how the orbiter was designed as a structure.  If I need to get approval from a NASA official to gain access to the drawings, please let me know.  I am very interested in the orbiters design, both scientifically and for my own personal knowledge.

Thank you for your time and any help anyone can give

Bryan Gambina
NASA-Goddard Space Flight Center
Hubble Servicing Mission 4
Mechanical I & T Engineer
Wide Field Planetary Camera 2 Manager


Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 11/09/2009 06:28 pm
1)  What is the pitch angle of the orbiter when attached to the External Tank?
            -Other ways to answer this question

                  a) What is the offset of the orbiter at the aft of the ET and what is the offset at the bipod assembly at the forward attachment?

2)  What are the dimensions of the SRB Thrust Beam inside the Intertank?  This is the beam that connects the port and starboard SRBs at the forward attachment point.  It also accounts for the dampening of the oscillations that originate from the SRBs.

You should download the Shuttle SLWT System Definition Handbook from this thread:

http://forum.nasaspaceflight.com/index.php?topic=14350.0 (http://forum.nasaspaceflight.com/index.php?topic=14350.0)

Its split over three separate pdf files, but the last one (Volume II - Layout Drawings SLWT_SDH_Vol.2.pdf) has detailed dimensioned drawings that should answer your questions on the orbiter attachment points and the thrust beam dimensions.

Hope that helps.
Title: Re: Shuttle Q&A Part 5
Post by: Fuji on 11/10/2009 03:28 am
3)  I am looking for structural drawings of the orbiter itself.  Mostly for wing profile and the like, but I would like to also see how the orbiter was designed as a structure.  If I need to get approval from a NASA official to gain access to the drawings, please let me know.  I am very interested in the orbiters design, both scientifically and for my own personal knowledge.

Could you check here? Not so detaild, but public acsess data.
http://spaceflight.nasa.gov/shuttle/reference/sodb/
Title: Re: Shuttle Q&A Part 5
Post by: wjbarnett on 11/16/2009 12:28 am
Anybody know success rate (%) of shuttle first launch attempt?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/16/2009 01:35 am
Around 40 percent, IIRC.  The AP did an analysis a few years ago. 
A Google search turned up a few relevant articles.

Anybody know success rate (%) of shuttle first launch attempt?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 11/16/2009 01:39 am
Plus it depends on your definition of "attempt"
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 11/16/2009 04:08 pm
Why the switch in flight engineers on STS-129?  Randy Bresnik is the ascent FE; Leland Melvin is FE on entry.  There is surely a reason for this. . .anybody know why?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/16/2009 07:03 pm
Well spotted. I'd been wanting to ask that for a few days after checking the wikipedia entry for the mission.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/16/2009 07:10 pm
Why the switch in flight engineers on STS-129?  Randy Bresnik is the ascent FE; Leland Melvin is FE on entry.  There is surely a reason for this. . .anybody know why?
I believe it was mentioned during the crew news conference pre-flight.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 11/17/2009 05:28 am
During this afternoon's countdown coverage on NTV, the PAO rolled a cool time-lapse video of Atlantis sitting on the MLP inside the VAB, looking down from above. It showed the crawler enter the VAB, drive under the MLP and back out of the VAB carrying the stack. I'd never seen it from that perspective before.

I noticed what appeared to be three large vans or buses and a smaller vehicle lined up on top of the MLP, near the edge opposite the shuttle. These vehicles remained in place as the stack left the VAB. Does anyone know what these vehicles are for and how they get them off the platform?
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 11/17/2009 05:39 am
Another question... Is STS-129 taking a recumbent seat for Nicole Stott to save weight (since there's only six crew going uphill) or is that standard procedure for bringing home long-duration ISS crew members?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/17/2009 06:04 am
During this afternoon's countdown coverage on NTV, the PAO rolled a cool time-lapse video of Atlantis sitting on the MLP inside the VAB, looking down from above. It showed the crawler enter the VAB, drive under the MLP and back out of the VAB carrying the stack. I'd never seen it from that perspective before.

I noticed what appeared to be three large vans or buses and a smaller vehicle lined up on top of the MLP, near the edge opposite the shuttle. These vehicles remained in place as the stack left the VAB. Does anyone know what these vehicles are for and how they get them off the platform?
See this post in the LC-39 Q&A thread: http://forum.nasaspaceflight.com/index.php?topic=14430.msg386436#msg386436
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 11/17/2009 06:19 am
See this post in the LC-39 Q&A thread: http://forum.nasaspaceflight.com/index.php?topic=14430.msg386436#msg386436

Thanks. Wow, they sure looked much larger from a 'god's eye' perspective!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/17/2009 10:26 am
Another question... Is STS-129 taking a recumbent seat for Nicole Stott to save weight (since there's only six crew going uphill) or is that standard procedure for bringing home long-duration ISS crew members?
More the latter -- it's been standard procedure since Shuttle-Mir.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/17/2009 10:52 am
attempt: /əˈtɛmpt/,
Noun
The action of trying at something.


Plus it depends on your definition of "attempt"
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/17/2009 11:02 am
(Sorry, doing this as bottom post)

Plus it depends on your definition of "attempt"
attempt: /əˈtɛmpt/,
Noun
The action of trying at something.
I think what Rob is getting at is, for example, was there an "attempt" to launch STS-51E?  And was that counted in the AP story?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/18/2009 11:31 am
Can someone explain what the green areas are on the MCC display of launch? Some sort of crossrange display or predicted locations?

Been meaning to ask for a while.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/18/2009 11:56 am
Can someone explain what the green areas are on the MCC display of launch? Some sort of crossrange display or predicted locations?
Can't explain it (Mark or the JSC folks can), but I believe that's the Downrange Abort Evaluator "footprint" in the Group Outplane display that's up during ascent.  There's a detailed explanation in one of the docs on L2.

(FWIW, that's always up on the middle of the three screens during ascent.)

Edit: Bumped that particular thread for anyone that's interested.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 11/18/2009 02:04 pm
Can someone explain what the green areas are on the MCC display of launch? Some sort of crossrange display or predicted locations?

Been meaning to ask for a while.

It is the the Downrange Abort Evaluator that gives a footprint of where the shuttle can land if all three engines quit right "now".  The dog house shaped section is called "the dog house".  It is where the shuttle can land in automatic control.  The other sections require manual control to a lower angle of attack to stretch to the landing site and I think maybe manual control of roll angle also.

Danny Deger

Edit: The picture you took is about as bad as it gets.  For only a few seconds of ascent the footprint is in the middle of the North Atlantic.  In the picture shown, the crew would probably stretch as best they could toward England/Ireland and bailout close to the coast.  Capsules like Orion can't stretch as far, but I think Orion has a large enough service module engine to burn it to avoid the North Atlantic.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jones36 on 11/18/2009 02:19 pm
I noticed that on my tracker I follow on Google. Thanks for the info Danny!
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/18/2009 02:31 pm
Thanks Danny!
Title: Re: Shuttle Q&A Part 5
Post by: Aeroman on 11/18/2009 07:39 pm
I have a question about Shuttle docking with the ISS.

In a number of movies with the shuttle in them (mainly James Bond 007, Moonraker) it shows the shuttle docking using the side hatch.  Why isn't that used?  Is it becuase of the docking configuration of the docking ports?
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 11/18/2009 07:42 pm
The side hatch isn't a docking hatch.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 11/18/2009 11:08 pm
I have a question about Shuttle docking with the ISS.

In a number of movies with the shuttle in them (mainly James Bond 007, Moonraker) it shows the shuttle docking using the side hatch.  Why isn't that used?  Is it becuase of the docking configuration of the docking ports?
'Cause Hollywood is usually stupid when it comes to spaceflight and actual space hardware. (Talking about the non-fantasy/sci-fi kind; in those almost anything is considered probable.)

There's very few that actually pay attention to facts and reality for a script, to sets, to special effects and CGI, to end up with realistic images and activities in the final film. (There's too many producers and directors of mainstream films that seem to consider reality too boring for enough action and drama to keep an audience interested. You want reality? Film a documentary.)

Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/19/2009 08:50 am
Realism is not always entertaining, you have to allow for a certain amount of artistic licence or you get something boring.

Edit: Don't get me wrong, I love things to be accurate but sometimes it's not appropriate or doesn't work.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/21/2009 11:55 am
Odd question, this, but here goes.

Why are the engines started 6 and a bit seconds before SRB ignition. Obviously, you have to:

1) Give them time to start one at a time
2) Give them time to ramp up to full thrust

But does this take all that time? Or is this time the time it takes for the GLS to go through all the right parameters before ignition? It seems like it's wasting fuel taking that long. Is there any way the sequence could be shortened, to provide extra upmass at all? Or is this just a limitation of the system how it is now?

Hypothetical, really, I'd be interested in any comments about it.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/21/2009 11:56 am
Odd question, this, but here goes.

Why are the engines started 6 and a bit seconds before SRB ignition.
The twang effect.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 11/21/2009 12:08 pm
Odd question, this, but here goes.

Why are the engines started 6 and a bit seconds before SRB ignition.
The twang effect.

More staggered ignition plus ramp up to full throttle with checks, including twang.


Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/21/2009 01:00 pm
3 seconds for start up and 3 seconds for the twang to come back to the starting point.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/21/2009 01:24 pm
Wow, as simple as that. Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 11/21/2009 08:30 pm
(Sorry, doing this as bottom post)

Plus it depends on your definition of "attempt"
attempt: /əˈtɛmpt/,
Noun
The action of trying at something.
I think what Rob is getting at is, for example, was there an "attempt" to launch STS-51E?  And was that counted in the AP story?


Very true. At what point do you consider an attempt made? Obviously, in order to launch you have to fill the ET. So does the official attempt only begin when propellants start flowing into the ET? Does the attempt start when the Countdown begins? Does the attempt start once the SOMD FRR sets the official target launch date? Does the attempt start when the Shuttle vehicle reaches the pad?   What is NASA official definition of an "attempt?"
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/21/2009 08:48 pm
I reckon that whenever you enter S0007, that's an attempt. You've got that far, you've started the terminal count, but something stopped it part-way through.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/21/2009 10:31 pm
When the FRR sets a date.
Title: Re: Shuttle Q&A Part 5
Post by: gordon on 11/22/2009 07:42 pm
Guys, I have a question,

I went to the STS-129 Atlantis launch and weather permitting I want to go back to KSC for it's landing.  I have been doing some research on landings and trying to understand the ground tracks to KSC when coming back from ISS.  I looked at STS 118, 119, 121, 122, 123, 124 and 127 and they all follow a similar pattern.  Generally, the approach is from the South on the first orbit try and then it shifts a little to the West for the next orbit.  Same pattern if landing 15 or 33.
But STS-120 landing on 33 is WAY different.  It approached form the Northwest!
Does anyone know why that was.
Thanks
Title: Re: Shuttle Q&A Part 5
Post by: kneecaps on 11/22/2009 10:48 pm
Guys, I have a question,

I went to the STS-129 Atlantis launch and weather permitting I want to go back to KSC for it's landing.  I have been doing some research on landings and trying to understand the ground tracks to KSC when coming back from ISS.  I looked at STS 118, 119, 121, 122, 123, 124 and 127 and they all follow a similar pattern.  Generally, the approach is from the South on the first orbit try and then it shifts a little to the West for the next orbit.  Same pattern if landing 15 or 33.
But STS-120 landing on 33 is WAY different.  It approached form the Northwest!
Does anyone know why that was.
Thanks

The missions you mention, STS-120 entered on the descending node of the orbit, the others on the ascending node.

I believe that that descending node entries are only available during certain times of the year due to noctilucent clouds at high latitudes.

The longitude of nodes of the orbit (where the ground track passes relative to the surface of the) regresses so the option is always open to enter on an ascending or descending node. However various operational reasons (eg the above mentioned clouds).

Hope this is clear enough. I'm sure others can add some more info too.

Pete



Title: Re: Shuttle Q&A Part 5
Post by: gordon on 11/22/2009 11:26 pm
Pete,

Thank you very much for your quick response.  You are absolutely correct and with your information I did some quick additional research and realized that NASA also doesn't like to use the descending node entry because the ground track is over so much land.  That became a concern after the Coumbia accident.  I remember the discussion about that now.  Thanks again.
I am hoping that they decide to land Atlantis on Friday.  I can go to KSC on that day and right now the weather looks promising.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 11/23/2009 04:28 pm
Has a wind shear for the ascent trajectory ever delayed a Shuttle launch?  No need to address RTLS aspects of this question or 51L.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/23/2009 07:00 pm
Has a wind shear for the ascent trajectory ever delayed a Shuttle launch?  No need to address RTLS aspects of this question or 51L.
There were a few launches in the 80s that were delayed due to upper level winds, though not sure if shear was a specific problem for all of them...for example, 51-A:
http://web.archive.org/web/19990922122353/http://members.aol.com/WSNTWOYOU/STS14MR.HTM

Quote
The STS 51-A mission was scheduled for launch on November 7, 1984, but the launch was scrubbed during the planned hold at T-20 minutes because the data indicated that the predicted winds-aloft would apply shear loads in excess of the design limits of the vehicle.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 11/23/2009 07:01 pm
Has a wind shear for the ascent trajectory ever delayed a Shuttle launch?  No need to address RTLS aspects of this question or 51L.

I think NASA used to scrub "all the time" before the first stage flight profile data could be uplinked to the shuttle while it was sitting on the pad (DOLILU).

What happens today is a balloon is launched, the flight profile data is calculated in the Mission Control Center, then uplinked to the shuttle.  With this capability, I don't think a mission has had to scrub for upper atmospheric winds.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/23/2009 07:31 pm
I think NASA used to scrub "all the time" before the first stage flight profile data could be uplinked to the shuttle while it was sitting on the pad (DOLILU).
Do you recall approximately (or specifically) when that was first used?  I recall some delays for a few launches in the RTF1 period, but those were with longer launch windows and some flights were able to launch later in the window for the day.
Title: Re: Shuttle Q&A Part 5
Post by: jhf on 11/24/2009 05:40 am
Is the ODS used today for docking with ISS substantially similar to the one used for Shuttle-Mir?  Is the same hardware still in use?

Wikipedia (I know, I know) says there's a difference between the Mir-type APAS and the APAS used aboard ISS, but it almost sounds like the main difference is that the new system isn't truly androgynous anymore -- i.e. that the APAS on the PMAs aren't capable of acting as active docking collars.

It's a lot of supposition on my part, I suppose, but it would make a lot of sense if the passive APAS-95 units on the PMAs were compatible with the (truly androgynous) APAS-89 units, but not other passive APAS-95 units:  the Russians could have put the same sort of APAS on Zarya as on Kristall, and the old ODS would have continued to work.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/24/2009 10:57 am
Is the ODS used today for docking with ISS substantially similar to the one used for Shuttle-Mir?  Is the same hardware still in use?


It is the exact same one(s), don't remember how many were there.
Title: Re: Shuttle Q&A Part 5
Post by: joncz on 11/24/2009 12:55 pm
When the shuttle performs its separation burn from the station, does it depart retrograde or prograde?

I'm wondering when it makes its pass overhead later that evening, who is in trail?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 11/24/2009 01:41 pm
When the shuttle performs its separation burn from the station, does it depart retrograde or prograde?

I'm wondering when it makes its pass overhead later that evening, who is in trail?

Retro, which puts the shuttle in the lead and ISS in trail (retro = lower, lower = faster).
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 11/25/2009 05:57 am
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 11/25/2009 08:58 am
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?


The undocks and flyarounds are always planned so the station can be viewed and photographed in daylight.
Title: Re: Shuttle Q&A Part 5
Post by: Lawntonlookirs on 11/25/2009 12:33 pm
I was just checking Heavens Above on the ISS Height Profile and noticed that they did show the 1.5 k re-boast that was performed yesterday.  However, I also noticed that the ISS had an altitude of almost 358 km around 1/10/09, and prior to yesterdays re-boast the altitude was 340 km, which is a drop of 18km.  During that perior they had a couple of re-boast in July, which raised the ISS about 2.5km.

With the 27 min burn yesterday to raise the ISS the 1.5km, what is the maximum re-boast that has ever been done?  Also related somewhat to the same question, what is the min altitude the ISS can get too before it needs a re-boast.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/25/2009 04:51 pm
When the shuttle performs its separation burn from the station, does it depart retrograde or prograde?

I'm wondering when it makes its pass overhead later that evening, who is in trail?

Retro, which puts the shuttle in the lead and ISS in trail (retro = lower, lower = faster).

Today SEP2 was posigrade. This is done to preserve re-rendezvous capability after Late Inspection.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/25/2009 04:53 pm
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?


The undocks and flyarounds are always planned so the station can be viewed and photographed in daylight.


They're planned so that only the *flyaround* part is in daylight. Undocking is at midnight -2 minutes so that sunrise occurs at flyaround start, but as a result the Vbar backout is in darkness.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisC on 11/25/2009 09:17 pm
Hi ... I posted this Monday night in the STS-129 viewing thread but didn't get any responses there, so I'll try it here.

I'm in Florida, 150 miles south of KSC, and will be driving up to KSC on Friday morning.  I can not drive up sooner than that.  With nominal landing time around 9:45am, I was wondering how close to KSC I would need to get to hear the sonic boom.  Here are some random quotes that I got from Googling around.

"I live 100miles south of the Cape just north of West Palm Beach (across from Lake Okeechobee) and even though the Shuttle is still invisible at 80,000ft there the house rattles from the double sonic booms as it goes over. Anywhere in West Palm, Stuart, Vero Beach, Melbourne and up to Titusville you'll know when it goes over."

"Altitude is irrelevant; when coming in over the US on past missions, it could be heard even at 40 miles altitude during entry."  (that's 200,000+ feet)

"Those who live near and around the Kennedy Space Center are accustomed to hearing the double booms of a returning shuttle, but those located under and close to the Shuttle path, perhaps all the way back to the Pacific coast, may also hear the booms as well. "

"From a location in the nation's midsection or over the northwest United States, where the altitude of the shuttle will be in the range of 100,000 to 200,000-feet, it will take time for the shock wave to propagate down to the ground.  Sound travels at roughly 1,100-feet per second, so depending on where you live relative to the track, it could be anywhere from 90 to 180 seconds after the shuttle has passed on by before you hear anything."

Obviously those last two are from a landing of a mission whose groundtrack took it across the US, which isn't likely this time, but they do illustrate that the sonic boom is apparently still heard even when the shuttle is that high up, thousands of miles away from KSC.

Can someone comment on these are all accurate?

What about crossrange distance?  If the groundtrack is coming across the peninsula on a northeast track (like this one (http://www.nasa.gov/images/content/407229main_sts129_ksc171_mid.gif)), are they going to hear it in West Palm Beach?

Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 11/26/2009 01:50 am
What exactly does the double sonic boom sound like?  I don't think I've ever heard even a single sonic boom.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 11/26/2009 02:41 am
A boom, then another boom? I'm not sure how else to describe it - you might do a YouTube hunt.
Title: Re: Shuttle Q&A Part 5
Post by: Pedantic Twit on 11/26/2009 02:44 am
What exactly does the double sonic boom sound like?  I don't think I've ever heard even a single sonic boom.
A boom, then another boom? I'm not sure how else to describe it - you might do a YouTube hunt.

At 2:50. BANG BANG.
http://www.youtube.com/watch?v=AAirZUdQB6g#t=2m48s
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 11/26/2009 08:53 am
Is there a orbiter bible anywhere for download? L2 I'm guessing?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/26/2009 10:21 am
Anyone know where I can find the PLB camera pan/tilt angles for FCS C/O?
Title: Re: Shuttle Q&A Part 5
Post by: daniela on 11/26/2009 12:29 pm
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?


The undocks and flyarounds are always planned so the station can be viewed and photographed in daylight.


In orbital daylight. Of course that does not mean that the bright ISS and shuttle are visible in the dark sky in a "convenient" location of earth, but that should happen regularly.
Please keep in mind that the station and shuttle don't remain visible for long, and it's even worse if you want them high enough on the horizon to do quality photos.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 11/26/2009 03:39 pm
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?


Assuming that Earth bound viewing is the same for docking as well as undocking - let me report that I watched the pair the other week just a few minutes prior to docking. Even with the naked eye one could discern both objects as separate light sources. ISS actually appeared slightly rectangular in shape and about as bright as Venus. It was shortly after sunset, my vantage point being a light polluted balcony in midtown. The NASA SkyWatch service http://spaceflight.nasa.gov/realdata/sightings/ can be used to check for overlaps between the sightings list for a given location and the time of undocking.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisC on 11/26/2009 04:28 pm
I'm really hoping someone can weigh in on the range of the sonic boom, asked here yesterday:

http://forum.nasaspaceflight.com/index.php?topic=17437.msg510131#msg510131
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 11/26/2009 05:35 pm
Out of curiosity, if un-docking and fly around occurs over the portion of the Earth that it is currently night time, is this visible to see? I would assume the large bright light that is shuttle/ISS connected would change a bit...

Has it ever been seen?


I've seen the two (Shuttle and Station) very shortly after undocking.  It was about 5:50am, and the sun was just rising so the two were very bright in the sky.  You could definitely tell that there were two objects in close proximity to each other.  It was hard to tell at first, but you could see the very small gap getting slightly (fractionally) bigger, was easier to tell with binoculars..  Don't have pictures as I didn't have a camera, but it was beautiful.
Title: Re: Shuttle Q&A Part 5
Post by: Gruff on 11/26/2009 06:15 pm
OK..I understand that "In the bucket" means the stack throttles back during maximum dynamic load, but where does this term come from?
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 11/26/2009 06:20 pm
The shape of the graph of the throttle on the y-axis and time on the x-axis. Looks like a little bucket. ---_---
Title: Re: Shuttle Q&A Part 5
Post by: Gruff on 11/26/2009 06:28 pm
The shape of the graph of the throttle on the y-axis and time on the x-axis. Looks like a little bucket. ---_---
That makes perfect sense. Thanks Hungry.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 11/26/2009 07:47 pm
I'm really hoping someone can weigh in on the range of the sonic boom, asked here yesterday:

Think about it in terms of the shock wave (cone in this case) that causes the boom.  You hear the boom when the shock wave passes over you.  It is not propagating sound like most of what we hear.

So there will be a shock cone that moves along the track on that map with the point at where the orbiter is located.  How far behind the orbiter the wave/cone impinges (and how wide that impingement line is) on the ground is obviously a function of altitude and Mach number (cone angle).  So if you're too close to KSC where the orbiter is subsonic, you won't hear it.  Similarly, if you're too far off the line, the cone will not impinge on the ground where you are.

That's my theoretical take on it.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 11/27/2009 01:25 am
Hi folks,

I have a number of questions with photos. 

1) Where does this reflection of ISS come from?

Am I correct in thinking it comes from the camera they use to record the events on board?

2) Since these vent openings are on the nose (near the star tracker ports) are they closed for reentry?  If not how come hot gases don't go in them?

3) What is this rescue sign for?

4) Why are some tiles "blacker" than others?

5) What are these "white lines" (they look like mose code) in downlinks from the shuttle?

6) What are these "smaller" connection on the T0 Ubilicals.  I know the "bigger" ones are for the fuel that goes to the ET?

Also has anyone ever asked the crews if the orange suits are harder to put on/take off in spce or on the ground?

Thanks Oxford750

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/27/2009 03:24 am
Hi folks,

I have a number of questions with photos. 

1) Where does this reflection of ISS come from?

2) Since these vent openings are on the nose (near the star tracker ports) are they closed for reentry?  If not how come hot gases don't go in them?

3) What is this rescue sign for?

4) Why are some tiles "blacker" than others?

5) What are these "white lines" (they look like mose code) in downlinks from the shuttle?

6) What are these "smaller" connection on the T0 Ubilicals.  I know the "bigger" ones are for the fuel that goes to the ET?

Also has anyone ever asked the crews if the orange suits are harder to put on/take off in spce or on the ground?

Thanks Oxford750



1.  window or camera

2.  yes, they are closed for entry

3. crash landing

4.  age

5.

6.  air conditioning, power, data, purge gases,
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/27/2009 08:28 am
The white lines in the downlink video are, if I recall correctly, some kind of timecode or data stream.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 11/27/2009 10:41 am
Thanks folks.

In reguards(spell) to the RESCUE sign on the right side of the shuttle,  I thought the only two escape routes where the hatch and/or the overhead windows on the flight deck.

Thanks again for the answers to my questions.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: haywoodfloyd on 11/27/2009 12:13 pm
Can someone point me to the link for the shuttle Ground Track Network for Google Earth?
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 11/27/2009 01:21 pm
RCS engines are responsible for gettin proper orientation before re-entry (nose of shuttle goes up, angle 40) ??
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/27/2009 01:24 pm
Thanks folks.

In reguards(spell) to the RESCUE sign on the right side of the shuttle,  I thought the only two escape routes where the hatch and/or the overhead windows on the flight deck.

Thanks again for the answers to my questions.

Oxford750

The sign points to a handle to jettison the hatch.

There is also a sign on the right side on where to cut a hole in the orbiter  for rescue
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/27/2009 04:05 pm
The white lines in the downlink video are, if I recall correctly, some kind of timecode or data stream.

They only appear in cameras externally plugged into the orbiter's video switching unit. The timecode is supposed to go in the vertical blank interrupt but it relies on a common sync provided by the VSU. An outside camera plugged in (e.g. camcorder) won't have that sync, so the timecode will appear to "crawl" across the screen.
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 11/27/2009 04:11 pm
What is the source of the glow around the shuttle right around MECO from the ET cams?  It's not all from the thrusters is it?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 11/27/2009 04:38 pm
What is the source of the glow around the shuttle right around MECO from the ET cams?  It's not all from the thrusters is it?

There is visible glow from the main engine plume.  I think it might for some reason get worse during shut down, but I am not sure.  Right after main engine shutdown, the down firing thrusters fire to get 4 feet/second velocity away from the tank.  Then on most flights, the commander pushes on a control to command the aft thrusters to fire to move the orbiter along the tank so cameras on the orbiter can take pictures of the tank to look for foam shedding.

For further information, even later the commander pitches the orbiter up so they can take pictures of the tank from the overhead windows.  This is the procedure General Bolden messed up on his first flight as a commander.  He pitched too soon and they were WAY too close to the tank when it came into view.  He said it was "impressive".  He also says it was his fault, but it was really mine because I didn't train him as well as I should have. 

He made it a point to announce to all of NASA he made a bad mistake that could have killed him and his crew.  I asked him to give me at least part of the blame but he refused.  Also, the call he got from mission control was not that good either and part of the blame was on their shoulders, but he didn't mention this either.

He is the right man to lead NASA.  As a military leader and pilot, EVERYTHING that happens under your command is by definition your fault.  General Bolden knows this and knows it well.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 11/27/2009 08:23 pm
I read that the slidewire baskets were considered for use with the on pad abort of sts 41D, but the controllers were afraid to have the astronauts use the untested escape system because it had never been tested with a human occupant.

Is there a reason why it was not tested with a human before the Challenger accident?

Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 11/27/2009 09:29 pm
Thanks Jim.

Oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/27/2009 10:09 pm
RCS engines are responsible for gettin proper orientation before re-entry (nose of shuttle goes up, angle 40) ??

yes
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 11/28/2009 04:53 am
I read that the slidewire baskets were considered for use with the on pad abort of sts 41D, but the controllers were afraid to have the astronauts use the untested escape system because it had never been tested with a human occupant.

Is there a reason why it was not tested with a human before the Challenger accident?



I think it was because all the astronauts are terrified of heights  ;D

Seriously, I thought they were test early in the program, but I am not sure. 

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 11/28/2009 01:18 pm
I think we have video of the slidewire being tested by a human (not an astro) on L2?
Title: Re: Shuttle Q&A Part 5
Post by: cd-slam on 11/28/2009 02:16 pm
I haven't seen the video, but I heard that the poor tech screamed all the way down.

As I understand, this system is designed to get the crew out of harm's way of an imminent explosion, hence made for speed not necessarily safety. It would never be considered for use during a normal abort.
Title: Re: Shuttle Q&A Part 5
Post by: sbt on 11/28/2009 05:44 pm
I haven't seen the video, but I heard that the poor tech screamed all the way down.

As I understand, this system is designed to get the crew out of harm's way of an imminent explosion, hence made for speed not necessarily safety. It would never be considered for use during a normal abort.

Agree. Think of it this way - (discounting the damage to the aircraft) would you use an Ejector Seat for normal exit from an aircraft? Or a free-fall lifeboat rather than the ships tender?

Many escape systems are inherently dangerous - it's just that they are less dangerous than what you are escaping FROM.

Rick
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 11/28/2009 06:02 pm
I haven't seen the video, but I heard that the poor tech screamed all the way down.

As I understand, this system is designed to get the crew out of harm's way of an imminent explosion, hence made for speed not necessarily safety. It would never be considered for use during a normal abort.

I think the "poor tech" was none other than Charlie Bolden:

http://en.wikipedia.org/wiki/Charles_F._Bolden,_Jr.

"Bolden was the first person to ride the Launch Complex 39 slidewire baskets which enable rapid escape from a space shuttle on the launch pad. The need for a human test was determined following a launch abort on STS-41-D where controllers were afraid to order the crew to use the untested escape system."
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 11/29/2009 02:32 pm
http://spaceflight.nasa.gov/gallery/images/station/crew-21/hires/iss021e032920.jpg

What are the two objects that remain the STS-129 payload bay in this flyaround image? Are these remnants of the two ELCs that were transported to ISS by STS-129?
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 11/29/2009 03:08 pm
Yes.
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 11/29/2009 06:04 pm
Which females in the astronaut corps can spacewalk that are active at this time?  What males cannot?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/30/2009 04:24 pm
Which females in the astronaut corps can spacewalk that are active at this time?  What males cannot?

all can and all males
Title: Re: Shuttle Q&A Part 5
Post by: ponybottle on 12/04/2009 08:45 pm
Hi All !

Well this is my first post to the site and if it doesn't make much sense then blame the half bottle of merlot coursing through my veins which I unwisely (?) consumed before comming to the keyboard. :o   

Now this is probably the dumbest question ever posted to this site ( well I am Oirish and we don't get many astronoughts in this neck of the woods )
Orrrrrrrrr - this is the cleverest post ever written in which they may be moving the Cape to Dublin in the near future to take advantage of the expertise in this here Emerald Isle  ;D

My query is - if the shuttle main engines burn 1000 gallons per second and if it takes 7 seconds to clear the tower why do they not just build a bit of a hill first ( I mean I know Floridians don't know what a hill is but it is basically a pimple on the landscape ) I mean you build a hill thing about as high as the gantry and THEN stick the shuttle on top. Hey Presto ! ( or is it Begorah?  - can't remember - we are all just getting toooo cosmopolitian in this global village these days ) you save 7000 gallons of fuel which translates ( very roughly ) to 30 tons of payload !

Now either I am totally wrong ( blame the Merlot ! ) or by building some wee hills you get an awful lot more into orbit with stone age technology.

Go on - tell me I'm wrong ( you'll probably be right ! ) :)

Cheers y'all

Chris 
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 12/04/2009 10:06 pm
Because it has to go from 0 to 100 mph no matter what.  The kinetic energy of LEO is an order of magnitude greater than the potential energy.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 12/05/2009 12:30 am
How would you get the shuttle up there?
Title: Re: Shuttle Q&A Part 5
Post by: ponybottle on 12/05/2009 01:20 am
Because it has to go from 0 to 100 mph no matter what.  The kinetic energy of LEO is an order of magnitude greater than the potential energy.

I think a longer explantion is required for this no doubt learned reply to be meaningful to this writer.

I think the point being made is that the vehicle is already moving at 100mph by the time it reaches the top of the tower and so if you shut down the engines at that point the momentum would carry it a good deal further so my simplistic assumption that the first 30 ton of fuel only gets it to the top of the tower and no further is obviously wrong.

Still begs the question how much fuel does the shuttle have to burn to just get it to the top of the gantry ? i.e the amount of extra payload it could carry if the pad itself were at this height ?

Cheers

Chris
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 12/05/2009 01:28 am
Still begs the question how much fuel does the shuttle have to burn to just get it to the top of the gantry ? i.e the amount of extra payload it could carry if the pad itself were at this height ?

Let's say, by magic, I placed the orbiter and the stack, at the height of its final orbit (not just a measly few hundred feet above the ground).  You know how much fuel that would save?  Around 10%.

The point is, most of the energy needed to get to orbit is *speed* not *height*.

EDIT:  According to the CEPE spreadsheet, the payload advantage of 100 meters of launch pad altitude is 4 kg.

EDIT 2:  If that's not enough brain twisting for you, let's say you use a giant slingshot to save those 30 tons of fuel by flinging the whole stack to 100mph.  You know how much extra cargo that would get you?  About 1.5 tons, assuming I didn't horribly mess up that calculation.
Title: Re: Shuttle Q&A Part 5
Post by: Orbiter on 12/06/2009 01:05 pm
What was the first mission to use an OMS burn during the ride uphill?
Similarly, what was the first mission to roll to a heads-up position during launch?


Orbiter
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/06/2009 01:13 pm
What was the first mission to use an OMS burn during the ride uphill?
Similarly, what was the first mission to roll to a heads-up position during launch?
Already asked in this thread...question post is here:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg419994#msg419994

Answers follow.
Title: Re: Shuttle Q&A Part 5
Post by: Mike_1179 on 12/09/2009 02:27 pm

My query is - if the shuttle main engines burn 1000 gallons per second and if it takes 7 seconds to clear the tower why do they not just build a bit of a hill first

Wayne Hale had a pretty decent write-up of the energy needed (both potential and kinetic) needed for various things.  It's all about velocity.

http://blogs.nasa.gov/cm/blog/waynehalesblog/posts/post_1251819060090.html

Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 12/10/2009 03:52 pm
I'm trying to get a better understanding of how attitude is specified for the orbiter. I've read through many of the docs available on L2 and resources on the web, but still have a few questions.

I believe that for LVLH attitude, Euler angles are specified in a pitch-yaw-roll (2-3-1) sequence, but I don't know whether the convention is to give the angle to rotate the body frame to the LVLH frame or vice-versa. Is there a standard convention for this?

Obviously, it makes a difference in the sign of the angles, but does it also make a difference in the sequence? In other words, if the PYR angles are (40, -10, 60) to rotate the LVLH frame to the body frame, is it correct that the Euler angles to rotate from the body frame to the LVLH frame are (1) also pitch-yaw-roll sequence and (2) the same values with opposite signs, that is (-40, 10, -60)?

Do the same answers apply to the inertial (M50) attitude, which I think is also pitch-yaw-roll sequence, and the LVIY attitude used during ascent?

During STS-129, I monitored the Java applet-based NASA orbital tracker (http://spaceflight.nasa.gov/realdata/tracking/index.html) and noticed that the attitude is frequently displayed there. Does anyone know relative to which frame this attitude is given? I noted some examples over the course of the mission, and I can dig those up. The applet also shows ISS attitude, which I would guess is relative to LVLH.

Again, please correct me if I'm wrong on any of this. I've seen contradictory information at times. Thanks for the information.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/10/2009 06:53 pm
Anyone know how many degrees around the SRB Y axis that the FWD BSMs are clocked?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/11/2009 12:55 am
I'm trying to get a better understanding of how attitude is specified for the orbiter. I've read through many of the docs available on L2 and resources on the web, but still have a few questions.

I believe that for LVLH attitude, Euler angles are specified in a pitch-yaw-roll (2-3-1) sequence, but I don't know whether the convention is to give the angle to rotate the body frame to the LVLH frame or vice-versa. Is there a standard convention for this?

Obviously, it makes a difference in the sign of the angles, but does it also make a difference in the sequence? In other words, if the PYR angles are (40, -10, 60) to rotate the LVLH frame to the body frame, is it correct that the Euler angles to rotate from the body frame to the LVLH frame are (1) also pitch-yaw-roll sequence and (2) the same values with opposite signs, that is (-40, 10, -60)?

Do the same answers apply to the inertial (M50) attitude, which I think is also pitch-yaw-roll sequence, and the LVIY attitude used during ascent?

The Euler sequence is for reference-to-body rotation, whatever the reference (M50, LVLH, LVIY, etc). Start with the body frame aligned with LVLH, then apply the rotations to the body in pitch-yaw-roll sequence to arrive at the proper attitude.

To go the opposite direction, you need not only to reverse the sign of the angles, but also to reverse the sequence (roll-yaw-pitch). It is possible, of course, to compute a pitch-yaw-roll sequence for the reverse rotation, but the angles won't just be sign-reversed, they'd be different angles.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 12/19/2009 02:51 am
When the orbiter is powered down and on an extended stay in the un-air-conditioned VAB, do they feed some of the systems purge air/gasses?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/19/2009 11:55 am
There are conditioned air purges through the T-0, just like the pad.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/27/2009 06:21 pm
Space shuttle Challenger STS 7 was suppose to be the first landing at KSC, but i have heard that it was delay from low clouds at the area and landed at Edwards instead. why didn't they land Challenger at KSC the next day.
The flight control team declared one of the APUs (#3) suspect due to an underspeed during its initial run for the flight control system checkout the day before landing.  Would also note that this was early in the program and I wouldn't assume the flight rules were the same as today.
Title: Re: Shuttle Q&A Part 5
Post by: Ray125 on 12/27/2009 07:11 pm
I heard that Shuttle Columbia STS-107 had some delays in 2000, 2001, and 2002, what was the problems?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 12/27/2009 07:15 pm
I heard that Shuttle Columbia STS-107 had some delays in 2000, 2001, and 2002, what was the problems?

Many, many things -- cracks in fuel lines, suspect wiring that had to be inspected, simply finding the most optimal spot on the manifest for STS-107 so that it wouldn't interfere with the ongoing construction of the ISS and Columbia's STS-109 mission to the HST.
Title: Re: Shuttle Q&A Part 5
Post by: Ray125 on 12/27/2009 07:26 pm
On the first space shuttle Columbia there was some problems like falling tiles which delay launch but i have heard that there some other delays. i don't know what were the other delays.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 12/27/2009 07:37 pm
On the first space shuttle Columbia there was some problems like falling tiles which delay launch but i have heard that there some other delays. i don't know what were the other delays.


Aside from the usual delays associated with integrating and launching a rocket for the first time, the only other major delay to STS-1 came from the scrubbed launch attempt on April 10.

Please refer to this list for the major launch delays.
http://www.cbsnews.com/network/news/space/launchland.html

Also, keep in mind that a lot of little things crop up that can push back a launch before NASA sets an official date. For example, the above links states that STS-123 launched "on time on first attempt." STS-123 on March 11, 2008 was originally set for February 14, 2008 but was pushed back to March 11 due to delays in the previous program flight. Yet, despite the fact that STS-123 launched one month after its target, we still consider the launch to have occurred "on time on the first attempt."

Also, this site has a "search" function located on the tool bar at the top of the page. There are 4 Question and Answer threads that will help you as well.
Title: Re: Shuttle Q&A Part 5
Post by: smh on 12/28/2009 12:42 pm
I read that the engines are throttled back to remain a 3G acceleration mostly for crew comfort. Would a higher slightly higher acceleration limit allow for a higher payload mass? If so, how much?

What is the structural limit of acceleration for a shuttle?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/28/2009 01:12 pm
I read that the engines are throttled back to remain a 3G acceleration mostly for crew comfort. Would a higher slightly higher acceleration limit allow for a higher payload mass? If so, how much?

What is the structural limit of acceleration for a shuttle?


3 g's for the structural limit.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 12/28/2009 02:38 pm
Why did Columbia never visit the ISS?
Was it just how it happened on the manifest?
Would she have been the orbiter picked to visit Hubble?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/28/2009 02:52 pm
Why did Columbia never visit the ISS?
Was it just how it happened on the manifest?
Would she have been the orbiter picked to visit Hubble?
1: Mostly because of her higher empty mass.
2: See 1.
3: She did get to visit HST, in March 2002 on STS-109/HST SM3B. And she was scheduled for HST SM4.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/28/2009 06:23 pm
Why did Columbia never visit the ISS?
Was it just how it happened on the manifest?
Would she have been the orbiter picked to visit Hubble?
1: Mostly because of her higher empty mass.
2: See 1.
3: She did get to visit HST, in March 2002 on STS-109/HST SM3B. And she was scheduled for HST SM4.

Columbia was scheduled to perform STS-118/ISS-13A.1 at the time of the accident. This mission was lighter than most other ISS assembly missions.

After the accident 118 was reassigned to another orbiter and the Spacehab module could be packed more heavily.
Title: Re: Shuttle Q&A Part 5
Post by: Ray125 on 12/28/2009 06:30 pm
if columbia wasn't destoryed it would have flown to bring hubble back to earth for the STS-144 Mission.
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 12/28/2009 10:36 pm
if columbia wasn't destoryed it would have flown to bring hubble back to earth for the STS-144 Mission.

I'm not sure STS-144 was ever officially instated as a flight that would return HST.  I know it was proposed, but perhaps someone can confirm the status of this flight at the time of the STS-107 accident.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/28/2009 11:17 pm
if columbia wasn't destoryed it would have flown to bring hubble back to earth for the STS-144 Mission.

I'm not sure STS-144 was ever officially instated as a flight that would return HST.  I know it was proposed, but perhaps someone can confirm the status of this flight at the time of the STS-107 accident.

It was on the FAWG manifest for 1/29/03, launch date 11/19/09 (on L2). But it was definitely too far in the future to be baselined. Can't be said that it definitely would have happened had the 107 accident not occurred, but its presence on the FAWG means it was being planned.
Title: Re: Shuttle Q&A Part 5
Post by: smh on 12/29/2009 07:51 pm
I read that the engines are throttled back to remain a 3G acceleration mostly for crew comfort. Would a higher slightly higher acceleration limit allow for a higher payload mass? If so, how much?

What is the structural limit of acceleration for a shuttle?


3 g's for the structural limit.

Thanks. Many websites suggest it's just for crew comfort.

How much extra payload would a limit of 3.2 or 3.5 G have allowed?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/29/2009 07:55 pm
I read that the engines are throttled back to remain a 3G acceleration mostly for crew comfort. Would a higher slightly higher acceleration limit allow for a higher payload mass? If so, how much?

What is the structural limit of acceleration for a shuttle?


3 g's for the structural limit.

Thanks. Many websites suggest it's just for crew comfort.

How much extra payload would a limit of 3.2 or 3.5 G have allowed?

Negative, once you account for the structural strengthening needed for the stack to withstand the higher g.
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 12/29/2009 10:31 pm
How much extra payload would a limit of 3.2 or 3.5 G have allowed?

Negative, once you account for the structural strengthening needed for the stack to withstand the higher g.

But neglecting structural limits and assuming the stack can withstand it, what would the ballpark increase be? I imagine not much as the throttling comes near MECO anyway with low gravity losses.
Title: Re: Shuttle Q&A Part 5
Post by: steve_slitheen on 12/29/2009 11:19 pm

But neglecting structural limits and assuming the stack can withstand it, what would the ballpark increase be? I imagine not much as the throttling comes near MECO anyway with low gravity losses.

Yeah, surely the stack is designed to withstand much greater than the load it will actually achieve during a mission.  Other engineered structures are designed to take multiples of the actual expected load before failure.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/30/2009 12:07 am

Yeah, surely the stack is designed to withstand much greater than the load it will actually achieve during a mission.  Other engineered structures are designed to take multiples of the actual expected load before failure.

not the same as civil engineering.  Aerospace factors are 1.25/1.4 times max loads and 2.0 times max expected loads for untested structures.

Not every piece of structure has the same margins of safety.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/30/2009 01:23 am

But neglecting structural limits and assuming the stack can withstand it, what would the ballpark increase be? I imagine not much as the throttling comes near MECO anyway with low gravity losses.

Yeah, surely the stack is designed to withstand much greater than the load it will actually achieve during a mission.

Not that much greater. See Jim's post. You don't give up margin unless you need to. If the g load increases, the structural strength must be increased to maintain the same factor of safety.

Quote
  Other engineered structures are designed to take multiples of the actual expected load before failure.

Other engineered structures have higher factors of safety because variance in material strength is much wider. They have to account for the concrete being mixed on-site by construction workers who may not speak English, for example.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 12/30/2009 02:53 pm
I read that the engines are throttled back to remain a 3G acceleration mostly for crew comfort. Would a higher slightly higher acceleration limit allow for a higher payload mass? If so, how much?

What is the structural limit of acceleration for a shuttle?
3 g's for the structural limit.
Thanks. Many websites suggest it's just for crew comfort.

Well, now that the STS is designed and built, it's really both.  The original rationale for the 3G requirement was crew comfort, so that (plus appropriate FS) was what the structure was designed to.  No point in designing to higher structural limit if another requirement is dictating lower.
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 01/02/2010 06:59 pm
What do the two triangles on the shuttle's HUD (see picture) represent? In the landing videos I've seen, they appear to be fixed at about 20 degrees glideslope; do the triangles indicate the ideal approach glideslope, or are they used for something else?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/02/2010 07:09 pm
What do the two triangles on the shuttle's HUD (see picture) represent? In the landing videos I've seen, they appear to be fixed at about 20 degrees glideslope; do the triangles indicate the ideal approach glideslope, or are they used for something else?

You're referring to the two horizontal triangles on the sides of the flight director bug? Those are also used as cues for preflare and final flare.
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 01/02/2010 09:31 pm
What do the two triangles on the shuttle's HUD (see picture) represent? In the landing videos I've seen, they appear to be fixed at about 20 degrees glideslope; do the triangles indicate the ideal approach glideslope, or are they used for something else?

You're referring to the two horizontal triangles on the sides of the flight director bug? Those are also used as cues for preflare and final flare.
Yes, I was referring to those two triangles. I know they're used for the flare, but what are they used for before the preflare?
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 01/06/2010 10:06 pm
I've seen a few posters on this site say something to the effect of "If a human were within 2 miles of the shuttle, the acustics would stop the human heart." 

Are there any animals that are killed near the launch site from acustics, not heat? 
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 01/07/2010 03:17 am
When the US signed an agreement with Russia on the ISS/Shuttle-Mir campaigns Russia offered to sell the US the Buran docking module for use on the STS, yet the US declined and instead developed their own derived from the existing US internal airlock. The Buran docking system was capable of autonomous dockings yet the US airlock has to utilize a crew of at least five.  If the US used the Buran docking system, could it have performed an autonomous docking (or at least lighten the crew work load) and if so why was it not chosen?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/07/2010 03:37 am
When the US signed an agreement with Russia on the ISS/Shuttle-Mir campaigns Russia offered to sell the US the Buran docking module for use on the STS, yet the US declined and instead developed their own derived from the existing US internal airlock.

That is not quite correct. The US did purchase (and continues to purchase) the APAS docking mechanism developed for Buran, and simply adapted it to the existing US airlock and a new US-developed truss structure to form the Orbiter Docking System (ODS).

Quote
The Buran docking system was capable of autonomous dockings yet the US airlock has to utilize a crew of at least five.  If the US used the Buran docking system, could it have performed an autonomous docking (or at least lighten the crew work load)

No. The Kurs system included with the Buran docking system was not compatible with the GNC systems on the shuttle and it would have taken a lot of time and money to make them compatible. The top-level program goal was a Shuttle-Mir docking in 1995 and it simply would not have been possible in the constrained budget environment.

Quote
and if so why was it not chosen?

The above plus:

The truss on the Buran docking system was not suitable for the shuttle orbiter's payload bay. Buran's trunnion system was designed to take loads in both the longeron and keel trunnions so their truss had only one longeron trunnion pin on each side, with pitch torque being absorbed through the keel. The orbiter's trunnion system is designed to take loads only through the longeron trunnions so it requires two longeron trunnion pins on each side.

The Buran docking system had a telescoping mount to extend the APAS mechanism above the payload bay moldline to improve clearance during docking. This was necessary for Buran since Kurs is not capable of as much precision during docking as a hand-flown docking, so a failed capture can results in much more dispersed bounce-off states. But the mount must retract before the payload bay doors can be closed, or the mechanism jettisoned via pyros. This was deemed unsafe.

The systems in the Buran airlock were not compatible with existing orbiter systems and would have required extensive adaptation. (The systems needed to interface the orbiter power system with the APAS were extensive enough by themselves).
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 01/07/2010 04:20 am
I've seen a few posters on this site say something to the effect of "If a human were within 2 miles of the shuttle, the acustics would stop the human heart."

Tangential question: does anyone have the lethal acoustic levels for a human?
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 01/07/2010 01:36 pm
That is not quite correct. The US did purchase (and continues to purchase) the APAS docking mechanism developed for Buran, and simply adapted it to the existing US airlock and a new US-developed truss structure to form the Orbiter Docking System (ODS).

Sorry Jorge, I did know about the APAS I was simply over simplifying, was talking more about the module itself than the docking mechanism.

Quote
No. The Kurs system included with the Buran docking system was not compatible with the GNC systems on the shuttle and it would have taken a lot of time and money to make them compatible. The top-level program goal was a Shuttle-Mir docking in 1995 and it simply would not have been possible in the constrained budget environment.

Was there ever any consideration for installing Kurs in between the Mir and ISS programs?  I know that there was time in between the two to allow so, however perhaps the US built system could not accommodate it.

Quote
The truss on the Buran docking system was not suitable for the shuttle orbiter's payload bay. Buran's trunnion system was designed to take loads in both the longeron and keel trunnions so their truss had only one longeron trunnion pin on each side, with pitch torque being absorbed through the keel. The orbiter's trunnion system is designed to take loads only through the longeron trunnions so it requires two longeron trunnion pins on each side.

Hmm, this was not mentioned in the Energiya-Buran book that I am reading right now that mentioned the offer to sell the Buran Docking system to the US.

Quote
The Buran docking system had a telescoping mount to extend the APAS mechanism above the payload bay moldline to improve clearance during docking. This was necessary for Buran since Kurs is not capable of as much precision during docking as a hand-flown docking, so a failed capture can results in much more dispersed bounce-off states. But the mount must retract before the payload bay doors can be closed, or the mechanism jettisoned via pyros. This was deemed unsafe.

The systems in the Buran airlock were not compatible with existing orbiter systems and would have required extensive adaptation. (The systems needed to interface the orbiter power system with the APAS were extensive enough by themselves).

I would have assumed with the US shuttle that the crew  would have taken over for the  last part of docking, I suppose though that autonomous docking really is not needed on the STS since a crew is required anyhow.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/07/2010 03:16 pm

No. The Kurs system included with the Buran docking system was not compatible with the GNC systems on the shuttle and it would have taken a lot of time and money to make them compatible. The top-level program goal was a Shuttle-Mir docking in 1995 and it simply would not have been possible in the constrained budget environment.

Was there ever any consideration for installing Kurs in between the Mir and ISS programs?  I know that there was time in between the two to allow so, however perhaps the US built system could not accommodate it.

No. The budgetary environment never improved.

Quote
Quote
The truss on the Buran docking system was not suitable for the shuttle orbiter's payload bay. Buran's trunnion system was designed to take loads in both the longeron and keel trunnions so their truss had only one longeron trunnion pin on each side, with pitch torque being absorbed through the keel. The orbiter's trunnion system is designed to take loads only through the longeron trunnions so it requires two longeron trunnion pins on each side.

Hmm, this was not mentioned in the Energiya-Buran book that I am reading right now that mentioned the offer to sell the Buran Docking system to the US.

It probably wasn't a major player in the decision; had the other issues not prevailed, the US probably would have bought the whole thing and then replaced the truss.

Quote
I would have assumed with the US shuttle that the crew  would have taken over for the  last part of docking, I suppose though that autonomous docking really is not needed on the STS since a crew is required anyhow.

That was the thinking, yes, that even if Kurs had been kept it would have been purely as a situational awareness sensor for the crew to use during manual piloting, with all the other Kurs automation features simply not wired into the orbiter GNC. But the US already had options for situational awareness sensors (TCS) that were already developed and cheaper.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 01/26/2010 08:47 pm
A few small questions that I just thought about:

1) If the ROFI sparklers failed to ignite at T-10, would this automatically cause an RSLS/GLS abort?

2) how did they find out about the "twang" and impliment it into the launch sequence before STS-1?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/26/2010 09:17 pm
A few small questions that I just thought about:

1) If the ROFI sparklers failed to ignite at T-10, would this automatically cause an RSLS/GLS abort?

2) how did they find out about the "twang" and impliment it into the launch sequence before STS-1?

1.  yes

2.  General engineering sense.  Push on a cantilevered object and it is going to move.
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 01/27/2010 01:29 pm
1.  yes

2.  General engineering sense.  Push on a cantilevered object and it is going to move.

I know STS-1 was the only shuttle mission to ever launch after the T0 mark.  Did they simply underestimate how long it would take for the vehicle to return to vertical?
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 01/27/2010 01:37 pm
Did they simply underestimate how long it would take for the vehicle to return to vertical?

Wouldn't that have been caught prior to launch, during the FRF?

http://www.myvideo.de/watch/2431762/Columbia_Flight_Readiness_Firing_FRF
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 01/27/2010 01:52 pm
Did they simply underestimate how long it would take for the vehicle to return to vertical?

Wouldn't that have been caught prior to launch, during the FRF?

http://www.myvideo.de/watch/2431762/Columbia_Flight_Readiness_Firing_FRF

You would think so, but it still leaves the question unanswered ;)
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/27/2010 02:06 pm
You would think so, but it still leaves the question unanswered ;)

The question being, why didn't it launch at T-0?
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 01/27/2010 02:35 pm
You would think so, but it still leaves the question unanswered ;)

The question being, why didn't it launch at T-0?

Here's what I've always read (someone feel free to correct it if it isn't true) -

The SSMEs lit around T-4 seconds instead of T-6.6 seconds like they do today because it was thought that the vehicle would be vertical after those four seconds.  When it wasn't vertical at the intended T0, the guidance didn't allow the SRBs to fire because they wouldn't be flying straight up as intended (I know it's not perfectly straight anyway but you get the idea).  When it finally returned to vertical a second or two after the T0 mark, the SRBs lit and off she went.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/27/2010 03:08 pm
The countdown was set up for SSME start at T-4.  When the timing of the twang was determined (6 seconds), the countdown development was too far along to change, so SRB ignition was set at T+2 sec (the guidance has nothing to do with it) .  The countdown was updated for later launches.
Title: Re: Shuttle Q&A Part 5
Post by: nathan.moeller on 01/27/2010 03:19 pm
The countdown was set up for SSME start at T-4.  When the timing of the twang was determined (6 seconds), the countdown development was too far along to change, so SRB ignition was set at T+2 sec (the guidance has nothing to do with it) .  The countdown was updated for later launches.

Thanks for the clarification, Jim.  That makes a lot more sense.
Title: Re: Shuttle Q&A Part 5
Post by: anik on 01/27/2010 03:35 pm
Quote from STS-2 press kit related to STS-1 two T-0s: "STS-1 had two T-0s, one at the estimated main engine 90 percent thrust time and the second at planned SRB ignition. The STS-2 countdown has been adjusted so that there is only one T-0"

Image from STS-1 press kit.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 01/28/2010 03:23 am
Regarding twang, does anyone have a graph of the displacement from one of the FRFs?  Just curious what the cycles look like and how quickly it dissipates.  Maybe a request for L2 Historical....
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 01/28/2010 03:25 pm
Regarding twang, does anyone have a graph of the displacement from one of the FRFs?  Just curious what the cycles look like and how quickly it dissipates.  Maybe a request for L2 Historical....

The graph below shows twang displacement of the STS-26 shuttle stack at the RH SRM igniter position.

This was a heavily instrumented flight for the redesigned SRBs (as you might imagine) with the displacement derived from the strain gauge and accelerometer sensor data.

I have marked the approximate times that the SSMEs start and the SRB bolts are released.  At rest the tips of the SRBs are displaced from the vertical by just under 3 inches due to the off-center CoG caused by the orbiter mass.  You can see the sway and partial recovery due to SSME thrust before the stack is released - it is less than one cycle for this launch.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 01/28/2010 08:05 pm
Coooool.

Actually I was talking about the post-MECO cycles.  There are 10 cycles in about 3.3 seconds.  No wonder Judy Resnik was freaked out on that one abort.  And more props for Steve "I thought we'd be a lot higher at MECO" Hawley.
Title: Re: Shuttle Q&A Part 5
Post by: engineerjl on 02/04/2010 02:26 pm
I am looking for the subsystem mass properties breakdown for the space shuttle. I formally had a digital copy of an old book that compared the mass of several space craft including the orbiter but cannot remember the name. This would be fine or even better a spreadsheet of the orbiter subsystem mass and cg.
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 02/05/2010 12:47 am
When the Shuttle docks with ISS, is does any power transfer occur via the APAS docking port? I vaguely recall some limited amount of power, plus data and commands can be sent via the docking system, but I don't know how or if any of this is actually implemented.

If power cannot be transferred from ISS to Shuttle, why not?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/05/2010 12:50 am
If power cannot be transferred from ISS to Shuttle, why not?

http://en.wikipedia.org/wiki/Electrical_system_of_the_International_Space_Station#Station_to_shuttle_power_transfer_system
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2010 12:52 am
When the Shuttle docks with ISS, is does any power transfer occur via the APAS docking port? I vaguely recall some limited amount of power, plus data and commands can be sent via the docking system, but I don't know how or if any of this is actually implemented.

If power cannot be transferred from ISS to Shuttle, why not?

That's the job of the Station to Shuttle Power Transfer System(SSPTS). However, only Discovery and Endeavour is equipped with SSPTS
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 02/05/2010 12:53 am
If power cannot be transferred from ISS to Shuttle, why not?

http://en.wikipedia.org/wiki/Electrical_system_of_the_International_Space_Station#Station_to_shuttle_power_transfer_system

Good information. Question: does the power flow through APAS, or is there a drag-through cable?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2010 01:11 am
If power cannot be transferred from ISS to Shuttle, why not?

http://en.wikipedia.org/wiki/Electrical_system_of_the_International_Space_Station#Station_to_shuttle_power_transfer_system (http://en.wikipedia.org/wiki/Electrical_system_of_the_International_Space_Station#Station_to_shuttle_power_transfer_system)

Good information. Question: does the power flow through APAS, or is there a drag-through cable?
It goes through one of the X-connectors on the APAS as indicated by this graphic: http://www.nasa.gov/images/content/181949main_08_abbot_preflight.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 02/05/2010 01:20 am
Okay, so the 8 Kw passes through the APAS X connector, and then somehow passes via the ODU into the PTU for use by Shuttle, if necessary. Any idea how and where the power gets from APAS into the Shuttle? Does the ODU have some capability of shunting that much power from APAS?

Just curious.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2010 01:26 am
Okay, so the 8 Kw passes through the APAS X connector, and then somehow passes via the ODU into the PTU for use by Shuttle, if necessary. Any idea how and where the power gets from APAS into the Shuttle? Does the ODU have some capability of shunting that much power from APAS?

Just curious.
That is taken care of by the PTU which is a direct replacement for the earlier APCU which was only capable of transferring power to the station. The new PTU and it's associated wiring on the orbiter is capable of transfers both to and from the station, IE it can transfer power both ways.
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 02/05/2010 01:27 am
That is taken care of by the PTU which is a direct replacement for the earlier APCU which was only capable of transferring power to the station. The new PTU and it's associated wiring on the orbiter is capable of transfers both to and from the station, IE it can transfer power both ways.

I guess I should have asked if the PTU sits in the ODU, or whether there is a honking big extension cord from APAS through the ODU into the nether regions of Shuttle.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/05/2010 01:30 am
Is this the droid you're looking for?
F=ma

I am looking for the subsystem mass properties breakdown for the space shuttle. I formally had a digital copy of an old book that compared the mass of several space craft including the orbiter but cannot remember the name. This would be fine or even better a spreadsheet of the orbiter subsystem mass and cg.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2010 01:45 am
That is taken care of by the PTU which is a direct replacement for the earlier APCU which was only capable of transferring power to the station. The new PTU and it's associated wiring on the orbiter is capable of transfers both to and from the station, IE it can transfer power both ways.

I guess I should have asked if the PTU sits in the ODU, or whether there is a honking big extension cord from APAS through the ODU into the nether regions of Shuttle.
No cable. The PTU is all integrated with the ODS and the orbiter EPS.

This is from the SCOM
Quote
OV-103 and OV-105 previously carried the
standalone version of the APCU described above, but
have been upgraded to the newer Station/Shuttle
Power Transfer System (SSPTS). Operated via
switches on panel A15 that were formerly used by the
EDO Cryo Pallet System (which is no longer used),
SSPTS consists of two power transfer units (PTUs),
each of which has a single APCU voltage step-up
converter similar to the ones discussed above, and two
voltage step-down orbiter power converter unit
(OPCU) converters. The OPCU allows 120 volt DC
power from the ISS solar arrays to be transferred to
the shuttle’s main buses A and B at 28 volts. The
OPCU portion of SSPTS offloads some electrical load
from the orbiter’s FCs onto the ISS solar arrays; the
reduction in load on the FCs reduces the cryo usage,
which is then used for mission extension days. The
APCU portion of SSPTS is usable at any point in the
mission, while the OPCU portion is only usable after
docking to the ISS. Data is visible to the crew on SM
SPEC 179 POWER TRANSFER.

Before any power can be converted either by an APCU
or OPCU, the PTUs must be connected to the
shuttle’s main buses. PTU 1 is associated with main
A, and PTU 2 is associated with main B. To connect
the PTU to the main bus, the CNTL PWR circuit
breakers on A15 row B must be pushed in first. These
breakers power the PTU/MAIN BUS switches and
talkbacks. Upon successful connection between a PTU
and main bus, the associated talkback will turn from
OFF to ON. At this point, an APCU may be
activated to convert orbiter DC power for payload
requirements, and, after docking, the OPCU can be
activated to convert ISS DC power for shuttle main
bus requirements.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 02/06/2010 11:30 pm
No cable. The PTU is all integrated with the ODS and the orbiter EPS.


Sorry DaveS, that's not quite right. This is from memory, I don't have any schematics here. Power comes down from the X connector through two 8 gage cables routed externally along the ODS truss and support beams mounted on the payload bay side wall. They make their way to the PTUs which are located in the left side of bay 5.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 02/07/2010 12:20 am
This diagram does not resolve the issue of how the connection between the APAS X-connectors and the orbiter PTUs is physically implemented (I don't know myself), but might help others visualise how the rest of the various sub-systems are connected.
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 02/08/2010 01:47 pm
 After MECO and ET jettison, I breathe a little easier. I know, nothing for sure until wheels stop, but you see where I'm headed. But, as I was turning off my television at 4:24am this morning, the following question came to mind. What if there is an OMS failure when the OMS 2 burn is supposed to occur? I understand this is probably very unlikely. My guesses are the following, but obviously I'm posting here because I don't know.
  If it is a single OMS engine failure, use the good one, get in a cirular orbit and work it out from there. Is the rendevous off if the second OMS engine can not be recovered?
  If both engines fail (I know, REALLY unlikely) but the RCS is still functioning, can it be used to circularze the orbit? My guess is yes, but now you would need it to deorbit too. So would they get stable and work the problem, or just reenter and treat it as and AOA? My thought is that a stable orbit is the safest place to be even if that means you're on a back up system to deorbit.
   Ok, so a lot of questions and I'm probably missing something, but I would be interested if anyone knows the procedures for such an event. Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/08/2010 10:25 pm
  If both engines fail (I know, REALLY unlikely) but the RCS is still functioning, can it be used to circularze the orbit?

I think it is impossible to make such manouvers with RCS. OMS are required to change parameters of the shuttle orbit. Fail of two OMS engines would mean a LOM probably but im not sure (better wait for someone with good knowledge :)) and in this situation it would end with re-enter and land in KSC. Dunno if it is possible but I remember tha I read here some post about such a operation with using only RCS to back from LEO.

And wanna ask about some shuttle first minutes of flight. Look at this graphic, it has a polish words but take a look on shape of this trajectory in function of time.

(http://i187.photobucket.com/albums/x9/PhD_airQ/Terminator-STS.jpg)

This graph is based on some today seen on Fox News graphic which showed similiar graph (on line Y there was altitude in km, on X line time of flight). So time for question - there is a conclusion in my mind after looking at this graph that shuttle is climbing to initial orbit to fifth minute, after that she doesn't get much km of altitude more. What's most interesting it seems to loose some altitude after fifth minute of flight (and before meco) - can You explain my why that happen? What is energetic sense of loosing this few kms on da begining?

Thanks for answers,
greetz,
Mike
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/08/2010 10:40 pm
After MECO and ET jettison, I breathe a little easier. I know, nothing for sure until wheels stop, but you see where I'm headed. But, as I was turning off my television at 4:24am this morning, the following question came to mind. What if there is an OMS failure when the OMS 2 burn is supposed to occur? I understand this is probably very unlikely. My guesses are the following, but obviously I'm posting here because I don't know.
  If it is a single OMS engine failure, use the good one, get in a cirular orbit and work it out from there. Is the rendevous off if the second OMS engine can not be recovered?
  If both engines fail (I know, REALLY unlikely) but the RCS is still functioning, can it be used to circularze the orbit? My guess is yes, but now you would need it to deorbit too. So would they get stable and work the problem, or just reenter and treat it as and AOA? My thought is that a stable orbit is the safest place to be even if that means you're on a back up system to deorbit.
   Ok, so a lot of questions and I'm probably missing something, but I would be interested if anyone knows the procedures for such an event. Thanks.

RCS is considered a deorbit method. Although it could also be used for circularization, flight rules forbid it for this case. Loss of two deorbit methods (e.g. both OMS engines) means coming home immediately.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/08/2010 10:41 pm
  If both engines fail (I know, REALLY unlikely) but the RCS is still functioning, can it be used to circularze the orbit?

I think it is impossible to make such manouvers with RCS. OMS are required to change parameters of the shuttle orbit. Fail of two OMS engines would mean a LOM probably but im not sure (better wait for someone with good knowledge :)) and in this situation it would end with re-enter and land in KSC. Dunno if it is possible but I remember tha I read here some post about such a operation with using only RCS to back from LEO.

And wanna ask about some shuttle first minutes of flight. Look at this graphic, it has a polish words but take a look on shape of this trajectory in function of time.

(http://i187.photobucket.com/albums/x9/PhD_airQ/Terminator-STS.jpg)

This graph is based on some today seen on Fox News graphic which showed similiar graph (on line Y there was altitude in km, on X line time of flight). So time for question - there is a conclusion in my mind after looking at this graph that shuttle is climbing to initial orbit to fifth minute, after that she doesn't get much km of altitude more. What's most interesting it seems to loose some altitude after fifth minute of flight (and before meco) - can You explain my why that happen? What is energetic sense of loosing this few kms on da begining?

Thanks for answers,
greetz,
Mike

It's trading some potential energy (altitude) for kinetic energy (speed). The idea is to get above the atmosphere as quickly as possible without overstressing the structure, then performing a long shallow dive to get more speed.
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/09/2010 12:19 am
It's trading some potential energy (altitude) for kinetic energy (speed). The idea is to get above the atmosphere as quickly as possible without overstressing the structure, then performing a long shallow dive to get more speed.

It seems logical. In this long shallow dive we get so much speed? How its possible if it is only few km of altitude?
What do u mean with 'overstressing the structure' - pressure which came from changing of acceleration? (Cause there are no aerodynamic stressing above - lets say 80 km of altitude).

edit: Second question - theoritically could the shuttle climb higher without going to this shallow dive? I mean climb further to point where she would get a required speed. I can imagine that it would cost a lot of fuel but wanna just ensure myself..
Title: Re: Shuttle Q&A Part 5
Post by: engineerjl on 02/09/2010 06:13 am
what is the OMS propellent budget?
assent, circulation, orbit, deorbit, reserve, residual...
Title: Re: Shuttle Q&A Part 5
Post by: tva on 02/09/2010 07:05 am
How its possible if it is only few km of altitude?
What do u mean with 'overstressing the structure' - pressure which came from changing of acceleration? (Cause there are no aerodynamic stressing above - lets say 80 km of altitude).
Keep in mind that the orbiter-ET combo is rapidly loosing mass while trust is constant. Combined with that long shallow dive it helps to accelerate. That shallow dive is partly caused of the modest level of trust after SRB separation. The trust level barely maintains 1g for half a minute.
Think at the analogy of throwing a stone. When the stone leaves your hand it still will climbs upwards for a while.
Without the shallow dive the stuttle would need to spend longer time in the thicker layers of the atmosphere.

Quote
edit: Second question - theoritically could the shuttle climb higher without going to this shallow dive? I mean climb further to point where she would get a required speed. I can imagine that it would cost a lot of fuel but wanna just ensure myself..
Shuttle is inserted in orbit at perigee. After MECO it is coasting (gaining) altitude without burning precious propellant.
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 02/09/2010 09:24 am
what is the OMS propellent budget?
assent, circulation, orbit, deorbit, reserve, residual...

Those figures would likely vary depending on the mission and payload mass. (and will also vary depending on the orbiter involved since they don't all have identical masses)

For each mission, the Flight Day Execute Package document will give the best figures for propellant remaining at the start of the flight day, and each PAD burn update will give calculated total orbiter mass.

If you're asking how much propellant is loaded at the beginning of a mission, I believe all tanks are filled completely both front and rear.

Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/09/2010 10:01 pm
How its possible if it is only few km of altitude?
What do u mean with 'overstressing the structure' - pressure which came from changing of acceleration? (Cause there are no aerodynamic stressing above - lets say 80 km of altitude).
Keep in mind that the orbiter-ET combo is rapidly loosing mass while trust is constant. Combined with that long shallow dive it helps to accelerate. That shallow dive is partly caused of the modest level of trust after SRB separation. The trust level barely maintains 1g for half a minute.
Think at the analogy of throwing a stone. When the stone leaves your hand it still will climbs upwards for a while.
Without the shallow dive the stuttle would need to spend longer time in the thicker layers of the atmosphere.

Quote
edit: Second question - theoritically could the shuttle climb higher without going to this shallow dive? I mean climb further to point where she would get a required speed. I can imagine that it would cost a lot of fuel but wanna just ensure myself..
Shuttle is inserted in orbit at perigee. After MECO it is coasting (gaining) altitude without burning precious propellant.

Ok, thanks for answers. One more thing - does someone know a document or page (whatever) where are described in detail all manouvers like this interesting one 5 minutes after launch?

Thanks for help,
Mike
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/09/2010 11:02 pm
what is the OMS propellent budget?
assent, circulation, orbit, deorbit, reserve, residual...

Those figures would likely vary depending on the mission and payload mass. (and will also vary depending on the orbiter involved since they don't all have identical masses)

For each mission, the Flight Day Execute Package document will give the best figures for propellant remaining at the start of the flight day, and each PAD burn update will give calculated total orbiter mass.

If you're asking how much propellant is loaded at the beginning of a mission, I believe all tanks are filled completely both front and rear.



The FRCS tanks are usually filled only 70% to keep the CG in the box.
The ARCS tanks are always loaded full.
The OMS tanks are not always loaded full. For 130 the load is 22761 lbm, which is a couple thousand pounds short of full.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/10/2010 03:14 am
Why TORVA?  Does using twice orbital rate minimize prop usage for the arc?  If so, the orbital mechanics there are not intuitive to me.
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/10/2010 06:55 am
One more thing - does someone know a document or page (whatever) where are described in detail all manouvers like this interesting one 5 minutes after launch?

I believe that there exist sth like this..  :P
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/10/2010 07:26 am
Why TORVA?  Does using twice orbital rate minimize prop usage for the arc?  If so, the orbital mechanics there are not intuitive to me.

It is a combination of orbital mechanics and the unique arrangement of RCS thrusters on the shuttle. The shuttle's primary RCS thrusters are sized for entry control authority and are quite oversized for orbit ops, especially compared to other (much smaller) ISS visiting vehicles. RCS plume impingement becomes a major concern during shuttle-ISS prox ops.

To minimize plume impingement, the shuttle must use a digital autopilot (DAP) mode called "Low Z" between 1000 and 75 ft which inhibits the +Z (upfiring) thrusters. To perform a +Z translation in Low Z, the DAP fires +X (aft-firing) and -X (forward-firing) thrusters simultaneously. The thrusters are canted slightly such that the X components cancel out and the Z components add, providing a small braking force. A Low Z pulse must fire 11 times as long as a normal Z pulse to provide the same delta-V, so it consumes a correspondingly higher amount of propellant.

It is therefore important that the approach profile be designed to minimize the need for Low Z (+Z) braking, even if this results in more firings in -Z and the other axes. One way to accomplish this for the Rbar to Vbar transition is to increase the rotation rate above the orbital rate. Although the physicist purist in me dislikes the concept of "centrifugal force", the analogy is useful to visualize what's going on. A higher flyaround rate means a higher tangential velocity, which has the tendency to "fling" the orbiter away from the station. This increases the +X and -X delta-V needed to start and stop the flyaround, but it greatly decreases the need for Low Z +Z braking. But this only works up to a point - eventually, the flyaround rate becomes fast enough that no +Z would ever be required, but the +X, -X, and -Z requirements would increase more than enough to balance things out.

It turns out that twice orbital rate is close to optimum for the shuttle. Hence the TORVA. Serendipitously, twice orbital rate also allows a full 360 degree flyaround to be completed during a single orbital daylight pass, so the rate was standardized for both approach and the post-undocking flyaround.
Title: Re: Shuttle Q&A Part 5
Post by: tva on 02/10/2010 08:08 am
Ok, thanks for answers. One more thing - does someone know a document or page (whatever) where are described in detail all manouvers like this interesting one 5 minutes after launch?

MikeMi,

I am not sure what you mean by "all manoeuvres like this interesting one 5 minutes after launch".
There aren't that much going on at that specific time frame.

SRB staging occurs approx. 2'20"
OMS assist starts right after that
the vehicle rolls heads up at about 5'45"

You can read the entire logg of ascent data for STS-119 attached to that earlier post of mine (http://forum.nasaspaceflight.com/index.php?topic=10600.msg395844#msg395844).
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/10/2010 08:46 am
I am not sure what you mean by "all manoeuvres like this interesting one 5 minutes after launch".
There aren't that much going on at that specific time frame.

Wanna know more about shuttle flight in first 8 minutes (in regards to this graph which I attached one page earlier in this thread), cause I didn't know that there are such manouevers like 'deep shallow dive' after reachin max altitude (109 km) then it goes down to around 102 km. How is this performing (i mean by RCS or ...)?. You see, if we take a look on this graph (attached page earlier) we can see a small hill - trajectory of shuttle (altitude as Y axis, time as X axis).
Just want to know if this situation with 'shallow dive' helps to get rid of ET tank. I suppose that we can have more accurate re-entry place of tank with using that techniq.
And to sum up (with longer answer please) is there really a plus summary energy with that play of trading potential to kinetic energy?

Does Soyuz make also similiar action with 'shallow dive'? I guess not since it has stronger construction..

Next question which came to my mind is if there could be greater g-load without throttling down with SSMEs around 7:22 time of flight.

And here u have that data for sts-130  :)
http://www.cbsnews.com/network/news/space/130/130ascentdata.html
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2010 08:56 am
1.  How is this performing (i mean by RCS or ...)?.

2.  Does Soyuz make also similiar action with 'shallow dive'? I guess not since it has stronger construction..

3.  Next question which came to my mind is if there could be greater g-load without throttling down with SSMEs around 7:22 time of flight.

1.  SSME gimbaling

2.  no, it is a launch vehicle specific (STS) maneuver driven by unique contraints

3.  The throttling is to limit gload
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/10/2010 09:50 am
2.  no, it is a launch vehicle specific (STS) maneuver driven by unique contraints

For example?

greetz,
Mike
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2010 10:04 am
2.  no, it is a launch vehicle specific (STS) maneuver driven by unique contraints


Abort posturing
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/10/2010 02:15 pm
Thanks for the excellent TORVA explanation, Jorge!
Title: Re: Shuttle Q&A Part 5
Post by: MikeMi. on 02/10/2010 07:25 pm
Abort posturing

Okay, thanks!

One more question - does somewhere exists a graph showing aerodynamic drag which works on shuttle during first 9 minutes of flight? (for example graph in function of time)

What is the limit of g-load shuttle could withstand (in theory) - twice, tripple more than 3g?
Title: Re: Shuttle Q&A Part 5
Post by: DansSLK on 02/10/2010 08:33 pm
What is the limit of g-load shuttle could withstand (in theory) - twice, tripple more than 3g?

Has been answered before, a search might turn up a number since my foggy memory can't find it in the old long term storage.

I know its not much more than 3g's, stronger structure tends to mean heavier structure.
Title: Re: Shuttle Q&A Part 5
Post by: Hobbs on 02/10/2010 11:52 pm
Are there any plans for any commemoratory events or anything during STS-133 or are they just going to end the shuttle program quietly?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/11/2010 01:35 am
3g axial x 1.4 factor of safety (typical for most components,
although FS may be 2 for the crew compartment?).
v/r, F=ma


What is the limit of g-load shuttle could withstand (in theory) - twice, tripple more than 3g?

Has been answered before, a search might turn up a number since my foggy memory can't find it in the old long term storage.

I know its not much more than 3g's, stronger structure tends to mean heavier structure.
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 02/11/2010 03:40 am
Is the docked ISS-shuttle TEA attitude the same for every flight, or is it specific to each shuttle mission? Is there a single TEA, or multiple options to choose from? I recall reading that the primary docked attitude is partially to shield the orbiter's TPS from MMOD damage, but I didn't know how the TEA factors into attitude selection. Any idea what the TEA is for this STS-130?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/11/2010 03:58 am
Is the docked ISS-shuttle TEA attitude the same for every flight, or is it specific to each shuttle mission?

It changes a few degrees every mission due to changes in the stack mass properties and drag profile.

Quote
Is there a single TEA, or multiple options to choose from? I recall reading that the primary docked attitude is partially to shield the orbiter's TPS from MMOD damage, but I didn't know how the TEA factors into attitude selection.

There are multiple TEAs (technically a TEA, or Torque Equilibrium Attitude, is any attitude where the environmental torques on the stack, mainly gravity gradient and aero, cancel out), but only two of them (biased ISS -XVV and +XVV) meet both shuttle and station thermal and power requirements, and only the -XVV TEA meets shuttle TPS protection criteria. So it is the only one operationally used.

Quote
Any idea what the TEA is for this STS-130?

Biased ISS -XVV, as has been standard since STS-107, and is almost certain to remain so for the remaining flights.
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 02/11/2010 04:36 am
Thanks, that makes sense.

Any idea what the TEA is for this STS-130?

Biased ISS -XVV, as has been standard since STS-107, and is almost certain to remain so for the remaining flights.

Does the terminology "biased -XVV" essentially mean start with -XVV (or whatever the particular reference) and rotate predetermined amounts about one or more of the PRY axes?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/11/2010 04:37 am
Thanks, that makes sense.

Any idea what the TEA is for this STS-130?

Biased ISS -XVV, as has been standard since STS-107, and is almost certain to remain so for the remaining flights.

Does the terminology "biased -XVV" essentially mean start with -XVV (or whatever the particular reference) and rotate predetermined amounts about one or more of the PRY axes?

Yes, except that for ISS it's defined as a YPR sequence, not PRY.
Title: Re: Shuttle Q&A Part 5
Post by: Antares on 02/11/2010 08:41 pm
I can't find a post on it.  What's the ballast for in the Orbiter aft compartment?  I know it's CG, but for which phase(s) of flight?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/11/2010 08:47 pm
I can't find a post on it.  What's the ballast for in the Orbiter aft compartment?  I know it's CG, but for which phase(s) of flight?

Entry/landing for both nominal and aborts (assumes a prop dump for the aborts).
Title: Re: Shuttle Q&A Part 5
Post by: Brian P on 02/12/2010 12:34 pm
Hi,

Does anyone know the procedures if a shuttle/station astronaut is outside during an EVA and something happens that requires an evacuation of the ISS?  Would they re pressurize, get out of the EMU and into a Soyuz suit or would they remain outside?  I assume the EMU's would not fit in the Soyuz capsule, but I could be wrong.  What about shuttle astronauts on an EVA if the same happened?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: cozmicray on 02/12/2010 04:53 pm
What is the reason for evacuation?
Well you could say the EVA astronaut is all ready evacuated, in his own safe
environment with life support for some 8 hours.
Evacuation of ISS may be for de-pressurization, fire, or pending collision.
As the other IVA astronauts would take safe haven in other parts of ISS
and isolate the problem, or take refuge in soyuz crafts,  The EVA astronaut
could provide assistance from outside, ie put his finger in the hole causing
de-pressurization until he could put a bandage on it.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/12/2010 10:30 pm
What is the maximum and nominal amount of ballast?


I can't find a post on it.  What's the ballast for in the Orbiter aft compartment?  I know it's CG, but for which phase(s) of flight?

Entry/landing for both nominal and aborts (assumes a prop dump for the aborts).
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/12/2010 10:31 pm
Anyone know how much the TSMs weigh?
Title: Re: Shuttle Q&A Part 5
Post by: Brian P on 02/13/2010 03:56 am
Something really serious like a major fire.  What happens if it takes longer than 8 hours to get the situation under control so they can go back on the station?  Or, if it happens near the end of a 6 hour space walk and they only have 2 hrs of life support left?
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 02/13/2010 05:56 am
Something really serious like a major fire.  What happens if it takes longer than 8 hours to get the situation under control so they can go back on the station?  Or, if it happens near the end of a 6 hour space walk and they only have 2 hrs of life support left?

Seal off problematic module. Astronaut then returns like normal.
That's my guess.
Title: Re: Shuttle Q&A Part 5
Post by: Mapperuo on 02/13/2010 03:03 pm
Searched hard but couldn't figure which topic this fitted into.

What site is NASA Tv produced in? Eg Kennedy Space Center or is it at Johnson?

Also, Are there any photos of this room?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: dgates on 02/15/2010 12:43 am
This may have been addressed in some earlier post but....

Given the limited number of remaining STS flights, why bother recovering the SRB's at this point?  Now, I have not studied the logistics or anything, but at some point there aren't going to be any further flights to reuse the SRB's on, right?

So, stipulate that the SRB's are expendables at some point:  Can upmass be saved by removing some parts of the recovery system like, say the parachutes? Just let them splash and sink.

Can this upmass then be used for cargo aboard the orbiter?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/15/2010 12:51 am
This may have been addressed in some earlier post but....

Given the limited number of remaining STS flights, why bother recovering the SRB's at this point?

The economics of SRB reuse have long understood to be largely a wash. The SRBs are now recovered primarily for safety reasons. They are examined to reveal any flaws that might cause problems for the remaining launches.  There will be no compromise on this. Remember Challenger.
Title: Re: Shuttle Q&A Part 5
Post by: dgates on 02/15/2010 12:58 am
OK, you have a point -- except for the last launch, after which there won't be any more SRB's used.  One would have to think that the "R&D" element value would be diluted to nearly nothing at this point, having examined so many SRB's in the past. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/15/2010 01:01 am
OK, you have a point -- except for the last launch, after which there won't be any more SRB's used.  One would have to think that the "R&D" element value would be diluted to nearly nothing at this point, having examined so many SRB's in the past. 

If 133 remains the last flight, its SRBs will be recovered to reveal any problems that may affect its LON rescue flight, 335.

If 135 is baselined, or if 335 must be launched, you have a point. Barely.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 02/15/2010 05:55 am
I just watched the STS-130 ascent video from inside the cabin and have a couple of questions:

1) I was surprised to see the crew open their helmets not long after SRB separation. Is this a recent procedure? I don't recall seeing this in earlier flights.

2) I noticed a flickering light reflecting off the crew's helmets, apparently emanating from outside and in front of the vehicle. It began about midway through ascent and continued until MECO. What could be causing that?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/15/2010 10:52 am
I just watched the STS-130 ascent video from inside the cabin and have a couple of questions:

1) I was surprised to see the crew open their helmets not long after SRB separation. Is this a recent procedure? I don't recall seeing this in earlier flights.

2) I noticed a flickering light reflecting off the crew's helmets, apparently emanating from outside and in front of the vehicle. It began about midway through ascent and continued until MECO. What could be causing that?

1.  No, it is common to every flight for quite some time

2.  The SSME plume
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 02/15/2010 12:05 pm
2.  The SSME plume

and to lesser extent the APU plume.
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 02/15/2010 12:38 pm
If it's the rhytmic flashes, I'd say that's mostly the APU plume.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 02/15/2010 03:27 pm
If it's the rhytmic flashes, I'd say that's mostly the APU plume.
Yes, the reflections are rhythmic. However, the light source appears to be coming from the front of the orbiter, based on position of reflections on front of helmets.

Could the APU plume be reflecting off the orbiter nose area in front of the windshield? Given the slope of the nose area, the geometry doesn't seem right.

OTOH, could plume light be entering from topside windows behind the crew and then reflect off the forward interior glass surfaces (panel, windshields, etc) and then back to the helmets? If so, it seems like we'd see evidence on cabin walls below the windows. Interesting....
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/16/2010 05:15 am
1) I was surprised to see the crew open their helmets not long after SRB separation. Is this a recent procedure? I don't recall seeing this in earlier flights.

That has been done ever since they started wearing the suits. The reason is that the suits are preasurized with pure oxygen and they are open loop (gas is vented out of the suit into the cabin instead of being rerouted back to the ECS) that leads to the concentration of O2 in the cabin building up more the longer they are in use, which is a fire hazard (remeber Apollo1). That is also why they don't close the visors at all durring entry after the preasure test.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 02/16/2010 05:33 am
That has been done ever since they started wearing the suits. The reason is that the suits are preasurized with pure oxygen and they are open loop (gas is vented out of the suit into the cabin instead of being rerouted back to the ECS) that leads to the concentration of O2 in the cabin building up more the longer they are in use, which is a fire hazard (remeber Apollo1). That is also why they don't close the visors at all durring entry after the preasure test.

I guess they can close those visors real fast in a depress event.
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 02/16/2010 06:04 am
That has been done ever since they started wearing the suits. The reason is that the suits are preasurized with pure oxygen and they are open loop (gas is vented out of the suit into the cabin instead of being rerouted back to the ECS) that leads to the concentration of O2 in the cabin building up more the longer they are in use, which is a fire hazard (remeber Apollo1). That is also why they don't close the visors at all durring entry after the preasure test.

I guess they can close those visors real fast in a depress event.

Actually, as I recall, that was one of the things mentioned by one of the Columbia reports. The cabin depressed too fast and everyone lost consciousness before they had a chance to close and lock visors.

The report in question was one of the more recent ones. It was posted in the historical section, I'll try to find it. 

EDIT: I believe that this is the report in question. (http://forum.nasaspaceflight.com/index.php?topic=15404.0)
Title: Re: Shuttle Q&A Part 5
Post by: butters on 02/16/2010 07:24 am
But the ACES suits, even with visors closed, would not have been sufficient to protect the crew from the dynamic pressure at which Columbia disintegrated.  The suits disintegrated themselves.

I know they can do Mach 3.2 at 80,000 ft, but I don't know exactly how much more dynamic pressure they can handle.  Loss of cabin pressure is one thing, but ACES can't help with severe loss of vehicle structural integrity through much of the reentry phase.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 02/16/2010 08:42 am
Now that Node 3 and cupola are installed in the ISS, will there be significant changes for future shuttle docking procedures from STS-131 onwards?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/16/2010 02:05 pm
Now that Node 3 and cupola are installed in the ISS, will there be significant changes for future shuttle docking procedures from STS-131 onwards?

No.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/16/2010 02:27 pm
Any shuttle DPS experts here? Then this question is for them: What is the font used for the MEDS DPS displays?
Title: Re: Shuttle Q&A Part 5
Post by: Gwilbor on 02/16/2010 02:57 pm
Seeing the launch footage of the shuttle, I was trying to understand what happens around external tank separation...

1. It seems to see some RCS firing after 10 seconds from zero-thrust (well before separation), am I correct? Which RCS?

2. The -Z thrust starts exactly at sep or before?

3. How many seconds after sep starts the +X thrust?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 02/16/2010 07:00 pm
Seeing the launch footage of the shuttle, I was trying to understand what happens around external tank separation...

1. It seems to see some RCS firing after 10 seconds from zero-thrust (well before separation), am I correct? Which RCS?

2. The -Z thrust starts exactly at sep or before?

3. How many seconds after sep starts the +X thrust?

1. No (if you are referring to the 10 second period prior to MECO).   What you are seeing are plasma dynamics and SSME plume contraction during throttle down and fine count.

2. -Z translation occurs after the SEP Command is issued, not before.  However, RCS firings can occur during the mated coast phase for attitude/rate control.  These firings are managed by the "Trans Dap" (transition digital auto pilot).

3.  +X is a manual input by the Commander which occurs 2 seconds after the general purpose computers transition to OPS 104 (this transition occurs when the -Z achieves a delta V of 4 feet per second).

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Gwilbor on 02/16/2010 07:52 pm
1. No (if you are referring to the 10 second period prior to MECO).

No, it's a plume that occurs roughly 10 seconds after MECO. Maybe is the attitude control you mentioned on answer #2. For example at 9:30 in this video:

http://www.youtube.com/watch?v=M_M4mxgCwXk

Or at 9:55 here:

http://www.youtube.com/watch?v=zsJpUCWfyPE

Quote
2. -Z translation occurs after the SEP Command is issued, not before.  However, RCS firings can occur during the mated coast phase for attitude/rate control.  These firings are managed by the "Trans Dap" (transition digital auto pilot).

3.  +X is a manual input by the Commander which occurs 2 seconds after the general purpose computers transition to OPS 104 (this transition occurs when the -Z achieves a delta V of 4 feet per second).

Mark Kirkman

Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 02/16/2010 10:24 pm
Forgive me if it's in the wrong place, but on the NASA TV map, what is the yellow line that goes roughly north-south?
Title: Re: Shuttle Q&A Part 5
Post by: ddunham on 02/17/2010 04:48 pm
Forgive me if it's in the wrong place, but on the NASA TV map, what is the yellow line that goes roughly north-south?

It's hard to see because of the map projection, but that line actually is basically circular on the earth, and shows the extent of coverage of one of the TDRS communication satellites at the altitude of the shuttle.  The green line is the extent of the other major one.

The satellites are shown on the graphic as well, with color coding corresponding to the coverage lines.
--
Darren
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 02/18/2010 08:09 pm
OH! duh! Thank you so much. I can't believe I didn't think about that. sheesh.
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 02/21/2010 12:38 am
EVA crew on STS-130 apparently got their metabolic rates up when dealing with the Cupola MLI, and they were instructed to hang out for a little while.  What's the tradeoff when planning EVAs for jettison vs. roll up the MLI and bring it back inside?  I seem to recall on a previous mission we jettisoned MLI or at least some kind of thermal cover.   
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 02/21/2010 03:09 am
STS -132 is named as ULF4 (Utilities and Logistics) while STS-131 is 19A (Assembly)? STS-132 carries MRM1 to be installed in the ISS while STS-132 carries MPLM Leonardo. I thought STS-132 must be an assembly flight while STS-131 must be a Utilities and Logistics flight. Any comments on this naming?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/21/2010 04:14 am
STS -132 is named as ULF4 (Utilities and Logistics) while STS-131 is 19A (Assembly)? STS-132 carries MRM1 to be installed in the ISS while STS-132 carries MPLM Leonardo. I thought STS-132 must be an assembly flight while STS-131 must be a Utilities and Logistics flight. Any comments on this naming?

Historical artifact.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 02/21/2010 04:45 am
In that case, why cant they rename the missions again? I mean with A's and ULF's

STS -132 is named as ULF4 (Utilities and Logistics) while STS-131 is 19A (Assembly)? STS-132 carries MRM1 to be installed in the ISS while STS-132 carries MPLM Leonardo. I thought STS-132 must be an assembly flight while STS-131 must be a Utilities and Logistics flight. Any comments on this naming?

Historical artifact.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/21/2010 05:09 am
In that case, why cant they rename the missions again? I mean with A's and ULF's

STS -132 is named as ULF4 (Utilities and Logistics) while STS-131 is 19A (Assembly)? STS-132 carries MRM1 to be installed in the ISS while STS-132 carries MPLM Leonardo. I thought STS-132 must be an assembly flight while STS-131 must be a Utilities and Logistics flight. Any comments on this naming?

Historical artifact.

They won't. There is too much internal documentation with the current mission designations. It would result in confusion. Keeping the names provides continuity in the documentation trail, even though the mission content has rendered the names obsolete.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/21/2010 09:58 am
STS -132 is named as ULF4 (Utilities and Logistics) while STS-131 is 19A (Assembly)? STS-132 carries MRM1 to be installed in the ISS while STS-132 carries MPLM Leonardo. I thought STS-132 must be an assembly flight while STS-131 must be a Utilities and Logistics flight. Any comments on this naming?

It is Utilization and Logistics.
Title: Re: Shuttle Q&A Part 5
Post by: theandrew on 02/21/2010 10:37 pm
I have another nasa tv question. When they are covering the shuttle launch/landing, they generally show a screen showing the earth, and the current orbit of the ISS and shuttle.

On this screen, there several circles/shapes with letters inside (SAA,TCSS...). What are those shapes? Also, there are some other indications on the screen, and some other satellites. Any descriptions?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/21/2010 11:27 pm
I have another nasa tv question. When they are covering the shuttle launch/landing, they generally show a screen showing the earth, and the current orbit of the ISS and shuttle.

On this screen, there several circles/shapes with letters inside (SAA,TCSS...). What are those shapes? Also, there are some other indications on the screen, and some other satellites. Any descriptions?


Search the shuttle Q&A thread
Title: Re: Shuttle Q&A Part 5
Post by: ddunham on 02/22/2010 07:17 pm
Search the shuttle Q&A thread

Any good tips for that?  On the previous question about the graphic I felt certain there should be some old posts with the answer, but after about 10 minutes of searching I hadn't found anything I could refer to.  So I just posted what's probably a redundant answer.

Wondering what all the elements of that graphic are were some of my first questions when I was watching missions.  I wish I knew of an easier resource to point at (or a way to create one).
--
Darren
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/22/2010 07:28 pm
Search the shuttle Q&A thread

Any good tips for that?  On the previous question about the graphic I felt certain there should be some old posts with the answer, but after about 10 minutes of searching I hadn't found anything I could refer to.  So I just posted what's probably a redundant answer.

Wondering what all the elements of that graphic are were some of my first questions when I was watching missions.  I wish I knew of an easier resource to point at (or a way to create one).
--
Darren

http://forum.nasaspaceflight.com/index.php?topic=6156.msg203875#msg203875

The brackets in the orbital trace indication orbital sunrise and sunset. 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 02/23/2010 08:29 am
SAA is South Atlantic Anomaly, to start you off. You'll probably find some more if you search for that, and then see when the question has come up etc,
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/23/2010 10:49 pm
OK, you have a point -- except for the last launch, after which there won't be any more SRB's used.  One would have to think that the "R&D" element value would be diluted to nearly nothing at this point, having examined so many SRB's in the past. 

If 133 remains the last flight, its SRBs will be recovered to reveal any problems that may affect its LON rescue flight, 335.

If 135 is baselined, or if 335 must be launched, you have a point. Barely.

Acutally, one of the weight saving items of interest for STS-133 was to eliminate the recovery assets of the SRBs.

Now, last I saw this was still under consideration. Has this been firmly decided against? I haven't seen anything since all the Cat-I weight savings objectives were incorporated into the mission's baseline.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 02/24/2010 04:49 pm
What is the advantage of 3G throttling over shutting down one engine a little earlier?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/24/2010 05:02 pm
What is the advantage of 3G throttling over shutting down one engine a little earlier?

With throttling you still have attitude control with all the engines, you don't have step changes to your guidance system caused by the shut down and you preserve your full engine out capability.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 02/24/2010 06:49 pm
What is the advantage of 3G throttling over shutting down one engine a little earlier?

With throttling you
1. still have attitude control with all the engines,
2. you don't have step changes to your guidance system caused by the shut down and
3. you preserve your full engine out capability.

It all seems to boil down to redundancy (3.) although I don't know what step changes in the guidance system (2.) are about. Attitude control (1.) and step changes (2.), or the lack thereof, can apparently be dealt with in the event of a single engine failure (STS-51F). Throttling comes with its own failure modes (STS-3) and one would expect reduced fuel efficiency and therefore performance margins.

Anyway, it is not my intention to challenge throttling the way it is. Thanks for the insight.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/24/2010 06:59 pm
or the lack thereof, can apparently be dealt with in the event of a single engine failure (STS-51F).


Not true.    Intentionally running on two engines would not be the same as running on two engines after the 3rd failed.
Title: Re: Shuttle Q&A Part 5
Post by: shuttlefan on 03/01/2010 01:08 pm
Were the SSMEs ever run at the theoretical 109% of full thrust during an actual ascent?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 03/01/2010 01:12 pm
No! 104.5% is the highest power level ever used in flight.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 03/03/2010 02:59 am
Why NASA decided STS-133's (planned last mission) duration to be only 8 days.

1. Discovery has SSTP and can tap into station power - Hence can stay longer in the space station?

2. Due to no more flights (or may be STS-135) isnt it better to do more science and experiments by staying more?. Some unique things they can do with the shuttle will be lost foreever.

3. Crew will have more time for transfers from the PMM to the ISS (and hence PMM can carry more equipement?)

4. What will have the largest impact if 8 days is to be changed to say 13 days?

5. May be more time in space means high risk of space debris problem? Is this the only reason why it is planned as a 8 day mission?
Title: Re: Shuttle Q&A Part 5
Post by: cd-slam on 03/03/2010 04:00 am
Why NASA decided STS-133's (planned last mission) duration to be only 8 days.

1. Discovery has SSTP and can tap into station power - Hence can stay longer in the space station?

2. Due to no more flights (or may be STS-135) isnt it better to do more science and experiments by staying more?. Some unique things they can do with the shuttle will be lost foreever.

3. Crew will have more time for transfers from the PMM to the ISS (and hence PMM can carry more equipement?)

4. What will have the largest impact if 8 days is to be changed to say 13 days?

5. May be more time in space means high risk of space debris problem? Is this the only reason why it is planned as a 8 day mission?
This mission will be different than the usual logistics mission, because the PMM will be left on board the station and is not returned to the shuttle's payload bay. Hence the ISS crew will be able to unload it at their leisure.

Instead the limitation on this flight will be the mass which can be carried to orbit. Each astronaut requires daily resources of air, water, food, etc which have to be carried up in the shuttle, thus any reduction in mission time (and crew size) translates to more cargo which can be carried in the PMM and on board the shuttle.

The fact the mission is shortened to 8 days gives you some idea of the desperation to get cargo to the station.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 03/05/2010 06:37 am
What is the MPLM that Atlantis is supposed to carry for STS-133 LON mission? Is it Rafaello? When will the processing of the MPLM will begun? (Read some where that although Donatello is the most advanced, it would stay in the ground ! )
Title: Re: Shuttle Q&A Part 5
Post by: Robson68 on 03/05/2010 04:32 pm
Is it possible to produce a blended thermal protection system instead of using tiles.

Could this not then be fitted to the shuttles?. I know pending fleet retirement but would this be possible.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/05/2010 08:28 pm
Is it possible to produce a blended thermal protection system instead of using tiles.

Could this not then be fitted to the shuttles?. I know pending fleet retirement but would this be possible.

It is "blended".  Tiles transition to blankets.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/06/2010 12:19 am
Is it possible to produce a blended thermal protection system instead of using tiles.

Could this not then be fitted to the shuttles?. I know pending fleet retirement but would this be possible.

It is "blended".  Tiles transition to blankets.

 Blankets & Tiles (from STS-130 RPM):
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/06/2010 02:41 am
1.What is the MPLM that Atlantis is supposed to carry for STS-133 LON mission? Is it Rafaello?

2.When will the processing of the MPLM will begun?

3.(Read some where that although Donatello is the most advanced, it would stay in the ground ! )

1. Yes, Raffaello.
2. Already underway in some fashion.
3. Yes. Dontello is "most advanced" in that is can hold powered payloads; and yes, it will not fly.
Title: Re: Shuttle Q&A Part 5
Post by: dafixer on 03/06/2010 11:19 am
I was watching NASAtv 2 nights ago and happened onto the middle of a NASA "music video" showing multiple SRB separations and ET drops, all set to music. It looked like it was a short movie showing the entire launch sequence and ending when the Orbiter reached orbit.

Does anybody have any idea what this movie is called? I'd love to see it in it's entirety. I just caught the last couple of minutes...
Title: Re: Shuttle Q&A Part 5
Post by: Cog_in_the_machine on 03/06/2010 11:31 am
This one? - http://tinyurl.com/yeurn9l
Title: Re: Shuttle Q&A Part 5
Post by: dafixer on 03/06/2010 11:47 am
This one? - http://tinyurl.com/yeurn9l

YES! That's the one! Thanks for posting the link. That is an awesome video!
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 03/06/2010 12:28 pm
youtube has previous highlights. Search ascent highlights.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 03/07/2010 01:25 pm
When did NASA stop using T 38s to follow the shuttle as it landed?

From pictures I can see they were used as late as STS 6.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/07/2010 01:32 pm
When did NASA stop using T 38s to follow the shuttle as it landed?

From pictures I can see they were used as late as STS 6.
There were a couple of 'firsts' after that: first heavyweight/Spacelab landing (STS-9), first KSC landing (STS-41B, postponed from STS-7).  Don't recall any after that.
Title: Re: Shuttle Q&A Part 5
Post by: ginahoy on 03/07/2010 06:36 pm
The closest I ever got to a complete shuttle stack was during a nighttime approach into Melbourne (MLB) on an Eastern Airlines flight (late eighties). It was either the night before, two nights before a launch. The pilot apparently flew as close to the launch complex as was allowed. If I had to guess, we were no more than 1/2 mile lateral and 3000 feet in altitude. He tipped the wing slightly, giving as many passengers as possible a spectacular view of the shuttle standing proudly in the Xenon lights with RSC pulled back. Needless to say, a chill went up my spine. I was fortunate enough to see the subsequent launch from the causeway, but the flyby was actually more impressive!

Does anyone know the rules (then or now) regarding how close to LC39 a commercial plane approaching MLB from the north can be vectored when a shuttle is on the pad?
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 03/07/2010 08:06 pm
During TCDT, does the orbiter hatch remain opened throughout the entire test?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/07/2010 08:11 pm
During TCDT, does the orbiter hatch remain opened throughout the entire test?
Believe so -- it was open during terminal count for the STS-114 test that was carried live.

(Since corrected by DaveS.  Added qualification.)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/07/2010 08:35 pm
During TCDT, does the orbiter hatch remain opened throughout the entire test?
Believe so -- it was during the STS-114 test that was carried live.

Partially. Once crew ingress is complete, they cycle the hatch closed, perform a simulated cabin leak test and then open the hatch again.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 03/21/2010 08:05 am
one brief question on a more historical subject.
When docked to ISS, the tail points downwards (albeit not straight down) the PLB  along the direction of the velocity vector to protect the TPS on the belly. Anyone knows what the orbiter attitude was during the Shuttle-Mir missions?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/21/2010 03:30 pm
one brief question on a more historical subject.
When docked to ISS, the tail points downwards (albeit not straight down) the PLB  along the direction of the velocity vector to protect the TPS on the belly. Anyone knows what the orbiter attitude was during the Shuttle-Mir missions?

For the most part, it was belly down, tail forward.
Title: Re: Shuttle Q&A Part 5
Post by: FinalFrontier on 03/21/2010 03:32 pm
Question: Which MPLM will become the PLM (permanent logistics module) and what mission is it flying on and what CBM is it going to be stuck to? PLM is basically a giant closet for ISS right?
Title: Re: Shuttle Q&A Part 5
Post by: Thorny on 03/21/2010 03:42 pm
Question: Which MPLM will become the PLM (permanent logistics module) and what mission is it flying on and what CBM is it going to be stuck to? PLM is basically a giant closet for ISS right?

Leonardo per the current plan. Will be reconsidered if STS-134 and 133 slip extensively. PMM will be on Node 1 Nadir.
Title: Re: Shuttle Q&A Part 5
Post by: dbooker on 03/23/2010 08:43 pm
Does anyone know the number of SSMEs that are currently in the shuttle program inventory? Also, is there a hard limit on the number of flights per SSME or does it just depend on the conditions on inspection.  Also, is the shuttle budget detailed enough to indicate the real cost of servicing and test firing the SSME for flight certification?  Of course you go on the NASA website and do a search and can't find any of this information.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/23/2010 10:35 pm
Does anyone know the number of SSMEs that are currently in the shuttle program inventory? Also, is there a hard limit on the number of flights per SSME or does it just depend on the conditions on inspection.  Also, is the shuttle budget detailed enough to indicate the real cost of servicing and test firing the SSME for flight certification?  Of course you go on the NASA website and do a search and can't find any of this information.

By my count there should be at least 14 Block II flight engines available and one new unit that may, or may not, have been tested.  By the current end of program (STS-133 mission) one of these will have flown 14 times, and two of them 13 times, with the youngest flight engine flown only twice (excludes the new one I'm not sure about).

Historically some engines have flown more than this - these were in earlier versions, and many had block conversions between times.  STS-93 seems to have had quite a well used set with 22, 17 and 19 flights on engines 1, 2, and 3 respectively.

Not able to answer your budgetary questions.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/23/2010 10:37 pm
Historically some engines have flown more than this - these were in earlier versions, and many had block conversions between times.  STS-93 seems to have had quite a well used set with 22, 17 and 19 flights on engines 1, 2, and 3 respectively.
STS-93 had tight performance margins; among other weight reduction efforts, it was flown with Phase 2 engines.  (As opposed to the Block IIA versions that were being flown otherwise.)
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 03/24/2010 12:00 am
At around T-3 seconds it looks like engines #3 and #2 reposition (essentially looking like they tilt inwards).  I am assuming this is a thrust vector reposition but does anyone know exactly why this occurs.  Also, does engine #1 move.  It doesnt looke like it does, but I havent been able to tell.  Thanks!!
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 03/24/2010 12:06 am
The engines have a start position - helps deal with shock from ignition - they then move to the null position for T-0 (SRB ignition) followed by thrust vector positioning by guidance/flight control after T-0 & Liftoff.

Stated another way the SSMEs have a start position, a null position for SRB ignition, and then they are used for flight control after T-0.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 03/24/2010 12:34 am
ok, i have noticed the slight and quick pivot right at T-0/liftoff.  Thanks Mark!!

Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 03/24/2010 03:37 pm
Did I read correctly, that IF somehow NASA gets a extension on the shuttle, it would take close to 2 years to produce the next tanks needed for more flights?
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 03/27/2010 08:05 pm
Did I read correctly, that IF somehow NASA gets a extension on the shuttle, it would take close to 2 years to produce the next tanks needed for more flights?

Check out smith5se's posts in yesterday's STS-131 Processing Latest thread for the ET situation.  She transcribed John Shannon's pretty detailed answer at the FRR News Conference. 
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 03/27/2010 11:27 pm
STS-36 back in 1990 was a classified DoD mission, and was famously unique in that it flew a dog-leg trajectory to get Atlantis to 62.0 degrees inclination for payload deployment.  Does anyone know if there are documented overflight risk numbers for that ascent, given that the stack overflew Cape Hatteras, Cape Cod, and Nova Scotia?

The main reason I'm asking is because there has been a lot of talk recently about the overflight risk studies for descending node reentries, and it got me to wondering if a similar study was done for that one unique ascent.  Or was it more of a case of "this is a mission of national security importance, so overflight risk be damned"?
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/30/2010 01:33 pm
Asked on the STS-131 thread, but I'll ask here as well.  Is the ATA flying on 131 the same one that returned on 128?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 03/30/2010 03:38 pm
Here's a math problem for our rocket scientists in the audience :)

What would be the performance increase of STS if NASA were to (hypothetically) launch from St. Anthony, Newfoundland (which is at approximately 51.6 degrees North)? 

Put a different way, do we benefit from the due east launch to ISS there, or does the slower rotation of the Earth there more than cancel out the benefits of a due-east launch?

For the purposes of this question, you can ignore the usual gotchyas like "it's too cold there!" or "That's in Canada!".
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/30/2010 03:54 pm
Here's a math problem for our rocket scientists in the audience :)

What would be the performance increase of STS if NASA were to (hypothetically) launch from St. Anthony, Newfoundland (which is at approximately 51.6 degrees North)? 

Put a different way, do we benefit from the due east launch to ISS there, or does the slower rotation of the Earth there more than cancel out the benefits of a due-east launch?

For the purposes of this question, you can ignore the usual gotchyas like "it's too cold there!" or "That's in Canada!".

As a first order approximation, the advantage from the due east azimuth and the disadvantage of the lower rotation speed cancel out. They'd cancel out exactly if the Earth were a perfect sphere. In the real world, KSC has a slight advantage due to the Earth's equatorial bulge.

Edit: found my earlier, more detailed answer:

http://forum.nasaspaceflight.com/index.php?topic=4392.msg402349#msg402349
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 03/30/2010 04:11 pm
Asked on the STS-131 thread, but I'll ask here as well.  Is the ATA flying on 131 the same one that returned on 128?  Thanks!

IIRC they sad the tank returned on STS-128 was going to be filled up and flown back up again.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/30/2010 04:48 pm
Asked on the STS-131 thread, but I'll ask here as well.  Is the ATA flying on 131 the same one that returned on 128?  Thanks!

IIRC they sad the tank returned on STS-128 was going to be filled up and flown back up again.

That's what I remember as well, but wanted some confirmation.  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 04/02/2010 04:09 am
Can some one explain how the payload canister is installed into the Shuttle's payload Bay?. is the payload removed form the canister at the pad and installed or is the canister being just loaded into the pay load bay?
Title: Re: Shuttle Q&A Part 5
Post by: racshot65 on 04/02/2010 07:40 am
Hi guys

Does anyone know why the STS 130 files aren't on NASA's site ?

http://www.nasa.gov/centers/johnson/news/flightdatafiles/foia_archive.html (http://www.nasa.gov/centers/johnson/news/flightdatafiles/foia_archive.html)
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 04/02/2010 08:15 am
Hi guys

Does anyone know why the STS 130 files aren't on NASA's site ?

http://www.nasa.gov/centers/johnson/news/flightdatafiles/foia_archive.html (http://www.nasa.gov/centers/johnson/news/flightdatafiles/foia_archive.html)

They will probably be up in a short time. They have just changed from STS-130 to STS-131 as the current mission where they post mission files so they probably haven't had time to add STS-130 files to the archive yet.
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 04/02/2010 08:23 am
Can some one explain how the payload canister is installed into the Shuttle's payload Bay?. is the payload removed form the canister at the pad and installed or is the canister being just loaded into the pay load bay?

They move the payloads from the canister to the Payload bay at the launchpad. The canister is just used for transporting the payloads to the launchpad from the processing facility.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/02/2010 12:13 pm
Can some one explain how the payload canister is installed into the Shuttle's payload Bay?. is the payload removed form the canister at the pad and installed or is the canister being just loaded into the pay load bay?

They move the payloads from the canister to the Payload bay at the launchpad. The canister is just used for transporting the payloads to the launchpad from the processing facility.
Not directly...I think this has been answered in the Q&A threads before, but I'm not finding a specific post at the moment.  There was an early thread that outlines things, though:
http://forum.nasaspaceflight.com/index.php?topic=8826.0
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 04/02/2010 01:08 pm
Not directly...I think this has been answered in the Q&A threads before, but I'm not finding a specific post at the moment.  There was an early thread that outlines things, though:
http://forum.nasaspaceflight.com/index.php?topic=8826.0

Here is a good NASA video that describes how it works.

http://www-pao.ksc.nasa.gov/kscpao/videos/metafiles/ksc_022805_htw_payload.ram
Title: Re: Shuttle Q&A Part 5
Post by: mogso on 04/03/2010 12:32 pm
QUESTION: somebody has drawings of a seat of the commander of the Shuttle. (The front , behind, below views, etc.) Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Cog_in_the_machine on 04/03/2010 12:57 pm
Your question has been moved to another thread so if this thread gets deleted you know where to look - http://forum.nasaspaceflight.com/index.php?topic=17437.msg567352#msg567352

Someone else on the forum most likely has more information than me, but as far as I know Shuttle seats are a variant of the SR-71 Blackbird's seats.

The one with the lady in it is an actual shuttle seat.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/03/2010 01:59 pm
Here's a math problem for our rocket scientists in the audience :)

What would be the performance increase of STS if NASA were to (hypothetically) launch from St. Anthony, Newfoundland (which is at approximately 51.6 degrees North)? 

Put a different way, do we benefit from the due east launch to ISS there, or does the slower rotation of the Earth there more than cancel out the benefits of a due-east launch?

For the purposes of this question, you can ignore the usual gotchyas like "it's too cold there!" or "That's in Canada!".

As a first order approximation, the advantage from the due east azimuth and the disadvantage of the lower rotation speed cancel out. They'd cancel out exactly if the Earth were a perfect sphere. In the real world, KSC has a slight advantage due to the Earth's equatorial bulge.

Edit: found my earlier, more detailed answer:

http://forum.nasaspaceflight.com/index.php?topic=4392.msg402349#msg402349

I agree.  To would be about the same.  The Russian's hurt their performance a bit because they have to launch a little bit north to avoid China, then they come back south to 51.6.  I learned this over vodka shots with them in Houston in about 1993, so it must be true  ;D

Off to go fishing in Houston.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/03/2010 02:10 pm
What is the advantage of 3G throttling over shutting down one engine a little earlier?

And we all know the shuttle throttle's to 3G to allow Navy fighter pilots to be able to fly the shuttle  ;D

Danny Deger
Former USAF fighter pilot.

P.S. I used to love to put this dig in my entry overview class to the Navy test pilot school class visiting at JSC.  It always generated a belly laugh and a groan.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/03/2010 03:10 pm
Your question has been moved to another thread so if this thread gets deleted you know where to look - http://forum.nasaspaceflight.com/index.php?topic=17437.msg567352#msg567352

Someone else on the forum most likely has more information than me, but as far as I know Shuttle seats are a variant of the SR-71 Blackbird's seats.

The original seats installed in Columbia were. The other orbiters never had the original seats; they had lightweight non-ejection seats. In the late 90s the seats were replaced again with even lighter seats for performance enhancement for ISS missions.
Title: Re: Shuttle Q&A Part 5
Post by: Cog_in_the_machine on 04/03/2010 03:23 pm
Thanks Jorge. The last picture probably shows the newest seat design.
Title: Re: Shuttle Q&A Part 5
Post by: cozmicray on 04/03/2010 03:24 pm
You could look at seat yourself at

http://www.panoscan.com/CubicDemos/Shuttle.html

Quicktime VR allows you to look all around
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/03/2010 03:29 pm
Thanks Jorge. The last picture probably shows the newest seat design.

I believe you're right. I think the seat upgrade was completed before MEDS.
Title: Re: Shuttle Q&A Part 5
Post by: rocketguy101 on 04/03/2010 05:04 pm
If you have L2 access, there were some pics of the seat in the assy ops manual for a spinal elongation experiment setup
http://forum.nasaspaceflight.com/index.php?topic=20489.0

pg 683 of the "AssyOps-20A.pdf" document
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 04/04/2010 01:52 pm
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.

Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 04/04/2010 02:00 pm
If a LON during STS-131 is required the shuttle is planned to stay attached for close to 30 days (don't remember exact number of days) so there is nothing that stops the shuttle from staying longer. I would guess the reason it isn't staying longer is because the crew would need to use ISS consumables and that's not something the program want.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/04/2010 02:17 pm
If a LON during STS-131 is required the shuttle is planned to stay attached for close to 30 days (don't remember exact number of days) so there is nothing that stops the shuttle from staying longer.
For this mission it was estimated at ~FD27, so a couple of days less than that on docked time.  That would probably have different cryo margins for the power necessary to do a post-undocking disposal re-entry (in that hypothetical) vs. a normal post-undocking timeline that has a significant power load prior to re-entry. 

Not sure cryos are the only limiting factor.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/04/2010 02:18 pm
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 04/04/2010 02:27 pm
The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.

It's too late for that now, but had such a requirement been in place earlier in the program, could the Shuttle have been relatively easily designed/modified to support this? Say by using active cooling with power supplied by the ISS or by using differently designed APUs for electrical power as well as hydraulics during deorbit and descent?

Edit: or using noncryogenic fuel cells...
Title: Re: Shuttle Q&A Part 5
Post by: grakenverb on 04/04/2010 02:28 pm
OK, I know this is not going to happen, but...........

Would it be possible, and if it was, would it be a good idea to leave a shuttle (with a spacehab  in the payload bay) attached to the ISS as an improvised new module? If it wasn't going to return to earth you wouldn't have to worry about post undocking fuel reserves.  As a bonus, the station looks much cooler with a shuttle docked to it.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/04/2010 02:30 pm
OK, I know this is not going to happen, but...........

Would it be possible, and if it was, would it be a good idea to leave a shuttle (with a spacehab  in the payload bay) attached to the ISS as an improvised new module?
Frequently asked question...short answer is no.  I'll see if I can find the thread again...

Edit -- here:
http://forum.nasaspaceflight.com/index.php?topic=13950.0
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 04/04/2010 03:34 pm
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


Real limiting factor is the crew. 
LDO
Title: Re: Shuttle Q&A Part 5
Post by: grakenverb on 04/04/2010 08:00 pm
OK, I know this is not going to happen, but...........

Would it be possible, and if it was, would it be a good idea to leave a shuttle (with a spacehab  in the payload bay) attached to the ISS as an improvised new module?
Frequently asked question...short answer is no.  I'll see if I can find the thread again...

Edit -- here:
http://forum.nasaspaceflight.com/index.php?topic=13950.0


Thanks for the link....  I had done a search before posting but didn't find it!
Title: Re: Shuttle Q&A Part 5
Post by: mogso on 04/04/2010 08:27 pm
2 rocketguy101

I have no such access, unfortunately. It is possible to see this page somehow?
Title: Re: Shuttle Q&A Part 5
Post by: Martin FL on 04/04/2010 08:48 pm
Yes, join L2, which is amazing.
http://www.nasaspaceflight.com/l2/

Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/04/2010 11:56 pm
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.

That would be really, really bad.  My 1941 Taylorcraft "Putt-Putt" and my 15 foot john boat don't require electricity to work.  My kind of space ship -- as y'all all know  ;D

Danny Deger

Attached are two pictures of "Putt-Putt".  The one with the attack helos were taken in Texas at a refueling stop.  She had to wait for her fuel, even though we were there first.  She understood and was happy to stand guard of the the helos while the crew of the helos took a potty break.  They were great guys -- and gals.  :P
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/04/2010 11:59 pm
Yes, join L2, which is amazing.
http://www.nasaspaceflight.com/l2/


I agree.  Support the crazy man that runs this site!!!

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/05/2010 12:01 am
Did my Entry Guidance Work Book get posted here??

Reply to [email protected]

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: jhf on 04/05/2010 01:03 am
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.

It's my understanding, also, that it's possible to turn down the fuel cells only so far before they start choking on their own exhaust, so to speak -- there have been a couple of recent shuttle missions where there was a concern that it would be necessary to throttle the fuel cells up to keep them operational, which would have required cutting the mission short.  I have no idea if the fuel cells can be shut down and restarted on orbit -- I know Apollo's couldn't, it required Ground Support Equipment.  Or, perhaps NASA just isn't interested in experimenting with the Shuttle these days.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/05/2010 09:42 am
Did my Entry Guidance Work Book get posted here??

Reply to [email protected]

Danny Deger

I'm sure you posted it months ago but if not I'll take any interesting documents you want to share :)
Title: Re: Shuttle Q&A Part 5
Post by: racshot65 on 04/05/2010 04:09 pm
Considering how important the Ku Band Attenna is for communicating video to the ground how come they don't have two on the shuttles ?

Are they really expensive ?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/05/2010 04:13 pm
Considering how important the Ku Band Attenna is for communicating video to the ground how come they don't have two on the shuttles ?
It's important, but not mission critical (they still have S-band for data and communications).  It's not like other systems where loss of the functionality might have more severe consequences to the mission (like a minimum duration, for example -- not the case for this).  There have been multiple missions with loss of one or both modes of the Ku antenna and those all accomplished their mission objectives. 

In this case, even assuming that both modes of the antenna have failed (which is not confirmed at this time), the question isn't so much whether or not the mission objectives can be accomplished, but how differently they might be accomplished than the plan going into the mission.
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 04/05/2010 04:17 pm
It's important, but not necessarily mission critical (they still have S-band for data and communications).  It's not like other systems where loss of the functionality might have more severe consequences to the mission (like a minimum duration, for example -- not the case for this).  There have been multiple missions with loss of one or both modes of the Ku antenna and those all accomplished their mission objectives.  In this case, even assuming that both modes of the antenna have failed, the question isn't so much whether or not the mission objectives can be accomplished, but how differently they might be accomplished than the plan going into the mission.

But since the Columbia disaster ku has been more important since it's crucial for the safety, with the OBSS inspection. In this case this is solved since they can use station ku but what would they have done if they lost ku during STS-125? Then they wouldn't have any chance at all to down-link the inspection video.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/05/2010 04:20 pm
It's important, but not necessarily mission critical (they still have S-band for data and communications).  It's not like other systems where loss of the functionality might have more severe consequences to the mission (like a minimum duration, for example -- not the case for this).  There have been multiple missions with loss of one or both modes of the Ku antenna and those all accomplished their mission objectives.  In this case, even assuming that both modes of the antenna have failed, the question isn't so much whether or not the mission objectives can be accomplished, but how differently they might be accomplished than the plan going into the mission.

But since the Columbia disaster ku has been more important since it's crucial for the safety, with the OBSS inspection. In this case this is solved since they can use station ku but what would they have done if they lost ku during STS-125? Then they wouldn't have any chance at all to down-link the inspection video.
The STS-125 case is the unique case.  Would have to check, but it might have been handled differently for that mission.

Edit -- would not have been huge mission impact to 125.  Flight rule for that is on L2.  (One of the actions, as with STS-92, would have been to use MILA and Dryden to downlink data -- in that case, high-priority inspection data.)
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 04/06/2010 04:13 am
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.

It's my understanding, also, that it's possible to turn down the fuel cells only so far before they start choking on their own exhaust, so to speak -- there have been a couple of recent shuttle missions where there was a concern that it would be necessary to throttle the fuel cells up to keep them operational, which would have required cutting the mission short.  I have no idea if the fuel cells can be shut down and restarted on orbit -- I know Apollo's couldn't, it required Ground Support Equipment.  Or, perhaps NASA just isn't interested in experimenting with the Shuttle these days.

Fuel cells were not my system, but I understand the "essential" dc busses can be used to start a cell on orbit.  I just heard this as cross talk while I was teaching astronauts how to fly the darn thing.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/06/2010 04:22 am
What are the internal factors that limit Shuttle visit times at ISS? Yes, I know there are constraints due to visiting vehicles not docking with ISS while Shuttle is attached, but I am trying to figure out why otherwise the Shuttle could not stay attached for 30 days, now that ISS can provide power and other consumables to Shuttle.


The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.

It's my understanding, also, that it's possible to turn down the fuel cells only so far before they start choking on their own exhaust, so to speak -- there have been a couple of recent shuttle missions where there was a concern that it would be necessary to throttle the fuel cells up to keep them operational, which would have required cutting the mission short.  I have no idea if the fuel cells can be shut down and restarted on orbit -- I know Apollo's couldn't, it required Ground Support Equipment.  Or, perhaps NASA just isn't interested in experimenting with the Shuttle these days.

Fuel cells were not my system, but I understand the "essential" dc busses can be used to start a cell on orbit.  I just heard this as cross talk while I was teaching astronauts how to fly the darn thing.

Danny Deger

The essential buses are themselves powered by the fuel cells, so you have to have at least one fuel cell already running for this to work.
Title: Re: Shuttle Q&A Part 5
Post by: sascha_l on 04/07/2010 06:42 am
The X-Plane manual states that the re-entry has been flown manually, which frankly, I find hard to believe.

Quote from: X-Plane manual
In reality, the autopilot flies the entire 30-minute re-entry, and the astronauts do not take over the controls of the shuttle until the final 2 minutes of the glide. The astronauts COULD fly the entire re-entry by hand, but it is officially discouraged by NASA. The reason is obvious. These speeds and altitudes are way outside of normal human conception, so our ability to "hand-fly" these approaches is next to nil.
In the history of Shuttle missions (the 100th mission has just come to a close as I write this), the real space shuttle has been hand-flown for the entire re-entry only ONCE, by an ex-marine pilot, as I understand it, who was ready for the ultimate risk and challenge.

Has anybody got more information on this?

I know that there were problems with oscillations in sideslip after the first roll reversal maneuver in STS-1, so in subsequent flights that first bank maneuver was flown by hand until they fixed the software (From Runway to Orbit p.221ff), but besides that, to my knowledge, the commander does not take control until the shuttle goes sub-sonic.

I also doubt that "COULD fly the entire re-entry by hand" part. This is a fly-by-wire system, and as far as I know the vehicles response varies dramatically with Mach numbers (especially in the hypersonic regime), so the computer always "translates" the control input and, depending on Mach number, determines which surfaces to move and which RCS jets to fire (M.I.T. open courseware 16.885J / ESD.35J Aircraft Systems Engineering)

Would still be interesting to know where that information comes from and if it's true.

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: hop on 04/07/2010 07:31 am
The X-Plane manual states that the re-entry has been flown manually, which frankly, I find hard to believe.

Has anybody got more information on this?
This may be related http://forum.nasaspaceflight.com/index.php?topic=17623.msg427231#msg427231 (you'll have to read through some noise and back and forth to get the whole picture)

Note that flying "manually" in any case wouldn't mean flying without computer aid. No computer, no control.

edit:
typo
Title: Re: Shuttle Q&A Part 5
Post by: sascha_l on 04/07/2010 07:58 am
Ok, thanks a lot!
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 04/07/2010 09:39 am
The fuel cell H2 boils off (the boiloff is still used to produce electrical power).  The shuttle needs the fuel cells to provide power post undocking, no H2, no electricity.
It's too late for that now, but had such a requirement been in place earlier in the program, could the Shuttle have been relatively easily designed/modified to support this? Say by using active cooling with power supplied by the ISS or by using differently designed APUs for electrical power as well as hydraulics during deorbit and descent?
Edit: or using noncryogenic fuel cells...

    The simplest solution was just to carry more cryo, and it was indeed designed in early. The EDO pallet first flew in the early 90's, taking up some mass and space in the payload bay, and Endeavour and Columbia were plumbed to accommodate it. IIRC, Columbia even flew a 17 day mission. She had it on -107, which is why later analysis showed the crew could have lasted about a month in orbit at minimum power consumption, long enough, perhaps, to rush Atlantis to the pad.

   The electric APU was a separate proposed mod. Not sure where the energy would have come from. More cryo fuel cells, charging batteries to deliver big currents to the hydraulic pumps during entry?

-Alex

-Alex
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 04/07/2010 10:23 am
    The simplest solution was just to carry more cryo, and it was indeed designed in early. The EDO pallet first flew in the early 90's, taking up some mass and space in the payload bay, and Endeavour and Columbia were plumbed to accommodate it. IIRC, Columbia even flew a 17 day mission. She had it on -107, which is why later analysis showed the crew could have lasted about a month in orbit at minimum power consumption, long enough, perhaps, to rush Atlantis to the pad.

Interesting, thanks!

Quote
   The electric APU was a separate proposed mod. Not sure where the energy would have come from. More cryo fuel cells, charging batteries to deliver big currents to the hydraulic pumps during entry?

I was thinking of an APU driving an electric generator as well as a hydraulic pump, not a source of electrical power driving a hydraulic pump. As an aside, weren't there also plans for electromechanical actuators to avoid the need for hydraulics?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/07/2010 10:30 am
The simplest solution was just to carry more cryo, and it was indeed designed in early. The EDO pallet first flew in the early 90's, taking up some mass and space in the payload bay, and Endeavour and Columbia were plumbed to accommodate it. IIRC, Columbia even flew a 17 day mission.
Sort of -- IIRC, there were multiple 16-day EDO missions that used one or two weather extension days.  STS-80 used two and flew for almost 18 days.  Most of the EDO mods were removed from Endeavour during the OMDP period that brought in the set of changes to fly to ISS.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/07/2010 10:55 am

1.   The simplest solution was just to carry more cryo, and it was indeed designed in early.

2.    The electric APU was a separate proposed mod. Not sure where the energy would have come from. More cryo fuel cells, charging batteries to deliver big currents to the hydraulic pumps during entry?


1.  Not viable, it would have reduced payload weight and volume to the ISS.

2.  Dedicated batteries.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 04/07/2010 06:15 pm
    The simplest solution was just to carry more cryo, and it was indeed designed in early. The EDO pallet first flew in the early 90's, taking up some mass and space in the payload bay, and Endeavour and Columbia were plumbed to accommodate it. IIRC, Columbia even flew a 17 day mission. She had it on -107, which is why later analysis showed the crew could have lasted about a month in orbit at minimum power consumption, long enough, perhaps, to rush Atlantis to the pad.

On the outline for early space station Freedom utilization, there was planned for an orbiter to use both an EDO pallet and what is now known as SSPTS for one to two month docked times.  At that phase the station would not have had a permanent crew as there was not a CRV.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 04/08/2010 12:37 am
Hi all.

I have been looking at defintions to what "nadir" means (the point below the observer that is directly opposite the zenith on the imaginary sphere against which celestial bodies appear to be projected)  and "still can't wrap my head around it".

Can anyone simplify it for me.

Thanks
Oxford750

Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/08/2010 12:40 am
Hi all.

I have been looking at defintions to what "nadir" means (the point below the observer that is directly opposite the zenith on the imaginary sphere against which celestial bodies appear to be projected)  and "still can't wrap my head around it".

Can anyone simplify it for me.

Thanks
Oxford750



Nadir is the direction that points toward the Earth's center of mass.
Title: Re: Shuttle Q&A Part 5
Post by: Webhamster on 04/08/2010 01:59 pm
The X-Plane manual states that the re-entry has been flown manually, which frankly, I find hard to believe.

I have read several times (I can't cite a source at the moment) that it was Joe Engle on STS-2 who manually flew the re-entry from Mach 24 to landing as part of the OFT program.  He did it because it was one of his flight test objectives to prove that it could be done if it ever had to be done.  I'm pretty sure he would have also been able to turn over control to the computer very quickly if he determined that he wasn't within his margins but I'm not sure what that would have meant for the Shuttle program.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/08/2010 07:32 pm
Story confirmed here:

http://www.jsc.nasa.gov/history/oral_histories/EngleJH/EngleJH_6-3-04.pdf
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/08/2010 10:09 pm
Story confirmed here:

http://www.jsc.nasa.gov/history/oral_histories/EngleJH/EngleJH_6-3-04.pdf
That's a fun one -- read his recounting of the 51-I launch.

(One of the tests during the early flights was an autoland test, and there was a short period after the orbiter was on final prior to flare and touchdown where the autoland system was in control.  IIRC, they did that for STS-2 through STS-5.)
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 04/09/2010 09:45 am
Thanks all


oxford750
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 04/09/2010 11:42 am
Anyone aware of plans for a new edition of the Jenkins STS book after the program ends? I'd love to pick up a copy of the 3rd edition (2001), but as it's 9 years and 30+ missions out of date I'd prefer to wait on an update if one is forthcoming.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/09/2010 12:28 pm
Anyone aware of plans for a new edition of the Jenkins STS book after the program ends? I'd love to pick up a copy of the 3rd edition (2001), but as it's 9 years and 30+ missions out of date I'd prefer to wait on an update if one is forthcoming.
Yes:
http://forum.nasaspaceflight.com/index.php?topic=15532.msg361636#msg361636
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 04/10/2010 12:10 am
You should still get the older editions. Looking through all three editions that I have, there are slight differences from one to another. Anyway, how could you possibly stand to wait!  :)
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/10/2010 12:34 am
You should still get the older editions. Looking through all three editions that I have, there are slight differences from one to another. Anyway, how could you possibly stand to wait!  :)

If practical, the fourth edition will restore materials that had to be deleted from the previous editions for space reasons.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 04/10/2010 04:58 pm
Why can Soyuz land in a few hours after undocking but shuttle takes at least one whole day (Depending when late inspection happens)?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/10/2010 05:03 pm
Why can Soyuz land in a few hours after undocking but shuttle takes at least one whole day (Depending when late inspection happens)?

Thanks

Undocking, flyaround, separation, late inspection, cabin stow, FCS checkout, deorbit prep.

These take time.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 04/12/2010 10:48 pm
A Columbia question, in two parts, based on this picture:
http://upload.wikimedia.org/wikipedia/en/c/c8/Spacehab_S107e05359.jpg

1) What's the innermost RCC panel that can be seen on this picture?  Obviously you can't see all the way to the damaged panel, which IIRC was number 8.

2) The shuttle's port wing looks like it has some dirt or discoloration on it, whereas the starboard wing looks pristine.  Could this be ejecta from the foam impact?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/12/2010 10:57 pm
A Columbia question, in two parts, based on this picture:
http://upload.wikimedia.org/wikipedia/en/c/c8/Spacehab_S107e05359.jpg

1) What's the innermost RCC panel that can be seen on this picture?  Obviously you can't see all the way to the damaged panel, which IIRC was number 8.

2) The shuttle's port wing looks like it has some dirt or discoloration on it, whereas the starboard wing looks pristine.  Could this be ejecta from the foam impact?
In the CAIB report, Volume 1.

1. RCC 12L.  Look at page 146.  (Don't forget that the damage was likely on the underside of the panel, too).

2. Pre-existing discoloration, likely same as pretty much everywhere else -- the outgassing of the waterproofing during previous re-entries.  You can find other, higher-res pre-launch imagery of the orbiter, but there's a low-res shot on page 10 of the report.

Edit: either same shot as in the report or very similar and higher-res, via NASA KSC Multimedia Gallery:
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=18056
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 04/13/2010 02:31 am
Thanks for the comprehensive and helpful answers!
Title: Re: Shuttle Q&A Part 5
Post by: smith5se on 04/16/2010 09:50 am
Quick question: In picture below (link), what is the red stuff repairing the cracked tiles (I'm assuming its some sort of repair)?

http://twitpic.com/1ejcrh/full
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/16/2010 12:11 pm
Quick question: In picture below (link), what is the red stuff repairing the cracked tiles (I'm assuming its some sort of repair)?

http://twitpic.com/1ejcrh/full

RTV
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 04/18/2010 08:29 am
What factors go into determining which of the 3 APUs will be used for the FCS checkout? 

And while I'm asking, what determines the start sequence prior to entry? 
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 04/19/2010 05:55 pm
Question re: OBSS placement during undocking and fly around, why is it placed in that manner (i.e. perpendicular across the payload bay) and does it have a term associated with it?
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 04/19/2010 07:05 pm
At what point in the entry trajectory does the plasma trail cease to be visible from the surface? Is it dependent on earth-relative velocity? Curious for viewing opportunities during Tuesday's entry if KSC is selected.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/19/2010 08:51 pm
Question re: OBSS placement during undocking and fly around, why is it placed in that manner (i.e. perpendicular across the payload bay)

Minimize loads on RMS/OBSS during a period of high orbiter RCS thruster activity.

Quote
and does it have a term associated with it?

"Undocking position".
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 04/19/2010 11:12 pm
Question re: OBSS placement during undocking and fly around, why is it placed in that manner (i.e. perpendicular across the payload bay)

Minimize loads on RMS/OBSS during a period of high orbiter RCS thruster activity.

Quote
and does it have a term associated with it?

"Undocking position".

Great!  Thanks Jorge!!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/21/2010 02:50 am
Question re: OBSS placement during undocking and fly around, why is it placed in that manner (i.e. perpendicular across the payload bay)

Minimize loads on RMS/OBSS during a period of high orbiter RCS thruster activity.

Quote
and does it have a term associated with it?

"Undocking position".

Great!  Thanks Jorge!!

FYI, all the RMS/OBSS positions can be found in the PDRS checklists:

http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html

Check the REFERENCE DATA section, both the generic and flight supplement. The UNDOCK position is in the 131 flight supplement, p 3-3.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 04/24/2010 02:23 am
Provided that STS-134 slips into November is a descending node entry possible?

Also in the case of a descending node entry, is the way of launch/orbit insertion etc different (compared to an ascending node entry)? 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/24/2010 03:31 am
Provided that STS-134 slips into November is a descending node entry possible?

Yes, the flight rule limitation for noctilucent clouds only applies in the summer. Whether 134 uses a descending node entry depends on the mission timeline and crew sleep-shifting.

Quote
Also in the case of a descending node entry, is the way of launch/orbit insertion etc different (compared to an ascending node entry)? 

No. The ascent is *always* ascending, due to range safety constraints on SRB recovery and ET disposal.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 04/27/2010 03:30 am
1. How was it possible for Columbia on STS-80 to stay upto 17 days in orbit since it did not have  SSTP ?

2. What is the maximum duration that Atlantis can stay up in Space ? (it also does not have a SSTP). I read some where that Shuttles were originally to stay upto 28 days in orbit. Is that correct?

Title: Re: Shuttle Q&A Part 5
Post by: kch on 04/27/2010 03:37 am
1. How was it possible for Columbia on STS-80 to stay upto 17 days in orbit since it did not have  SSTP ?

2. What is the maximum duration that Atlantis can stay up in Space ? (it also does not have a SSTP). I read some where that Shuttles were originally to stay upto 28 days in orbit. Is that correct?


http://en.wikipedia.org/wiki/Extended_Duration_Orbiter
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 04/27/2010 07:00 pm
1. How was it possible for Columbia on STS-80 to stay upto 17 days in orbit since it did not have  SSTP ?

2. What is the maximum duration that Atlantis can stay up in Space ? (it also does not have a SSTP). I read some where that Shuttles were originally to stay upto 28 days in orbit. Is that correct?



2. Atlantis can stay in space for 12-days with 2 additional days for landing wave-off contingencies (like weather). Basically, STS-132 is extended as long as possible... a 12+0+2 day mission.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/27/2010 11:14 pm
How does Atlantis do that and the others can't? More refined orbiter design, I would obviously guess?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/27/2010 11:41 pm
How does Atlantis do that and the others can't? More refined orbiter design, I would obviously guess?

Actually, it's the reverse, sort-of.  The other two orbiters can stay longer on ISS missions because they are equipped with SSPTS so they can draw power from the station while they're docked, thus preserving their own cryos.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/28/2010 11:36 am
Haha, thats nuts, but I understand the reasoning.
Title: Re: Shuttle Q&A Part 5
Post by: Thorny on 04/28/2010 01:17 pm
Haha, thats nuts, but I understand the reasoning.

This all goes back to 2006, when Atlantis was going to be retired in 2008 rather than go through another every-seventh-flight Orbiter Major Modification inspection period (after which there would only be a year or so left in the Shuttle program.) So NASA didn't install SSPTS in Atlantis. But then NASA determined Atlantis could make another couple of flights without an OMM, so Atlantis ended up being the odd bird out.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/28/2010 03:08 pm
I think I was a little confused re the Atlantis question.

Was the original question how long can Atlantis stay at the station compared to other SSPTS-capable orbiters? I sort of already knew that it couldn't stay as long as the others, but I wondered how much.

Essentially I think the question is, if you take each orbiter (all 5), do they have similar periods of mission duration possible, and the answer, clearly, is no.

Apart from the SSPTS, and the Extended Duration Orbiter, are there any other things that affect it? As I mentioned, over the years orbiter design was refined, so perhaps did that play any part in extending possible duration?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 04/28/2010 03:26 pm

On some of the ascent launch videos around t -10 seconds i hear something that I think is "Nav init".

What does that mean and what is being performed / checked?

Also, right after liftoff both CDR and PLT say "auto" and "small numbers".
What are they referring to?

Thanks!
-Giles
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/28/2010 03:40 pm
1: Nav Int is short for navigation internal, that the nav systems are online.
2: It's "102, auto, auto". 102 refers to the software that he onboard GPCs are using. It's a verbal check that the GPCs have moded over from the prelaunch software to the stage 1 software, 102. There's a similar callout post-SRB sep, which is 103.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/28/2010 05:22 pm

Apart from the SSPTS, and the Extended Duration Orbiter, are there any other things that affect it? As I mentioned, over the years orbiter design was refined, so perhaps did that play any part in extending possible duration?

No, the limiting factor was cryogens (O2 and H2) onboard.  Most orbiters could carry 4 tank sets but 102 and 105 could carry 5.  So 102 could stay on orbit longer than newer vehicles.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 04/28/2010 07:47 pm
Which is sort of what I said then? I guess.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/28/2010 08:12 pm
Which is sort of what I said then? I guess.

The refined design did not have a part in extending the orbiter's duration. I don't include EDO and SSPTS as part of the orbiter design, they are kits.   
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 04/28/2010 11:25 pm
No, the limiting factor was cryogens (O2 and H2) onboard.  Most orbiters could carry 4 tank sets but 102 and 105 could carry 5.  So 102 could stay on orbit longer than newer vehicles.
    Why 102 and 105 -- did the fittings for the tank sets cost enough dry mass, or obstruct part of the payload bay, to make it worthwhile to spread around the capability? In practice, did the orbiters fly with less than their max # of tank sets? And, were the four sets in the EDO pallet the same in capacity to the standard four sets in each orbiter (ie, Atlantis could have doubled her duration had she ever flown with it, 102 and 105 a bit less)?
Thanks,    -Alex
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 04/28/2010 11:40 pm

Apart from the SSPTS, and the Extended Duration Orbiter, are there any other things that affect it? As I mentioned, over the years orbiter design was refined, so perhaps did that play any part in extending possible duration?

No, the limiting factor was cryogens (O2 and H2) onboard.  Most orbiters could carry 4 tank sets but 102 and 105 could carry 5.  So 102 could stay on orbit longer than newer vehicles.

Actually the baseline is 5 tank sets for all the vehicles. 
OV-103 will remove her 5th tank set for STS-133 for weight savings.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/29/2010 12:50 am


Actually the baseline is 5 tank sets for all the vehicles. 
OV-103 will remove her 5th tank set for STS-133 for weight savings.

No, the baseline is 3.  The 4th and 5th are kits.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/29/2010 12:53 am

    Why 102 and 105 -- did the fittings for the tank sets cost enough dry mass, or obstruct part of the payload bay, to make it worthwhile to spread around the capability? In practice, did the orbiters fly with less than their max # of tank sets? And, were the four sets in the EDO pallet the same in capacity to the standard four sets in each orbiter (ie, Atlantis could have doubled her duration had she ever flown with it, 102 and 105 a bit less)?
Thanks,    -Alex


So they didn't have to go and put in and take out the tanks for different missions.  102 was the Spacelab vehicle.

There was no since in carrying the tanks when there no need for them and they would be dead mass.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 04/29/2010 01:06 am

On some of the ascent launch videos around t -10 seconds i hear something that I think is "Nav init".

What does that mean and what is being performed / checked?

Also, right after liftoff both CDR and PLT say "auto" and "small numbers".
What are they referring to?

Thanks!
-Giles


Just to expand slightly on the explanation that DAVE S provided:

“NAV INIT”   stands for nav initialization.  At T-4 minutes the three IMU (inertial measurement unit) platforms are released and enter the inertial mode, however, they are not used for propagation of the state vector by the navigation software yet.  That comes at T-11 seconds when the onboard computers  [ Redundant Set Launch Sequencer (RSLS) as opposed to the Ground Launch Sequencer (GLS) ]  command “NAV INIT”.

“AUTO AUTO”  is a verification that the flight control system (FCS) is in the auto mode, this is checked by looking at the eyebrow panel (F2 & F4) lights for Pitch and Roll/Yaw – these two lights, labeled AUTO should be lit indicating the flight software is in Auto mode as opposed to CSS.  CSS stands for control stick steering and is the manual mode of flying the orbiter.

“102, 102”  refers to Major Mode 102 of the flight software.  After coming out of the built-in-hold at T-20 minutes in the launch countdown the commander will mode the flight computers (GPCs or general purpose computers) to OPS 1 which is the operational sequence software for the countdown & launch.  OPS 1 is divided into sub modes labeled 101, 102, 103 etc.  101 is used for the terminal countdown beginning at T-20 minutes.  At SRB ignition the software is supposed to automatically transition to 102 (the software for first stage) on the primary (4 of them referred to as PASS) and backup (1 of them referred to as BFS) computers.  At SRB ignition the commander will look at the CRTs, located on the forward instrument panels between the commander and pilot seats, he/she will verify that the title of one of the PASS displays has changed to 102 Ascent Traj and that the BFS computer screen says the same thing. 102 is the software used for first stage flight and 103 is used in second stage (beginning at SRB separation)

“NAV INIT”, “AUTO AUTO”, & “102 102” are calls that are usually made by the Commander.  You will usually here the Pilot call “Engine start, three at 100” meaning that all three main engines have started and are at the commanded throttle level of 100% this is followed by another call just a few seconds after liftoff of “3 at 104” which indicates the three main engines have throttle up to the 104.5% level – this is commanded at  ~T+4 seconds.


Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 04/29/2010 01:23 am


Actually the baseline is 5 tank sets for all the vehicles. 
OV-103 will remove her 5th tank set for STS-133 for weight savings.

No, the baseline is 3.  The 4th and 5th are kits.
Which all the vehicles have.  OK call it standard instead of baseline...semantics.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/29/2010 01:55 am
Which all the vehicles have.  OK call it standard instead of baseline...semantics.

No, standard/baseline what ever, is 3 tank sets.  4 & 5 are options.  They may have been left in for every ISS flight but they are not part of the standard orbiter.  The documentation has to account for them being installed on each mission.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 04/29/2010 01:52 pm
re: NAV INIT, Auto
Thank you very much DaveS and Mark.

Any idea on "Small numbers" ?

Thanks again!
-Giles
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 04/29/2010 10:53 pm
Which all the vehicles have.  OK call it standard instead of baseline...semantics.

No, standard/baseline what ever, is 3 tank sets.  4 & 5 are options.  They may have been left in for every ISS flight but they are not part of the standard orbiter.  The documentation has to account for them being installed on each mission.
Tank Set 3 is a kit also.

Many installations are not "standard" but have always flown.  Documentation is also required if they are removed.

Bottom line is all the remaining orbiters have flown 5 tank sets for >15 years.  I was just correcting an error in which it was stated that 103 & 104 didn't have the 5th tank set.   
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/30/2010 02:08 am


Bottom line is all the remaining orbiters have flown 5 tank sets for >15 years.  I was just correcting an error in which it was stated that 103 & 104 didn't have the 5th tank set.   

<15 years, AXAF launched in 1999
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 04/30/2010 03:22 pm
You could look at seat yourself at

http://www.panoscan.com/CubicDemos/Shuttle.html

Quicktime VR allows you to look all around

Ok, so we have an idea of where the orbiters may end up going, but what will end up happening to the sims?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 04/30/2010 03:28 pm
re: NAV INIT, Auto
Thank you very much DaveS and Mark.

Any idea on "Small numbers" ?

Thanks again!
-Giles


"Small numbers" is not a formal callout, could be a reference to the MPS Helium Useage on the System Summary Display or ADI Error Digitals on the BFS Trajectory display, both of which should be small numbers.

I would have to know the context and who said it, can you point me to the particular video you heard this on?

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 04/30/2010 03:34 pm


I would have to know the context and who said it, can you point me to the particular video you heard this on?

Mark Kirkman
Sure! Here;

http://www.youtube.com/watch?v=_vLl3K8yzOk

Around 42 second mark just after crew calls roll program.

Also, could you please comment on;
1:02
"1000 low"
1:23
"1500 low"

What caused this and how did the crew know?


Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/30/2010 04:22 pm
You could look at seat yourself at

http://www.panoscan.com/CubicDemos/Shuttle.html

Quicktime VR allows you to look all around

Ok, so we have an idea of where the orbiters may end up going, but what will end up happening to the sims?

Not all have been dispositioned yet. The Shuttle Mission Simulator Motion Base is going to Texas A&M University's Aerospace Engineering department, but that's all I know so far.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 04/30/2010 04:24 pm


I would have to know the context and who said it, can you point me to the particular video you heard this on?

Mark Kirkman
Sure! Here;

http://www.youtube.com/watch?v=_vLl3K8yzOk

Around 42 second mark just after crew calls roll program.

Also, could you please comment on;
1:02
"1000 low"
1:23
"1500 low"

What caused this and how did the crew know?


Thank you!


Yeah the “small numbers” call sounds like a reference to the BFS ADI Digitals.  During the roll maneuver the crew will cross check the values for R (roll), P (pitch), & Y (yaw) on the BFS version of the Ascent Trajectory Display against what they are seeing on the ADI (attitude director Indicator).  The PASS (primary) computers are controlling the maneuver and that is where the info on the ADI is coming from but by verifying that the error values on the BFS Traj Display are small the crew knows that the BFS computer closely agrees with where the PASS computers are taking the vehicle.  If the values were large then that would be a clue that the BFS does not agree with the PASS computers.

My best guess for the second set of numbers you asked about during throttle down is that the crew is cross checking the values on the Ascent ADI cue card which is attached with Velcro to the forward panels next to the two ADIs (a copy of the cue card is always in the Ascent checklist).  The card provides a rough estimate of values for pitch, altitude (in thousands of feet), altitude rate (climb rate in feet per second) at a given time (in first stage) or a given velocity (in second stage).  These are the pre-flight predictions of what the trajectory should be and can be affected by the real time conditions on launch day such as ambient temperature (which affects solid rocket booster performance) or winds, etc…

While there are some so called formal or standard intercom callouts made within the cockpit, each crew develops their own pattern/rhythm and you will notice these differences if you watch different ascent videos from other missions or sims.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/30/2010 05:13 pm
FWIW, this is STS-113.



I would have to know the context and who said it, can you point me to the particular video you heard this on?

Mark Kirkman
Sure! Here;

http://www.youtube.com/watch?v=_vLl3K8yzOk

Around 42 second mark just after crew calls roll program.

Also, could you please comment on;
1:02
"1000 low"
1:23
"1500 low"

What caused this and how did the crew know?


Thank you!


Yeah the “small numbers” call sounds like a reference to the BFS ADI Digitals.  During the roll maneuver the crew will cross check the values for R (roll), P (pitch), & Y (yaw) on the BFS version of the Ascent Trajectory Display against what they are seeing on the ADI (attitude director Indicator).  The PASS (primary) computers are controlling the maneuver and that is where the info on the ADI is coming from but by verifying that the error values on the BFS Traj Display are small the crew knows that the BFS computer closely agrees with where the PASS computers are taking the vehicle.  If the values were large then that would be a clue that the BFS does not agree with the PASS computers.

My best guess for the second set of numbers you asked about during throttle down is that the crew is cross checking the values on the Ascent ADI cue card which is attached with Velcro to the forward panels next to the two ADIs (a copy of the cue card is always in the Ascent checklist).  The card provides a rough estimate of values for pitch, altitude (in thousands of feet), altitude rate (climb rate in feet per second) at a given time (in first stage) or a given velocity (in second stage).  These are the pre-flight predictions of what the trajectory should be and can be affected by the real time conditions on launch day such as ambient temperature (which affects solid rocket booster performance) or winds, etc…

While there are some so called formal or standard intercom callouts made within the cockpit, each crew develops their own pattern/rhythm and you will notice these differences if you watch different ascent videos from other missions or sims.

Mark Kirkman

Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 04/30/2010 07:55 pm


Bottom line is all the remaining orbiters have flown 5 tank sets for >15 years.  I was just correcting an error in which it was stated that 103 & 104 didn't have the 5th tank set.   

<15 years, AXAF launched in 1999
Chandra flew on 102 which is why I stated "remaining orbiters"   :P
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 05/02/2010 03:38 am
Why was the clean launch pad approached, which was used for Saturn V, not used for the Space Shuttle?  Was it due to the weight of the SRBs? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/02/2010 12:49 pm
Why was the clean launch pad approached, which was used for Saturn V, not used for the Space Shuttle?  Was it due to the weight of the SRBs? 

The need to install payloads at the pad drove the RSS and there was no place to stick an FSS on the MLP.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 05/03/2010 01:47 am
The need to install payloads at the pad drove the RSS

Why was there such a need?  Why couldn't the payloads be installed in the VAB?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/03/2010 01:17 pm
Many thanks Mark re: "small numbers" and other ascent call outs.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/03/2010 01:39 pm
The need to install payloads at the pad drove the RSS

Why was there such a need?  Why couldn't the payloads be installed in the VAB?

No clean room. Also, the payloads don't want to be in the orbiter for more than 4 weeks
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/08/2010 12:23 am
TPS configuration question: Take a look on this photo of OV-105's payload bay doors: http://www-pao.ksc.nasa.gov/kscpao/images/large/07pd1853.jpg

Does the other orbiters have the same TPS configuration on the top of the PLBDs? Or is it strictly an OV-105 configuration?

Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 05/09/2010 09:34 pm
what is the difference between the RS-24 and RS-25? From this document, the RS-25 seems to be the disposable version of the SSME:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070002143_2007001281.pdf
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 05/11/2010 12:25 pm

No clean room. Also, the payloads don't want to be in the orbiter for more than 4 weeks

I think also that the Air Force wanted the ability to install and change payloads at the pad.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 05/12/2010 02:51 am

No clean room. Also, the payloads don't want to be in the orbiter for more than 4 weeks

I think also that the Air Force wanted the ability to install and change payloads at the pad.

Wouldn't that depend on payload latches, which as far as I know can only be changed in the OPF?
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 05/12/2010 10:15 pm
For anyone that's been involved with the shuttle program pre-Challenger...
I was watching a video the other day that showed a crew in the white room preparing to enter the orbiter.
As was normal in those days, they wore the blue flight suits.
What surprised me was that they put their helmets on in the white room.
Was there a reason for not putting them on while in the orbiter, as is done presently?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: wally on 05/13/2010 09:38 am
I would like to better understand how the shuttle rendezvous with the ISS. I've practice a bit in Orbiter, but I'm not sure it's a very accurate approach the one I do there.

So, after MECO, the shuttle it's on a stable, closed orbit. What parameters does this first orbit generally have (periapsis, apoapsis, inclination)? At what point on orbit are the first corrections made, and how? When is the inclination correction made, and how does the real shuttle does that? I guess that the rendezvous maneuverer follows the inclination correction. How does a shuttle get close to ISS? What comes to mind is a shuttle orbit something like 350x180 km (first being approximatively the altitude of ISS, second being high enough to avoid significant atmospheric drag) and then wait to catch ISS, usually takes 2-4 days in Orbiter, if launched accordingly (real date and time for a specific mission). Is this a realistic, fuel efficient, approach?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/13/2010 02:14 pm
I would like to better understand how the shuttle rendezvous with the ISS. I've practice a bit in Orbiter, but I'm not sure it's a very accurate approach the one I do there.

So, after MECO, the shuttle it's on a stable, closed orbit. What parameters does this first orbit generally have (periapsis, apoapsis, inclination)?

For ISS missions, HA=122 nmi, HP=32 nmi, and i=51.6 deg.

Quote
At what point on orbit are the first corrections made, and how?

OMS-2 burn, near the apogee of the post-MECO trajectory (~40 min after launch). Posigrade burn, raises the other side of the orbit to at least 85 nmi, but exact magnitude depends on the phase angle between the orbiter and ISS (in other words, OMS-2 isn't just a circularization burn, it's also the first rendezvous phasing burn, though the name doesn't reflect that).

Quote
When is the inclination correction made, and how does the real shuttle does that?

The shuttle launches in-plane with ISS, so no "inclination correction" maneuver is necessary. There is a placeholder for a planar correction burn (NPC) on flight day 2, but it is normally only needed to take out dispersions.

Quote
I guess that the rendezvous maneuverer follows the inclination correction. How does a shuttle get close to ISS? What comes to mind is a shuttle orbit something like 350x180 km (first being approximatively the altitude of ISS, second being high enough to avoid significant atmospheric drag) and then wait to catch ISS, usually takes 2-4 days in Orbiter, if launched accordingly (real date and time for a specific mission). Is this a realistic, fuel efficient, approach?

There are typically phasing maneuvers at the beginning and end of each flight day prior to rendezvous day to adjust the phasing rate. So NC-1 at the end of flight day 1, NC-2 at the beginning of flight day 2, and NC-3 at the end of flight day 2. There is also the aforementioned NPC burn placeholder during flight day 2. NPC may be combined with either NC-2 or NC-3 if the common node between the planes happens to coincide with either burn.

On flight day 3, the crew enters the rendezvous timeline. There is an optional NH burn to adjust the height (specifically to place apogee near ISS altitude). This burn may not be required for short phasing cases since previous burns may have already raised apogee (in the extreme short phasing case, OMS-2 itself would raise apogee to ISS and the remaining NC burns just gradually raise perigee). At the post-NH apogee, the orbiter performs the final NC burn (NC-4). This should occur at a point 40 nmi behind ISS and adjusts the phasing rate to put the orbiter 8 nmi behind ISS one orbit later. From NC-4 on, the trajectory and procedures are standard and can be found in the publicly available flight data file.
Title: Re: Shuttle Q&A Part 5
Post by: wally on 05/13/2010 03:19 pm
Great, thank you very much!
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 05/14/2010 08:13 am
From The Space Shuttle Decision (http://www.nss.org/resources/library/shuttledecision/chapter09.htm#loose1):

Quote
Though recent research had increased confidence that they indeed would serve, what made tiles more attractive yet was that NASA could count with reasonable assurance on using ablative heat shields as a backup. Ongoing work with ablatives had cut their cost dramatically while reducing their weight to 15 pounds per square foot, matching the weight of the tiles.

This was the first time I'd ever heard of ablative TPS on the Shuttle. Given that the tiles turned out to be so much more expensive than expected, would they still be less expensive than an ablative shield? How does an ablative shield compare when it comes to ruggedness? Could it withstand foam strikes or even MMOD strikes better than the tiles? Was an ablative TPS ever considered again after the loss of Columbia?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/14/2010 01:27 pm
I am interested to know more about the KU band failure on the previous mission- what was the cause, how was it diagnosed, how was it fixed, what checks / fixes if any were done on Atlantis. I do not have L2 access.

Thanks!

Title: Re: Shuttle Q&A Part 5
Post by: wally on 05/14/2010 01:28 pm
As I understand, it was a deployment failure. It was fixed on the ground and now it's up and running.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/14/2010 01:33 pm
I am interested to know more about the KU band failure on the previous mission- what was the cause, how was it diagnosed, how was it fixed, what checks / fixes if any were done on Atlantis. I do not have L2 access.

As I understand, it was a deployment failure. It was fixed on the ground and now it's up and running.
No, it was a transistor failure in the deployed assembly (in the exciter), not a deploy mechanism failure.

The DA box on Discovery was replaced with a spare unit.  The one on Atlantis was checked out fine and will fly as-is.  If the unit flying on this mission were to have a similar failure, the flight control teams and flight crew would pretty much execute the same procedures they did on the last mission.

Story on this was published on May 4th:
http://www.nasaspaceflight.com/2010/05/sts-132-agency-frr-ku-band-root-cause-found/
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/14/2010 01:42 pm
I am interested to know more about the KU band failure on the previous mission- what was the cause, how was it diagnosed, how was it fixed, what checks / fixes if any were done on Atlantis. I do not have L2 access.

Thanks!

The news articles include many of the important points made on L2.  In this case:

http://www.nasaspaceflight.com/2010/05/sts-132-agency-frr-ku-band-root-cause-found/
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/14/2010 02:19 pm
Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 05/14/2010 06:31 pm
Is there any video that NASA has released that keeps the camera on the ET rolling after seperation and shows it as it re enters until the camera burns up?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/14/2010 06:33 pm
Is there any video that NASA has released that keeps the camera on the ET rolling after seperation and shows it as it re enters until the camera burns up?
ET camera 101:
http://forum.nasaspaceflight.com/index.php?topic=9814.msg186120#msg186120

The breakup of the ET was imaged from the ground a few times much earlier in the program.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/14/2010 07:31 pm
She walked into MCC about 10 mins ago. Doesnt appear to be a shift change going on.
Title: Re: Shuttle Q&A Part 5
Post by: chksix on 05/14/2010 07:49 pm
MCC layout: http://spaceflight.nasa.gov/shuttle/reference/mcc/mcc.html
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/14/2010 07:54 pm
She walked into MCC about 10 mins ago. Doesnt appear to be a shift change going on.
Edit -- nope, I was wrong.  It wasn't a break, it was a shift change -- an upcoming shift change.  There's always a handover period between shifts and she (Orbit 2 FAO) was coming into the flight control room with the rest of the Orbit 2 team to get ready to take the handover from the ascent team.
Title: Re: Shuttle Q&A Part 5
Post by: hygoex on 05/14/2010 08:47 pm
Will they send the booster recovery ships out for the final mission?   If so, are they going to ship them back to Utah for reuse (Ares I?), scrap them, or send the spent SRBs to museums?
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 05/14/2010 11:54 pm
What is the name for the structure at the base of the orbiter that partially shields the SSMEs from the SRB plumes?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/15/2010 12:00 am
What is the name for the structure at the base of the orbiter that partially shields the SSMEs from the SRB plumes?

Body flap.  It is aerosurface.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 05/15/2010 12:01 am
You mean the rectangular piece that extends the bottom of the orbiter back under the engines? That's the body flap and it's actually an aerosurface used to control pitch trim.

ETA: Jim beat me.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 05/15/2010 12:43 am
Yes, the body flap.  Thanks!  There's an incredible new photo at http://www-pao.ksc.nasa.gov/kscpao/images/large/2010-3354.jpg.  It shows via the visible illumination what the radiative thermal environment in that area must be like.  (The bottom of the ET for example is literally glowing with reflected illumination, and you can see up inside the SSME expansion nozzles!)

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_coord.html#body_flap doesn't mention any kind of active cooling for the body flap.  What keeps it from melting?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/15/2010 12:57 am

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_coord.html#body_flap doesn't mention any kind of active cooling for the body flap.  What keeps it from melting?

It has tiles
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/15/2010 01:09 am

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_coord.html#body_flap doesn't mention any kind of active cooling for the body flap.  What keeps it from melting?

It has tiles

Which can be seen here:

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-127/hires/iss020e021615.jpg
http://spaceflight.nasa.gov/gallery/images/station/crew-20/hires/iss020e021624.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Alpha Control on 05/15/2010 03:22 am
I have a question regarding the ET SEP event. As I watched it today during the 132 launch, I was wondering about the forces involved during this key event. 

As the orbiter initiates ET SEP, does the tank have a downward force component that naturally pulls it away from the orbiter? In other words, if the orbiter did not perform any RCS firings, what are the tank dynamics at the moment of separation?  Would the tank automatically drift downward relative to the orbiter? Or are the orbiter RCS firings required to achieve separation?

Obviously the orbiter is using RCS firings to increase the separation, but are these required (tank will not separate without the RCS firings), or desired (easier to achieve photography)?

Thanks,
David
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/15/2010 03:37 am
The tank would move away from the orbit due to the release of the stored energy in the sep bolts.
Title: Re: Shuttle Q&A Part 5
Post by: Alpha Control on 05/15/2010 04:58 pm
The tank would move away from the orbit due to the release of the stored energy in the sep bolts.

Thanks Jim!
Title: Re: Shuttle Q&A Part 5
Post by: aurora899 on 05/15/2010 05:09 pm
On a slightly different note, does anyone know who the woman in the black suit with the long, blonde hair is walking out with the STS-132 astronauts? She can just be seen in this photo above Toni Antonelli's head.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/15/2010 05:13 pm
I have a question regarding the ET SEP event. As I watched it today during the 132 launch, I was wondering about the forces involved during this key event. 

As the orbiter initiates ET SEP, does the tank have a downward force component that naturally pulls it away from the orbiter? In other words, if the orbiter did not perform any RCS firings, what are the tank dynamics at the moment of separation?  Would the tank automatically drift downward relative to the orbiter? Or are the orbiter RCS firings required to achieve separation?

Obviously the orbiter is using RCS firings to increase the separation, but are these required (tank will not separate without the RCS firings), or desired (easier to achieve photography)?

Thanks,
David

The RCS firings do help to create safe relative motion. They are required in the RTLS case, because ET SEP occurs at a lower altitude and the combination of propellant slosh and aerodynamic forces can result in recontact.
Title: Re: Shuttle Q&A Part 5
Post by: Alpha Control on 05/15/2010 09:48 pm
I have a question regarding the ET SEP event. As I watched it today during the 132 launch, I was wondering about the forces involved during this key event. 

As the orbiter initiates ET SEP, does the tank have a downward force component that naturally pulls it away from the orbiter? In other words, if the orbiter did not perform any RCS firings, what are the tank dynamics at the moment of separation?  Would the tank automatically drift downward relative to the orbiter? Or are the orbiter RCS firings required to achieve separation?

Obviously the orbiter is using RCS firings to increase the separation, but are these required (tank will not separate without the RCS firings), or desired (easier to achieve photography)?

Thanks,
David

The RCS firings do help to create safe relative motion. They are required in the RTLS case, because ET SEP occurs at a lower altitude and the combination of propellant slosh and aerodynamic forces can result in recontact.

Thanks Jorge. I appreciate the info.
Title: Re: Shuttle Q&A Part 5
Post by: DiggyCoxwell on 05/15/2010 09:52 pm

   The Space Shuttle's LOX/LH2 rocket motors, the
LOX/LH2 tank, and the strap-on solids have for decades
inspired engineers to design an unmanned HLV using those components.
i.e., 4 strap-ons + the modified propellant with shuttle rocket motors
fitted to its base capable of lofting more than 200 tons into LEO.

  My question is?

Have any bean-counters published an estimate recently of how much it would cost to modify an external shuttle propellant-tank to fit a cluster of shuttle rocket motors at its base; to fit four attachment points instead of two for the SRB's; and to fit a payload carrying platform on top of the propellant tank to lift a 200 ton payload into orbit?

How much would it cost today to do that?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/15/2010 10:02 pm


Have any bean-counters published an estimate recently of how much it would cost to modify an external shuttle propellant-tank to fit a cluster of shuttle rocket motors at its base; to fit four attachment points instead of two for the SRB's; and to fit a payload carrying platform on top of the propellant tank to lift a 200 ton payload into orbit?


No, because it isn't a viable configuration.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 05/16/2010 01:14 am
fit four attachment points instead of two for the SRB's;

If we ever see the day when a vehicle is built up in the VAB with two five-segment solids, we're all going to hold our breath as that vehicle is transported out to a pad.  Ten segments will be massive! 

A vehicle with sixteen segments (four SRBs of four segments each) would not successfully complete the trip.
Title: Re: Shuttle Q&A Part 5
Post by: wally on 05/16/2010 08:01 am
In this  (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=17437.0;attach=221861)picture, the third panel, the one at the right, with the shuttle simulation/visualization, what is the software they use on MCR during shuttle missions? Looks like something available for WindowsXP, is it available for public use?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/16/2010 12:04 pm
In this  (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=17437.0;attach=221861)picture, the third panel, the one at the right, with the shuttle simulation/visualization, what is the software they use on MCR during shuttle missions?

Birds Eye View (BEV)

Quote
Looks like something available for WindowsXP,

Yes.

Quote
is it available for public use?

Not as far as I know.
Title: Re: Shuttle Q&A Part 5
Post by: kkattula on 05/16/2010 12:09 pm
fit four attachment points instead of two for the SRB's;

If we ever see the day when a vehicle is built up in the VAB with two five-segment solids, we're all going to hold our breath as that vehicle is transported out to a pad.  Ten segments will be massive! 

A vehicle with sixteen segments (four SRBs of four segments each) would not successfully complete the trip.

i.e.  KSC is built on a swamp.  The causeway is not engineered to support that mass, it would sink. Unevenly probably, thus tipping over.

NB:  Saturn V was moved to the pad unfueled.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/16/2010 11:17 pm

Some questions regarding calls (as it sounds to me) made on the flight loop for the STS-132 ascent;

http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=5954

"OMS PDO" or "ON PDO" (8:45)

"trend of minus 6" (9:35)

"fine count" (12:44)

Thanks!




Title: Re: Shuttle Q&A Part 5
Post by: TJL on 05/16/2010 11:40 pm
The woman seen in the STS 132 crew walkout is Janet Kavandi...
DEPUTY DIRECTOR, FLIGHT CREW OPERATIONS, JOHNSON SPACE CENTER.

Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 05/16/2010 11:46 pm

Some questions regarding calls (as it sounds to me) made on the flight loop for the STS-132 ascent;

http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=5954 (http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=5954)

"OMS PDO" or "ON PDO" (8:45)

"trend of minus 6" (9:35)

"fine count" (12:44)

Thanks!


On PDL (the Ponce De Leon Tracking Station).  The SRB plumes prevent a good line of sight to MILA for a time during first stage.

I believe the trend of minus 6 is FIDO giving a performance call. 

Fine count:  Close to MECO, guidance is still computing time left (TGO) and small changes in position error could produce large changes in the thrust turning rate vector, and cause overcontrolling as the closed-loop guidance goes through its NAV cycles (each cycle taking a finite amount of time to compute).  Fine count terminates closed-loop guidance (stops trying to go to a target position vs. current position feedback), and the time to go (TGO) is computed solely on VGO (desired velocity change).  Guidance is then waiting to see the correct inertial velocity to shut down the SSMEs (taking into account tailoff impulse as the engines shut down).  Throttles are going to 67% for fine count. 
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/16/2010 11:51 pm

Some questions regarding calls (as it sounds to me) made on the flight loop for the STS-132 ascent;

http://www.space-multimedia.nl.eu.org/index.php?option=com_content&view=article&id=5954

"OMS PDO" or "ON PDO" (8:45)

"trend of minus 6" (9:35)

"fine count" (12:44)

I'm sure someone will correct me if I'm wrong, but I think the trend is the difference between a model and the vehicle performance, the model being used to determine boundaries such as abort this way or abort that way if something were to happen at a particular time.  Fine count is, I believe, the mode just before MECO where the system is calculating the precise MECO time including throttle down and tail off thrust to hit the desired point in space and the correct velocity.  Don't know what ON PDO means.
Title: Re: Shuttle Q&A Part 5
Post by: aurora899 on 05/17/2010 10:23 am
The woman seen in the STS 132 crew walkout is Janet Kavandi...
DEPUTY DIRECTOR, FLIGHT CREW OPERATIONS, JOHNSON SPACE CENTER.



Thanks. That would make sense but I must admit that I didn't recognise her. I think she's changed her hair colour!
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/17/2010 04:01 pm
Has a GPC ever been outvoted / failed during a mission?

Would that necessitate an immediate return?

Also, what is the story behind the GPC failure during the first Enterprise entry / landing test;

"GPC light." "Big X on computer #2"

?


Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/17/2010 04:22 pm
Has a GPC ever been outvoted / failed during a mission?

Yes, multiple times, but more frequently with the old GPCs than the current ones.

Quote
Would that necessitate an immediate return?

No, not for first-fail. Two GPC failures requires a shortened mission.
Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 05/17/2010 04:29 pm
...
Also, what is the story behind the GPC failure during the first Enterprise entry / landing test;

"GPC light." "Big X on computer #2"

?


Thanks!

I think it had something to do with failed solder joints or something...
I remember hearing the story when I was listening to these:
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/index.htm
Maybe it was lecture 16?
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/detail/embed16.htm
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/17/2010 04:39 pm
...
Also, what is the story behind the GPC failure during the first Enterprise entry / landing test;

"GPC light." "Big X on computer #2"

?


Thanks!

I think it had something to do with failed solder joints or something...
I remember hearing the story when I was listening to these:
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/index.htm
Maybe it was lecture 16?
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/detail/embed16.htm


Failed solder joints sounds more like the multiple GPC fail scenario from STS-9.

Unfortunately the shuttle IFA database doesn't include ALT...
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/17/2010 04:51 pm


Yes, multiple times, but more frequently with the old GPCs than the current ones.

Old GPCs has me curious. I remember reading multiple posts on here about why dont they upgrade the computer hardware on the orbiters since they date back to a 1960/70 design. The response was understandably that the computers have proved themselves, and that to update them would be too costly. So, when were the GPC's replaced, and how are they better?
 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/17/2010 06:09 pm


Yes, multiple times, but more frequently with the old GPCs than the current ones.

Old GPCs has me curious. I remember reading multiple posts on here about why dont they upgrade the computer hardware on the orbiters since they date back to a 1960/70 design. The response was understandably that the computers have proved themselves, and that to update them would be too costly. So, when were the GPC's replaced, and how are they better?
 

Early 1990s, went from the AP-101B to the AP-101S, binary-compatible with the old GPC, has the I/O Processor (IOP) integrated into the GPC case, twice as much memory (enables the entry software to be stored in an upper-memory archive for quick recall in case of emergency deorbit), solid state memory instead of core.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/17/2010 10:17 pm
Has a GPC ever been outvoted / failed during a mission?

Would that necessitate an immediate return?

Also, what is the story behind the GPC failure during the first Enterprise entry / landing test;

"GPC light." "Big X on computer #2"

?


Thanks!


There was a "Fail to sync" of GPC @ on the first free flight of Enterprise, it occured right at separation from the SCA (747). 

If you look on this site (NSF) you should be able to find the ALT Program Flight Test results document (I don't know the exact title) and it should go into a lot of detail on what happend.  If it is not here you might try the NASA Tech Reports server.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 05/17/2010 10:19 pm
...
Also, what is the story behind the GPC failure during the first Enterprise entry / landing test;

"GPC light." "Big X on computer #2"

?


Thanks!

I think it had something to do with failed solder joints or something...
I remember hearing the story when I was listening to these:
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/index.htm
Maybe it was lecture 16?
http://ocw.mit.edu/OcwWeb/Aeronautics-and-Astronautics/16-885JFall-2005/LectureNotes/detail/embed16.htm


Failed solder joints sounds more like the multiple GPC fail scenario from STS-9.
...
Yes, I believe that's what I was actually thinking of. Thanks, Jorge. :)
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/18/2010 02:44 am


Early 1990s, went from the AP-101B to the AP-101S, binary-compatible with the old GPC, has the I/O Processor (IOP) integrated into the GPC case, twice as much memory (enables the entry software to be stored in an upper-memory archive for quick recall in case of emergency deorbit), solid state memory instead of core.

I remember reading someware once that after the Challenger accident, they were able to reconstruct some of the data from the GPCs memory. The ferrite core cells maintained its magnetized state after the power failed. That wouldn't happen with modern, solid state memory.
Title: Re: Shuttle Q&A Part 5
Post by: Chandonn on 05/18/2010 02:56 am


Early 1990s, went from the AP-101B to the AP-101S, binary-compatible with the old GPC, has the I/O Processor (IOP) integrated into the GPC case, twice as much memory (enables the entry software to be stored in an upper-memory archive for quick recall in case of emergency deorbit), solid state memory instead of core.

I remember reading someware once that after the Challenger accident, they were able to reconstruct some of the data from the GPCs memory. The ferrite core cells maintained its magnetized state after the power failed. That wouldn't happen with modern, solid state memory.

I hadn't heard that about Challenger, but I believe they were able to reconstruct some of the last moments of Columbia in that manner.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/18/2010 03:35 am


Early 1990s, went from the AP-101B to the AP-101S, binary-compatible with the old GPC, has the I/O Processor (IOP) integrated into the GPC case, twice as much memory (enables the entry software to be stored in an upper-memory archive for quick recall in case of emergency deorbit), solid state memory instead of core.

I remember reading someware once that after the Challenger accident, they were able to reconstruct some of the data from the GPCs memory. The ferrite core cells maintained its magnetized state after the power failed. That wouldn't happen with modern, solid state memory.

I hadn't heard that about Challenger, but I believe they were able to reconstruct some of the last moments of Columbia in that manner.

No, he's right, Challenger's GPC memory could be partially reconstructed, but Columbia's could not. The Columbia reconstructions were done using the MADS recorder and a couple of bursts of downlist data that were recorded at White Sands but rejected at Houston in realtime because they failed the quality tests.
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 05/19/2010 07:45 pm
Question from Chris's article at http://www.nasaspaceflight.com/2010/05/sts-132-atlantis-sunday-docking-extremely-clean-et-136/ (http://www.nasaspaceflight.com/2010/05/sts-132-atlantis-sunday-docking-extremely-clean-et-136/).

Quote
“No problems or issues were noted during the ascent phase,” listed the official MER report. “The Reusable Solid Rocket Booster (RSRB) shutdown occurred at 134/18:22:09 GMT [00/00:02:06 Mission Elapsed Time (MET)] and the separation was visible.

A nominal Orbital Maneuvering System (OMS) assist maneuver was performed following SRB separation. Ignition occurred at 134/18:22:24.3 GMT (00/00:02:16 MET, and the maneuver was 90.2 sec in duration. MECO occurred at 134/18:28:34 GMT (00/00:08:32 MET).

What is this OMS assist maneuver, and under what circumstances would it be required?

Many thanks, Martin
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 05/19/2010 08:05 pm
What is this OMS assist maneuver, and under what circumstances would it be required?
Many thanks, Martin
    The OMS engines fire during second-stage flight as additional thrust. In effect, the shuttle is both a hydrolox and hypergolic rocket at that point. The effect is quite small, naturally, but apparently it adds a little extra mass delivered to ISS, part of seeking to maximize every bit of performance out of STS.
     A while back, someone mentioned (IIRC) that this was controversial when first proposed, operating both MPS and OMS simultaneously adding risk?
-Alex
Title: Re: Shuttle Q&A Part 5
Post by: aurora899 on 05/19/2010 08:46 pm
What is this OMS assist maneuver, and under what circumstances would it be required?
Many thanks, Martin
    The OMS engines fire during second-stage flight as additional thrust. In effect, the shuttle is both a hydrolox and hypergolic rocket at that point. The effect is quite small, naturally, but apparently it adds a little extra mass delivered to ISS, part of seeking to maximize every bit of performance out of STS.
     A while back, someone mentioned (IIRC) that this was controversial when first proposed, operating both MPS and OMS simultaneously adding risk?
-Alex

Yes, wasn't Mike Mullane tasked to work on it and he found himself being bitterly opposed by John Young? Mullane refers to it in "Riding Rockets" I think.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 05/20/2010 01:09 am
What is this OMS assist maneuver, and under what circumstances would it be required?
Many thanks, Martin
    The OMS engines fire during second-stage flight as additional thrust. In effect, the shuttle is both a hydrolox and hypergolic rocket at that point. The effect is quite small, naturally, but apparently it adds a little extra mass delivered to ISS, part of seeking to maximize every bit of performance out of STS.
     A while back, someone mentioned (IIRC) that this was controversial when first proposed, operating both MPS and OMS simultaneously adding risk?
-Alex

Yes, wasn't Mike Mullane tasked to work on it and he found himself being bitterly opposed by John Young? Mullane refers to it in "Riding Rockets" I think.

Affirmative, it was described in Mike Mullane's book. 
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 05/20/2010 06:43 am
Many thanks for all the answers.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 05/20/2010 09:21 am
I always wondered why they didn't just not load that OMS propellant, I wasn't sure whether the extra thrust produced outweighed the amount of OMS that was burnt.
Title: Re: Shuttle Q&A Part 5
Post by: KelvinZero on 05/20/2010 11:35 am
I just had a throw away question not important enough for its own thread.

I was thinking of an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, throttling back to keep acceleration constant as total mass drops, and then is restarted or throttled up when the first stage drops away.

However this would put the exhaust of the second stage, being on top, rather close to the solid first stage. I was wondering if that was acceptable for solid rockets or rules this idea out. Also I was wondering what seriously considered plans most resembled this.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/20/2010 11:59 am
I just had a throw away question not important enough for its own thread.

I was thinking of an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, throttling back to keep acceleration constant as total mass drops, and then is restarted or throttled up when the first stage drops away.

However this would put the exhaust of the second stage, being on top, rather close to the solid first stage. I was wondering if that was acceptable for solid rockets or rules this idea out. Also I was wondering what seriously considered plans most resembled this.

Side mount SDLV
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/20/2010 01:41 pm
I always wondered why they didn't just not load that OMS propellant, I wasn't sure whether the extra thrust produced outweighed the amount of OMS that was burnt.
i seem to remember that very questioned was asked, answered and discussed somewhere on here....
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/20/2010 01:47 pm

There was a "Fail to sync" of GPC @ on the first free flight of Enterprise, it occured right at separation from the SCA (747). 

If you look on this site (NSF) you should be able to find the ALT Program Flight Test results document (I don't know the exact title) and it should go into a lot of detail on what happend.  If it is not here you might try the NASA Tech Reports server.

Mark Kirkman

Many thanks to everyone who responded to this. According to this;
http://klabs.org/DEI/Processor/shuttle/alt_gpc2/index.htm

It was a solder problem;

 
Quote
However, the problem was reproduced at the vendor's facility when the flight unit (input-output processor, serial number 7) was subjected to low-level vibration testing at 0.01 g2/Hz. Subsequent inspection revealed a solder crack at a prom lead on the queue page (fig. 7-3). The solder had failed to wick in a plated-through hole. The unit had been acceptance tested at 0.04 g2/Hz after 1848 hours of field run time.
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 05/20/2010 02:59 pm
When is the inclination correction made, and how does the real shuttle does that?

The shuttle launches in-plane with ISS, so no "inclination correction" maneuver is necessary. There is a placeholder for a planar correction burn (NPC) on flight day 2, but it is normally only needed to take out dispersions.

I have a few related questions about rendezvous and ascent G&C, specifically about the target orbital plane.

I read in the Ascent Guidance and Flight Control Workbook (in L2, I believe) that the I-loaded target orbital plane (IY) is defined by the longitude of the ascending node and the inclination. Are these specified relative to M50?

I assume the IY values are based on the longitude of the ascending node and inclination of the ISS orbit. If so, are they based on those values at T-0 or is it more complicated than that?

The layman's explanation of selecting T-0 is that it is the moment when the ISS plane passes directly above the launch site, but I have a feeling that's the simplified version. Nodal regression rates differ by altitude and inclination, and the shuttle generally orbits at a lower altitude until rendezvous. Therefore, I would guess that in order to match the ISS plane at rendezvous, the orbiter's initial plane would have to be slightly different. How is this difference accounted for (i.e., how is IY calculated, given the ISS orbital elements)? Are there any other factors that affect the calculation of IY? In practice, how different is IY from the ISS plane at T-0?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/20/2010 03:17 pm
Does anybody know if it has ever been a mission in which they had problems in opening/closing the payload bay doors? Furthermore do you know if there is any document explaining how the payload bay can be closed by means of EVA? I remember reading in Skywalking that Tom Jones briefly describe the procedure but I don't have the book with me and anyway I'd like to read some document explaining this contingency EVA in more details.

Thanks

Davide

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/20/2010 03:26 pm
Does anybody know if it has ever been a mission in which they had problems in opening/closing the payload bay doors? Furthermore do you know if there is any document explaining how the payload bay can be closed by means of EVA? I remember reading in Skywalking that Tom Jones briefly describe the procedure but I don't have the book with me and anyway I'd like to read some document explaining this contingency EVA in more details.


STS-3
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/20/2010 04:05 pm
When is the inclination correction made, and how does the real shuttle does that?

The shuttle launches in-plane with ISS, so no "inclination correction" maneuver is necessary. There is a placeholder for a planar correction burn (NPC) on flight day 2, but it is normally only needed to take out dispersions.

I have a few related questions about rendezvous and ascent G&C, specifically about the target orbital plane.

I read in the Ascent Guidance and Flight Control Workbook (in L2, I believe) that the I-loaded target orbital plane (IY) is defined by the longitude of the ascending node and the inclination. Are these specified relative to M50?

Yes, M50 is the standard inertial frame used by the shuttle. IY is defined by the ascending node and inclination, but internally it is represented by a unit vector normal to the plane, in the opposite direction of orbital angular momentum.

Quote
I assume the IY values are based on the longitude of the ascending node and inclination of the ISS orbit. If so, are they based on those values at T-0 or is it more complicated than that?

The layman's explanation of selecting T-0 is that it is the moment when the ISS plane passes directly above the launch site, but I have a feeling that's the simplified version. Nodal regression rates differ by altitude and inclination, and the shuttle generally orbits at a lower altitude until rendezvous. Therefore, I would guess that in order to match the ISS plane at rendezvous, the orbiter's initial plane would have to be slightly different. How is this difference accounted for (i.e., how is IY calculated, given the ISS orbital elements)? Are there any other factors that affect the calculation of IY? In practice, how different is IY from the ISS plane at T-0?

IY targets a "phantom plane" that will regress into the ISS orbital plane by the time of the planned rendezvous. It will vary based on the phase angle between the shuttle and ISS because large phase angles require lower altitudes to catch up by a given time, while small phase angles require higher altitudes.

IY is uplinked by FDO on launch day and represents the phantom plane at the opening of the launch window. As the launch slips, the phase angle changes and the target orbit plane regresses, and so a new IY is computed onboard at SRB ignition using the node slope equation.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 05/20/2010 04:50 pm
an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, [putting] the exhaust of the second stage, being on top, rather close to the solid first stage.  [...] what seriously considered plans most resembled this.

Side mount SDLV

KelvinZero seems to be suggesting an in-line arrangement, where the second stage (ground-started) SSMEs are turned outward (presumably on gimbals) such that their exhaust plumes pass by the first stage.  Could the SRB continue to function safely in the periphery of the SSME exhaust plumes?  What about in the extreme case where the gimbals point the throttled back SSMEs out at 90 degrees during the first stage of flight?

Tractor-style abort motors do something like this, don't they?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/20/2010 05:22 pm
an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, [putting] the exhaust of the second stage, being on top, rather close to the solid first stage.  [...] what seriously considered plans most resembled this.

Side mount SDLV

KelvinZero seems to be suggesting an in-line arrangement, where the second stage (ground-started) SSMEs are turned outward (presumably on gimbals) such that their exhaust plumes pass by the first stage.

Incredibly wasteful due to cosine losses on the thrust, would require additional weight for TPS to protect from plume impingement.

Quote
What about in the extreme case where the gimbals point the throttled back SSMEs out at 90 degrees during the first stage of flight?

One SSME failure = instant LOC due to pitch rate and excessive side loads on vehicle. You wouldn't be able to shut the opposing engine down prior to loss of control/breakup.

Quote
Tractor-style abort motors do something like this, don't they?

Yes. They don't need to be efficient, just high thrust, and they don't impinge on the launch vehicle throughout the entire first stage like this design does.
Title: Re: Shuttle Q&A Part 5
Post by: Propforce on 05/21/2010 03:03 pm
I just had a throw away question not important enough for its own thread.

I was thinking of an Ares 1-like rocket, but where the second stage is positioned so that it can also contribute to the thrust during lift off, throttling back to keep acceleration constant as total mass drops, and then is restarted or throttled up when the first stage drops away.

However this would put the exhaust of the second stage, being on top, rather close to the solid first stage. I was wondering if that was acceptable for solid rockets or rules this idea out. Also I was wondering what seriously considered plans most resembled this.

Just build a better 1st stage.

In the case of Ares 1, the problem is not the lack of thrust from the 1st stage, it is the lack of "range", e.g., need more propellant therefore a bigger diameter SRB. 

In your proposed idea, then we will need to build a "bigger" 2nd stage tank because you're taking the propellant dedicated for a 2nd stage flight to "subsidize" the 1st stage.  But if you build a bigger 2nd stage tank, it gets heavier and we will need "more" thrust from the 1st stage which is exactly the problem we try to fix.  See the problem?
Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 05/22/2010 10:13 pm
What was the mass of the rescue balls, including the 1-hour life support?
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 05/23/2010 03:09 pm
Is there a way to get the live displays in MCC on your computer. Such as the live map and live configuration?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 05/23/2010 03:25 pm
Not the official one but there are lots of other ones that do similar things like show the map etc.
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 05/23/2010 04:40 pm
That's a missed opportunity from NASA PAO.

They really should provide an app which shows the big MCC map, indicating ISS, Shuttle, Soyuz, Progress, ATV, HTV, COTS & CCDev, plus Hubble of course :)

They should do it as a screensaver and/or an active wallpaper.   I think there would be thousands of people who would use it as their default screens.   It would be good 'advertising' for NASA.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 05/24/2010 02:06 am
That's a missed opportunity from NASA PAO.

They really should provide an app which shows the big MCC map, indicating ISS, Shuttle, Soyuz, Progress, ATV, HTV, COTS & CCDev, plus Hubble of course :)

They should do it as a screensaver and/or an active wallpaper.   I think there would be thousands of people who would use it as their default screens.   It would be good 'advertising' for NASA.

Ross.
Couldn't agree with you more.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/26/2010 04:40 pm

Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75

Thanks!


Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/26/2010 04:42 pm

What is the name of the screen on the right side?

What is it showing?

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=21764.0;attach=229194;image

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/26/2010 06:03 pm

Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75

That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun.  They are constantly changing during entry.  The angle of attack is what is fixed. 
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/27/2010 01:58 pm

Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75

That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun.  They are constantly changing during entry.  The angle of attack is what is fixed. 

Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/27/2010 02:12 pm


Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?


It isn't the same because the orbits are slightly different, the orbit in relation to the landing site is different, the orbiter's weight is different, the amount of OMS propellant is different and the amount of excess OMS propellant that needs to be burned off is different.

The attitude is a function of how efficient the burn has to be (the more excess OMS propellant that needs to be burn the more inefficient the attitude is for the deorbit burn).  There is a slight affect on cross range with the burn also.

Yes, tens of degree matter, it feeds back in the burn parameters.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/27/2010 02:19 pm

What is the name of the screen on the right side?

What is it showing?

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=21764.0;attach=229194;image

Thanks!


Can't really read it well enough from that screen grab, but it looks like the plot of Vrel versus RGO (relative velocity vs Range to Go) used by the FDO (FIDO or fligh dynamics officer) folks.  The boundaries represent thermal limits on the left (i.e. don't burn the wings off) and toward the right are minmum bank angles which help assess max range capability.

You may also see other displays such as Altitude vs RGO or E/W (energy) vs RGO and the ground track.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/27/2010 06:07 pm

Regarding entry attitude. What dictates the attitude? Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Looking at reply #82 in this thread;
http://forum.nasaspaceflight.com/index.php?topic=21764.75

That is the attitudes in relation to LVLH (local vertical local horizon), inertial and the sun.  They are constantly changing during entry.  The angle of attack is what is fixed. 

Thanks for the reply. Sorry, I should have been more specific. I am referring to the numbers called up to the crew for the maneuver to the deorbit position. Why isn't it always the same attitude for every entry? Why arent they "nice" whole numbers. Do the 10th's of a degree really matter?

Thanks!


Not quite sure what you're referring to here, then. You referenced this post:

http://forum.nasaspaceflight.com/index.php?topic=21764.msg595853#msg595853

1) That is the Bird's Eye View (BEV) display of the Entry Interface (EI) attitude, not the deorbit attitude
2) That display is the actual attitude, not the attitude called up to the crew, and the flight controllers like to see it in tenths.
3) The attitude called up to the crew is in whole-number degrees. This is because the MM303 DEORB MNVR COAST display only shows attitude in whole-number degrees. See the DEORBIT MNVR PAD in the ENTRY C/L, items 24-26:

http://www.nasa.gov/centers/johnson/pdf/381558main_ENT_G_H_6.pdf

4) The numbers will be different for every entry because the attitude on MM303 is an inertial M50 attitude. Even if the entry attitude was exactly the same in LVLH on every mission, it would be different in M50 due to the rotation of the Earth.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/28/2010 02:00 pm
Not quite sure what you're referring to here, then.
I think I am confused. Let me read the info you kindly provided me and see if I can figure it out.

Thanks to you, Jim and Mark for previous replies.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/28/2010 02:05 pm
What was SM OPS 4 designed for? It looks exactly like SM OPS 2.

ref: http://www.nasa.gov/centers/johnson/pdf/383444main_crew_software_interface_21002.pdf

Was it ever used?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: chksix on 05/28/2010 04:42 pm
A discussion on a pilot's forum has arisen about the exact speeds and timeframe for Max Q (Max Dynamic Pressure) on the vehicle during launch.

Is the throttle in the bucket during Max Q or in preparation for it?
STS 132 had M .64 to M 1.13. Is that the speed of the vehicle as it passes through Max Q? And is it the same as going through the transonic region in flight?

I searched this section but couldn't find the exact description...

The thread with the discussion: http://www.pprune.org/jet-blast/414736-sts-132-shuttle-atlantis-4.html (near bottom of page and cont. on next.)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/28/2010 05:01 pm
Max-q varies for every vehicle and it has nothing to do transsonic. 

q= 1/2 * rho * v2

rho is the density of air.  But rho decreases with altitude and v is increasing.  So early in flight velocity increases and so does q but as altitude is gained, the decrease in rho overtakes velocity and q starts decreasing. 

To determine Max-q, the above equation would have to be expanded to include rho as a function of altitude and v as a function of altitude and then the finding the first derivative wrt to altitude and solve for 0.

Title: Re: Shuttle Q&A Part 5
Post by: chksix on 05/28/2010 09:34 pm
Thank you Jim. Do you know more about the Mach speeds for the throttle bucket in the ascent checklist?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/28/2010 10:31 pm
Thank you Jim. Do you know more about the Mach speeds for the throttle bucket in the ascent checklist?

I wish I would have seen the graph and it would have made the explanation easier.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 05/28/2010 11:00 pm
I have questions regarding the shuttle fly-around upon leaving MIR.

Was this performed back then as is currently with ISS?

If so, on STS 63 was this maneuver flown by shuttle PLT Collins?
Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/28/2010 11:17 pm
I have questions regarding the shuttle fly-around upon leaving MIR.

Was this performed back then as is currently with ISS?

Yes.

Quote
If so, on STS 63 was this maneuver flown by shuttle PLT Collins?
Thanks.

No. On STS-63 the CDR (Wetherbee) flew all the Mir prox ops (I think Collins flew some of the SPARTAN prox ops). The practice of allowing the PLT to perform the flyaround started with Precourt on STS-71.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 05/31/2010 06:41 pm
Not so sure if this is specifically a shuttle question.

Many have mentioned that the use of Saturn heritage equipment has kept the program costs astronomical.  Is the reason for such high infrastructure costs due to the old age/labor intensive operations or is it due to the sheer size fo things like the pad/MLP/VAb?  I know that for Ares V a new crawler/transporter was looked at (see l2), could a newer ML/CT and newer HLV infrastructure save much reoccurring costs?
Title: Re: Shuttle Q&A Part 5
Post by: butters on 05/31/2010 08:02 pm
Not so sure if this is specifically a shuttle question.

Many have mentioned that the use of Saturn heritage equipment has kept the program costs astronomical.  Is the reason for such high infrastructure costs due to the old age/labor intensive operations or is it due to the sheer size fo things like the pad/MLP/VAb?  I know that for Ares V a new crawler/transporter was looked at (see l2), could a newer ML/CT and newer HLV infrastructure save much reoccurring costs?

The DIRECT guys seem to conclude that the orbiter and its processing flow is the low-hanging fruit for reducing the cost of the KSC/STS operation.

I'm fairly sure that's true, but I'm not sure how much cheaper the equivalent missions could have been executed. 

I think it's just inherently uneconomical the way we dip our feet in the water of human spaceflight (mainly to prove we can), and it may be that the only way to really get a better return on investment is to increase spending by like an order of magnitude.

I should think it's becoming clear to most space enthusiasts that we're just not operating on a scale that makes economic sense, and the questions we need to answer begin with "why" rather than "how". 
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/07/2010 02:31 pm
Can anyone tell me what this grille in the vertical stabablizer is for? I've never noticed it in any photos before and I have never read anything about it.

 In the high resolution image, you can see that it is a perf-metal plate with fasteners. The interesting thing is the round feature of a different color in the center of the plate. It looks like a discoloration caused by hot gasses passing through the vent. Is this possibly for the exhaust products of the deployment mortar for the pilot chute?

edit- I outlined the pannel in question, but it is hard to see in the thumbnail. It is about midway up on the very left side of the photo.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/07/2010 03:11 pm
It doesn't look a grille to me, it looks a composite flat panel with a honeycomb "shadow"
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 06/07/2010 03:47 pm
Any need for venting of the stab?

Even more interesting... what is the lettering on the pink tags surrounding it.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/12/2010 08:39 am
Hi all.

Are you awere of any documents explaining or showing the history of the development of the RMS? On Heppenheimer's Development of the Space Shuttle book there are just 2 pages. I'd like to find something more specific about the problems met during the development and building of the RMS.

Thanks in advance

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 06/14/2010 01:01 pm
Even more interesting... what is the lettering on the pink tags surrounding it.

Seriously... what is on those pink (and green ones elsewhere in the photo) tags around the area in question? I've seen them in other photos as well. I assume they indicate an area that is in work or requires attention.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/14/2010 01:02 pm
They are marking which tiles need work.
Title: Re: Shuttle Q&A Part 5
Post by: NASAGeek on 06/14/2010 04:56 pm
on the famous picture of Bruce McCandless flying the MMU on STS-41B. I noticed what looks like above the  helmet visor it looks like what the current EVA suits have with the camera and its not the MMU camera but on the spacesuit itself above the visor. I forget what its called but I think the acronym is WVS? but my question is I thought the camera above the visor showing what the astronaut sees were first introduced on STS-97 unless it was first introduced on an earlier flight and I missed it. Because I seen it a couple of times in early shuttle eva photos.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/18/2010 08:40 am
Hi all.

A couple of quick question about the RMS:

1)   Has never been any major malfunction to the RMS in any of the space shuttle missions till now performed? I mean some kind of malfunction that prevented the RMS to be used. To my knowledge it’s never happened but I’d like to be 100% sure of it.
2)   In which way astronauts are trained to be RMS operator? Which kind of failure and contingency scenario are they trained for? How long does it take for being trained on the RMS use? Is there any manual available explaining in the main the training for RMS operators?
3)   I know that there is a jettison system that allows the crew to get rid of the RMS in case at the end of the mission is not possible to restow it. However it’s not clear, from what I’ve read till now, if for this operation is necessary to have someone outside in EVA. I mean, in which way can they control  the trajectory of the discarded RMS once it’s been jettisoned so that it doesn’t hit the orbiter?

Thanks in advance

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/18/2010 02:09 pm
STS-11/41-B had an RMS failure
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 06/19/2010 04:00 am
At what point in the approach phase do the guidance modes displayed on the HUD change (e.g. from OGS to FLARE, and FLARE to FINAL)? Are these based on altitude, or something else?
Title: Re: Shuttle Q&A Part 5
Post by: trebloc on 06/19/2010 07:52 pm
Often wondered why the shuttle airlock was internal pre ISS and not placed in the payload bay as it is now. It would have generated a lot of additional space in the crew compartment. Was it to do with useable space in the payload or center of gravity?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/19/2010 08:00 pm
Often wondered why the shuttle airlock was internal pre ISS and not placed in the payload bay as it is now. It would have generated a lot of additional space in the crew compartment. Was it to do with useable space in the payload or center of gravity?

The former (assuming by "payload" you mean "payload bay").
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/19/2010 09:22 pm
Often wondered why the shuttle airlock was internal pre ISS and not placed in the payload bay as it is now. It would have generated a lot of additional space in the crew compartment. Was it to do with useable space in the payload or center of gravity?

It was to maximize the useable length of the payload bay. That was a big part of the reason why Columbia was used to launch Chandra, it was the only one it could fit into. Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. The high inclination orbit meant that the shuttle couldn't cary payloads heavy enough that they would take up the entire bay anyways.

By the way, I have seen drawings dating back to 1982 that show the basic design of the exterior airlock, so even back then, they were thinking about it.
Title: Re: Shuttle Q&A Part 5
Post by: trebloc on 06/20/2010 03:57 pm
Often wondered why the shuttle airlock was internal pre ISS and not placed in the payload bay as it is now. It would have generated a lot of additional space in the crew compartment. Was it to do with useable space in the payload or center of gravity?

It was to maximize the useable length of the payload bay. That was a big part of the reason why Columbia was used to launch Chandra, it was the only one it could fit into. Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. The high inclination orbit meant that the shuttle couldn't cary payloads heavy enough that they would take up the entire bay anyways.

By the way, I have seen drawings dating back to 1982 that show the basic design of the exterior airlock, so even back then, they were thinking about it.

Thank you, always wondered about that.
Title: Re: Shuttle Q&A Part 5
Post by: trebloc on 06/20/2010 03:57 pm
Often wondered why the shuttle airlock was internal pre ISS and not placed in the payload bay as it is now. It would have generated a lot of additional space in the crew compartment. Was it to do with useable space in the payload or center of gravity?

The former (assuming by "payload" you mean "payload bay").
Yes Payload bay,...my error.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 06/20/2010 07:01 pm
(...) Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. (...)
Does that mean that they actually flew some missions with two airlocks: with the newly installed external airlock and docking system, and with the internal airlock not yet removed? If so, which missions were they, and did they at least remove some parts of the internal airlock to save some weight?
Or do I missunderstand your statement?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/20/2010 07:10 pm
(...) Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. (...)
Does that mean that they actually flew some missions with two airlocks: with the newly installed external airlock and docking system, and with the internal airlock not yet removed? If so, which missions were they, and did they at least remove some parts of the internal airlock to save some weight?

Most of the Shuttle-Mir missions flew in this config.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/20/2010 07:59 pm
(...) Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. (...)
Does that mean that they actually flew some missions with two airlocks: with the newly installed external airlock and docking system, and with the internal airlock not yet removed? If so, which missions were they, and did they at least remove some parts of the internal airlock to save some weight?

Most of the Shuttle-Mir missions flew in this config.
More specifically, all the OV-104 Shuttle-Mir missions. When OV-103 and OV-105 made their dockings they both had the permanent ODS configuration used today.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/20/2010 08:04 pm
(...) Even after they developed the external airlock and docking system, they didn't remove the internal airlocks until they were committed to building the ISS. (...)
Does that mean that they actually flew some missions with two airlocks: with the newly installed external airlock and docking system, and with the internal airlock not yet removed? If so, which missions were they, and did they at least remove some parts of the internal airlock to save some weight?

Most of the Shuttle-Mir missions flew in this config.

Plus, all of the SpaceLab and SpaceHab flights from STS-9 to STS-107 flew with a component called a tunnel adaptor that functioned as an external airlock, so some of the Shuttle-Mir flights actually had 3 airlocks installed.
As far as parts being removed, I'm not sure, but I believe they usually removed the normal external hatch from the internal airlock at least. the 4 bar hinges are attached by pins so it realatively easy to remove between flights. That is also why the hatch is D-shaped.
Title: Re: Shuttle Q&A Part 5
Post by: Andy_MKST on 06/20/2010 09:09 pm
Other then the seats, what additional hardware was installed for the ejection system?

I assumed there must have been something to blow out the overhead panels and the pressure structure.

Does anyone know of anything?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/20/2010 09:23 pm

I assumed there must have been something to blow out the overhead panels and the pressure structure.


Yes, there was and the handle to do it was in the center console
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/21/2010 03:43 am

I assumed there must have been something to blow out the overhead panels and the pressure structure.


Yes, there was and the handle to do it was in the center console

Actually, that handle is for blowing out the outer 2 panels of the port-side, overhead window. The overhead hatches above each seat would have been linked to the seats ejection handles.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/23/2010 06:20 am
Hi all.

I was looking for some technical documents about the OBSS.

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/28/2010 11:46 pm


Yes, multiple times, but more frequently with the old GPCs than the current ones.

Old GPCs has me curious. I remember reading multiple posts on here about why dont they upgrade the computer hardware on the orbiters since they date back to a 1960/70 design. The response was understandably that the computers have proved themselves, and that to update them would be too costly. So, when were the GPC's replaced, and how are they better?
 

Early 1990s, went from the AP-101B to the AP-101S, binary-compatible with the old GPC, has the I/O Processor (IOP) integrated into the GPC case, twice as much memory (enables the entry software to be stored in an upper-memory archive for quick recall in case of emergency deorbit), solid state memory instead of core.

A bit of a late follow-up to this topic, but a short web article on the GPCs has just been posted by NASA:

http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/01/2010 07:58 pm
At what point in the approach phase do the guidance modes displayed on the HUD change (e.g. from OGS to FLARE, and FLARE to FINAL)? Are these based on altitude, or something else?

Hopefully the chart I attached will help answer your question rearding the Guidance/Nav modes on the space shuttle's HUD during the approach.  If not ask away and eventually someone with the answer will reply.

Begining on the HAC (Heading alignment Cone) the modes you will see are HDG (Heading), PRFNL (Pre-final), CAPT (Capture), OGS (outer glide slope), Flare, FNFL (Final Flare).

The right hand side of the chart shows the conditions that need to be satisfied to transition thru these modes.  FYI, "Gamma" refers to flight path angle.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 07/02/2010 12:09 pm
Thanks for the chart mkirk.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/02/2010 03:44 pm
Hi Mkirk.

where have  you found that chart?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/05/2010 08:10 pm
I know some people in the past have asked about the Stabilized Payload Deployment System(SPDS). This is a nice document I found on NTRS about it with rather nice and clear graphics: http://hdl.handle.net/2060/19890014524
Title: Re: Shuttle Q&A Part 5
Post by: dwfx on 07/07/2010 07:26 am
What is the maximum altitude that would be achieved during an RTLS abort? 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/07/2010 07:52 am
Usually a little higher isn't it? They loft the trajectory.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 07/07/2010 10:45 am
What is the maximum altitude that would be achieved during an RTLS abort? 

The diagram below shows a typical RTLS abort profile - the maximum altitude is about 430,000ft in this instance.  I don't know what the variation would be over the range of scenarios considered in the planning of this type of abort.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/07/2010 03:20 pm
Has it been ever used the Stabilized Payload Deployment System(SPDS)? I didn't know the existance of this mechanism before DaveS posted that link a couple of posts ago.

thanks.

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/07/2010 03:26 pm
Has it been ever used the Stabilized Payload Deployment System(SPDS)? I didn't know the existance of this mechanism before DaveS posted that link a couple of posts ago.


It was use on STS-  ;) ;) ;)
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 07/12/2010 03:38 pm
What is the contingency plan if the flash evaporator fails after reentry burn?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/12/2010 05:40 pm
What is the contingency plan if the flash evaporator fails after reentry burn?

Timing of the failure is everything (how long after TIG), but generally you would rely on the “Cold Soak” of the radiators, which was conducted prior to payload bay door closure, and use of the ammonia boilers to provide enough cooling thru landing.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 07/12/2010 06:32 pm
What is the contingency plan if the flash evaporator fails after reentry burn?
Timing of the failure is everything (how long after TIG), but generally you would rely on the “Cold Soak” of the radiators, which was conducted prior to payload bay door closure, and use of the ammonia boilers to provide enough cooling thru landing.
     In a contingency situation, would one risk shutting down an APU? (Or for early failure, delaying startup of #2 and #3?) I assume that's the biggest heat load. IIRC, the flight surfaces still travel at full speed with two APUs.
     -Alex
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 07/12/2010 08:40 pm
That was going to be my follow-up. Well played!
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/13/2010 06:11 pm
What is the contingency plan if the flash evaporator fails after reentry burn?
Timing of the failure is everything (how long after TIG), but generally you would rely on the “Cold Soak” of the radiators, which was conducted prior to payload bay door closure, and use of the ammonia boilers to provide enough cooling thru landing.
     In a contingency situation, would one risk shutting down an APU? (Or for early failure, delaying startup of #2 and #3?) I assume that's the biggest heat load. IIRC, the flight surfaces still travel at full speed with two APUs.
     -Alex

No, the orbiter's Auxialiary Power Units (APUs) would be operated as normal.  There should be sufficient cooling from the Radiator Cold Soak and (earlier) than normal operation of the Amonia Boiler [at entry interface as opposed to the nominal activation at ~120,000 feet].

APU/HYD cooling is really a separate animal entirely and not part of the ECLSS Freon Cooling Loops except for an interface thru the Hydraulic/Freon Heat Exchanger which is used to pick up heat [as opposed to rejecting it to the loop] from the loops to help keep the hydraulic fluid warm.

Mark Kirkman
(Space Shuttle Hugger)
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 07/14/2010 12:47 am
What is the contingency plan if the flash evaporator fails after reentry burn?
Timing of the failure is everything (how long after TIG), but generally you would rely on the “Cold Soak” of the radiators, which was conducted prior to payload bay door closure, and use of the ammonia boilers to provide enough cooling thru landing.
     In a contingency situation, would one risk shutting down an APU? (Or for early failure, delaying startup of #2 and #3?) I assume that's the biggest heat load. IIRC, the flight surfaces still travel at full speed with two APUs.
     -Alex

No, the orbiter's Auxialiary Power Units (APUs) would be operated as normal.  There should be sufficient cooling from the Radiator Cold Soak and (earlier) than normal operation of the Amonia Boiler [at entry interface as opposed to the nominal activation at ~120,000 feet].

APU/HYD cooling is really a separate animal entirely and not part of the ECLSS Freon Cooling Loops except for an interface thru the Hydraulic/Freon Heat Exchanger which is used to pick up heat [as opposed to rejecting it to the loop] from the loops to help keep the hydraulic fluid warm.

Mark Kirkman
(Space Shuttle Hugger)

When the APU's are up the hyd hx dumps heat (a lot actually) to the freon loops.  It's the other way on orbit.
Also the ammonia boilers are designed to be used below 100,000 ft, not sure if earlier activation would be effective. 
And finally it would take multiple failures for a total loss of FES cooling. 
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/14/2010 01:52 am
What is the contingency plan if the flash evaporator fails after reentry burn?
Timing of the failure is everything (how long after TIG), but generally you would rely on the “Cold Soak” of the radiators, which was conducted prior to payload bay door closure, and use of the ammonia boilers to provide enough cooling thru landing.
     In a contingency situation, would one risk shutting down an APU? (Or for early failure, delaying startup of #2 and #3?) I assume that's the biggest heat load. IIRC, the flight surfaces still travel at full speed with two APUs.
     -Alex

No, the orbiter's Auxialiary Power Units (APUs) would be operated as normal.  There should be sufficient cooling from the Radiator Cold Soak and (earlier) than normal operation of the Amonia Boiler [at entry interface as opposed to the nominal activation at ~120,000 feet].

APU/HYD cooling is really a separate animal entirely and not part of the ECLSS Freon Cooling Loops except for an interface thru the Hydraulic/Freon Heat Exchanger which is used to pick up heat [as opposed to rejecting it to the loop] from the loops to help keep the hydraulic fluid warm.

Mark Kirkman
(Space Shuttle Hugger)

When the APU's are up the hyd hx dumps heat (a lot actually) to the freon loops.  It's the other way on orbit.
Also the ammonia boilers are designed to be used below 100,000 ft, not sure if earlier activation would be effective. 
And finally it would take multiple failures for a total loss of FES cooling. 


Thanks!  I don’t want to be factually wrong but in my defense it has been almost 9 years since I have studied or practiced such scenarios. 

Yes it does make more sense that the HYD fluid is dumping heat during ascent/entry…those lines get pretty hot when the HYD Pumps are running.  Somehow I was always under the impression that the fluid bypassed the heat exchanger when the Freon Loops were at a specified temperature, but I really don’t know for sure. I have to plead system ignorance there and look it up in the books.

Yes this situation would be several failures deep but as for the original question however, procedurally the APUs are not a factor as I recall after the burn.  The cold soak and the ammonia boilers are what you will rely on thru landing.  On the other hand, failures that occur prior to the burn can be pretty diverse, and depending on the exact timing of the failure, can result in various power downs and/or use of the Contingency De-orbit procedures for “Loss of FES”.

As for the Ammonia Boilers; I was always taught that they could be used “off nominally” at Entry Interface (400,000 ft) if no “cold soak” was performed, or in the case we are discussing here, a total “Loss of FES”.  Nominally the Ammonia Boiler Controller is commanded by the BFS below ~120,000 feet.

FYI:  some of the details of this scenario should be in the Entry Pocket Checklist and the AESP (Ascent Entry Systems Procedures).   I’m pretty sure those are available on the public NASA FDF page for those who are interested.

Mark Kirkman
(Space Shuttle Hugger)


P.S.
Here is that Public FDF NASA page;

http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/19/2010 10:51 pm
Hi all.

In this period I’m trying to understand the mechanics of the rendezvous maneuver with the ISS. Now I understand in which way the shuttle gets in proximity of the station, it’s a matter of orbital mechanics, neither more nor less. What I can’t understand is what happen during the manual phase of the maneuver.

For example see the first picture attached. The shuttle is after MC4, that’s to say the manual phase has taken over. We have to get from point 1 to point 7. how does the shuttle get there? It’s my understanding that RCS is fired in the direction of travel (+X axis) in order to increase the velocity of the shuttle, lifting therefore the altitude slowing down at the same time. This because the lower the altitude and the faster the orbital speed. Is that correct? Or is there anything else that happen? Or maybe the RCS is fired downward (+ Z axis) so that the Shuttle goes up? Does it work from an orbital mechanics’ point of view?

After the R bar pitch maneuver the Shuttle goes in front the station for a V bar approach. With reference to the second picture attached, is my understanding that through continuous firings of the RCS system the altitude of the shuttle respect to the station’s altitude is constantly changed in order to continually slow down till when the station “hit” the shuttle itself. I’ll explain this better. Always with reference to the second picture, at point 8 the shuttle fires the RCS upwards so that it goes in a slightly lower orbit than the station. In this way the shuttle goes a little bit fastener. Then a second faring (point 9) this time downward, taking the shuttle in a slightly higher orbit than the station has, decreasing this time the speed. And the story goes in this way  till to docking. I’m trying to find another explanation but it seems to me the only one reasonable taken into account the principle of orbital mechanics.

Any help is very appreciated.

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/20/2010 01:33 am
Hi all.

In this period I’m trying to understand the mechanics of the rendezvous maneuver with the ISS. Now I understand in which way the shuttle gets in proximity of the station, it’s a matter of orbital mechanics, neither more nor less. What I can’t understand is what happen during the manual phase of the maneuver.

For example see the first picture attached. The shuttle is after MC4, that’s to say the manual phase has taken over. We have to get from point 1 to point 7. how does the shuttle get there? It’s my understanding that RCS is fired in the direction of travel (+X axis) in order to increase the velocity of the shuttle, lifting therefore the altitude slowing down at the same time. This because the lower the altitude and the faster the orbital speed. Is that correct? Or is there anything else that happen? Or maybe the RCS is fired downward (+ Z axis) so that the Shuttle goes up?

Both, and more. MC4 is a Lambert-targeted maneuver from the MC4 point (900 ft behind, 0 ft out-of-plane, and 1800 ft below nominally, but dispersions generally take the trajectory away from the nominal MC4 point) to the Rbar at 600 ft (0 ft behind, 0 ft out-of-plane, and 600 ft below), with a transfer time of 13 minutes. The delta-V for MC4 is therefore whatever Lambert comes up with. It is nominally around 2 fps in the orbiter +X body direction, but considering dispersions there may be Y and Z components present.

Quote
After the R bar pitch maneuver the Shuttle goes in front the station for a V bar approach. With reference to the second picture attached, is my understanding that through continuous firings of the RCS system the altitude of the shuttle respect to the station’s altitude is constantly changed in order to continually slow down till when the station “hit” the shuttle itself. I’ll explain this better. Always with reference to the second picture, at point 8 the shuttle fires the RCS upwards so that it goes in a slightly lower orbit than the station. In this way the shuttle goes a little bit fastener. Then a second faring (point 9) this time downward, taking the shuttle in a slightly higher orbit than the station has, decreasing this time the speed. And the story goes in this way  till to docking. I’m trying to find another explanation but it seems to me the only one reasonable taken into account the principle of orbital mechanics.

Any help is very appreciated.

Thanks

Davide


At this point the control of the orbiter is automatic in rotation, but entirely manual in translation. The orbiter rotates to the Vbar attitude at 0.13 deg/sec. When the attitude maneuver is complete, the orbiter stops rotating but the upward momentum of the orbiter causes ISS to drop in the centerline camera. The CDR then performs -X RCS translation as necessary to null the motion of ISS in the centerline camera. Generally the CDR uses heuristic knowledge of orbital mechanics to "bend" the curve to make a smooth arrival at the Vbar, but it's entirely manual - this is not a targeted maneuver.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/20/2010 05:24 am
Hi Jorge. Thanks for the explanation. I’d like however to ask you few other questions for clarifications.

1)   when MC4 is fired, the trajectory followed by the shuttle for getting from point 1 to point 7 (always with reference to first picture of my first post) is basically dictated by orbital mechanics, there is no manual action taken by the CDR. Is that correct? The CDR takes over manually only during the Vbar approach, right? The MC4 is computed by Mission Control or by shuttle onboard computers?
2)   During the Vbar approach, which is the physical phenomena thanks to which the shuttle can get till to the ISS? I mean, I understand that the CDR makes firings in order to stay centered with the ISS, but than why (from an orbital mechanical point of view) the shuttle slows down so that it can dock with the station? Or put it in another way, why does the shuttle goes toward the station rather then station keeping? If station keeping is required, how is performed and how you can resume the motion toward the station for docking?
3)   Given a inertial reference system, let’s say a system centered on the Earth and fixed, is the shuttle that goes toward the ISS or is the ISS going toward the Shuttle?
4)   For missions like STS-92 and STS-98 I suppose an Rbar approach has been used. In this case, was this Rbar approach the same of the Rbar approach used for the Shuttle-Mir missions?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/20/2010 06:23 am
Hi Jorge. Thanks for the explanation. I’d like however to ask you few other questions for clarifications.

1)   when MC4 is fired, the trajectory followed by the shuttle for getting from point 1 to point 7 (always with reference to first picture of my first post) is basically dictated by orbital mechanics, there is no manual action taken by the CDR. Is that correct? The CDR takes over manually only during the Vbar approach, right?

No, the CDR takes over manually after the MC4 burn is completed, and flies the rest of the approach manually. Only translation is performed manually; rotation is performed by the digital autopilot (DAP), except for a period during the RPM when the DAP is in free drift and the orbiter is not under active control at all.

In theory, MC4 places the orbiter on a trajectory that will reach 600 ft on the Rbar with no manual action required, but due to limitations of the sensors (rendezvous radar), navigation Kalman filter, Lambert guidance, and burn trim accuracy, some manual action is always required. At the very least, the theoretical post-MC4 trajectory is too fast at 600 ft for the RPM (-0.8 fps vs the -0.2 to -0.3 fps required), so typically some manual braking is required.

Quote
The MC4 is computed by Mission Control or by shuttle onboard computers?

Onboard. On the standard shuttle day-of-rendezvous trajectory, only the NH and NC burns are nominally ground-targeted. NCC, Ti, and MC1-4 are all computed onboard.

Quote
2)   During the Vbar approach, which is the physical phenomena thanks to which the shuttle can get till to the ISS? I mean, I understand that the CDR makes firings in order to stay centered with the ISS, but than why (from an orbital mechanical point of view) the shuttle slows down so that it can dock with the station? Or put it in another way, why does the shuttle goes toward the station rather then station keeping? If station keeping is required, how is performed and how you can resume the motion toward the station for docking?

Second question first. With the orbiter on the Vbar, the CG is near the orbital altitude of ISS. If the orbiter is traveling the same speed as ISS, it will remain at that altitude and naturally maintain a near-stable position. So to initiate stationkeeping, the CDR performs +Z (braking) until the rdot is zero. To resume the approach, the CDR performs -Z translations to establish the desired rdot.

Now, the first question. When the orbiter is approaching ISS on the Vbar (whether by the CDR performing -Z or by naturally "turning the corner" at Vbar arrival), the orbiter is traveling retrograde relative to ISS and is therefore flying too slow to remain at that orbital altitude, and will tend to drop. The CDR counters this tendency by performing +X translations, creating a series of small "hops" on the Vbar. The size of the hops is a matter of CDR preference. In theory it is possible to perform a Vbar approach using nothing but +X, and a few CDRs have approached that ideal, but total perfection is elusive, alas.

Typically at Vbar arrival, after "turning the corner", the orbiter is closing on ISS at around -0.2 fps. Nominal approach speed at docking is -0.1 fps. In theory that should require braking (+Z). But the orbiter +X RCS thrusters are canted to point through the CG, so +X translation also induces a bit of +Z. The CDR can take advantage of this by using the +X hops to "nibble away" at the approach speed and avoid braking.

Quote
3)   Given a inertial reference system, let’s say a system centered on the Earth and fixed, is the shuttle that goes toward the ISS or is the ISS going toward the Shuttle?

I'm not sure there's a meaningful answer to that question. In an inertial reference system, both vehicles are moving in independent orbits at 25000 fps. Which is moving toward the other depends on which relative reference system one chooses, though since ISS never performs rendezvous maneuvers, it makes more sense to think of the shuttle approaching the ISS rather than the other way around.

Quote
4)   For missions like STS-92 and STS-98 I suppose an Rbar approach has been used. In this case, was this Rbar approach the same of the Rbar approach used for the Shuttle-Mir missions?

STS-88, 96, 101, 106, and 92 performed -Rbar approaches, in which the orbiter flew 180 degrees around ISS and approached from above. This type of approach was not used during Shuttle-Mir.

STS-97 and 98 performed +Rbar approaches, with the orbiter approaching from below and yawing to a tail-forward orientation at 600 ft. This is essentially the same approach used for Shuttle-Mir missions STS-76, 79, 81, 84, and 86.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/20/2010 07:33 am
ok it's getting clearer and clearer, but I still have few questions, if you don't mind.

Quote
No, the CDR takes over manually after the MC4 burn is completed, and flies the rest of the approach manually. Only translation is performed manually; rotation is performed by the digital autopilot (DAP), except for a period during the RPM when the DAP is in free drift and the orbiter is not under active control at all.

The translation in performed along all the 3 axis or only along two axes? I mean translation along the Rbar shouldn't be controlled since the motion along this vector is due to the MC4 burn which, you've said, aims to take the shuttle to a position 600ft under the station.

Quote
When the orbiter is approaching ISS on the Vbar (whether by the CDR performing -Z or by naturally "turning the corner" at Vbar arrival), the orbiter is traveling retrograde relative to ISS and is therefore flying too slow to remain at that orbital altitude, and will tend to drop. The CDR counters this tendency by performing +X translations, creating a series of small "hops" on the Vbar. The size of the hops is a matter of CDR preference. In theory it is possible to perform a Vbar approach using nothing but +X, and a few CDRs have approached that ideal, but total perfection is elusive, alas.

so the orbiter is travelling retrograde relative to ISS because after having turned the corner the GC is higher then the GC's station and therefore the shuttle goes slower, right? why do you say that the shuttle is flying to slow to and tends to drop? in the diagram I posted I see a firing aimed to lower shuttle altitudine so it doesn't seem it tends to drop. what am I missing?

Quote
STS-88, 96, 101, 106, and 92 performed -Rbar approaches, in which the orbiter flew 180 degrees around ISS and approached from above. This type of approach was not used during Shuttle-Mir.

I didn't know of this kind of approach. which is the reason behind this kind of approach? is there anything peculiar respect to a +Rbar approach, or is just a mirror copy of a +Rbar approach?

OT: just for curiosity, are you a flight controller? how do you know all this things? I've been founding documents explaining in detail the mechanics of flight of the shuttle during the rendezvous and proximity operation but till now I haven't found what I really want.

Thanks again

ps: probably I'll have some questions about the undocking and flyaround, but later. For today it's enough. ;D
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/20/2010 09:55 pm
STS-88, 96, 101, 106, and 92 performed -Rbar approaches, in which the orbiter flew 180 degrees around ISS and approached from above. This type of approach was not used during Shuttle-Mir.

STS-97 and 98 performed +Rbar approaches, with the orbiter approaching from below and yawing to a tail-forward orientation at 600 ft. This is essentially the same approach used for Shuttle-Mir missions STS-76, 79, 81, 84, and 86.
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link (http://klabs.org/richcontent/general_technology/shuttle_rendezvous_with_hubble.pdf)) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.  It may just be that the memory of the LDEF rendezvous, with the orbiter flying out in front and then over the top, sticks out to me.

FWIW, I threw in a screen capture of a figure from another reference, in NTRS:
http://hdl.handle.net/2060/20070018243
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/21/2010 12:19 am
Quote
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.  It may just be that the memory of the LDEF rendezvous, with the orbiter flying out in front and then over the top, sticks out to me.

FWIW, I threw in a screen capture of a figure from another reference, in NTRS:
http://hdl.handle.net/2060/20070018243

I read both links you posted...they are both very good. One thing that I can't understand is the difference between inertial and Rbar approach.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/21/2010 12:58 am
Quote
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.  It may just be that the memory of the LDEF rendezvous, with the orbiter flying out in front and then over the top, sticks out to me.

FWIW, I threw in a screen capture of a figure from another reference, in NTRS:
http://hdl.handle.net/2060/20070018243

I read both links you posted...they are both very good. One thing that I can't understand is the difference between inertial and Rbar approach.
Jorge would definitely be a good person to take that...here's another interesting paper by John Goodman:
http://klabs.org/DEI/lessons_learned/shuttle/cr-2007-2136974.pdf

Based on more foggy memory, I was looking for whether or not a Ti Delay had ever needed to be used; the reference above notes one usage on STS-49, but has details on other historical events.  (Some of those early missions with lots of flight testing would be fun to go back and revisit, like 41-B.)
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 07/21/2010 03:23 pm
Can someone explain why the launch and entry helmets, last used on STS 51L, are still used today for training?
Thanks.

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-133/lores/jsc2010e075082.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/25/2010 10:24 pm
Quote
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.  It may just be that the memory of the LDEF rendezvous, with the orbiter flying out in front and then over the top, sticks out to me.

FWIW, I threw in a screen capture of a figure from another reference, in NTRS:
http://hdl.handle.net/2060/20070018243

I read both links you posted...they are both very good. One thing that I can't understand is the difference between inertial and Rbar approach.
Jorge would definitely be a good person to take that...here's another interesting paper by John Goodman:
http://klabs.org/DEI/lessons_learned/shuttle/cr-2007-2136974.pdf

Based on more foggy memory, I was looking for whether or not a Ti Delay had ever needed to be used; the reference above notes one usage on STS-49, but has details on other historical events.  (Some of those early missions with lots of flight testing would be fun to go back and revisit, like 41-B.)


STS-49 was the only Ti delay to date.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/25/2010 10:26 pm
Quote
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.  It may just be that the memory of the LDEF rendezvous, with the orbiter flying out in front and then over the top, sticks out to me.

FWIW, I threw in a screen capture of a figure from another reference, in NTRS:
http://hdl.handle.net/2060/20070018243

I read both links you posted...they are both very good. One thing that I can't understand is the difference between inertial and Rbar approach.

The difference is how the orbiter attitude is maintained. In an inertial approach the orbiter attitude is held fixed in an inertial frame of reference, while in an Rbar (or Vbar) approach the attitude is held fixed in the rotating LVLH frame of reference. In both cases the CDR maintains a fixed line-of-sight to the target along the orbiter's -Z axis (straight above the payload bay).
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/25/2010 10:36 pm
STS-88, 96, 101, 106, and 92 performed -Rbar approaches, in which the orbiter flew 180 degrees around ISS and approached from above. This type of approach was not used during Shuttle-Mir.

STS-97 and 98 performed +Rbar approaches, with the orbiter approaching from below and yawing to a tail-forward orientation at 600 ft. This is essentially the same approach used for Shuttle-Mir missions STS-76, 79, 81, 84, and 86.
Could be bad memory, but it seemed like there were more -R bar approaches prior to Shuttle-Mir...or were those inertial approaches?

I think STS-32 was the only -Rbar approach prior to STS-88. Would need to check, though.

There were several inertial approaches, including HST, EURECA, and some of the SPARTANs. These tended to be used for spacecraft that could not hold a grapple attitude in the LVLH frame of reference (which makes sense for astronomical spacecraft, since their intended targets are all inertial).

Quote
  One of the papers on rendezvous that I stumbled onto recently (on HST mission rendezvous, link (http://klabs.org/richcontent/general_technology/shuttle_rendezvous_with_hubble.pdf)) seems to suggest that the +R bar approaches started during Shuttle-Mir were then applied to at least some orbiter rendezvous approaches to other spacecraft, such as HST.

That's true. But the +Rbar approach was first tested on STS-66, with CRISTA-SPAS, before being used on Mir.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/25/2010 10:48 pm
ok it's getting clearer and clearer, but I still have few questions, if you don't mind.

Quote
No, the CDR takes over manually after the MC4 burn is completed, and flies the rest of the approach manually. Only translation is performed manually; rotation is performed by the digital autopilot (DAP), except for a period during the RPM when the DAP is in free drift and the orbiter is not under active control at all.

The translation in performed along all the 3 axis or only along two axes?

All three.

Quote
I mean translation along the Rbar shouldn't be controlled since the motion along this vector is due to the MC4 burn which, you've said, aims to take the shuttle to a position 600ft under the station.

In theory, yes. In practice, *some* control in all three axes is always required.

Quote

Quote
When the orbiter is approaching ISS on the Vbar (whether by the CDR performing -Z or by naturally "turning the corner" at Vbar arrival), the orbiter is traveling retrograde relative to ISS and is therefore flying too slow to remain at that orbital altitude, and will tend to drop. The CDR counters this tendency by performing +X translations, creating a series of small "hops" on the Vbar. The size of the hops is a matter of CDR preference. In theory it is possible to perform a Vbar approach using nothing but +X, and a few CDRs have approached that ideal, but total perfection is elusive, alas.

so the orbiter is travelling retrograde relative to ISS because after having turned the corner the GC is higher then the GC's station and therefore the shuttle goes slower, right?

No, it's based on relative velocity, not position. Retrograde means the relative velocity is directed toward the -Vbar. It's not strongly dependent on CG position.

Quote
why do you say that the shuttle is flying to slow to and tends to drop?

Because in order to remain in an orbit the same altitude as ISS, the orbiter needs to be traveling the same speed. That would imply zero relative velocity, so the orbiter would neither approach nor separate.

Quote
in the diagram I posted I see a firing aimed to lower shuttle altitudine so it doesn't seem it tends to drop. what am I missing?

You're missing the relative velocity part, which is not easy to depict directly on a plot of relative position but can be inferred from the direction of relative position over time. Prior to Vbar arrival, the orbiter is traveling mostly radially up and slightly retrograde. The firing you point out is intended not to lower the orbiter's altitude, but to null the radial up velocity so it doesn't shoot right through the Vbar.

Quote
Quote
STS-88, 96, 101, 106, and 92 performed -Rbar approaches, in which the orbiter flew 180 degrees around ISS and approached from above. This type of approach was not used during Shuttle-Mir.

I didn't know of this kind of approach. which is the reason behind this kind of approach?

To prevent the orbiter from blocking the line-of-sight between Russian ground stations and the antennas on ISS. Back in those days, before there was a crew aboard ISS, Russian commanding capability at docking was considered critical.

Quote
is there anything peculiar respect to a +Rbar approach, or is just a mirror copy of a +Rbar approach?

I assume one of those was supposed to be a -Rbar. The difference is that the rendezvous is always from below and behind and ends on a trajectory intersecting the +Rbar. So a +Rbar approach can be performed directly after the rendezvous, while a -Rbar approach requires a 180 degree flyaround to place the orbiter above the target.

Quote
OT: just for curiosity, are you a flight controller? how do you know all this things?

Did flight control up to 1995, have been an instructor since then.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/25/2010 10:52 pm
Thanks for the answers, Jorge.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/26/2010 10:13 am
Anyone know what the black upper wing chines on Columbia was? It doesn't look like to be HRSI tiles or black painted FRSI blankets.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 07/26/2010 10:32 pm
Anyone know what the black upper wing chines on Columbia was? It doesn't look like to be HRSI tiles or black painted FRSI blankets.

Your second guess was correct. It was a black thermal coating (paint) applied over the FRSI and white LRSI tiles with rollers. It was done prior to the OPF rollout for STS-1. Some of the thermal engineers thought it would help keep the hydraulic lines on the floor of the payload bay at a more constant temperature.
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 08/02/2010 04:06 am
Another question about the HUD: during the HDG phase, the HUD guidance diamond shows pitch and roll errors. During the PREFINAL and FLARE phases, when the fixed flight director symbol is replaced by the velocity vector symbol, does the guidance diamond show the target velocity vector, or does it still show pitch/roll errors?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/05/2010 02:27 pm
Does anyone know the the height and width of the ET intertank stringers? Both the main ones and the ones on the SRB Thrust Panels.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/08/2010 11:30 pm
Which component causes the GOX streams coming from the SSME nozzles and is there anything specific that triggers it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/09/2010 01:33 am
Which component causes the GOX streams coming from the SSME nozzles and is there anything specific that triggers it?

Purge valves.  The different purge sequences (1-4)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/10/2010 07:24 pm
Here's a question about something has bugged me for a while now.

In all the animations of ET sep from the the orbiter post-MECO the ET is always shown as pitching down relative to Earth and the orbiter. But here's the part that's bugging me: Just about every launch since RTF in 2005 with the ET Cam shows the ET as being stationary WRT to the horizon after sep.

So, is the animations wrong or is the ET really pitching down after ET sep?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/10/2010 07:39 pm
If the orbiter pitches up, wouldn't plume impingement from the FRCS force the ET to pitch down a bit?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/10/2010 07:47 pm
If the orbiter pitches up, wouldn't plume impingement from the FRCS force the ET to pitch down a bit?
Don't know, all that I know is that from the ET cam the horizon stays pretty much stationary the FOV, only slowly moving, I guess from any non-zeroed post-MECO rates.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/10/2010 10:45 pm
Here's a question about something has bugged me for a while now.

In all the animations of ET sep from the the orbiter post-MECO the ET is always shown as pitching down relative to Earth and the orbiter. But here's the part that's bugging me: Just about every launch since RTF in 2005 with the ET Cam shows the ET as being stationary WRT to the horizon after sep.

So, is the animations wrong or is the ET really pitching down after ET sep?

Almost all of the umbilcle well and post sep flight deck photos of the tank are almost side on to the tank. That means that a line from the camera (on the orbiter) is perpendicular to the longitudinal axis of the tank which would indicate that the tank is not pitching. Personanly, I think the tank stays basicly in the same attitude until the O2 vent valve blows.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/10/2010 10:58 pm
In all the animations of ET sep from the the orbiter post-MECO the ET is always shown as pitching down relative to Earth and the orbiter. But here's the part that's bugging me: Just about every launch since RTF in 2005 with the ET Cam shows the ET as being stationary WRT to the horizon after sep.
What is the vintage of the animation?  If it's old, as in flight test era, perhaps they were trying to depict the operation of the (no longer employed) tumble system.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/11/2010 12:56 am
Almost all of the umbilcle well and post sep flight deck photos of the tank are almost side on to the tank. That means that a line from the camera (on the orbiter) is perpendicular to the longitudinal axis of the tank which would indicate that the tank is not pitching.

If that were true that would mean the tank is pitching (down) since the orbiter is translating forward before and during those pictures.
Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 08/12/2010 05:39 pm
I originally posted this in the Exportation Alternatives section but didn't get an answer, thought I might get one here.



I saw this image

(http://www.nasaspaceflight.com/wp-content/uploads/2010/06/A8.jpg)

in the "Completed SD HLV assessment highlights low-cost post-shuttle solution"
http://www.nasaspaceflight.com/2010/06/sd-hlv-assessment-highlights-post-shuttle-solution/

I was wondering how much force is taken up by the nose tripod of the Shuttle/ET connection, and how much the ET would have to be reengineered to make this work? Is it really a practical low cost alternative?



Thank you for your time,

Steve
Title: Re: Shuttle Q&A Part 5
Post by: parham55 on 08/12/2010 08:55 pm
I originally posted this in the Exportation Alternatives section but didn't get an answer, thought I might get one here.



I saw this image

(http://www.nasaspaceflight.com/wp-content/uploads/2010/06/A8.jpg)

in the "Completed SD HLV assessment highlights low-cost post-shuttle solution"
http://www.nasaspaceflight.com/2010/06/sd-hlv-assessment-highlights-post-shuttle-solution/

I was wondering how much force is taken up by the nose tripod of the Shuttle/ET connection, and how much the ET would have to be reengineered to make this work? Is it really a practical low cost alternative?



Thank you for your time,

Steve

I'm sure someone will chime in with more detailed information but the short answer is, not much. You'll find a bit more information here: http://forum.nasaspaceflight.com/index.php?topic=10600.msg331064#msg331064
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 08/14/2010 05:47 pm
The bipod mount for the nose is only for side (yaw) loads. No structural (or thrust)  loads,.....as I just now saw the linkparham55 posted.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 08/17/2010 12:56 am
The way I understand it the rear mounts take all of the thrust, the nose bipod just stabilizes the nose of the orbiter.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 08/17/2010 04:55 pm
I heard many years ago from a long forgotten source that the parachute door of STS-95 fell off during launch and nearly hit one of the H2 lines on one of the SSME's (No. 1, IIRC). Can I get confirmation about that please?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/17/2010 05:08 pm
I heard many years ago from a long forgotten source that the parachute door of STS-95 fell off during launch and nearly hit one of the H2 lines on one of the SSME's (No. 1, IIRC). Can I get confirmation about that please?
It did hit the nozzle of the center engine:
http://www.jsc.nasa.gov/news/columbia/anomaly/STS95.pdf

"During Main Engine ignition at approximately T-5 seconds, ground-based photography showed the drag chute door detach from the Orbiter and impact the rim of SSME bell #1 during its downward descent."

A sped up clip of it can be downloaded/viewed here:
http://spaceflight.nasa.gov/gallery/video/shuttle/sts-95/mpg/95d01c7.mpg

Wouldn't be surprised if it's on YouTube, also.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 08/17/2010 05:15 pm
Wow, thanks for the quick reply, Philip! Much obliged.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 08/17/2010 06:06 pm
While thinking about it...can I get a rundown of What-if scenarios? What if it did hit the H2 line? Would the valve to that cooling loop be closed intime to prevent anything worse to happen? RUD? RTLS? TAL?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/17/2010 06:24 pm
While thinking about it...can I get a rundown of What-if scenarios? What if it did hit the H2 line? Would the valve to that cooling loop be closed intime to prevent anything worse to happen? RUD? RTLS? TAL?
See STS-93. Three coolant tubes were ruptured on the center engine during ignition and H2 leaked leading to a LOX LLCO some 0.15 seconds prior to targeted MECO.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 08/17/2010 07:42 pm
Ah, I hadn't even thought of that drama. Thanks again.
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/18/2010 11:49 pm
I have an airlock question here.

On STS-96/2A.1, STS-101/2A.2a, and STS-106/2A.2b, how did the crews perform spacewalks?  The LDM was in the payload bay and the access tunnel connected to the aft hatch of the ODS where spacewalks were usually carried out when docked to the ISS.  Of course, the zenith hatch was connected to the PMAs.

The logical explanation, of course, would be if the spacewalks were to be conducted out the SPACEHAB transfer tunnel, however the ICC was present on each of these three missions above the chamber, so no spacewalking hatch could be added.

Mind you, Quest was installed on 7A (STS-104) in 2001, well after the last of the three aforementioned missions.

How did the six astronauts (Barry, Jernigan, Lu, Malenchenko, Voss, and Williams) exit the station on these missions?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/19/2010 12:33 am
I have an airlock question here.

On STS-96/2A.1, STS-101/2A.2a, and STS-106/2A.2b, how did the crews perform spacewalks?  The LDM was in the payload bay and the access tunnel connected to the aft hatch of the ODS where spacewalks were usually carried out when docked to the ISS.  Of course, the zenith hatch was connected to the PMAs.

The logical explanation, of course, would be if the spacewalks were to be conducted out the SPACEHAB transfer tunnel, however the ICC was present on each of these three missions above the chamber, so no spacewalking hatch could be added.

Mind you, Quest was installed on 7A (STS-104) in 2001, well after the last of the three aforementioned missions.

How did the six astronauts (Barry, Jernigan, Lu, Malenchenko, Voss, and Williams) exit the station on these missions?

The ICC was mounted aft of the Tunnel Adapter that was used for the EVAs
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/19/2010 01:32 am
I have an airlock question here.

On STS-96/2A.1, STS-101/2A.2a, and STS-106/2A.2b, how did the crews perform spacewalks?  The LDM was in the payload bay and the access tunnel connected to the aft hatch of the ODS where spacewalks were usually carried out when docked to the ISS.  Of course, the zenith hatch was connected to the PMAs.

The logical explanation, of course, would be if the spacewalks were to be conducted out the SPACEHAB transfer tunnel, however the ICC was present on each of these three missions above the chamber, so no spacewalking hatch could be added.

Mind you, Quest was installed on 7A (STS-104) in 2001, well after the last of the three aforementioned missions.

How did the six astronauts (Barry, Jernigan, Lu, Malenchenko, Voss, and Williams) exit the station on these missions?

The ICC was mounted aft of the Tunnel Adapter that was used for the EVAs

Allright, thanks – Just for curiosity, the shortened version of that tunnel cannot feature an airlock when the ICC is attached, correct?

Lastly, what hatches need to be closed to operate the airlock in the tunnel while docked to ISS (would station hatches need to be closed?)
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/19/2010 03:46 pm
Allright, thanks – Just for curiosity, the shortened version of that tunnel cannot feature an airlock when the ICC is attached, correct?

Lastly, what hatches need to be closed to operate the airlock in the tunnel while docked to ISS (would station hatches need to be closed?)

The tunnel length is driven by the location of the spacehab module wich is driven in turn by CG requirements. If the spacehab module was mounted forward for some reason, the ICC would simply be mounted behind it.

They would never have flown a SpaceHab or SpaceLab module without the tunnel adaptor to act as an airlock. It would be required in the case of a late EVA to manually close the playload bay doors. You couldn't use to ODS hatch of the external airlock because A) they would never risk the suits around the ODS mechanism and B) there wouldn't be enough room to get back in after the doors were closed.

The Tunnel Adaptor had internal hatches at either end to minimize the air lost when cycling it. Those would have been the only hatches that needed to be closed.
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/21/2010 01:45 pm
Allright, thanks – Just for curiosity, the shortened version of that tunnel cannot feature an airlock when the ICC is attached, correct?

Lastly, what hatches need to be closed to operate the airlock in the tunnel while docked to ISS (would station hatches need to be closed?)

The tunnel length is driven by the location of the spacehab module wich is driven in turn by CG requirements. If the spacehab module was mounted forward for some reason, the ICC would simply be mounted behind it.

They would never have flown a SpaceHab or SpaceLab module without the tunnel adaptor to act as an airlock. It would be required in the case of a late EVA to manually close the playload bay doors. You couldn't use to ODS hatch of the external airlock because A) they would never risk the suits around the ODS mechanism and B) there wouldn't be enough room to get back in after the doors were closed.

The Tunnel Adaptor had internal hatches at either end to minimize the air lost when cycling it. Those would have been the only hatches that needed to be closed.

How long are the transfer tunnels (long and short), just out of curiosity?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/21/2010 07:02 pm


How long are the transfer tunnels (long and short), just out of curiosity?

They vary.  22 inches to several feet
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/22/2010 12:53 am


How long are the transfer tunnels (long and short), just out of curiosity?

They vary.  22 inches to several feet

22 inches in length is enough for an airlock?  I can't find data on transfer tunnels anywhere (googled them of course, etc.), but the short SPACEHAB tunnel looks at shortest 5 feet – though I am bad at estimation.  So essentially, you're saying that the transfer tunnel is 22 inches LONG, or in Diameter?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/22/2010 02:14 am


How long are the transfer tunnels (long and short), just out of curiosity?

They vary.  22 inches to several feet

22 inches in length is enough for an airlock?  I can't find data on transfer tunnels anywhere (googled them of course, etc.), but the short SPACEHAB tunnel looks at shortest 5 feet – though I am bad at estimation.  So essentially, you're saying that the transfer tunnel is 22 inches LONG, or in Diameter?
The Airlock is in the tunnel adaptor, not the tunnel itself. The adaptor is about 50" in inside diameter while the tunnel is about 40"

Here are a couiple of photos of the adaptor from the early Shuttle/Mir flights where the external airlock was mounted in Bay 3 and the Adaptor was mounted between the crew compartment and the EA. On later flights, this was reversed.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/22/2010 02:55 am
The current certified limit loads on the SLWT forward bipod are (ref. page N-50 of the SDHLLV Assessment, NSTS 60583 report): FTO1 = +96.4/-127.8 kips (1 kip = 1000 lbs), and FTO2 = +64.5/-70.9 kips.  FTO1 is perpendicular to the ET, and FTO2 is lateral.  Positive FTO1 is tensile, and negative is compressive on the bipod apex.  Positive FTO2 is to the right.  Per the above report, there is significant excess structural capability (at least +25 percent, including a 1.4 safety factor) in the current bipod hardware.

The various struts are arranged to provide a "statically determinate" interface connecting the ET and Orbiter.  This means that there are no internal forces generated, either when the ET and Orbiter are mated, or when the cryoprops are loaded (which cause the ET to shrink).  In other words, the ET doesn't distort the Orbiter, and vice versa.

The back-right tripod on the ET is (ideally) a "pinned" attachment point, where all three displacements are constrained, and all three rotations are free.  The back-left bipod is hinged to allow the Orbiter attachment point to expand/contract laterally relative to the ET, and the forward bipod is also hinged to allow the Orbiter attachment point to expand/contract axially relative to the ET. 

As others have noted, the thrust loads from the Orbiter enter the ET through the angled thrust struts at the back of the ET.  The LH2 tank skins are seriously thick (up to 0.55 inches) back there to distribute these stresses.  The minimum LH2 tank skin thickness is 0.089 inches, sized by the internal pressure loads.

F=ma

I originally posted this in the Exportation Alternatives section but didn't get an answer, thought I might get one here.

I saw this image (clipped)

in the "Completed SD HLV assessment highlights low-cost post-shuttle solution" (clipped)

I was wondering how much force is taken up by the nose tripod of the Shuttle/ET connection, and how much the ET would have to be reengineered to make this work? Is it really a practical low cost alternative?

Thank you for your time,

Steve
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/22/2010 03:14 am


How long are the transfer tunnels (long and short), just out of curiosity?

They vary.  22 inches to several feet

22 inches in length is enough for an airlock?  I can't find data on transfer tunnels anywhere (googled them of course, etc.), but the short SPACEHAB tunnel looks at shortest 5 feet – though I am bad at estimation.  So essentially, you're saying that the transfer tunnel is 22 inches LONG, or in Diameter?
The Airlock is in the tunnel adaptor, not the tunnel itself. The adaptor is about 50" in inside diameter while the tunnel is about 40"

Here are a couiple of photos of the adaptor from the early Shuttle/Mir flights where the external airlock was mounted in Bay 3 and the Adaptor was mounted between the crew compartment and the EA. On later flights, this was reversed.

Okay, so in place of the tunnel itself, you CAN use just the tunnel adaptor to connect the ODS to the SPACEHAB itself, but diameter aside it's a whole 5 feet in length for the tunnel adaptor?
Title: Re: Shuttle Q&A Part 5
Post by: Danderman on 08/22/2010 05:22 am
Here are a couple of photos of the adaptor from the early Shuttle/Mir flights where the external airlock was mounted in Bay 3 and the Adaptor was mounted between the crew compartment and the EA. On later flights, this was reversed.

This begs the question of why the Adapter/APAS was not mounted as close to the SpaceHAB module as possible, to put the APAS closer to the vehicle c/g.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2010 01:03 pm

This begs the question of why the Adapter/APAS was not mounted as close to the SpaceHAB module as possible, to put the APAS closer to the vehicle c/g.


many reasons.  To save room.  An ICC could be mounted over the tunnel.  Also, there was only one long tunnel segment, not many choices in layout
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2010 01:08 pm

Okay, so in place of the tunnel itself, you CAN use just the tunnel adaptor to connect the ODS to the SPACEHAB itself, but diameter aside it's a whole 5 feet in length for the tunnel adaptor?

No, there are many reasons why
My point, due to spacing and the cargo attach points in the payload bay, a tunnel of around 22 inches was required.

The module was required to be as far back in the bay as possible for CG reasons.
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/22/2010 02:46 pm

Okay, so in place of the tunnel itself, you CAN use just the tunnel adaptor to connect the ODS to the SPACEHAB itself, but diameter aside it's a whole 5 feet in length for the tunnel adaptor?

No, there are many reasons why
My point, due to spacing and the cargo attach points in the payload bay, a tunnel of around 22 inches was required.

The module was required to be as far back in the bay as possible for CG reasons.

…So it's ~2 feet long and 50 inches in diameter?  Seems awful short because an EMU spacesuit is way larger than 22 inches :)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2010 02:52 pm

Okay, so in place of the tunnel itself, you CAN use just the tunnel adaptor to connect the ODS to the SPACEHAB itself, but diameter aside it's a whole 5 feet in length for the tunnel adaptor?

No, there are many reasons why
My point, due to spacing and the cargo attach points in the payload bay, a tunnel of around 22 inches was required.

The module was required to be as far back in the bay as possible for CG reasons.

…So it's ~2 feet long and 50 inches in diameter?  Seems awful short because an EMU spacesuit is way larger than 22 inches :)

I am only talking tunnel, not tunnel adapter and ODS.  A tunnel adapter is always required with a Spacehab module.  The tunnel is the remaining straight section.
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/22/2010 03:05 pm

Okay, so in place of the tunnel itself, you CAN use just the tunnel adaptor to connect the ODS to the SPACEHAB itself, but diameter aside it's a whole 5 feet in length for the tunnel adaptor?

No, there are many reasons why
My point, due to spacing and the cargo attach points in the payload bay, a tunnel of around 22 inches was required.

The module was required to be as far back in the bay as possible for CG reasons.

…So it's ~2 feet long and 50 inches in diameter?  Seems awful short because an EMU spacesuit is way larger than 22 inches :)

I am only talking tunnel, not tunnel adapter and ODS.  A tunnel adapter is always required with a Spacehab module.  The tunnel is the remaining straight section.

Okay, alright, I think I understand what you are saying now.  I attached a graphic of the payload bay as visible from the station during the STS-118 rendezvous sequence, and I added numbers representing the payloads.  Please tell me if I am correct:

1). ODS
2). SPACEHAB Tunnel Adaptor (which is about 5 feet?)
3). SPACEHAB Short Tunnel (~22 inches)
4). SPACEHAB Logistics Single Module (LSM)
5). S5 Truss short spacer
6). External Stowage Platform (ESP)-3
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/22/2010 03:20 pm

Okay, alright, I think I understand what you are saying now.  I attached a graphic of the payload bay as visible from the station during the STS-118 rendezvous sequence, and I added numbers representing the payloads.  Please tell me if I am correct:

1). ODS
2). SPACEHAB Tunnel Adaptor (which is about 5 feet?)
3). SPACEHAB Short Tunnel (~22 inches)
4). SPACEHAB Logistics Single Module (LSM)
5). S5 Truss short spacer
6). External Stowage Platform (ESP)-3

Yes, except the tunnel adaptor is about 10 to 12 feet long not 5.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/22/2010 06:31 pm
How are the SRM segment stacking order determined? I've always thought that there's no real order, they just take one and stack it. But recently I have gotten reason to question this.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2010 07:36 pm


1). ODS
2). SPACEHAB Tunnel Adaptor (which is about 5 feet?)
3). SPACEHAB Short Tunnel (~22 inches)
4). SPACEHAB Logistics Single Module (LSM)
5). S5 Truss short spacer
6). External Stowage Platform (ESP)-3

That tunnel is not the 22 inch one, which was used on the first few missions without ODS

Also, it is SPACELAB Tunnel Adaptor
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/22/2010 07:52 pm


1). ODS
2). SPACEHAB Tunnel Adaptor (which is about 5 feet?)
3). SPACEHAB Short Tunnel (~22 inches)
4). SPACEHAB Logistics Single Module (LSM)
5). S5 Truss short spacer
6). External Stowage Platform (ESP)-3

That tunnel is not the 22 inch one, which was used on the first few missions without ODS

Also, it is SPACELAB Tunnel Adaptor

Okay, so how many tunnels are there, when were they used, and which one was used for STS-118?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2010 07:59 pm

Okay, so how many tunnels are there, when were they used, and which one was used for STS-118?

There might have been 4 different tunnels.

STS-107 had a unique one

MIR/ISS

the early missions

 and the one for last two missions
Title: Re: Shuttle Q&A Part 5
Post by: orbiter62995 on 08/26/2010 04:08 am

Okay, so how many tunnels are there, when were they used, and which one was used for STS-118?

There might have been 4 different tunnels.

STS-107 had a unique one

MIR/ISS

the early missions

 and the one for last two missions

Thanks, I finally have THAT settled.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/29/2010 02:22 am
A question for anyone out there with more machining experience than I:  how much can you get for aluminium-lithium scraps?  I found out that the shuttle ET's liquid H2 tank panels generate over 74 tons of al-li chips when they're made.  So how much are all these bits and pieces worth?  Can they be remelted back into al-li ingots, or are there too many impurities/contaminants from the machining?
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/29/2010 03:11 pm
This is something that has me puzzled. What are those holes in the circled area in the attached photo? The orbiter is Atlantis during her transfer from Palmdale to Edwards for the delivery trip to KSC.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 08/29/2010 09:33 pm
I think I recall hearing that those were vents of some sort but not sure.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/29/2010 10:59 pm
I think I recall hearing that those were vents of some sort but not sure.

Well, they aren't listed in any documents I have come across. The only deactivated vents are vents 4 and 7 on the mid-body, none on the aft compartment.

They also only seem to exist on the Centaur capable orbiters(Challenger, Discovery and Atlantis). And once the Centaur got canceled these holes disappeared as fast as the RBUS at both pads did. So this leads me to theorize that they're part of the Centaur capability modifications done to the orbiters.

It would be great if someone could confirm this.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 08/30/2010 12:27 am
How are the SRM segment stacking order determined? I've always thought that there's no real order, they just take one and stack it. But recently I have gotten reason to question this.

I am sure someone smarter than me can give the best answer, but to my knowledge they are stacked to make propellant grains and casting sets.  Meaning, you want to make sure you have the same propellant on both sides since some propellant can burn faster or stronger than others.  Matching the sets prevents asymmetric thrust.

Hope that helps!!! 

Jeff
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/30/2010 12:36 am
How are the SRM segment stacking order determined? I've always thought that there's no real order, they just take one and stack it. But recently I have gotten reason to question this.

I am sure someone smarter than me can give the best answer, but to my knowledge they are stacked to make propellant grains and casting sets.  Meaning, you want to make sure you have the same propellant on both sides since some propellant can burn faster or stronger than others.  Matching the sets prevents asymmetric thrust.

Hope that helps!!! 

Jeff
I know that, but I was more curious on the stacking order of the actual segments in the VAB.

Like what makes them stack for example LA, RA, LAC, LFC, LF, RAC, RFC for one mission but then go all the left segments then all the right segments before topping the motors with the FWD Skirt Assys for another.

Doesn't seem to be any logic or reason in it, just taking them from the Surges and stacking them.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 09/02/2010 09:22 am
It would be great if someone could confirm this.

Good deduction. Those are the receptacles for the RBUS hydrogen umbilical foot fittings. Very similar to the orbiters T-0 umbilical, just smaller. If you look further to the rear towards the base heat shield you will see another similar opening, that's one of the fittings for the orbiters umbilical. Draw a straight line up from that opening and you will see the other fitting, mounted externally on a bracket due to the slope of the base heat shield. It doesn't show up too well in that photo but I'm sure you can find another shot that shows it in more detail.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/02/2010 09:35 am
It would be great if someone could confirm this.

Good deduction. Those are the receptacles for the RBUS hydrogen umbilical foot fittings. Very similar to the orbiters T-0 umbilical, just smaller. If you look further to the rear towards the base heat shield you will see another similar opening, that's one of the fittings for the orbiters umbilical. Draw a straight line up from that opening and you will see the other fitting, mounted externally on a bracket due to the slope of the base heat shield. It doesn't show up too well in that photo but I'm sure you can find another shot that shows it in more detail.
Thanks. So the actual umbilical ports on the orbiter is in the Midbody Payload Umbilical well that is covered by the last "S" in "States"?

Any photos of the umbilical ports or the RBUS carrier plate?
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 09/04/2010 01:32 am
The umbilicals and plumbing were removed long ago, before I started working in the midbody. But yes, they were in that panel. I couldn't find any photos but I did find a link to a technical paper on the RBUS here:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19830016629_1983016629.pdf

Hope that helps.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/04/2010 10:11 pm
Anyone know the equatorial diameter of the EO-2/EO-3 balls on the ET? Also, what color do they have? Some photos show it as mix between gold and bronze, while other photos show it as a gray metal look.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 09/05/2010 12:47 am
Anyone know the equatorial diameter of the EO-2/EO-3 balls on the ET? Also, what color do they have? Some photos show it as mix between gold and bronze, while other photos show it as a gray metal look.

Here is a description of the EO-2 & EO-3 inteface to the orbiter:

ET/Orbiter Aft Left Attachment
[...] The direct physical interface with the Orbiter is formed by a large hemispherical surface at the bipod apex that engages with the Orbiter socket. Attachment hardware is Orbiter-provided, and consists of a 2.5-inch diameter tension bolt coupled with a frangible nut housed in the Orbiter.

The forged aluminum-alloy ball interface fitting, weighing approximately 530 pounds, joins the tubular thrust strut and the I-section vertical strut to provide the Orbiter interfacing hemispherical surface. This surface is machined to a 5.275-inches spherical radius, but is flattened 4- 1/2 inches- above the spherical center to compensate for an Orbiter protuberance. A Z-axis bore of 2.875-inches diameter extends 1.5 inches below this flattened surface, where it enlarges to a 5.5-inch diameter and continues through the base of the fitting. This 5.5-inch diameter cavity allows installation of the interface bolt and associated torquing tool.


I don't have any information on color.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/05/2010 02:04 pm
Anyone know the equatorial diameter of the EO-2/EO-3 balls on the ET? Also, what color do they have? Some photos show it as mix between gold and bronze, while other photos show it as a gray metal look.

Here is a description of the EO-2 & EO-3 inteface to the orbiter:

ET/Orbiter Aft Left Attachment
[...] The direct physical interface with the Orbiter is formed by a large hemispherical surface at the bipod apex that engages with the Orbiter socket. Attachment hardware is Orbiter-provided, and consists of a 2.5-inch diameter tension bolt coupled with a frangible nut housed in the Orbiter.

The forged aluminum-alloy ball interface fitting, weighing approximately 530 pounds, joins the tubular thrust strut and the I-section vertical strut to provide the Orbiter interfacing hemispherical surface. This surface is machined to a 5.275-inches spherical radius, but is flattened 4- 1/2 inches- above the spherical center to compensate for an Orbiter protuberance. A Z-axis bore of 2.875-inches diameter extends 1.5 inches below this flattened surface, where it enlarges to a 5.5-inch diameter and continues through the base of the fitting. This 5.5-inch diameter cavity allows installation of the interface bolt and associated torquing tool.


I don't have any information on color.
Thanks for information. For now I'll go with the metallic color.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 09/10/2010 05:17 am
Can some one explain what the "Scottish flag" looking things near to the nose of the orbiter?


Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/10/2010 06:27 am
Can some one explain what the "Scottish flag" looking things near to the nose of the orbiter?
Just a cover for the purge/checkout and servicing panels for the FRCS module.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/11/2010 10:59 am
Some very nice photos of the EO2/EO3 aft interface hardware in Chris's article on the Discovery/STS-133 soft-mate issue.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 09/13/2010 01:59 am
while we are talking about things during rollover, i have noticed there is some tape on the bottom of the wings.  it is always toward the wingtip and is shaped in a squarish pattern that comes to a point (hope that made sense).  Anyone know what THAT is for??  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 09/14/2010 03:22 am
while we are talking about things during rollover, i have noticed there is some tape on the bottom of the wings.  it is always toward the wingtip and is shaped in a squarish pattern that comes to a point (hope that made sense).  Anyone know what THAT is for??  Thanks!

That outlines areas where it is safe to push on the wing, if need be to prevent any accidental contact between the orbiter and the VAB platforms while it's being lowered down into position for mating to the ET.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/14/2010 07:02 am
While we're still on the subject of rollovers, how is the aft secured to the OTS? Or is the orbiter aft just resting on the ball joints on the OTS?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/14/2010 05:25 pm
Does anyone know what the yellow electronics(?) box in the screenshot is used for?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 09/14/2010 07:31 pm
Does anyone know what the yellow electronics(?) box in the screenshot is used for?

Do you have the contex of the photo? All I can tell is that there is a ET in the vertical position in the background. Is the photo from Michoud, a checkout cell in the VAB or a stacking bay?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/14/2010 07:42 pm
Does anyone know what the yellow electronics(?) box in the screenshot is used for?

Do you have the context of the photo? All I can tell is that there is a ET in the vertical position in the background. Is the photo from Michoud, a checkout cell in the VAB or a stacking bay?
H/B-4 ET checkout cell. The ET is ET-137 being prepared for lift-to-mate with the SRBs in H/B-3.
Title: Re: Shuttle Q&A Part 5
Post by: bidptl on 09/15/2010 02:46 pm
I know thi smust have been covered before but it would take me too long to dig it out from the 5 parts of Q&A.

is there a reason why payload are installed at the launch pad and not at the OPF before rollover and mate, or at the VAB before rollout ?

thanks in advance ....
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/15/2010 02:56 pm
I know thi smust have been covered before but it would take me too long to dig it out from the 5 parts of Q&A.

is there a reason why payload are installed at the launch pad and not at the OPF before rollover and mate, or at the VAB before rollout ?

thanks in advance ....

A. VAB doesn't have a clean room
b.  the DOD had a requirement for late as possible installation.
c.  Most payloads like a vertical orientation
d.  The payload would spend months in the orbiter if installed at the OPF
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 09/15/2010 09:06 pm
I know thi smust have been covered before but it would take me too long to dig it out from the 5 parts of Q&A.

is there a reason why payload are installed at the launch pad and not at the OPF before rollover and mate, or at the VAB before rollout ?

thanks in advance ....

A. VAB doesn't have a clean room
b.  the DOD had a requirement for late as possible installation.
c.  Most payloads like a vertical orientation
d.  The payload would spend months in the orbiter if installed at the OPF

And another REALLY big reason, you do not want to lift an expensive payload and an expensive orbiter together.  Not only for lift-crane mass reasons but also in the event something happens you don't damage both.
Title: Re: Shuttle Q&A Part 5
Post by: bidptl on 09/16/2010 02:14 am
ar see ... many thanks Jim and OV106. Appreciated.
Title: Re: Shuttle Q&A Part 5
Post by: Space Pete on 09/17/2010 12:42 pm
I know thi smust have been covered before but it would take me too long to dig it out from the 5 parts of Q&A.

is there a reason why payload are installed at the launch pad and not at the OPF before rollover and mate, or at the VAB before rollout ?

thanks in advance ....

Also, some payloads require power from the Orbiter (such as the MPLM, which takes power through the ROEU). If the payloads were installed in the OPF, then the Orbiter would have to power them for months before liftoff.

Plus, all the perishable goods (called late stow items) inside the MPLM would rot away before launch.
Title: Re: Shuttle Q&A Part 5
Post by: MBK004 on 09/26/2010 07:36 am
I have noticed that Atlantis has never carried an MPLM.  Is there a technical reason why not or was it just luck of the draw?  Thanks.
Pure luck of the draw, she was configured and even rolled over the the VAB twice for STS-114 pre-Columbia and STS-121 before it was reassigned to Discovery.
Title: Re: Shuttle Q&A Part 5
Post by: Endeavour126 on 09/29/2010 06:54 pm
Is there anybody knows how long it takes to traslate the payload from the changeout room to payload bay?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/29/2010 07:23 pm
Is there anybody knows how long it takes to traslate the payload from the changeout room to payload bay?

Minutes
Title: Re: Shuttle Q&A Part 5
Post by: dave k on 09/30/2010 01:58 pm
I have been looking at this every day for awhile on the KSC video feeds. Does anyone have a hi res photo of this wall?
Title: Re: Shuttle Q&A Part 5
Post by: Endeavour126 on 09/30/2010 04:15 pm
Is there anybody knows how long it takes to traslate the payload from the changeout room to payload bay?

Minutes

Thank you Jim.
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 10/02/2010 05:23 pm
Why does Harwood and/or NASA say the shuttle launches from a starting altitude of 23 ft below sea level?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/02/2010 08:18 pm
Why does Harwood and/or NASA say the shuttle launches from a starting altitude of 23 ft below sea level?

This is a footnote from a table of ascent data produced by NASA in one of their "Math and Science @ Work" publications:

"Note: Notice from the table that the altitude is negative at liftoff. Zero altitude can be described as a specific distance from the center of the Earth. Since the Earth is not perfectly spherical the location of the launch just happens to be below this specified point. Also, because this is a calculated number, some degree of error may be present."

http://www.nasa.gov/pdf/466711main_AP_ST_ShuttleAscent.pdf
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 10/03/2010 11:34 am
Why does Harwood and/or NASA say the shuttle launches from a starting altitude of 23 ft below sea level?

This is a footnote from a table of ascent data produced by NASA in one of their "Math and Science @ Work" publications:

"Note: Notice from the table that the altitude is negative at liftoff. Zero altitude can be described as a specific distance from the center of the Earth. Since the Earth is not perfectly spherical the location of the launch just happens to be below this specified point. Also, because this is a calculated number, some degree of error may be present."

http://www.nasa.gov/pdf/466711main_AP_ST_ShuttleAscent.pdf

Quote
Velocity is defined as the rate of change of the vertical position.

The resulting orbital velocity is horizontal, not vertical.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2010 04:39 am
How is the AoA maintained through entry? Is it only done by the elevons or does the bodyflap as I suspect help out?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/04/2010 11:03 am
How is the AoA maintained through entry? Is it only done by the elevons or does the bodyflap as I suspect help out?

both
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2010 11:22 am
How is the AoA maintained through entry? Is it only done by the elevons or does the bodyflap as I suspect help out?

both
Thanks. So, alone the elevons cannot maintain the 40° AoA and needs the assistance from the bodyflap? Is that correct?
Title: Re: Shuttle Q&A Part 5
Post by: David413 on 10/04/2010 12:46 pm
The bodyflap positioning during entry is a function of mach number.  The bodyflap position is used primarily to keep the elevons within a given range of operation and prevent "saturation".
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 10/04/2010 04:30 pm
Is there anybody knows how long it takes to traslate the payload from the changeout room to payload bay?

Minutes

um, just curious, how do you figure minutes? If you're talking installing into the orbiter from the PCR, quite a bit more than minutes
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/04/2010 04:34 pm
Is there anybody knows how long it takes to traslate the payload from the changeout room to payload bay?

Minutes

um, just curious, how do you figure minutes? If you're talking installing into the orbiter from the PCR, quite a bit more than minutes

Not installation but the actual translation (and not the final few inches). 
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 10/04/2010 04:44 pm
Gotcha, that's what I figured you meant.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2010 05:12 pm
The bodyflap positioning during entry is a function of mach number.  The bodyflap position is used primarily to keep the elevons within a given range of operation and prevent "saturation".
THat's what I thought about it, but does it aid in the AoA maintenance? The reason for these questions is some disagreement between me and another developer of the SpaceShuttleUltra project.

I have always thought that the bodyflap assisted in AoA maintenance as the elevons are not strong enough to maintain it on their own.

It would be great if you guys could help us settle this issue once and for all.
Title: Re: Shuttle Q&A Part 5
Post by: David413 on 10/04/2010 09:44 pm
I've got a complete listing of the various inputs to the entry DAP that includes the specifics for each individual input (body flap, pitch jets, etc.).  I'll check it again, but as near as I can tell, the elevons are sufficient for AoA control, provided the body flap is periodically adjusted to ensure the elevons have full authority.  The body flap is fixed until mach 16 during entry, that much I remember. 
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2010 10:26 pm
I've got a complete listing of the various inputs to the entry DAP that includes the specifics for each individual input (body flap, pitch jets, etc.).  I'll check it again, but as near as I can tell, the elevons are sufficient for AoA control, provided the body flap is periodically adjusted to ensure the elevons have full authority.  The body flap is fixed until mach 16 during entry, that much I remember. 
Thanks. BTW, what kind of aerosurface data do you use in the Shuttle Fleet? We actually had strengthen the elevons to be able to maintain the 40° AoA which has lead to the orbiter being far to responsive to RHC control inputs. Maybe you would like to help us with this so we get it right?
Title: Re: Shuttle Q&A Part 5
Post by: NASAaddict on 10/08/2010 06:33 am
Hey guys, I was wondering if anybody could tell me what all these feed lines, pipes, etc. are on the SSME, and a brief description please? Listed below are 3 different angles from an SSME used on the previous mission.

Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 10/08/2010 12:23 pm
Looking at images 2010-1918 & -1920, the SSME looks to be cantilievered from the nozzle. That came as a surprise to me.

Why is it handled like this?

I would have guessed it would be handled more like image 2009-6813.

Thanks, Martin
Title: Re: Shuttle Q&A Part 5
Post by: zeke01 on 10/08/2010 12:40 pm
Quote
Why is it handled like this?
How else would you get these engines installed in the shuttle aft compartment?   It's a very tight fit, I understand.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/08/2010 12:52 pm
Looking at images 2010-1918 & -1920, the SSME looks to be cantilievered from the nozzle. That came as a surprise to me.

Why is it handled like this?

I would have guessed it would be handled more like image 2009-6813.

Thanks, Martin

Most engines are installed by handling the nozzle.  It is no big deal since the nozzle transmits the thrust through the combustion chamber into the gimbal.
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 10/08/2010 08:55 pm
Many thanks to both of you.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: Longhorn John on 10/09/2010 02:04 am
Hey guys, I was wondering if anybody could tell me what all these feed lines, pipes, etc. are on the SSME, and a brief description please? Listed below are 3 different angles from an SSME used on the previous mission.



Do you have a subscription to the excellent L2? There's a brilliant presentation on every part of the SSME here:
http://forum.nasaspaceflight.com/index.php?topic=6533.0

Also check out the long list of resources via here:
http://forum.nasaspaceflight.com/index.php?action=tags&tags=SSME
Title: Re: Shuttle Q&A Part 5
Post by: NASAaddict on 10/09/2010 04:25 pm
Yes, I joined a few days ago. I will check those links.

Thanks,

Frank
Title: Re: Shuttle Q&A Part 5
Post by: NASAaddict on 10/10/2010 12:25 am
The twin Solid Rocket Boosters have a decibel level of 180 (right? wrong?). Can someone tell me how that is calculated please?

Air pressure and/or temperature +.....?

Thanks,

Frank
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/10/2010 01:18 am
The twin Solid Rocket Boosters have a decibel level of 180 (right? wrong?). Can someone tell me how that is calculated please?



measured
Title: Re: Shuttle Q&A Part 5
Post by: NASAaddict on 10/10/2010 02:12 am
Ok... How is the 180 db level of the SRB's thrust measured?
Title: Re: Shuttle Q&A Part 5
Post by: kch on 10/10/2010 03:34 am
Ok... How is the 180 db level of the SRB's thrust measured?

Here's a general overview of sound level measurement:

http://en.wikipedia.org/wiki/Sound_level_meter

:)
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 10/10/2010 08:54 pm
My questions would be "180dB at what distance"?

I don't see how this could be "180dB at 1M", because 1M from the acoustic centre would be within the motor's plume and possibly within the nozzle itself, ie very much "near field", the acoustic equivalent of http://en.wikipedia.org/wiki/Near_and_far_field (http://en.wikipedia.org/wiki/Near_and_far_field).

Perhaps loudness is measured in the far field, then an "equivalent loudness at a notional 1M" is calcuated as 180dB?

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: NASAaddict on 10/11/2010 06:25 am
I was reading posts in this section I believe Friday or Saturday and someone recommended 2 rocket propulsion/engine books to someone else, but I don't remember the name of the 2nd book. The first book was Rocket Propulsion Elements by George P. Sutton. The other book had 3 authors.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/17/2010 07:59 am
I've got a complete listing of the various inputs to the entry DAP that includes the specifics for each individual input (body flap, pitch jets, etc.).  I'll check it again, but as near as I can tell, the elevons are sufficient for AoA control, provided the body flap is periodically adjusted to ensure the elevons have full authority.  The body flap is fixed until mach 16 during entry, that much I remember. 

IIRC the body flap is strictly a trim device and only drives to put the elevons back on schedule.  And that schedule is a function of center of gravity location. 

On STS-1 the estimated pitch moment was so far off the body flap almost saturated.  The error was do to the strong shock wave brakes oxygen molecules into two single atoms.  This changes the nature of the gas (air) enough to cause the error.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 10/19/2010 03:01 am
Does anyone have close-up photos of the payload bay door strongback
and torque tube attachment points and hardware?  If so, would you
please post them?

Thanks!
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: neilh on 10/22/2010 06:33 pm
(wasn't sure if this should go in Q&A or be a separate thread)

This is more of a historical shuttle Q, but when/why was the decision made to go with hydrogen for the Space Shuttle instead of kerosene? Would it have made any sense to use the F-1 engines instead of developing the SSMEs? Would the F-1's have been able to survive being next to the SRBs?
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 10/22/2010 06:47 pm
I'd think the F-1 would better fit the SRB role than SSME, i.e. a configuration mirroring that of Buran. As it stands, a really high Isp engine was needed in order to have 1.5 stage to orbit so SSME was kind of a no-brainer.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/22/2010 06:48 pm
(wasn't sure if this should go in Q&A or be a separate thread)

This is more of a historical shuttle Q, but when/why was the decision made to go with hydrogen for the Space Shuttle instead of kerosene?

Performance. Kerosene is better for first stages due to density and T/W, but for the rest of the climb to orbit hydrogen is more efficient.

Quote
Would it have made any sense to use the F-1 engines instead of developing the SSMEs?

No. It might have made sense to use the F-1 engines instead of the SRBs, though.
Title: Re: Shuttle Q&A Part 5
Post by: neilh on 10/22/2010 07:05 pm
(wasn't sure if this should go in Q&A or be a separate thread)

This is more of a historical shuttle Q, but when/why was the decision made to go with hydrogen for the Space Shuttle instead of kerosene?

Performance. Kerosene is better for first stages due to density and T/W, but for the rest of the climb to orbit hydrogen is more efficient.

Quote
Would it have made any sense to use the F-1 engines instead of developing the SSMEs?

No. It might have made sense to use the F-1 engines instead of the SRBs, though.

Gotcha, thanks! My mind was totally drawing a blank and forgot that after the SRBs and hydrogen SSMEs, there aren't any other stages. ;)
Title: Re: Shuttle Q&A Part 5
Post by: sfxtd on 10/22/2010 08:33 pm
Perhaps loudness is measured in the far field, then an "equivalent loudness at a notional 1M" is calcuated as 180dB?

That is the process, even for normal audio applications.
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 10/23/2010 02:12 pm
Thanks.

Cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: dbscars2 on 10/27/2010 03:53 pm
Going to my first launch for STS-133, but am curious how much wind speed it takes for them to cancel a launch?  13 hours in a car is bad enough, but to have it cancelled when I get there due to wind would be worse!
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 10/27/2010 05:43 pm
Is there a particular reason why the Spacehab modules were flat on the top rather than being rounded like Spacelab?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/27/2010 09:19 pm
Is there a particular reason why the Spacehab modules were flat on the top rather than being rounded like Spacelab?

To allow for an EVA path in case the doors don't close.  Also to allow viewing of the payloads behind the module.
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 10/29/2010 08:22 am
Can anyone enlighten me to the issue just before STS-117 launched around the T-35 second mark?

On the net, you can hear something about "ET Helium Inject Delta P #2 .. (pao talking) .. We are go"

Was this the ET pressurization issue that was noted a few days after launch?
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 10/29/2010 09:29 am
Can anyone enlighten me to the issue just before STS-117 launched around the T-35 second mark?

On the net, you can hear something about "ET Helium Inject Delta P #2 .. (pao talking) .. We are go"

Was this the ET pressurization issue that was noted a few days after launch?

There's discussion here (http://forum.nasaspaceflight.com/index.php?topic=8297.msg145850#msg145850) on L2.  Does that help? 

I recall loving Norm Knight's reaction and response on the Ascent Flight Control Team Video Replay. 

ETA:  The issue that was discussed just outside of AUTO SEQUENCE START was an ET Helium Inject delta-P #2 issue (was not a LCC violation). 

From the SSP MER Problem Summary for STS-117, at approximately 3 minutes 30 seconds after launch, there was a LH2 pressure transducer that went off-scale high instantly on the SSME in the #3 position.   
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 10/29/2010 10:22 am
Thanks for that, TLI.  Answered my questions.  Was going through my old footage and heard that, it cropped up my curiosity.  :)
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 10/29/2010 11:21 am
Before the recent STS-133 OV-103 ROMS XFEED flange issue, I wasn't familiar with the term AHC.  In what applications are AHCs (Air Half-Couplings) typically used on the vehicles?  How do they differ from other types of connectors?
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 10/30/2010 04:26 am
Before the recent STS-133 OV-103 ROMS XFEED flange issue, I wasn't familiar with the term AHC.  In what applications are AHCs (Air Half-Couplings) typically used on the vehicles?  How do they differ from other types of connectors?

Just watched the STS-133 Pre-Countdown Status Briefing with NTD Jeff Spaulding, and from his context I take it that "Air Half" just refers to the portion of the connection that is on the vehicle, as opposed to the GSE.  I guess that makes sense. :)

(Maybe it should be called a Space Half-Coupling? :) )
Title: Re: Shuttle Q&A Part 5
Post by: dave k on 10/30/2010 01:40 pm
I have been looking at this every day for awhile on the KSC video feeds. Does anyone have a hi res photo of this wall?

Answered my own question.
" Kennedy employees who have supported the Space Shuttle Program throughout the last 30 years have been signing the wall as a tribute to the program."
http://mediaarchive.ksc.nasa.gov/imageviewer.cfm?mediaid=49120&mr=l&w=0&h=0&fn=2010-5168&sn=KSC-2010-5168

Title: Re: Shuttle Q&A Part 5
Post by: robertross on 10/30/2010 03:43 pm
Here I go, posting a question in the shuttle Q&A thread...

anik just posted in the ISS thread that there will be no re-boost of the ISS from Discovery because of the DAM performed earlier in the week.

Q: Does this allow Discovery to gain a few more seconds in the launch window as it won't need as much reserve propellant from the OMS engines? Or is all that factored in ahead of time and they would only use whatever mass margin was left in the mission to aid in re-boost?

Obviously the amount of launch window gained is minimal in the grand scheme of things.
Title: Re: Shuttle Q&A Part 5
Post by: steveS on 10/30/2010 11:56 pm
Due to STS-133 launch shift from Nov.1 to Nov. 3, the launch had been brought forward by about 1 hour. Does it mean a  reduce mission time? or due to orbital mechanics, the landing will be 1 hour more than planned (mission duration does not reduce/increase regardless of the liftoff time change)?.
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 10/31/2010 06:01 am
In Chris' recent article about the history of space shuttle Discovery, I was reminded that she launched six times in 12 months in 1984 and 1985. Similarly, Atlantis launched on her two opening missions back to back in October and November 1985. Clearly times were different back then, as NASA was attempting to ramp up the launch rate and politics were driving the push to launch a single orbiter as frequently as mentioned above.

So my question for those of you who were around back then: how much different was an Orbiter processing flow back then versus now? Ignoring the obvious answer about the mountains of paperwork that now have to be done that weren't an issue in '85, can someone speak to the pace, pressure, stress level, etc that were present during the processing flows back then? How much maintenance was being deferred to future flows, as opposed to the present-day behavior of trying to launch the vehicle in "pristine" condition every time?

As an example, Atlantis landed on 51-J at EAFB on 10/7/85, and was flown back to KSC on 10/11/85. The vehicle was in the OPF from 10/11/85 to 11/8/1985 (28 days), before being rolled over for mating, and then was hard down at the pad four days later. Two weeks later, the vehicle was launched. Seems like barely enough time to pull out the SSMEs, install three new ones, and launch...

--Craig
   
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/31/2010 11:12 am
there were two full shifts and a partial third shift with large amounts of overtime.  the mountains of paper were the same back then and well as flying them in a "pristine" condition.  Just had more people and money.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/31/2010 12:46 pm
Seems like barely enough time to pull out the SSMEs, install three new ones, and launch...
Didn't always do that; different spares/logistics situation back then.  The engines came out in that case, but after the post-firing inspections, maintenance, and retesting, they went back in the same orbiter and flew on that ship's next flight.  (Same thing for some other orbiters and engine sets at the time.)
Title: Re: Shuttle Q&A Part 5
Post by: klausd on 11/04/2010 12:55 am

What was the reason for only can doing 3 launch attempts in a row? fuel-cells?
Title: Re: Shuttle Q&A Part 5
Post by: TheFallen on 11/04/2010 12:58 am

What was the reason for only can doing 3 launch attempts in a row? fuel-cells?


The main reason being that by November 8 the ISS will start being at an unfavorable angle to the Sun (Beta angle cutout) where it can't generate enough electricity and support a docked shuttle at the same time.

NASA has a limited launch window to send off Discovery before it has to wait till early December to try again.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 11/04/2010 01:03 am

What was the reason for only can doing 3 launch attempts in a row? fuel-cells?


A little bit of expendables, a little bit of fatigue. If you scroll up, you'll see there is a slim chance that they can use Monday if absolutely necessary.
Title: Re: Shuttle Q&A Part 5
Post by: klausd on 11/04/2010 01:07 am
thx, but I know about the beta cutout and the launch-windows. But if they try thursday, friday and Saturday, they can't go for sunday.

What is the main reason for that limit? You said expendables? So no refuelling for the fuel cell tanks necessary on Sunday if that happens?


where it can't generate enough electricity

I thought the reason was cooling. Because the shuttle would be exposed to the sun too much and it cannot cool itself enough...
Title: Re: Shuttle Q&A Part 5
Post by: Alboita on 11/05/2010 08:39 am
Hi all,
I have a question about the fuel used.
Where is stored the H2 and O2 before tanking operations?
And from where it come, where is produced?

Thanks
Alberto from Italy
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/05/2010 02:51 pm
1.  There are two separate OMS systems.  Double failure is unlikely

2.  There is RCS backup
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 11/05/2010 03:10 pm
Hi all,
I have a question about the fuel used.
Where is stored the H2 and O2 before tanking operations?
And from where it come, where is produced?

Thanks
Alberto from Italy

I know that this has been covered previously in this or the preceeding lineages of this thread.  Pictures were provided, too.  It's stored in (separately located) tanks near, but not too near the pad.  At some time shortly before a launch, a convoy of tanker trucks comes in from "local" area cryo vendors and fill these holding tanks.  Someone has even captured an image of this arriving convoy on past launches IIRC.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/05/2010 03:14 pm
LH2 comes from Louisiana
Title: Re: Shuttle Q&A Part 5
Post by: rbfnet on 11/05/2010 09:54 pm
Relating to the issues from earlier this week on the main engine controllers, at what point in the countdown would the failure of an engine controller no longer trigger a cutoff or hold?  That is, if the backup engine controller for one of the SSMEs failed before T-31 would they not go past T-31?  Inside of T-31 would RSLS cutoff automatically?  After main engine ignition but before SRB ignition, would it trigger a pad abort?  Some other point?

Is it the same answer if it's the primary, rather than the backup, engine controller that fails?

(I realize at the presser they said the transient they observed couldn't trigger a pad abort, because it wasn't severe enough to shutdown a controller.  I'm asking about a hypothetical case where it is severe enough to cause a controller to fail.)


Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/05/2010 10:07 pm
Relating to the issues from earlier this week on the main engine controllers, at what point in the countdown would the failure of an engine controller no longer trigger a cutoff or hold?
After liftoff, I believe.
Title: Re: Shuttle Q&A Part 5
Post by: racshot65 on 11/06/2010 12:11 pm
Not sure where to post this but theres a super cool space shuttle graphic on space.com

http://www.space.com/missionlaunches/infographic-space-shuttle-nasa-spacecraft-101102.html (http://www.space.com/missionlaunches/infographic-space-shuttle-nasa-spacecraft-101102.html)


Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/06/2010 09:07 pm
Just checking here: the monoball on the bipod yoke, is that one is ejected along with the rest of the yoke structure at ET sep? Or does it remain with the orbiter and is removed post-flight in the OPF during turn-around ops?
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 11/07/2010 01:13 pm
Not sure where to post this but theres a super cool space shuttle graphic on space.com

http://www.space.com/missionlaunches/infographic-space-shuttle-nasa-spacecraft-101102.html (http://www.space.com/missionlaunches/infographic-space-shuttle-nasa-spacecraft-101102.html)

Excellent.

But I think key number 9 should be "fuel & oxidizer tanks for thrusters"?

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: chempilot on 11/07/2010 02:56 pm
there' is a lot of info on Emergency Orbiter Egress procedures, but not a whole lot about Emergency Ingress/Rescue procedures. I was wondering this because on the side hatch of the orbiters have the following Rescue instructions:
1. Insert Tool-Unlock
2. Rotate to Vent Detent
3. Wait 2 minutes
4. Rotate to Hard Stop

anyone know who carries the special tool (if it is a special tool)?  also why wait two minutes....that's a long time in an emergency!

thanks!!
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 11/07/2010 04:11 pm
Not sure who has the tool, but seeing as how the two minute wait comes after the "Rotate to Vent" step, the wait is most likely to let the crew module pressure to equalize with the outside pressure.
Title: Re: Shuttle Q&A Part 5
Post by: chempilot on 11/07/2010 04:16 pm
thanks for the reply!  that's what i thought too, but aren't the orbiters pressurized to 14.7psi (1atm), the same as outside pressure?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 11/07/2010 04:40 pm
there' is a lot of info on Emergency Orbiter Egress procedures, but not a whole lot about Emergency Ingress/Rescue procedures. I was wondering this because on the side hatch of the orbiters have the following Rescue instructions:
1. Insert Tool-Unlock
2. Rotate to Vent Detent
3. Wait 2 minutes
4. Rotate to Hard Stop

anyone know who carries the special tool (if it is a special tool)?  also why wait two minutes....that's a long time in an emergency!

thanks!!

The tools are kept at the TAL sites as part of the emergency kit.

http://www-pao.ksc.nasa.gov/nasafact/talsup.htm

I couldn't find a description of the tool itself but it is probably some sort of socket wrench with an extention and the correct sized drive on it. you could probably buy the makings of one at a hardware store. Interestingly, the soyuz also uses a hatch opening tool, but they mount 3 of them on the bottom of the vehicle, behind the heat shield, so that anybody who gets to the capsule first can get the crew out.

As far as the two minutes thing, the latches on the hatch go over-center and are loaded by the cabin preasure, so it is probably impossible to actually unlatch them until the preasure is equalized.

 I always thought it was a little strange that, after they added the tunnel thrusters, they did not add an external hatch jettison mechanism or at least tie it in to the ovehead panel jetison handle on the right side of the vehicle, but I assume there was a good reason.

Edit, 08-11-2010: On second thought, the latches probably can be unlatched under preasure. Otherwise, whats the point of having an outward opening hatch? The reason to wait until the preasure is equalized maybe because the location where the tool is inserted is on the face of the hatch and therefore, whoever is opening it will be standing right in front of it and could get smacked by it. The hatch weighs a few hundred pounds.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 11/07/2010 04:51 pm
thanks for the reply!  that's what i thought too, but aren't the orbiters pressurized to 14.7psi (1atm), the same as outside pressure?

They could have landed at a high altitude site. Zaragoza is 863 ft above sea level. Combine that with a local low preasure area and the preasure differential could be 2 or 3 psi easy.
Title: Re: Shuttle Q&A Part 5
Post by: chempilot on 11/07/2010 05:04 pm
thanks JayP!  that makes sense about the different landing sites.  sounds like the russians have the right idea about having the tool attached to the vehicle.

i was thinking the two minutes was for decompressing of the gasket that seals the hatch or maybe a reset of the hatch pyro separation system. 
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/08/2010 11:20 am
The monoball stays with the bipod.  As I understand it, the pyro bolt fractures to permit separation, then the Orbiter internal fitting rotates so that the bolt fracture surface is parallel to and part of the Orbiter OML for re-entry.  There are photos and diagrams out on the interwebs somewhere.
F=ma


Just checking here: the monoball on the bipod yoke, is that one is ejected along with the rest of the yoke structure at ET sep? Or does it remain with the orbiter and is removed post-flight in the OPF during turn-around ops?
Title: Re: Shuttle Q&A Part 5
Post by: Tnarg on 11/08/2010 02:47 pm
If you used a single Space Shuttle main engine for the first stage of a normal rocket how much would it's payload to LEO be? and how do you work it out?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 11/08/2010 03:17 pm
If you used a single Space Shuttle main engine for the first stage of a normal rocket how much would it's payload to LEO be? and how do you work it out?

Divide the sea level thrust by 1.2 and then take 5% of that as a first cut. I come up with about 20,000 pounds.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: nickyp on 11/08/2010 08:30 pm
Is the SSME in any way related to the J-2 family of engines?
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 11/08/2010 08:45 pm
No.   Some of the general depth of knowledge & understanding that was developed during Apollo, certainly fed into the engineering process that ultimately produced SSME, but beyond that there is little, or even no, heritage back to J-2.   SSME was a thoroughly clean-sheet design intended to push the envelope in nearly every area -- and it did.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: lucspace on 11/10/2010 01:00 pm
Some basic questions about rocket fuel tanks, I think, but connected with Discovery's current hold-up:

The leak occurred in a pipe carrying excess hydrogen away from the tank. How can it occur that there is EXCESS hydrogen when the tank is not completely full? I would think all fuel is required to end up in the tank?

How does boil-off work? When the fuel is in the tank, a sealed vessel, how does liquid H2 disappear?

Thanks,

Luc
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 11/10/2010 01:11 pm
Some basic questions about rocket fuel tanks, I think, but connected with Discovery's current hold-up:

The leak occurred in a pipe carrying excess hydrogen away from the tank. How can it occur that there is EXCESS hydrogen when the tank is not completely full? I would think all fuel is required to end up in the tank?

How does boil-off work? When the fuel is in the tank, a sealed vessel, how does liquid H2 disappear?

Thanks,

Luc

The answer to both is the same - boiloff.  The liquid H2 is at roughly 4 degress above absolute zero so it's always boiling (turning to a gas) because it's absorbing heat from the Florida environment (which is distinctly above 4K) and the gas needs to be removed or the tank will over pressurize and explode.
Title: Re: Shuttle Q&A Part 5
Post by: lucspace on 11/10/2010 03:57 pm
Thanks Lee!
I guess the trouble of cooling a rocket to keep the fuel liquid just would be too cumbersome to make it practical or worthwhile?
Title: Re: Shuttle Q&A Part 5
Post by: sbt on 11/10/2010 06:07 pm
Thanks Lee!
I guess the trouble of cooling a rocket to keep the fuel liquid just would be too cumbersome to make it practical or worthwhile?

Cooling is generally done by passing a cold fluid to the object to be
cooled, allowing it to absorb heat from that object, and then removing
it from the object. In most systems the fluid is then recycled by
allowing it to shed its heat energy in some way - but not in all cases.
Think about cooling a burn by running water from a tap over it or
blowing air past the CPU in your PC (although mine is water cooled -
but you get the idea).

What is happening in the LH tank is that a cold fluid, LH2, is passing
into the tank at a slow rate ('Topping') to replace the boiloff. The
LH2 is absorbing the heat and boiling, producing GH2 which is removed.
The 'Topping' of the tank with LH to replace the H2 lost as GH is doing
the cooling - the working fluid is just not being recycled, but then
Hydrogen is relatively cheap. Any additional cooling system would have
to be more cost effective overall than the current method.
Title: Re: Shuttle Q&A Part 5
Post by: lucspace on 11/10/2010 07:18 pm
Thanks guys, I learnt useful and interesting stuff today!
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 11/10/2010 10:15 pm
When a Shuttle stack is at the pad, are the forward SRB attach points accessible for examination?  Speculatively, if as the STS-133 tank were being filled there had been relative motion at one of those points, could it have led to both observed failures, i.e. pulled the GUCP out of alignment and placed the intertank stringer under out-of-specification transient loads?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/10/2010 11:02 pm
When a Shuttle stack is at the pad, are the forward SRB attach points accessible for examination?  Speculatively, if as the STS-133 tank were being filled there had been relative motion at one of those points, could it have led to both observed failures, i.e. pulled the GUCP out of alignment and placed the intertank stringer under out-of-specification transient loads?

There is always relative motive.  The ET contracts several inches and the stack leans several inches when propellants are loaded.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/11/2010 02:09 pm
Does anyone know how many stringers there are on the ET intertank? Also how much are they separated by (in degrees)?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 11/11/2010 02:33 pm
Does anyone know how many stringers there are on the ET intertank? Also how much are they separated by (in degrees)?

Eighteen external stringers per normal skin panel with 6 panels per intertank.  The two machined thrust panels do not have stringers, but instead have external stiffening ribs (26 longitudinal & 7 circumferential) formed by milling the solid metal.

Each panel occupies 45 degrees, so the stringers are separated by 2.5 degrees on those panels that have them.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/11/2010 05:01 pm
Does anyone know how many stringers there are on the ET intertank? Also how much are they separated by (in degrees)?

Eighteen external stringers per normal skin panel with 6 panels per intertank.  The two machined thrust panels do not have stringers, but instead have external stiffening ribs (26 longitudinal & 7 circumferential) formed by milling the solid metal.

Each panel occupies 45 degrees, so the stringers are separated by 2.5 degrees on those panels that have them.
Thank you very much.
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 11/12/2010 11:24 am
REALLY dumb question, but my mind has gone completely blank.

Why can't they roll out the stack to the pad with the payload already installed?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/12/2010 11:31 am
REALLY dumb question, but my mind has gone completely blank.

Why can't they roll out the stack to the pad with the payload already installed?
Can't install payloads in the VAB.  No clean environment (environmental control is opening doors), no access to the payload bay for installing payloads.

Some payloads did roll out to the pad in the orbiter, but were installed in the OPF before the orbiter was mated.  Or were installed at the pad and then rolled back to the VAB in the orbiter.  Some payloads that were more environmentally sensitive (like HST and components) probably couldn't spend any time in the VAB.
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 11/12/2010 11:35 am
Boom, there we go. Thanks Philip :)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/12/2010 02:22 pm
Does anyone have photos or diagrams of the Orbiter hoist point fittings that they can share?  I assume that they are covered with TPS after the Orbiter is mated to the ET.  Or are they left uncovered for launch?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/12/2010 05:24 pm
uncovered.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/12/2010 05:47 pm
uncovered.
Sorry Jim but here you are wrong. Both the forward and aft hoist points on the orbiter is covered with TPS while in the VAB prior to rollout.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/12/2010 06:05 pm
I stand corrected
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 11/12/2010 06:18 pm
Thanks Lee!
I guess the trouble of cooling a rocket to keep the fuel liquid just would be too cumbersome to make it practical or worthwhile?

It could be done in theory with Helium as the working fluid.  The trouble is, taking heat out of a 4K gas takes a huge system and a huge amount of energy, especially if there is a large volume of gas to be re-condensed.  This volume can be drastically reduced by really good insulation of the vessel (i.e. vacuum), but that makes the vessel heavy.  Since the ET has to be taken to near-orbital velocity, the insulation has to be light, and thus not very good.  So there's a lot of gas volume and that means a really, really huge cooling system - so huge as to be impractical.  So they do KISS and just remove the gas and flare it off.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 11/14/2010 01:38 am
From the shuttle processing threads, it sounds like they are doing NDE of the stringers from inside the intertank.  How does that work?  Do they have a guy clambering around on top of the dome of the LH2 tank?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/14/2010 09:44 am
From the shuttle processing threads, it sounds like they are doing NDE of the stringers from inside the intertank.  How does that work?  Do they have a guy clambering around on top of the dome of the LH2 tank?

There is an access door and internal platforms that can be installed.
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 11/14/2010 05:12 pm
Is there any possibility that the stringer cracks seen on ET-137 have been the root cause of the ET foam liberation issues  all along?  I know that the root cause had been chalked up to cryopumping long ago, but perhaps these small cracks in the Al-Li stringers have been cropping up when the tank is chilled down, but have gone unnoticed because the tank structure is usually not inspected after tanking?

I am not making an expert claim here...rather, I am asking the experts to tell me if there is any merit to this hypothesis.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/15/2010 11:33 am
Here's a question for the GN&C experts around here:

What does the shuttle GN&C software look at during entry to command the roll reversals? I know that the rolls are closed-loop guidance commanded so it must be some dynamic values that it looks at and decides it time to command a roll in one direction or the other.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 11/16/2010 02:57 am
I had to do a double-take at this picture on Wikipedia:
http://upload.wikimedia.org/wikipedia/commons/f/fe/STS-103_Hubble_EVA.jpg

This is from STS-103/Discovery, a Hubble servicing mission.  But that thing in the foreground sure looks like an Orbiter Docking System.  Why is it there -- did NASA just not bother to remove it between ISS flights?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/16/2010 03:10 am
I had to do a double-take at this picture on Wikipedia:
http://upload.wikimedia.org/wikipedia/commons/f/fe/STS-103_Hubble_EVA.jpg

This is from STS-103/Discovery, a Hubble servicing mission.  But that thing in the foreground sure looks like an Orbiter Docking System.  Why is it there -- did NASA just not bother to remove it between ISS flights?

Since NASA removed the internal airlocks from the orbiters, the ODS airlock doubles as the EVA airlock for shuttle-based EVAs. The APAS can be removed from the top of the ODS (and was, for STS-125) but it was not necessary to remove it for STS-103, so it remained.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/16/2010 03:21 am
Here's a question for the GN&C experts around here:

What does the shuttle GN&C software look at during entry to command the roll reversals? I know that the rolls are closed-loop guidance commanded so it must be some dynamic values that it looks at and decides it time to command a roll in one direction or the other.

Delta-azimuth (DEL-AZ), the angle between the velocity vector and the vector to the tangent on the HAC. A roll reversal is performed when DEL-AZ exceeds a velocity-dependent value.

The Entry Guidance workbook on L2 explains this, also:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19790075283_1979075283.pdf
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 11/16/2010 06:43 am
Since NASA removed the internal airlocks from the orbiters, the ODS airlock doubles as the EVA airlock for shuttle-based EVAs. The APAS can be removed from the top of the ODS (and was, for STS-125) but it was not necessary to remove it for STS-103, so it remained.

Cool, thanks.  I remember reading notes on L2 about Atlantis's ODS being reinstalled after STS-125, which is why I was confused.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 11/16/2010 11:19 pm
This image is so cool!  It is apparently the inside of the STS-133 intertank.  It certainly gives the impression the LOX tank is is directly supported by the thrust beam.  Is that correct?
Title: Re: Shuttle Q&A Part 5
Post by: robertross on 11/16/2010 11:27 pm
This image is so cool!  It is apparently the inside of the STS-133 intertank.  It certainly gives the impression the LOX tank is is directly supported by the thrust beam.  Is that correct?

Nope. That's done from the tank's outer wall.
The thrust beam just transmits the loads from the two SRBs.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/17/2010 01:59 am
I cant get over how close both tanks are....I dont know what I was picturing in my mind, but WOW, they are close!!  Thanks for the pic!!
Title: Re: Shuttle Q&A Part 5
Post by: chrisking0997 on 11/17/2010 02:04 am
trying to get perspective on that pic....how tall is the thrust beam (the part we are looking at)?
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 11/17/2010 02:20 am
trying to get perspective on that pic....how tall is the thrust beam (the part we are looking at)?

According to the SLWT SDH:

"The SRB beam assembly is a rectangular box beam. It is 42.95 inches deep at the center and tapers to 26 inches (at the ends) by 15 inches wide, and spans 345 inches between the centerlines of the two SRB thrust fittings which form the ends of the assembly."

The beam is designed to be able to flex up & down, by to 6" during flight, in order to dampen the vibrations normally created by the SRB's (what you and I know as "Thrust Oscillation").

You can clearly see one of the SRB beams in this memorable image from 2003:

(http://images.ksc.nasa.gov/photos/2003/low/KSC-03PD-3154.gif)

http://science.ksc.nasa.gov/gallery/photos/2003/captions/KSC-03PD-3154.html

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: robertross on 11/17/2010 02:22 am
trying to get perspective on that pic....how tall is the thrust beam (the part we are looking at)?


(paraphrasing): "42.95 inches deep at the center, and tapers to 26" at the ends, 15" wide, and spans 345" between the centerlines of the SRB thrust fittings..."

Also, the 'SLWT catalog' indicates "The crossbeam deflections are limited since the dynamic clearance between the thrust beam and the LO2 & LH2 domes are small"

awww...Ross beat me to it  :(  :)
Title: Re: Shuttle Q&A Part 5
Post by: chrisking0997 on 11/17/2010 04:47 pm
thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 11/18/2010 03:38 pm
On several sources on the internet, the SSME has both the numeric designations RS-24 and RS-25.  Is there any difference between the two, and why the dual designation?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 11/18/2010 03:50 pm
trying to get perspective on that pic....how tall is the thrust beam (the part we are looking at)?

You can clearly see one of the SRB beams in this memorable image from 2003:

(http://images.ksc.nasa.gov/photos/2003/low/KSC-03PD-3154.gif)

http://science.ksc.nasa.gov/gallery/photos/2003/captions/KSC-03PD-3154.html

Ross.

That's what that support structure was! I had always wondered!
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/21/2010 02:31 pm
The LOX anti-geyser line on the SWTs, did it connect to the aft vertical strut or the elbow of the LOX feedline?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 11/23/2010 06:28 am
Hi all.

I was reading this paper http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf)  about the early conceptual studies for the manipulator system (aka robotic arm) of the shuttle. At page 40 there is an interesting paragraph explaining two configurations studied for the end effector.

My question is: why these early concept were discarded? I mean for which reason it has been chosen the configuration that we know for the robotic arm end effector?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 11/25/2010 05:31 pm
Hi all.

I was reading this paper http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19750021700_1975021700.pdf)  about the early conceptual studies for the manipulator system (aka robotic arm) of the shuttle. At page 40 there is an interesting paragraph explaining two configurations studied for the end effector.

My question is: why these early concept were discarded? I mean for which reason it has been chosen the configuration that we know for the robotic arm end effector?

 Its hard to tell without a detailed analysis, but looking at this design, the central pin has to make contact with the bottom of the grapple fixture  with enough force to center the effector before the latches can grab the lip at the edge of the fixture. This could imart a motion on the grappled payload that would push it away before they can actually grab it. The SRMS end effector design allows the grapple to be snarred before any axial loads are placed on the payload. It's probably more likely to succeed that the first design.

Basically, this design is a simplified version of the Apollo docking probe. That is probably where they started from when they wrote this report.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 11/26/2010 03:51 pm
For the ET, how long does it take for the foam to cure and turn to the familiar orange  color the ET has?

On the SRBs what was the reason for the bolt patterns seen in some of the earlier flights. As an example http://www.axmpaperspacescalemodels.com/images/stack1a.gif
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/27/2010 03:02 pm
Assuming no wheel braking at all, what is the rollout distance of the orbiter on a concrete runway without the drag-chute? This for a lightweight orbiter (220k lbs).
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/27/2010 05:42 pm
during the last press conference for STS-133, Gerst mentioned that shuttle performance is reduced starting in the Feb timeframe.  Is that due to warm temperatures reducing propellant performance??

thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/27/2010 06:03 pm
during the last press conference for STS-133, Gerst mentioned that shuttle performance is reduced starting in the Feb timeframe.  Is that due to warm temperatures reducing propellant performance??


No, 

1.  Temp has the opposite affect, warmer SRM's have higher performance.

2.  I believe it is the transition period.  There is a summer and winter flight profile and they have to use a compromise profile during the transition.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 11/27/2010 08:06 pm
2.  I believe it is the transition period.  There is a summer and winter flight profile and they have to use a compromise profile during the transition.

Can you (or someone else) please elaborate on that? What is different about the summer and winter flight profiles and why are they necessary? Is it because of atmospheric properties or abort/recovery considerations or perhaps gravitational effects related to the slightly different distance from the Sun?

Is this common to ELVs? Is it common to all non-equatorial launch sites?
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/27/2010 09:45 pm
Yeah, and I understand warmer SRB's = good performance, but I thought there was something with the SSME's and their propellant that suggested colder was better...

thanks for the answer!!!
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 11/27/2010 10:37 pm
or perhaps gravitational effects related to the slightly different distance from the Sun?

You're kidding.

Right?

I think this is what Jim had in mind: http://www.nasaspaceflight.com/2006/04/low-q-option-for-sts-121/
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/27/2010 11:21 pm

Can you (or someone else) please elaborate on that? What is different about the summer and winter flight profiles and why are they necessary?


Prevailing upper level winds change seasonally
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 11/28/2010 04:25 pm
I have a question regarding this NASA photo taken of the STS 5 launch.

I'm guessing that it is somewhere east of the Delta 2 launch pads (17), or is it actually south of that near Port Canaveral?
Thank you.
 
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 11/28/2010 05:55 pm
I have a question regarding this NASA photo taken of the STS 5 launch.

I'm guessing that it is somewhere east of the Delta 2 launch pads (17), or is it actually south of that near Port Canaveral?
Thank you.
 

I'd say it was someware off of the point of the cape. If it had been from the mouth of the port canaveral channel, the line of blockhouses would have been to the right of the image instead of the left.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 11/29/2010 09:48 am
I'd say that was bang on based on my experience of flying approaches in Orbiter and SSM 07.
Title: Re: Shuttle Q&A Part 5
Post by: tva on 11/29/2010 10:28 am
I assume that lift-off occurs within tight tolerances in respect of cross-range to the orbital plane of ISS.

How big is this offset measured i kilometers in case of a "default" ascent profile ?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 11/29/2010 08:32 pm
For the ET, how long does it take for the foam to cure and turn to the familiar orange  color the ET has?


actually a fresh ET, ie one that hasn't ever been to the pad, is more of a yellow color. Exposure to the sun causes it to turn dark orange over time.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/29/2010 09:07 pm
I assume that lift-off occurs within tight tolerances in respect of cross-range to the orbital plane of ISS.

How big is this offset measured i kilometers in case of a "default" ascent profile ?

There's no default; it depends on the phase angle.
Title: Re: Shuttle Q&A Part 5
Post by: mdo on 12/01/2010 11:55 am
With respect to the still missing root cause for the cracked stringers on ET-137:
Could the problem during mating operations with the orbiter (reference (http://www.nasaspaceflight.com/2010/09/sts-133-engineers-repair-on-discovery-et-mate-issue/), IPR-39, Sep. 10) have anything to do with it?
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 12/02/2010 02:20 pm
How come the ET only can handle 13 cycles? What drives that it can't have more? And have a tank ever gotten close to the max 13 cycles?
Title: Re: Shuttle Q&A Part 5
Post by: dcbecker on 12/02/2010 02:31 pm
How come the ET only can handle 13 cycles? What drives that it can't have more? And have a tank ever gotten close to the max 13 cycles?

material fatigue
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 12/03/2010 07:48 pm
That metal can only be cycled to -423 F and back to ambient only so many times. Heck, at that temp you are basically changing the physical properties of the material. Funny unexpected things tend to happen when it's that cold.  Just look at the GUCP. We can leak check it a hundred times at normal temps and it will act like a totally different animal when it goes cryo.   
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 12/04/2010 01:25 pm
Given the GUCP, has the end  attaching to the vent arm  been replaced whenever that problem has happened or has the GUCP problem always been on the ET itself?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 12/08/2010 07:23 pm
IIRC the problems with the GUCP in the past few years have all been with the 7" QD, which is actually part of the tank. Once the GSE swing arms shop disconnects the vent line from the GUCP then the ET guys take over for the most part.
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 12/09/2010 04:06 pm
I am thinking about the ET and would like to ask some questions.

When tanking the ET goes through some cryogenic torture. How much does the ET shrink when exposed to this relatively extreme temperature change?

Does this shrinkage occur uniformly?

I would think that the different temp.s of the LOX and the LH2 in tandem with the intertank’s non exposure (and different structure) would lead to very different relative movement “shrinkage” over the whole surface area of the ET.

I would assume that the feed lines on the orbiter are hard points, while the tripod mount would act like a ball joint of sorts to accommodate this movement. Is this correct?

On ascent the ET is pressurized with gaseous O2 and H2 that come from the fuel (LH2) and oxidizer (LOX) supply once it has gone through a heat exchanger on the SSME. These gasses are supplied through the 5 inch lines that parallel the 17 inch LOX feed line (that’s as big as a compact disc in diameter).

At what temperature are these gasses fed to their respective tanks?

These feed lines do not appear to have any insulation on them. If “warm” gas is fed to these tanks, what does that do for the cryogenic environment?

Does this increase boil off for the short duration the ET is in flight?
On ascent does the foam provide a good barrier (relative to the interior) from atmospheric heating?

How much does the ET deform in flight (both from off loading of propellants and flight dynamics)? Which of these two influence this deformation the most?

I have read that the ET is discarded with high pressure in the 2 tanks to aid in reentry burn up. Somewhat like a balloon just ready to pop. What would happen to the ET on reentry if there was no internal pressure? Wouldn’t it still break up and burn satisfactorily?

On ET jettison is the forward attach point (tripod) preloaded fore/aft from the ET stretching/contracting during flight? If so, does it “twang” when released?

What happens to all of the fuel and oxidizer still in the feed lines inside the orbiter upon ET jettison (from the disconnects all the way to the combustion chamber)? For that matter what about the amount still in the feed lines on the ET? 

Thanks so much for any answers.

I was looking at some KSC processing photos of STS-133 and I just stared at the wall for a few minutes thinking about the ET.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/09/2010 04:32 pm

1.  I would assume that the feed lines on the orbiter are hard points, while the tripod mount would act like a ball joint of sorts to accommodate this movement. Is this correct?

2.  Does this increase boil off for the short duration the ET is in flight?

3. On ascent does the foam provide a good barrier (relative to the interior) from atmospheric heating?

4.  I have read that the ET is discarded with high pressure in the 2 tanks to aid in reentry burn up. Somewhat like a balloon just ready to pop. What would happen to the ET on reentry if there was no internal pressure? Wouldn’t it still break up and burn satisfactorily?


5.  What happens to all of the fuel and oxidizer still in the feed lines inside the orbiter upon ET jettison (from the disconnects all the way to the combustion chamber)?

6.For that matter what about the amount still in the feed lines on the ET? 


1.  yes.

2.  Not really, The point of adding the gas to maintain head pressure for the engines and to keep the liquid from boiling off

3. Yes, that is one of its main jobs

4.  Don't know, that is why it is pressurized

5.  Vented during OMS burns through nozzles and ground umbilical disconnect

6.  the same as the rest of the remaining propellant in the ET
Title: Re: Shuttle Q&A Part 5
Post by: pagoda on 12/16/2010 01:24 pm
This seems to be the place for random questions.

Who are the closest people to the shuttle when it launches and where are they located (other than the astronauts)?  I'm guessing that there are people to assist with emergency egress if it is needed, but that's just a guess.
Title: Re: Shuttle Q&A Part 5
Post by: sitharus on 12/16/2010 05:51 pm
This seems to be the place for random questions.

Who are the closest people to the shuttle when it launches and where are they located (other than the astronauts)?  I'm guessing that there are people to assist with emergency egress if it is needed, but that's just a guess.

This has been answered in one of the earlier Q&As, but from memory about three miles, possibly more. In emergencies the astronauts have to get out and to the bunker by themselves.
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 12/16/2010 09:31 pm
There are a few long-distance camera operators that are 2.4 miles from the pad, closer than the fallback area at 3 miles distance.  I can't find anyone closer after looking at a quick search.  I know the crew themselves do get out on their own, and are taught how to operate the M-113's by themselves - they used to have people operate the M-113s and were staged inside in case of an emergency.

That's about all I know.
Title: Re: Shuttle Q&A Part 5
Post by: TheGame0135 on 12/18/2010 10:41 am
I wasn't sure if I should post this on the STS-133 thread or not so I put it here, administrators please move accordingly. And perhaps this was answered, but i didn't feel like reading through hundreds of pages to look. But is it possible that the GUCP caused the stringer crack seen on the 1st launch attempt? After yesterday's successful tanking test (in the sense of the GUCP didn't leak) and there were no visible problems with the tank could it be thought that perhaps the issue came from possible vibrations from the GUCP as it leaked considering these were off the chart readings when it leaked, meaning i would assume that the GUCP's unseen leak could have also caused unseen problems? Perhaps the vibrations caused more stress on the stringers is basically what I'm asking, obviously I don't work there and am just curious from my basic knowledge of vibrations and introductory knowledge of engineering. thanks to whoever can help me with this.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 12/18/2010 01:25 pm
... is it possible that the GUCP caused the stringer crack seen on the 1st launch attempt?

As reported in Chris B's article on Nov 8:

The crack was overviewed on Monday morning by the KSC Engineering Review Board (ERB), noting the time the crack appeared and the opening forward plan.
[...]
“The crack appeared at 7:08 am EDT, which was a few minutes prior to the initiation of the GUCP LH2 leak."


http://www.nasaspaceflight.com/2010/11/sts-133-plan-to-repair-et-137-foam-cracks-at-pad
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 12/23/2010 09:37 pm
Are the domes of the Lo2 and LH2 tanks inside the intertank also foam covered or is something else used? To show what I mean look at http://www-pao.ksc.nasa.gov/kscpao/images/medium/2010-5953-m.jpg and http://www-pao.ksc.nasa.gov/kscpao/images/medium/2010-5943-m.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/23/2010 10:08 pm
Are the domes of the Lo2 and LH2 tanks inside the intertank also foam covered or is something else used? To show what I mean look at http://www-pao.ksc.nasa.gov/kscpao/images/medium/2010-5953-m.jpg and http://www-pao.ksc.nasa.gov/kscpao/images/medium/2010-5943-m.jpg

It is the same foam as the outside but since it is not exposed to UV rays it does not turn orange
Title: Re: Shuttle Q&A Part 5
Post by: onyx_08 on 12/27/2010 07:25 pm
Hello, i have to say my english ist not very good but i will try my best that you can understand me. I have some question about the early days of the  Space Shuttle.

1. Between STS-5 and STS-51L the shuttle crews donned light blue coveralls. Just before the crews entered the shuttle, they put on a helmet (what type of helmet was that??) an some type of a life west. Could this life wests saved crews when they had to make a landing in the water?
Why they did'nt used pressure suits at that time?

2. Some times the astronauts were posing in dark blue flight suits instead of the light blue suits. But the dark blue suits never used in flight! Why?

3. When i'm watching old shuttle launchs on youtube i hear the downlink calls ("Roger, go at throttle up!" and so on...), i can hear a different sounding transmission than the later calls. I can hardly describe how it sounds, i hope you can understand what i mean. Starting from STS-26 the calls sounds "normal" like we can hear it today. Which was the reason for it?

4. Joe Kerwin was still in active status in 1985, but he never flown again in space. Why did'nt he fly a shuttle mission when he was still in the astronaut office?

5. John Young was supposed to fly aboard Atlantis in the mid of 1986 to bring Hubble into orbit. But the flight was cancelled after the Challenger-disaster and he never flown again. Why?

6. Also Bob Crippen never flown again. Why?

7. STS-135 will be the last Space Shuttle mission ever. When you could chose the crew, who would you like to see on this historical flight? It would be great to see Anna Lee Fisher on that last flight because she had just one flight at all in 1985. She's still in active status. Also it would cool to see Crippen command the last flight. I know it's unrealistic, but it would be nice.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/27/2010 08:59 pm
1. 
a.  launch and entry helmet
b.  yes, life vest were for water landing
c.  Shuttle was suppose to be safe and have intact aborts.  They didn't think there was a need for space suits.

2.  Blue suits are for aircraft

3.  Performance is nominal

4. There is no logic to astronaut selection

5.  Too old and wrote some bad letters about management and forgot he was part of management

6. Went into management

7.  Crew has been selected
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 12/29/2010 12:05 pm
I was looking at a picture of Discovery in the VAB online this morning, and it was a shot showing alot of the surface of the MLP, and I was starting to wonder, at launch how much damage is done to the MLP and how much refurb work goes into it before the next launch? Does it get repainted every time also? I was looking at it and I dont see any burn marks, etc which Id expect to see from the SME and the SRB's. Also do any of the large pipes around the SRB area get torn up, etc during a launch? Does anyone have pictures of the MLP after a launch?

Also I have always wondered, what are the 2 large peices that are on the MLP that are on in front of each wing, is that a deflector for the flames at lift off?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/29/2010 12:20 pm
I was looking at a picture of Discovery in the VAB online this morning, and it was a shot showing alot of the surface of the MLP, and I was starting to wonder, at launch how much damage is done to the MLP and how much refurb work goes into it before the next launch? Does it get repainted every time also? I was looking at it and I dont see any burn marks, etc which Id expect to see from the SME and the SRB's. Also do any of the large pipes around the SRB area get torn up, etc during a launch? Does anyone have pictures of the MLP after a launch?

Also I have always wondered, what are the 2 large peices that are on the MLP that are on in front of each wing, is that a deflector for the flames at lift off?

Little damage, no real burn marks, just residue.  The larger objects are the tail service masts, which provide propellants, power, cooling, conditioned air, etc to the orbiter.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 12/29/2010 12:29 pm
Thanks, I was always wondering what exactly those were for.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/02/2011 03:58 pm
This should be an easy one: how many degrees the Ku band DA rotate around its pivot point in the payload bay? Is it 113°s as the SCOM and Ku band antenna ops workbook states?
Title: Re: Shuttle Q&A Part 5
Post by: PeterAlt on 01/05/2011 02:56 am
I see that Atlantis is the only orbiter not equipped with SSPTS. Any chance they would remove Discovery's SSPTS adapter after STS-133 and install it to Atlantis for STS-135?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 01/05/2011 03:09 am
No.
Title: Re: Shuttle Q&A Part 5
Post by: PeterAlt on 01/05/2011 04:00 am
Any chance of using Discovery or Endeavor instead of Atlantis for STS-135, since those orbiters are better equipped for docking to ISS (as those two orbiters can stay an extended duration because they are equipped and upgraded with SSPTS). The extended stay could give the ISS a much-need science boost. Atlantis would continue to be prepared for its LON mission for STS-134, while Discovery (or Endeavor) would begin immediate processing for STS-135 after STS-133 (or STS-134). I bring up Endeavor because I think it is the most underused and most capable orbiter and I would love to see more use of it, though I realize there would be less time available to process it for it to be on time for a June launch. I understand that a June launch is the optimum time frame NASA managers have in mind for STS-135, but delaying the launch for a better orbiter may be a better option. Since The shuttle program will (most likely) get funded for all of FY2011, the funds are there to do this.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/05/2011 11:35 am
The extended stay could give the ISS a much-need science boost.

How is that?  A few more manhours for a few days is not going to increase science output of the ISS. 
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 01/05/2011 12:19 pm
Any chance of using Discovery or Endeavor instead of Atlantis for STS-135, since those orbiters are better equipped for docking to ISS (as those two orbiters can stay an extended duration because they are equipped and upgraded with SSPTS).

No. Atlantis will have STS-335/135.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 01/11/2011 06:24 pm
I was looking at a picture of Discovery in the VAB online this morning, and it was a shot showing alot of the surface of the MLP, and I was starting to wonder, at launch how much damage is done to the MLP and how much refurb work goes into it before the next launch? Does it get repainted every time also? I was looking at it and I dont see any burn marks, etc which Id expect to see from the SME and the SRB's. Also do any of the large pipes around the SRB area get torn up, etc during a launch? Does anyone have pictures of the MLP after a launch?

Sorry for the late reply. Most of the damage at launch is paint being burnt/ blasted off, mostly around the SRB holes. The handrail around the Zero Level is usually down to bare metal on the side towards the vehicle. Not sure if I have any post launch pics, but I'll check. About the only time you see any real damage is with a very heavy payload or something isn't secured correctly, like the LOX TSM door a few launches back.
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 01/12/2011 01:35 am
Looking at pictures of the shuttle's underbelly and the colour contrast between new tiles and old tiles got me thinking....how many flights have the oldest tiles seen? Do tiles have a maximum number of reentries lifetime or do they only get replaced when they get damaged? Or are the majority of tiles the same ones each orbiter came with at delivery?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 01/12/2011 01:48 am
Looking at pictures of the shuttle's underbelly and the colour contrast between new tiles and old tiles got me thinking....how many flights have the oldest tiles seen? Do tiles have a maximum number of reentries lifetime or do they only get replaced when they get damaged? Or are the majority of tiles the same ones each orbiter came with at delivery?

Some tiles have been on Discovery since her maiden voyage. So the most any TPS tile on the vehicle fleet has seen is 38 flights to date -- soon to be 39. Not sure about a max number of reentries for tiles, but they are only replaced when they are damaged beyond the point of surface repair in the OPF.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/12/2011 01:49 am
Only replaced when damaged
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 01/12/2011 04:43 am
As problematic as tiles have been as a thermal protection system, that's still incredible! Thanks Jim.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/12/2011 05:04 am
For OV-104, almost 84 percent of the tiles on the vehicle are from the original build. And many of the replacements were for reasons other than TPS failure (for instance, all of the ETB-8 and BRI-18 were added just because we wanted the better tile).

Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 01/12/2011 12:35 pm
Is it possible for the shuttle to land on water in case of an emergency?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/12/2011 12:37 pm
Is it possible for the shuttle to land on water in case of an emergency?

Ditching was not deemed survivable, that is why the escape pole was developed.
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 01/12/2011 03:10 pm
For OV-104, almost 84 percent of the tiles on the vehicle are from the original build. And many of the replacements were for reasons other than TPS failure (for instance, all of the ETB-8 and BRI-18 were added just because we wanted the better tile).

There wouldn't be some kind of map as to which tiles are still "original" would there?  or a "statistically this area has needed more replacement than other areas" map?  I imagine the tiles on the underside that get chewed up the most, particularly near the landing gear due to landing debris.
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 01/12/2011 05:06 pm
From a NYT article published just after Columbia was lost.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 01/12/2011 08:45 pm
What was the use for the extra LH2 line seen on the first shuttle flights? For example STS-1.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/12/2011 09:06 pm
What was the use for the extra LH2 line seen on the first shuttle flights? For example STS-1.
You mean the large thick line right next to the 17" LOX feedline? That's the LOX anti-geyser line. Starting with the LWTs, the LOX anti-geyser line was replaced with a direct GHe injection which goes through the right aft vertical strut.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 01/13/2011 01:18 pm
What was the reason for the odd foam color of the ET used on STS-124? In the videos it looks like some foam was darker as if it was left in the sun for some time. Look http://i.ytimg.com/vi/p1mvfhvMzlQ/0.jpg The whole bottom area looks like that for this ET.
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 01/13/2011 03:13 pm
From a NYT article published just after Columbia was lost.

Ross.

Interesting, will have to look up that article, thanks Ross.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/13/2011 04:17 pm
What was the reason for the odd foam color of the ET used on STS-124? In the videos it looks like some foam was darker as if it was left in the sun for some time. Look http://i.ytimg.com/vi/p1mvfhvMzlQ/0.jpg The whole bottom area looks like that for this ET.

Exactly, it turns orange from UV exposure
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 01/13/2011 05:55 pm
I've noticed alot of the tiles have old yellow, dot-matrix type Id numbers on them. I'd imagine those are original tiles.
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 01/13/2011 06:13 pm
Sorry, this is just a nit pick.

The Shuttle picture posted by Ross was almost certainly printed in the NY Times during STS-114 (Discovery), the first Return to Flight after Columbia (a little over 2 years).

Not,"right after Columbia".

The paragraph below the "15,000 Hits and Counting" headline mentions Discovery's launch. Return to Flight got alot of media coverage so it is no surprise that this picture would have been printed.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 01/13/2011 10:55 pm
I meant on what was the reason for the tank looking like that? I know the sun causes the foam to change color. Normally the ET has a very light, almost yellow tone to it fresh from Michoud. STS-124's tank has a sun burned bottom. Was this tank at one point put in the sun? The photo shows what I mean.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/14/2011 12:04 am
There wouldn't be some kind of map as to which tiles are still "original" would there?  or a "statistically this area has needed more replacement than other areas" map?  I imagine the tiles on the underside that get chewed up the most, particularly near the landing gear due to landing debris.

If you look at photos of the underside of the Orbiter, the most common places for replaced tiles are around the edges of the landing gear and ET umbilical well doors, over the various antenas and the body flap.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/18/2011 07:36 am
What does the "landing count" mean? Here's the context:

"Your A/G is enabled for the landing count". It is a call made by GC to FLIGHT during entry and landing.
Title: Re: Shuttle Q&A Part 5
Post by: brodo on 01/19/2011 04:11 pm
Do all Mission Specialists get training to be a Flight Engineer?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/19/2011 09:09 pm
Hi all.

do you know if during the development of the structure of the orbiter engineers had to overcome some particular difficulty? or if during construction they had some kind of problem that forced to change the design of the structure (i.e. a given structural component made bigger or with a different size)?

thanks.

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 01/20/2011 06:55 pm
Do all Mission Specialists get training to be a Flight Engineer?

No.  MS-2 is the "Flight Engineer" and there is only one per flight.  Most of the MS's are not flight engineers.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: agman25 on 01/25/2011 07:52 pm
What were the abort modes like for the planned shuttle launches from VAFB ? What would the equivalent of a TAL be?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/25/2011 08:15 pm
What were the abort modes like for the planned shuttle launches from VAFB ? What would the equivalent of a TAL be?

They are the same, except the down range abort was initially called TPL.  NASA later changed TAL to mean Transoceanic Abort Landing. The AOA drove the crossrange requirement.  NASA was looking for other airfields in Washington and Alaska to reduce the range.
Title: Re: Shuttle Q&A Part 5
Post by: agman25 on 01/25/2011 08:21 pm
What were the abort modes like for the planned shuttle launches from VAFB ? What would the equivalent of a TAL be?

They are the same, except the down range abort was initially called TPL.  NASA later changed TAL to mean Transoceanic Abort Landing. The AOA drove the crossrange requirement.  NASA was looking for other airfields in Washington and Alaska to reduce the range.

I was always under the impression that downrange was south.  Thanks for clearing that up.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/25/2011 08:39 pm
What were the abort modes like for the planned shuttle launches from VAFB ? What would the equivalent of a TAL be?

They are the same, except the down range abort was initially called TPL.  NASA later changed TAL to mean Transoceanic Abort Landing. The AOA drove the crossrange requirement.  NASA was looking for other airfields in Washington and Alaska to reduce the range.

I was always under the impression that downrange was south. Thanks for clearing that up.


It is, Washington and Alaska were for AOA.  Christmas Islands were looked at for TAL.   There would have been SCA range problem with getting an orbiter off these islands. 
It is. 
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 01/25/2011 09:55 pm
Hi all.

do you know if during the development of the structure of the orbiter engineers had to overcome some particular difficulty? or if during construction they had some kind of problem that forced to change the design of the structure (i.e. a given structural component made bigger or with a different size)?

thanks.

Davide

Every time one blew up on the test stand, they changed designs :)   

For example I think the helium purge between the tubine section and the pump section on one of the two turbopumps was the result of a test stand failure.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Nittany Lion on 01/25/2011 10:09 pm
What were the abort modes like for the planned shuttle launches from VAFB ? What would the equivalent of a TAL be?

They are the same, except the down range abort was initially called TPL.  NASA later changed TAL to mean Transoceanic Abort Landing. The AOA drove the crossrange requirement.  NASA was looking for other airfields in Washington and Alaska to reduce the range.

I was always under the impression that downrange was south. Thanks for clearing that up.


It is, Washington and Alaska were for AOA.  Christmas Islands were looked at for TAL.   There would have been SCA range problem with getting an orbiter off these islands. 
It is. 


Wrong holiday. Christmas Island is in the Indian Ocean.

The shuttle TAL site in the Pacific was Mataveri International Airport on Easter Island.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/25/2011 11:06 pm

Wrong holiday. Christmas Island is in the Indian Ocean.

The shuttle TAL site in the Pacific was Mataveri International Airport on Easter Island.


I beg to differ

http://en.wikipedia.org/wiki/Kiritimati

but you are right, it was Easter Island

 
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 01/25/2011 11:09 pm
The shuttle TAL site in the Pacific was Mataveri International Airport on Easter Island.
       "Shuttle Down"
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 01/26/2011 02:38 am
The shuttle TAL site in the Pacific was Mataveri International Airport on Easter Island.
       "Shuttle Down"

Yes, by G. Harry Stein, I believe.  I remember reading that originally serialized in Analog SF magazine about three decades back.
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 01/26/2011 04:37 am

I beg to differ

http://en.wikipedia.org/wiki/Kiritimati

but you are right, it was Easter Island

There are actually several Islands called Christmas Island and one of them is located in the Indian Ocean so I can see the confusion.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/26/2011 11:11 am
Danny - I think Dave is asking about the airframe here...
F=ma

Hi all.

do you know if during the development of the structure of the orbiter engineers had to overcome some particular difficulty? or if during construction they had some kind of problem that forced to change the design of the structure (i.e. a given structural component made bigger or with a different size)?

thanks.

Davide

Every time one blew up on the test stand, they changed designs :)   

For example I think the helium purge between the tubine section and the pump section on one of the two turbopumps was the result of a test stand failure.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 01/26/2011 12:15 pm
Hi all.

do you know if during the development of the structure of the orbiter engineers had to overcome some particular difficulty? or if during construction they had some kind of problem that forced to change the design of the structure (i.e. a given structural component made bigger or with a different size)?

thanks.

Davide

Early on, there was wind tunnel data that resulted in the lightweight delta wing, which decreased weight.  Work in the wind tunnel also resulted in moving the relative placement of the SRBs, and changed the shape of the LO2 section of the ET.

I think you're asking about later, once the design was more mature.  There was a problem in the aft compartment with the placement of the RGAs located in areas where the vibration or bending loads (someone please clarify) were too high.  There may have been some structural changes to the aft compartment, but I believe the fix was to relocate the RGAs within the aft compartment.

 

 
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 01/26/2011 06:38 pm
On changes to shuttle, some of the white tiles were replaced with the lighter weight blankets based on test data showing the temps were lower than expected.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Sarah on 01/29/2011 03:44 am
This has been driving me crazy for years. Why do SSME's 2 and 3 move closer together at about T-2 seconds?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/29/2011 12:42 pm
This has been driving me crazy for years. Why do SSME's 2 and 3 move closer together at about T-2 seconds?

All three move closer.  They are spaced far apart for engine start so that they don't hit each other from start transients.  Once they have settled down, they are moved into flight positions.
Title: Re: Shuttle Q&A Part 5
Post by: Seer on 01/30/2011 07:40 am
Why was the Shuttle crew cabin atmosphere selected to be one atmosphere? Why not half an atmoshere, say? This would be a comprise between the Apollo and Shuttle atmospheric pressures. Does anyone know how much the mass saving would be?

A second question is about the material used on the orbiter. As I understand it, titanium wasn't used for the structure because of scarcity concerns (seems unbelievable to me), but could have the orbiter that replaced Challenger used it?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/30/2011 12:01 pm
Why was the Shuttle crew cabin atmosphere selected to be one atmosphere? Why not half an atmoshere, say? This would be a comprise between the Apollo and Shuttle atmospheric pressures. Does anyone know how much the mass saving would be?

A second question is about the material used on the orbiter. As I understand it, titanium wasn't used for the structure because of scarcity concerns (seems unbelievable to me), but could have the orbiter that replaced Challenger used it?
The reason for using aluminum over titanium was actually manufacturer experience. Not many airframe manufacturers had experience with large titanium airframes. By using aluminum many more could bid on the orbiter contract.

For the second question: No. Endeavour was assembled from spare parts contracted by NASA during the construction of the last two production orbiters (Discovery and Atlantis).
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/30/2011 01:38 pm
Because we live in one atmosphere
Title: Re: Shuttle Q&A Part 5
Post by: Seer on 01/30/2011 01:45 pm
Because we live in one atmosphere

So I take it you don't know.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/30/2011 02:27 pm
Because we live in one atmosphere

So I take it you don't know.

That is exactly the reason and everything falls from it.  Habitability, science, international relations, etc
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 01/30/2011 04:10 pm
how does the GLS handoff to the RSLS
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 01/31/2011 12:39 am
Because we live in one atmosphere

That's not really a reason.  We lived in one atmosphere during Apollo, yet Apollo didn't use one atmosphere.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/31/2011 01:09 am
Because we live in one atmosphere

That's not really a reason.  We lived in one atmosphere during Apollo, yet Apollo didn't use one atmosphere.
[/quote

Yes, it is.  Look at what Apollo goals were and look what the shuttle's goals were. Or do I have spell it out?
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 01/31/2011 12:18 pm
I was reading in the article on the front page about the roll out of Discovery, and how once back from her flight she will spend some time in storage in the VAB due to another vechicle will be taking over OPF-3, which it stated could be the X-37. Why would something that small get a facility as large to house and take care of a shuttle?? Was just suprsed to read that today. They could fit a fleet of the X-37's in there...lol.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 01/31/2011 12:56 pm
I was reading in the article on the front page about the roll out of Discovery, and how once back from her flight she will spend some time in storage in the VAB due to another vechicle will be taking over OPF-3, which it stated could be the X-37. Why would something that small get a facility as large to house and take care of a shuttle?? Was just suprsed to read that today. They could fit a fleet of the X-37's in there...lol.

Similar processing tools and needs. Also, X-37B launches from CCAFS on the Atlas Vs, so it makes sense in many ways to use/modify existing structures at KSC that are no longer needed for Shuttle for use by an "in the family" type vehicle.

Plus, and to be brutally honest here, we no longer need 3 OPFs for Shuttle. We can do just fine with two.

Remember here that we originally only had two OPFs for the first decade of the Shuttle program. OPF-3 was brought online in the early 1990s (IIRC). At that point, we then had 3 OPFs for 4 orbiters. So OPF rotations/juggling is nothing new to the Shuttle program. In fact, it was only after the loss of Columbia 8 years ago that each of the remaining orbiters was given a designated/dedicated OPF following Discovery's and Endeavour's OMDPs at Kennedy.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 01/31/2011 01:30 pm
Hmm... Must be a new member. You'll learn, lol.
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 01/31/2011 02:18 pm
Because we live in one atmosphere

So I take it you don't know.

That is exactly the reason and everything falls from it.  Habitability, science, international relations, etc

I think what Jim means to say is that the goals of the two different programs dictated why the pressures were set this way.

In Apollo, the goal was simply to get to the moon via whatever means possible.  The astronauts were all hardened ex-military or test pilots and stuff, as such they were used to tolerating extreme conditions and it was just part of getting the job done.  They NEEDed the lower pressure to make the cabin lighter and get to the moon and back.

In shuttle, the original goal was to be able to bring up any old regular joe to space.  It was supposed to be a shirt-sleeve environment just like an airliner.  So launch G forces were limited to 3 to make it more comfortable, whereas I believe Saturn V launches were upwards of 6Gs.  3G is like a fast roller coaster, 6G and most untrained people would probably pass out.  Same goes for the cabin pressure, they tried to keep it as similar to ground level as possible so that it would be as familiar and "normal" an environment as possible.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/31/2011 04:23 pm
Because we live in one atmosphere

So I take it you don't know.

That is exactly the reason and everything falls from it.  Habitability, science, international relations, etc

I think what Jim means to say is that the goals of the two different programs dictated why the pressures were set this way.

In Apollo, the goal was simply to get to the moon via whatever means possible.  The astronauts were all hardened ex-military or test pilots and stuff, as such they were used to tolerating extreme conditions and it was just part of getting the job done.  They NEEDed the lower pressure to make the cabin lighter and get to the moon and back.

In shuttle, the original goal was to be able to bring up any old regular joe to space.  It was supposed to be a shirt-sleeve environment just like an airliner.  So launch G forces were limited to 3 to make it more comfortable, whereas I believe Saturn V launches were upwards of 6Gs.  3G is like a fast roller coaster, 6G and most untrained people would probably pass out.  Same goes for the cabin pressure, they tried to keep it as similar to ground level as possible so that it would be as familiar and "normal" an environment as possible.

Not just the crew, the materials. Apollo required special non-flammable materials everywhere due to the fire risk in the pure O2 atmosphere. The program desire to be able to carry "off-the-shelf" equipment aboard shuttle dictated air. There are many materials flown on the shuttle that could never have been carried aboard Apollo due to the fire risk.
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 01/31/2011 05:32 pm
A second question is about the material used on the orbiter. As I understand it, titanium wasn't used for the structure because of scarcity concerns (seems unbelievable to me), but could have the orbiter that replaced Challenger used it?
   AIUI, most of the world titanium deposits (at least as available in the 1960s & 70s) were in the Soviet Union. I've read that the SR-71 was in large part built with Soviet titanium, for which the CIA needed to set up a series of front companies to contrive the purchases. Titanium metalworking and welding was also in its infancy.

   Concorde, which was approximately contemporary to Shuttle, went with an aluminum body, thereby limiting its max speed to around Mach 2.2. Even the Soviets went with stainless steel instead of titanium (on cost grounds?) for the Mig-25.
   -Alex
Title: Re: Shuttle Q&A Part 5
Post by: agman25 on 02/01/2011 08:02 pm
A pure O2 question. Does it make EVA's easier if the spacecraft has a pure O2 atmosphere?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/01/2011 08:09 pm
   AIUI, most of the world titanium deposits (at least as available in the 1960s & 70s) were in the Soviet Union. I've read that the SR-71 was in large part built with Soviet titanium, for which the CIA needed to set up a series of front companies to contrive the purchases. Titanium metalworking and welding was also in its infancy.

Titanium is exceptionally common.  It's what gives white paint its whiteness.  The problem with Titanium isn't digging it up, it's processing it into a a usable metal - much the same as Aluminum.
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 02/01/2011 08:50 pm
Because we live in one atmosphere

So I take it you don't know.

That is exactly the reason and everything falls from it.  Habitability, science, international relations, etc

I think what Jim means to say is that the goals of the two different programs dictated why the pressures were set this way.

In Apollo, the goal was simply to get to the moon via whatever means possible.  The astronauts were all hardened ex-military or test pilots and stuff, as such they were used to tolerating extreme conditions and it was just part of getting the job done.  They NEEDed the lower pressure to make the cabin lighter and get to the moon and back.

In shuttle, the original goal was to be able to bring up any old regular joe to space.  It was supposed to be a shirt-sleeve environment just like an airliner.

Bad analogy. Airliners aren't maintained at sea level air pressure! (But people don't live in airliners for many days at a time, either.)

However, I do wonder whether there would have been any really significant mass saving to using an Apollo-type atmosphere.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 02/01/2011 08:53 pm
Hmm... Must be a new member. You'll learn, lol.

Yes, but Jim wears one-word answers as a badge of honour. I think he might be interested if someone found a way to post partial syllables or reduce the pixel count on that one word. (It's just an affectionate joke, Jim).

Actually, I've long suspected that Jim types most of his responses on a Blackberry or similar, and I wouldn't want to type long responses on that sort of keyboard.

Nevertheless, this sometimes provides an opportunity for someone with more time on their hands to backup Jim's encyclopaedic knowledge (the Jimopedia?) with a greater depth of insight.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 02/01/2011 10:17 pm
I suspect that it's mostly a function of time. Jim is a prolific poster, and NSF is always fortunate to have someone of encyclopedic knowledge willing to answer so many questions here. Presumably, he has plenty of work to do, and his personal compromise is brutal efficiency against politeness.

The more interesting posts can be the long ones -- when Jim, or Dr. Elias, or Blackstar (to mention just a few) are willing to go into some lengths, that suggests a subject of personal interest.

 -Alex
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/01/2011 11:33 pm
The avionics are also aircooled.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/02/2011 12:01 am
A pure O2 question. Does it make EVA's easier if the spacecraft has a pure O2 atmosphere?

Technical answer; Yes. In a pure O2 atmosphere, there is no risk of the bends when depressing down to the suit pressure.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 02/02/2011 03:09 am
I know Jim is laconic by nature, but come on, this is a Q&A thread. :)  Elaboration is instructive, and aren't we all here to learn?

By Jim's second post I figured out what he was driving at, but I really appreciated Naito's and Jorge's more detailed answers.  (Especially Jorge's, since materials science is not immediately obvious and not really something that could have been deduced from Jim's post.)
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 02/02/2011 07:11 am
I suspect that it's mostly a function of time. ... Presumably, he has plenty of work to do, and his personal compromise is brutal efficiency against politeness.

That's exactly what I meant by "someone with more time on their hands".

Quote
Jim is a prolific poster, and NSF is always fortunate to have someone of encyclopedic knowledge willing to answer so many questions here.

Damn right. NSF would be much the poorer without him!

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: oannes on 02/02/2011 11:39 pm
Columbia question:

If Columbia was limited to less glamorous missions because of its weight, was anything special required to get it to Hubble's high orbit on STS-109?  Did it need an OMS burn during launch, for example?  Or does the nearly-empty cargo bay of a Hubble servicing mission make the difference, i.e. maybe Columbia could not have launched Hubble but she could service it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/03/2011 01:08 am
Columbia question:

If Columbia was limited to less glamorous missions because of its weight, was anything special required to get it to Hubble's high orbit on STS-109?  Did it need an OMS burn during launch, for example?  Or does the nearly-empty cargo bay of a Hubble servicing mission make the difference, i.e. maybe Columbia could not have launched Hubble but she could service it?

Correct on the last line.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/03/2011 08:09 pm
Why was the EVA translation slidewires removed from all the orbiters prior to RTF after the Columbia accident? They made a brief comeback on STS-125 but then was removed again following the flight.
Title: Re: Shuttle Q&A Part 5
Post by: Moe Grills on 02/04/2011 08:01 pm
   
I could think of three possibilities offhand; which is correct?

Are the Space Shuttle windows made of:
!) Polycarbonate?
2) Tempered glass?
3) or a combination of the two (laminate)?
Title: Re: Shuttle Q&A Part 5
Post by: go4mars on 02/04/2011 08:06 pm
   
I could think of three possibilities offhand; which is correct?

Are the Space Shuttle windows made of:
!) Polycarbonate?
2) Tempered glass?
3) or a combination of the two (laminate)?

Transparent aluminum (star trek shuttles).  As to the current US ones, I've no idea either. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/04/2011 08:07 pm
   
I could think of three possibilities offhand; which is correct?

Are the Space Shuttle windows made of:
!) Polycarbonate?
2) Tempered glass?
3) or a combination of the two (laminate)?

http://spaceflight.nasa.gov/shuttle/reference/shutref/structure/windows.html
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 02/04/2011 08:20 pm
And to go with Jorge's link - a graphic showing how the panes are arranged.
Title: Re: Shuttle Q&A Part 5
Post by: Moe Grills on 02/04/2011 08:24 pm
    Thanks, Jorge. 
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/05/2011 03:41 pm
What was the need for the extra LH pressurization line seen on the first two external tanks for STS-1 thru 5?

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2011 04:00 pm
What was the need for the extra LH pressurization line seen on the first two external tanks for STS-1 thru 5?


There was not an extra LH2 press line on the first batch of SWTs. The large thick line right next to the 17" LOX feedline was a LOX-anti-geyser line.

Once a direct GHe injection method had been certified at then the NSTL, the LOX anti-geyser line was removed and the LH2 press line was relocated to right next to the LOX press line.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/05/2011 10:07 pm
I see. I wondered what the small pipe seen here http://www.axmpaperspacescalemodels.com/images/stack1a.gif on the left side of the LH2 portion of the ET was used for. Thanks for clearing that up.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2011 10:39 pm
I see. I wondered what the small pipe seen here http://www.axmpaperspacescalemodels.com/images/stack1a.gif on the left side of the LH2 portion of the ET was used for. Thanks for clearing that up.
Yes. That is the GH2 press line.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 02/07/2011 09:36 am
I've noticed, watching the sts-1 launch on youtube, that the rcs on the attached image is open. But on later missions they start closed and are 'blown' open at launch. What was the reason for this change?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/07/2011 10:32 am
I've noticed, watching the sts-1 launch on youtube, that the rcs on the attached image is open. But on later missions they start closed and are 'blown' open at launch. What was the reason for this change?

To prevent water entering the chamber.  They are no covered with sheets of a material.  I will let someone else provide the name of material.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 02/07/2011 10:42 am
Tyvek, by DuPont
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/07/2011 01:35 pm
I noticed in the video in the STS-1 thread I made why in the video the LOX vent arm/ hood is retracted so early in the launch count as compared to today's missions?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/07/2011 01:37 pm
I noticed in the video in the STS-1 thread I made why in the video the LOX vent arm/ hood is retracted so early in the launch count as compared to today's missions?
The answer is in this technical conference paper on NTRS: http://hdl.handle.net/2060/19820015490
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/07/2011 11:36 pm
Cool. I'll check it out.

Say what is that circular object seen right next to the  LO2  cable tray and gaseous oxygen line? You can see it right next to GO@ line at the nose cap fairing. http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/ET_Photos/ET-37_Nose.jpg
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/08/2011 03:28 pm
Can someone please remind me where the RTLS dump port for the Centaur LH2 system was on the orbiter?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/08/2011 03:35 pm
Can someone please remind me where the RTLS dump port for the Centaur LH2 system was on the orbiter?

vertical stablizer
Title: Re: Shuttle Q&A Part 5
Post by: Space Invaders on 02/08/2011 03:38 pm
By how much would the payload to LEO increase if the Shuttle flew unmanned and therefore could use a more agressive ascent profile?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/08/2011 03:40 pm
By how much would the payload to LEO increase if the Shuttle flew unmanned and therefore could use a more agressive ascent profile?

As nothing to do with the crew, it is structural limits
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/08/2011 03:42 pm
Can someone please remind me where the RTLS dump port for the Centaur LH2 system was on the orbiter?

vertical stablizer
Thanks! So there wasn't a dedicated LH2 dump port located below the RBUS umbilical port on the orbiter?
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 02/08/2011 05:18 pm
By how much would the payload to LEO increase if the Shuttle flew unmanned and therefore could use a more agressive ascent profile?

As nothing to do with the crew, it is structural limits

From what I understand, there's a decent factor of safety on that - the structure is supposed to be able to take up to 3.5 or 3.6G's, right? Would there be any performance gain from throttling the SSME's to 3.1 or 3.2 late in ascent?
Title: Re: Shuttle Q&A Part 5
Post by: Pheogh on 02/08/2011 05:45 pm
Is anyone aware or can point me to any video of the crew arriving at the Pad for launch that has audio. Just saw a replay of a video of Mike Massamino on Craig Ferguson describing the sounds out at the Pad when the stack is fueled and ready to go. Just wondering if there is any media (movies) out there that capture the ambient noise he is talking about.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/08/2011 06:12 pm
I guess this one is for Jim: Any idea on the color of the CISS LH2/LOX service pipes? Right now I'm going with same color as the pipes on the EDO pallet.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 02/09/2011 08:37 am
I found this 70s shuttle concept picture and I wonder what the intention was for the canard like structe on the nose.. Minuature solar panel?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/09/2011 10:12 am
I think some of the early concepts had deployable RCS pods.

I found this 70s shuttle concept picture and I wonder what the intention was for the canard like structe on the nose.. Minuature solar panel?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/09/2011 11:14 am
I think some of the early concepts had deployable RCS pods.

I found this 70s shuttle concept picture and I wonder what the intention was for the canard like structe on the nose.. Minuature solar panel?

Bingo
Title: Re: Shuttle Q&A Part 5
Post by: simonbp on 02/09/2011 06:47 pm
IIRC, even as late as 1975, after the positions of the RCS had been finalized, they still had doors covering them. The full-scale mock-up that NAA-Rockwell built, for example, had them.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 02/10/2011 07:24 am
IIRC, even as late as 1975, after the positions of the RCS had been finalized, they still had doors covering them. The full-scale mock-up that NAA-Rockwell built, for example, had them.

I think I've found your info on this page
http://www.boeing.com/defense-space/space/hsfe_shuttle/sts1/recollections.html
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/10/2011 01:52 pm
What is the use of these white paper  covers on the ET? http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/STRUTS_interfaces/Shuttle_Umbilical_Hydrogen.jpg From launch videos showing close ups of this area, they aren't removed prior to launch either.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/10/2011 05:09 pm
What is the use of these white paper  covers on the ET? http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/STRUTS_interfaces/Shuttle_Umbilical_Hydrogen.jpg From launch videos showing close ups of this area, they aren't removed prior to launch either.
They are early indicators of a H2 fire. The reason for that is that hydrogen burns with an invisible flame only visible to IR cameras. So to maximize the detection chances, some patches of paper were added to the left-aft struts.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/10/2011 05:31 pm
What is the use of these white paper  covers on the ET? http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/STRUTS_interfaces/Shuttle_Umbilical_Hydrogen.jpg From launch videos showing close ups of this area, they aren't removed prior to launch either.
They are early indicators of a H2 fire. The reason for that is that hydrogen burns with an invisible flame only visible to IR cameras. So to maximize the detection chances, some patches of paper were added to the left-aft struts.

Was this after the 41D abort incident or more recent than that?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/10/2011 07:10 pm
Out of curiosity, what is the procedure for removing a tile? You can't stick something under it from the side and pry it off and I would think that somehow latching onto the outer surface and pulling would cause the tile to split at the densification layer, so how do they do it?
Title: Re: Shuttle Q&A Part 5
Post by: JonC on 02/10/2011 07:44 pm
Here's a shuttle question I can't find an answer for...

What was the reason why the name of the shuttle was moved from the payload bay door to behind the cockpit? Similarly, adding the orbiter name on the top of the wing?

If I recall correctly, Columbia and Challenger were the only two to have the name on the payload doors, but then it was moved on Columbia during an overhaul.

Similarly, you had the dark sections on the wing root of Columbia, which eventually went away. Maybe this was due to changes in the thermal protection?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 02/10/2011 07:52 pm
Here's a shuttle question I can't find an answer for...

What was the reason why the name of the shuttle was moved from the payload bay door to behind the cockpit? Similarly, adding the orbiter name on the top of the wing?

If I recall correctly, Columbia and Challenger were the only two to have the name on the payload doors, but then it was moved on Columbia during an overhaul.

Similarly, you had the dark sections on the wing root of Columbia, which eventually went away. Maybe this was due to changes in the thermal protection?

It's more cool that way and you can still see it when the doors are open.  ;)

They "standardized" Columbia, with respect to the name/logo on the wing during the last OMDP.  All the vehicles were tweaked when NASA changed back to the "meatball" logo. 

Columbia's black tles on the chine area were there do to unknowns about the heating environment on the first flights and kept that way always to give her a bit of "distinction" from the rest of the fleet as the first. 
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/10/2011 07:54 pm
Here's a shuttle question I can't find an answer for...

What was the reason why the name of the shuttle was moved from the payload bay door to behind the cockpit? Similarly, adding the orbiter name on the top of the wing?

If I recall correctly, Columbia and Challenger were the only two to have the name on the payload doors, but then it was moved on Columbia during an overhaul.

Similarly, you had the dark sections on the wing root of Columbia, which eventually went away. Maybe this was due to changes in the thermal protection?

Moving the name to the cockpit was to enable reading it in on-orbit photgraphs and videos  (taken from the RMS cameras and durring EVAs)

Challenger's name was always on the cockpit.

The name on the wing was to make it visible in footage of the vehicle on the pad.

The black chines on Columbia were a bit of thermal protection overkill. Untill they actually flew a reentry, there was some concern about the flow dynamics over the wing roots durring reentry.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/11/2011 10:45 pm
Where are the antennas on the orbiter that transmit shuttle telemetry during launch, what band is used and what transmission format?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/11/2011 11:25 pm
Where are the antennas on the orbiter that transmit shuttle telemetry during launch, what band is used and what transmission format?
4 omni-directional S-band antennas placed around the Xo576 bulkhead. They can be either PM or AM. UHF is available as back-up in case S-band is not available.
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 02/11/2011 11:25 pm
Where are the antennas on the orbiter that transmit shuttle telemetry during launch, what band is used and what transmission format?

I believe there are diagrams of antenna locations in Jenkins.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/11/2011 11:29 pm
Where are the antennas on the orbiter that transmit shuttle telemetry during launch, what band is used and what transmission format?
4 omni-directional S-band antennas placed around the Xo576 bulkhead. They can be either PM or AM. UHF is available as back-up in case S-band is not available.

Thank you.

That's the aft-crew cabin bulkhead at the front of the payload bay, right?  So these transmit through the payload bay doors?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/11/2011 11:34 pm
Where are the antennas on the orbiter that transmit shuttle telemetry during launch, what band is used and what transmission format?
4 omni-directional S-band antennas placed around the Xo576 bulkhead. They can be either PM or AM. UHF is available as back-up in case S-band is not available.

Thank you.

That's the aft-crew cabin bulkhead at the front of the payload bay, right?  So these transmit through the payload bay doors?
No. They're located around the bulkhead, ahead of the doors. Not inside the payload bay.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 02/12/2011 12:18 am
No. They're located around the bulkhead, ahead of the doors. Not inside the payload bay.

Oh, well see, that makes a whole bunch more sense.  Thanks Dave!
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/14/2011 10:06 pm
Just confirming something here: The diameter of the cylindrical portion of the payload bay is 180" right? Adding the sill longerons, it is 200"?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/16/2011 10:51 am
Hi all.

I have a question regarding the TPS tiles around the forward RCS thrusters. As shown in the attached picture, it seems to me that the tiles just around the upper edge of nozzles have some sort of grooves on their surface.

Am I right or wrong? either cases, what are they and why?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/16/2011 03:06 pm
The grooved areas on the thrusters are metal. http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/ICD_Data/Nose_thrusters4.gif  and http://k41.pbase.com/g1/54/503354/2/110378416.iyVSnnri.jpg
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/16/2011 11:28 pm
Hi MarkD.

thanks for this. Do you know which kind of material is used? I suppose those plates are put in place for helping the nozzles to passively cool down, with the grooves adding more radiating surface and strengthening the plates itself. Am I right or wrong?

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/17/2011 12:06 am
No problem. :) I'm sorry I don't. Probably inconel. Yes, maybe they are for that or to act as a barrier between the RCS plumes and the times. My guess is the thruster jet plumes would damage the tiles by erosion.

Dennis R. Jenkins space shuttle books might give something. *shrugs*
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/17/2011 07:32 am
Hi all.

some question for who of you works directly with the orbiters at the KSC.

between a tile and blanket, which is the most difficult to install? and why?

which is the area of the orbiter where is more difficult to install the TPS?

which is the more demanding task in installing/removing a tile? what is it easier: removing or installing a tile/blanket?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 02/18/2011 03:02 am
Why was the EVA translation slidewires removed from all the orbiters prior to RTF after the Columbia accident? They made a brief comeback on STS-125 but then was removed again following the flight.

Wouldn't they have simply been for EVA's requiring more payload bay walking to make it easier to move about the bay rather than having to re-tether every time you move.
Just my guess, maybe someone else can chime in.
Title: Re: Shuttle Q&A Part 5
Post by: david1971 on 02/20/2011 10:04 pm
Quick question, looking at the timeline at http://www.scibuff.com/2010/05/14/sts-132-launch-timeline/

I see the following:
19:20:42 GMT @ T+00:33 – Throttle down from 104.5% to 72.0% engine power level at Mach 0.9.

19:20:52 GMT @ T+00:43 – Mach 1.

19:20:54 GMT @ T+00:45 –Throttle up back to 104.5% engine power level.

19:21:09 GMT @ T+01:00 – Max-Q (the point of the greatest dynamic pressure).

I had thought that the throttle down / throttle up was to reduce stresses as the shuttle went through Max-Q, and therefore throttle up was after Max-Q.  What am I missing?  Is it that the throttle sequence produces a new (lesser) Max-Q later in the ascent?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/21/2011 12:00 am
Yes
Title: Re: Shuttle Q&A Part 5
Post by: parham55 on 02/24/2011 06:41 pm
I've never seen any video of the astronauts getting suited and strapped in while on orbit preparing for entry.  Does any exist? If not is it more difficult or less than the process before launch? Anyone care to take a stab at describing the process, what is more or less difficult? Thanks.
Rob
Title: Re: Shuttle Q&A Part 5
Post by: ChrisC on 02/24/2011 08:18 pm
Right around now we normally have some folks wondering about "LOX drainback hold time".  Here's a post that explains it:

http://forum.nasaspaceflight.com/index.php?topic=625.msg23596#msg23596
Title: Re: Shuttle Q&A Part 5
Post by: Moe Grills on 02/24/2011 08:25 pm
   
Is it still Captain Kirk who is in command of the SRB recovery ship
out there in the waters off Florida?
I'm not joking; I learned from an CNN program that 'a' Captian Kirk was
in command of the space shuttle SRB recovery ship.
Is he still the one in command of that ship?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/24/2011 10:42 pm
Hi all.

to your knowledge, do you know if there is any contingency procedure in case some of the doors of the purge and vent system along the side of the mid fuselage don't open during the ascent?

Thanks

regards

Davide
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 02/25/2011 01:07 am
Hi all.

to your knowledge, do you know if there is any contingency procedure in case some of the doors of the purge and vent system along the side of the mid fuselage don't open during the ascent?

Thanks

regards
Davide

Launch would not happen if the vent doors were not in the correct configuration:

"The vent doors must be opened prior to liftoff. The vent door opening sequence is automatically initiated at T - 28 seconds. The vent doors are commanded open in a staggered sequence at approximately 2.5-second intervals. At T - 7 seconds, the Redundant Set Launch Sequence (RSLS) checks that all vent doors are open. If any door is out of configuration, a launch hold will be issued."

See section 2.4 of the Mechanical Systems Training Manual (MECH SYS 21002)
http://www.nasa.gov/centers/johnson/pdf/383449main_mechanical_systems_workbook_21002.pdf

There is a good collection of generic Flight Data Files and Workbooks/Training Manuals available on the NASA website for anyone wanting to get into the nitty-gritty of shuttle systems here (including nine STS-133 specific FDFs):

http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html




Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 08:53 am
I thought LOX drainback started at T-4 minutes 55 seconds.  We were told that there were only 2 seconds of LOX Drainback hold time remaining when they picked up the count at T-5 minutes for STS-133 though.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 02/25/2011 11:04 am
What exactly is your question?
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 11:55 am
The question is why they were in danger of running out of LOX Drainback hold time when the count was held at T-5 minutes?  If LOX Dranback hadn't yet started then it shouldn't have been an issue and they could at least have waited until the end of the launch window.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/25/2011 12:49 pm
The question is why they were in danger of running out of LOX Drainback hold time when the count was held at T-5 minutes?  If LOX Dranback hadn't yet started then it shouldn't have been an issue and they could at least have waited until the end of the launch window.

It starts at T-5
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 12:58 pm
If hold time at T-5 minutes is limited by LOX drainback then why not continue on down to T-31 seconds?  What is the benefit of holding at T-5 minutes?
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 02/25/2011 01:00 pm
APU start would be right after T-5. That's why they insert the hold there prior to that.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 01:14 pm
In that case then shouldn't they have waited at T-9 a bit longer so as to maximize available time?  They could have picked up the count when there were 9 minutes left in the launch window and then scrubbed when they got to T-5 if the issue hadn't been resolved.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/25/2011 02:13 pm
In that case then shouldn't they have waited at T-9 a bit longer so as to maximize available time?  They could have picked up the count when there were 9 minutes left in the launch window and then scrubbed when they got to T-5 if the issue hadn't been resolved.

In the hope that those extra 4 minutes (between t-9:00 and t-5:00) would give the SRO team time to fix the problem without slipping the launch time at all.

The whole launch window was only 5 min long, so they were not going to get any more time by adding  t-9:00 hold
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 02:22 pm
In that case then shouldn't they have waited at T-9 a bit longer so as to maximize available time?  They could have picked up the count when there were 9 minutes left in the launch window and then scrubbed when they got to T-5 if the issue hadn't been resolved.

In the hope that those extra 4 minutes (between t-9:00 and t-5:00) would give the SRO team time to fix the problem without slipping the launch time at all.

The whole launch window was only 5 min long, so they were not going to get any more time by adding  t-9:00 hold

LOX drainback was not what constrained us to "3 mins of hold time" at T-5mins. I thought they made this very clear yesterday. The launch window was only 6mins long yesterday, not 10mins long. Therefore, with "in-plane" launch targets, there were only 3mins of window beyond 16:50:27 EST. So, when we started holding at T-5mins yesterday, we only had 3mins of hold time to still launch within in the window.

Yes, there was a LOX drainback hold time call AFTER the clocks resumed from the T-5min hold. This call served to update the launch team that they could only hold an additional 2-secs (if needed later in the count) despite the fact that there were 3-secs left in the launch window.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 02:34 pm
This is a bit confusing:

The NTD during the T-20 briefing (which for some unknown reason was done during the T-9 hold not the T-20) said that LOX Drainback hold time was 1 minute 59 seconds.  SRO is not go and they decide to take the count to T-5 minutes.

When they get to T-5 minutes they have 3 minutes of hold time as you say but this is where the confusion is:

If LOX Drainback starts at T-5 minutes and holding then after 1 minute and 59 seconds they should have scrubbed.

If LOX Drainback starts at T-5 minutes and counting then 1 minute and 59 seconds of LOX Drainback hold time should have still been available when they picked up the count although as you say only 3 seconds remained in the launch window.

Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 02:43 pm
This is a bit confusing:

The NTD during the T-20 briefing (which for some unknown reason was done during the T-9 hold not the T-20) said that LOX Drainback hold time was 1 minute 59 seconds.  SRO is not go and they decide to take the count to T-5 minutes.

When they get to T-5 minutes they have 3 minutes of hold time as you say but this is where the confusion is:

If LOX Drainback starts at T-5 minutes and holding then after 1 minute and 59 seconds they should have scrubbed.

If LOX Drainback starts at T-5 minutes and counting then 1 minute and 59 seconds of LOX Drainback hold time should have still been available when they picked up the count although as you say only 3 seconds remained in the launch window.



LOX drainback starts at T-4mins 55secs. It is based on actual loads into the ET and real time monitoring. There are also engine temp requirements during LOX drainback that affect the hold time available. Basically, the temp of the LOX in the feedline down the side of the tank is "warmer" than the LOX in the tank itself and the LOX flowing into the TSMs and Orbiter aft. As drainback begins, the warmer LOX flows into the engines and warms them. At a certain point, with this warm LOX flowing through them, the engine temps violate the max temps allowed for engine start.

LOX drainback hold time is monitored throughout the count. The final "hold time remaining" is based either on engine temp limits or the amount of LOX drained back -- LOX which is no longer available for use by the SSMEs during ascent. Whichever constraint comes first (engine temp or amount of LOX drained) is what triggers the LOX drainback hold time.

What we saw yesterday was an update to the LOX drainback hold time based on these constraints and the late-in-the-window launch. Remember, also, that the further past the "in-plane" time we go, the more prop we're going to need from an Ascent Performance Margin standpoint. So, the further into the window we went, the more LOX we needed to have onboard to ensure we could meet our nominal MECO targets.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 02:47 pm
Thanks, quite a change then from an estimated 1 minute 59 seconds to an actual 2 seconds then and also a very good reason not to continue on down to T-31 seconds.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/25/2011 02:50 pm
As drainback begins, the warmer LOX flows into the engines and warms them. At a certain point, with this warm LOX flowing through them, the engine temps violate the max temps allowed for engine start.

Actually, I thought it was the other way around, as the line drains down, colder fluid from the tank replaces it and the engines can get to cold to start.

Either way, you are correct in that the Drainback hold time didn't drive the choice of when to start the extra hold.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 02:52 pm
As drainback begins, the warmer LOX flows into the engines and warms them. At a certain point, with this warm LOX flowing through them, the engine temps violate the max temps allowed for engine start.

Actually, I thought it was the other way around, as the line drains down, colder fluid from the tank replaces it and the engines can get to cold to start.

Either way, you are correct in that the Drainback hold time didn't drive the choice of when to start the extra hold.

Yes, this is true. But it takes 15 minutes of nominal LOX drainback time to actually drainback the entire LOX Feedline to get to that colder LOX.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 02:54 pm
So you can hold at T-5 minutes then for as long as the launch window allows?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 02:58 pm
So you can hold at T-5 minutes then for as long as the launch window allows?

It's not desirable as it is not a standard Built In Hold time, and there are other factors that need to be taken into consideration since the final 9mins of the count is a very dynamic and critical time. If you have a long launch window, you would just continue to hold at T-9mins. We really only count down to and hold at T-5mins if there's an issue being worked that we have a chance of clearing within a short launch window. What spurred us to count to T-5mins and hold yesterday was the short, 3min long launch window.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 03:02 pm
If you have a long launch window, you would just continue to hold at T-9mins.
That's interesting, on the January 7 launch attempt of STS-61-C (not to be confused with the eventful January 6 launch attempt), the count was held at T-9 minutes for some time due to weather.  Then they decided to recycle back to T-20 minutes and count back down to T-9 minutes where after waiting for a second time they scrubbed due to weather.  Going back to T-20 seems a bit pointless here if you can hold at T-9 for as long as you want.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 03:07 pm
If you have a long launch window, you would just continue to hold at T-9mins.
That's interesting, on the January 7 launch attempt of STS-61-C (not to be confused with the eventful January 6 launch attempt), the count was held at T-9 minutes for some time due to weather.  Then they decided to recycle back to T-20 minutes and count back down to T-9 minutes where after waiting for a second time they scrubbed due to weather.  Going back to T-20 seems a bit pointless here if you can hold at T-9 for as long as you want.

You are confusing your 61C launch attempts.

The launch attempt on January 6, 1986 was terminated at T-31 seconds because of a problem in a valve in the liquid oxygen system. The countdown was recycled to T-20 minutes for a second launch attempt on the same day but was held at T-9 minutes and then scrubbed as the launch window expired.

Another launch attempt was made on January 7 and was scrubbed because of bad weather at contingency landing sites at Dakar, Senegal and Moron, Spain.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 03:15 pm
I was going by what it said in "Some Trust in Chariots" book about Challenger which claims there were recycles on both days,
January 6 was T-31 seconds - T-20 minutes - T-9 minutes - SCRUB.
January 7 was T-9 minutes - T-20 minutes - T-9 minutes - SCRUB.
This is according to the book.

One final question also:  Was any advantage gained on STS-133 by counting down to T-5 when they did rather than holding at T-9 minutes and picking up the count at the last possible moment and the scrubbing if the issue wasn't resolved when the clock reached T-5 minutes?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 03:26 pm
I was going by what it said in "Some Trust in Chariots" book about Challenger which claims there were recycles on both days,
January 6 was T-31 seconds - T-20 minutes - T-9 minutes - SCRUB.
January 7 was T-9 minutes - T-20 minutes - T-9 minutes - SCRUB.
This is according to the book.

One final question also:  Was any advantage gained on STS-133 by counting down to T-5 when they did rather than holding at T-9 minutes and picking up the count at the last possible moment and the scrubbing if the issue wasn't resolved when the clock reached T-5 minutes?

I will have to go look at the January 7th launch info.

On the STS-133 question: Yes, gained a tremendous advantage. Not only did we launch ( ;)) but by counting to T-5mins and holding, we gave the Range 4 extra minutes to work the issue.

Think of it this way, if we had held at T-9mins, we would only have been able to hold for 3mins. That means the Range would have had to have cleared their issue by 16:44:27 EST in order for us to pick up the count and launch within the window which closed at 16:53:27 EST. They did not do this. If we had held at T-9mins, we would have scrubbed for the day.

By counting to T-5mins and holding (which began at 16:45:27 EST), the Range had those 4-minutes from T-9mins to T-5mins) plus an additional 3-mins of time once we started holding. Thus, by counting to T-5mins, the Range effectively had until 16:48:27 EST to work and clear the issue. They cleared the issue (manual switch throw from "hold" to "proceed") at 16:48:10 EST and the count resumed at 16:48:24 EST.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 03:30 pm
I was resuming the count at T-9 minutes 1 second before the end of the launch window even if the range was still no-go.  The clock would then count down to T-5 minutes and if they didn't have a go by that time then the launch would be scrubbed.  You wouldn't lose any time if you did it that way.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 03:33 pm
I was resuming the count at T-9 minutes 1 second before the end of the launch window even if the range was still no-go.  The clock would then count down to T-5 minutes and if they didn't have a go by that time then the launch would be scrubbed.  You wouldn't lose any time if you did it that way.

Yes, you would. You would lose 4-minutes of troubleshooting time. Re-read my post directly about this one  ;).
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 03:44 pm
The launch window clsoed at 16:53:27 EST.  T-5 is as low as you would want to go in the count as going beyond there would invovle starting the APUs and if you are not going to launch you don't want to start them.  If you resumed at 16:44:27.  What I'm saying is that you could have resumed the count at this time regardless of the range.  The range would still have had the extra 3 minutes of the T-9 hold plus the time to count down from T-9 to T-5 to troubleshoot the issue before a scrub would have to be decalred.  The clock would have reached T-5 minutes at 16:48:27, the same point at which a scrub would have been declared by the way you did it.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 03:48 pm
The launch window clsoed at 16:53:27 EST.  T-5 is as low as you would want to go in the count as going beyond there would invovle starting the APUs and if you are not going to launch you don't want to start them.  If you resumed at 16:44:27.  What I'm saying is that you could have resumed the count at this time regardless of the range.  The range would still have had the extra 3 minutes of the T-9 hold plus the time to count down from T-9 to T-5 to troubleshoot the issue before a scrub would have to be decalred.  The clock would have reached T-5 minutes at 16:48:27, the same point at which a scrub would have been declared by the way you did it.

No. If you pick up the count at T-9mins with no option to hold at T-5mins because a department is "no go" then you are in violation of the Launch Commit Criteria. They could no have done this. The only reason we were allowed to proceed past T-9mins, was because we had hold time at T-5mins.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 03:55 pm
I wasn't saying not have a hold at T-5.  Keep the hold in there to stop the clock at T-5 minutes.  The clock would reach T-5 minutes exactly 5 minutes before the end of the window and would then hold so a scrub could be declared.  The count would have entered the T-5 hold at the exact same time that STS-133 would have been scrubbed even f you had already counted down to T-5 and waited there.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 03:59 pm
I wasn't saying not have a hold at T-5.  Keep the hold in there to stop the clock at T-5 minutes.  The clock would reach T-5 minutes exactly 5 minutes before the end of the window and would then hold so a scrub could be declared.  The count would have entered the T-5 hold at the exact same time that STS-133 would have been scrubbed even f you had already counted down to T-5 and waited there.

Again, it doesn't work like that. There would be no option to "hold" at T-5mins if you were targeting the end of the window. Thus, all systems would have had to have been "GO" to resume the count at T-9mins for an exact "end of window" launch. This was not and would not have been the case yesterday.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/25/2011 04:00 pm
I wasn't saying not have a hold at T-5.  Keep the hold in there to stop the clock at T-5 minutes.  The clock would reach T-5 minutes exactly 5 minutes before the end of the window and would then hold so a scrub could be declared.  The count would have entered the T-5 hold at the exact same time that STS-133 would have been scrubbed even f you had already counted down to T-5 and waited there.

There is no T-5 hold.  T-5 is a hold point.  There are other hold points like LO2 hood retract, Auto sequencer start, etc.  The point is that there are no holds after T-9 until there is a problem
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 04:05 pm
So you are not allowed to specify a hold point then if are targetting the end if window.  So in the event that you were to target the end of the window and you resumed the count at T-9 minutes and you needed to stop the clock would you call a hold, inform the crew you are going to scrub and then call GLS cutoff or would you just directly call GLS cutoff regardless of how far down the count you were?

Thanks for the replies everyone, I have a better understanding now.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/25/2011 04:09 pm
So you are not allowed to specify a hold point then if are targetting the end if window.  So in the event that you were to target the end of the window and you resumed the count at T-9 minutes and you needed to stop the clock would you call a hold, inform the crew you are going to scrub and then call GLS cutoff or would you just directly call GLS cutoff regardless of how far down the count you were?

Thanks for the replies everyone, I have a better understanding now.

You would be in an automatic scrub scenario. I believe you would continue to count to the next GLS milestone and then issue a GLS cutoff.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 04:12 pm
I've actually never heard a HOLD! HOLD! HOLD! call on a shuttle launch but then manual hold requets after T-9 minutes do seem quite rare.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/25/2011 04:16 pm
I've actually never heard a HOLD! HOLD! HOLD! call on a shuttle launch but then manual hold requets after T-9 minutes do seem quite rare.

No, the shuttle syntax is "GLS give cut off"
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 04:17 pm
I thought that was only after T-31 seconds.  If a hold is called before that time it doesn't automatically mean a cutoff.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/25/2011 04:20 pm
I thought that was only after T-31 seconds.  If a hold is called before that time it doesn't automatically mean a cutoff.

Before that it is "GLS, Hold for XXXX"

Hold, Hold, Hold is only used for ELV's
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/25/2011 04:40 pm
Anyone know why the T-20 briefing was done during the T-9 hold for STS-133?
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 02/25/2011 05:29 pm
In one of the ascent reports on L2, it mentions a 2-second "RCS window protect firing" occurring about 10 seconds before the OMS assist burn. I haven't seen this term before, and a quick search doesn't show any other mentions of this burn.

Can someone provide some insight into this burn?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/25/2011 05:37 pm
In one of the ascent reports on L2, it mentions a 2-second "RCS window protect firing" occurring about 10 seconds before the OMS assist burn. I haven't seen this term before, and a quick search doesn't show any other mentions of this burn.

Can someone provide some insight into this burn?

http://forum.nasaspaceflight.com/index.php?topic=2030.msg33768#msg33768
Title: Re: Shuttle Q&A Part 5
Post by: pummuf on 02/25/2011 06:52 pm
What's involved with the SSME servicing between flights?
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 02/25/2011 08:45 pm
D'oh.

I searched for both "RCS window protect firing" and then "window protect firing".

I was one dropped word away...
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/25/2011 09:37 pm
There a RCS window protecting firing in the moment in which the SRM separate from the ET in order to avoid that the exaust coming off the SRM separation thrusters could damage the forward windows. The forward RCS jets are fired so that they don't allow this exaust to hit the windows. In this way the maintenance of the forward windows is eased.

there is an explanation of this firing in the RCS Workbook on L2.

hope this help
Title: Re: Shuttle Q&A Part 5
Post by: chriswaterrockets on 02/26/2011 11:42 am
Hi all,

Before the launch of every shuttle there is some kind of gas exiting at the base of the main engines. (see picture) I wanted to know what exactly that is. I read somewhere that it is gaseous oxygen that is vented. Is that correct? If yes, what's the purpose?

Thanks for your answers.

chris
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/26/2011 11:45 am
 It is to chill down the engines
Title: Re: Shuttle Q&A Part 5
Post by: chriswaterrockets on 02/26/2011 11:51 am
Ok, thanks, but isn't oxygen awfully corrosive, at least when liquid? Why don't they use the liquid hydrogen?
Title: Re: Shuttle Q&A Part 5
Post by: dsmillman on 02/26/2011 12:16 pm
Ok, thanks, but isn't oxygen awfully corrosive, at least when liquid? Why don't they use the liquid hydrogen?
They don't want hydrogen around the engines at SSME ignition.  If you watch a shuttle countdown you see the gaseous hydrogen around the SSME's is deliberately burned off just before the SSME's are ignited.
Title: Re: Shuttle Q&A Part 5
Post by: chriswaterrockets on 02/26/2011 12:22 pm
Okay, thanks very much.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/26/2011 12:26 pm
Ok, thanks, but isn't oxygen awfully corrosive, at least when liquid? Why don't they use the liquid hydrogen?

flammable
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/26/2011 10:26 pm
hi all.

few questions about the TPS.

1. in which way tiles, gap fillers and filler bars are removed?
2. in which way tiles are repaired if there is for instance damage like scratches or gouges?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: rbfnet on 02/27/2011 03:10 am
During the STS-133 countdown, I thought I heard that the limiting factor in how long the T-5 hold (for the range issue) could last was LOX drainback (rather than the end of the full 10 minute launch window) ... and that ultimately they got the count restarted with only 2 seconds of hold time left (again, LOX drainback limited).  But LOX replenish doesn't terminate until T-4:55, so they would have been replenishing during the hold ... so I would have expected a T-5 hold to be able to last up until the point where the resulting T-0 would be out of the 10 minute launch window.  Am I missing something?
Title: Re: Shuttle Q&A Part 5
Post by: wally on 02/27/2011 09:56 am
During STS-133 hatch closing (http://cl.ly/3t0G432a0o1D0F0a410E)
Isn't there a No Step sign? :)
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 02/27/2011 11:05 am
During the STS-133 countdown, I thought I heard that the limiting factor in how long the T-5 hold (for the range issue) could last was LOX drainback (rather than the end of the full 10 minute launch window) ... and that ultimately they got the count restarted with only 2 seconds of hold time left (again, LOX drainback limited).  But LOX replenish doesn't terminate until T-4:55, so they would have been replenishing during the hold ... so I would have expected a T-5 hold to be able to last up until the point where the resulting T-0 would be out of the 10 minute launch window.  Am I missing something?

A few posts back there was a long conversation about this, starting here: http://forum.nasaspaceflight.com/index.php?topic=17437.msg697651#msg697651

Also see here: http://forum.nasaspaceflight.com/index.php?topic=625.msg23596#msg23596
Title: Re: Shuttle Q&A Part 5
Post by: glanmor05 on 02/27/2011 04:39 pm
Today the SSMRS had to get the OBSS out of the payload bay and hand it off to the Shuttle Arm.  Before docking the Shuttle Arm could get its own OBSS.  Was today just about clearance issues?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/27/2011 05:08 pm
Today the SSMRS had to get the OBSS out of the payload bay and hand it off to the Shuttle Arm.  Before docking the Shuttle Arm could get its own OBSS.  Was today just about clearance issues?
More like interference issues. The SRMS can't reach the forward OBSS grapple fixture due PMA2/Node2 being in the way.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/27/2011 05:09 pm
Today the SSMRS had to get the OBSS out of the payload bay and hand it off to the Shuttle Arm.  Before docking the Shuttle Arm could get its own OBSS.  Was today just about clearance issues?

Yes, specifically between the shuttle RMS and the JEM.
Title: Re: Shuttle Q&A Part 5
Post by: glanmor05 on 02/27/2011 05:44 pm
Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/27/2011 05:55 pm
Quote from: sivodave
hi all.

few questions about the TPS.

1. in which way tiles, gap fillers and filler bars are removed?
2. in which way tiles are repaired if there is for instance damage like scratches or gouges?

thanks

Hi guys...nobody of you has any answer to my questions? I'm doing a research work about this subject and I'm curious to know the answers to these questions.

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Gary on 02/27/2011 07:22 pm
What's the difference between air to ground & space to ground and how does the 'big loop' actually work?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/27/2011 07:34 pm
What's the difference between air to ground & space to ground

Terminology. A/G is used for shuttle and S/G is used for ISS.

Quote
and how does the 'big loop' actually work?

Loops A/G 1 and S/G 1 are tied together so that transmissions on one loop are heard on the other. During free-flight the loops are tied using the UHF radios (SSOR on the shuttle and SSSR on ISS). During docked ops there is a hardline connection.
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 02/27/2011 07:55 pm
Quote from: sivodave
hi all.

few questions about the TPS.

1. in which way tiles, gap fillers and filler bars are removed?
2. in which way tiles are repaired if there is for instance damage like scratches or gouges?

thanks

Hi guys...nobody of you has any answer to my questions? I'm doing a research work about this subject and I'm curious to know the answers to these questions.

thanks

Davide

Don't give up. It's a weekend, and some of the folks who could accuratly answer are probably busy working STS-133. :)
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/27/2011 10:15 pm
Quote from: sivodave
hi all.

few questions about the TPS.

1. in which way tiles, gap fillers and filler bars are removed?
2. in which way tiles are repaired if there is for instance damage like scratches or gouges?

thanks

Hi guys...nobody of you has any answer to my questions? I'm doing a research work about this subject and I'm curious to know the answers to these questions.

thanks

Davide

Don't give up. It's a weekend, and some of the folks who could accuratly answer are probably busy working STS-133. :)

I basically asked the same as your question 1 a couple of weeks ago with no results. I have never seen any PR photos of the process either, so it may be somthing NASA feels is sensative and the people around here are respecting that.

As far as your question 2, small dings and chips in the borosilicate glass coating of the tiles is repaired with a putty compound. That is what they did the other day durring Discovery's launch when they got a chip in one of the tiles when removing the protective sheets after closing the hatch. Normally they would coat the repair with a water-proofing compound (similar to 3M's scotchguard but a different formula), but they waived that this time.

Good luck with your research.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 02/27/2011 11:52 pm
Saw the explanation of LOX drainback from Mark.

Is there a document that explains that and other functions we routinely hear about?

I looked around L2 and no luck.....

thanks!!

Jeff
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 02/28/2011 12:19 am
I guess it depends on what other functions you are after? Do a search for handbook or ssme bible? Searching GLS gave the second hit as something you might be after? Try looking around using tags. http://forum.nasaspaceflight.com/index.php?action=tags
Title: Re: Shuttle Q&A Part 5
Post by: AnimatorRob on 02/28/2011 05:13 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/28/2011 05:26 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

No,

Even though PR shots always show the vehicle uncovered, in real life, the shuttle is always covered.

It is uncovered only a few times during a mission.
1.  rollout
2.  APU hot fire
3.  Payload installation into the PCR
4. launch

Only 1 & 4 happen every mission.  The other two happen occasionally and only for a day
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 02/28/2011 05:33 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

I believe during roll-out to the pad, the public is still allowed to see it from the pad tourist location/gantry.  I think that would be your best bet.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 02/28/2011 06:03 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

I believe during roll-out to the pad, the public is still allowed to see it from the pad tourist location/gantry.  I think that would be your best bet.

Yes, but rollouts occur during non-public tour times.

Both STS-134 and STS-135 will target rollouts in the evening/overnight hours.
Title: Re: Shuttle Q&A Part 5
Post by: AnimatorRob on 02/28/2011 06:47 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

I believe during roll-out to the pad, the public is still allowed to see it from the pad tourist location/gantry.  I think that would be your best bet.

Yes, but rollouts occur during non-public tour times.

Both STS-134 and STS-135 will target rollouts in the evening/overnight hours.

Thanks for the responses guys, it looks like I may be out of luck. Still at least I can get a pic of him while the RSS is closed. Not as cool, but still I think he'll appreciate it when he's older. I wish I had a photo of myself with a Saturn on the pad. At least he'll be able to see the actually flown orbiters in a museum.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/01/2011 03:42 pm
Regarding the Shuttle I was wondering if anyone knew why the main engines of the shuttle were attached to the Shuttle itself.  It would of made sense to me if the shuttle had the capability to store a significant amount of fuel on board and there was some sort of fuel depot architecture that would allow the shuttle to refuel in orbit.  Now I understand that the current architecture does make the engines reusable, but as I understand it the need to completely rebuild the engines at every launch makes the re-usability hardly any better than the expendable one.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/01/2011 03:45 pm
Regarding the Shuttle I was wondering if anyone knew why the main engines of the shuttle were attached to the Shuttle itself.  It would of made sense to me if the shuttle had the capability to store a significant amount of fuel on board and there was some sort of fuel depot architecture that would allow the shuttle to refuel in orbit.  Now I understand that the current architecture does make the engines reusable, but as I understand it the need to completely rebuild the engines at every launch makes the re-usability hardly any better than the expendable one.

The orbiter does have a significant amount of prop onboard.  However, they are not used by the SSMEs.  They do not function for the duration of the flight after MECO.  You essentially answered your own question about why they are on the back of the orbiter so they can be reused.

The engines are also not "completely rebuilt". 
Title: Re: Shuttle Q&A Part 5
Post by: pummuf on 03/01/2011 03:56 pm
Regarding the Shuttle I was wondering if anyone knew why the main engines of the shuttle were attached to the Shuttle itself.  It would of made sense to me if the shuttle had the capability to store a significant amount of fuel on board and there was some sort of fuel depot architecture that would allow the shuttle to refuel in orbit.  Now I understand that the current architecture does make the engines reusable, but as I understand it the need to completely rebuild the engines at every launch makes the re-usability hardly any better than the expendable one.

The orbiter does have a significant amount of prop onboard.  However, they are not used by the SSMEs.  They do not function for the duration of the flight after MECO.  You essentially answered your own question about why they are on the back of the orbiter so they can be reused.

The engines are also not "completely rebuilt". 
What is involved in servicing between missions?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/01/2011 04:14 pm
Not completely sure of the exact requirements since I am not on SSME Project but inspections, functional checks, green runs, etc. 
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 03/01/2011 08:34 pm
Regarding the Shuttle I was wondering if anyone knew why the main engines of the shuttle were attached to the Shuttle itself.  It would of made sense to me if the shuttle had the capability to store a significant amount of fuel on board and there was some sort of fuel depot architecture that would allow the shuttle to refuel in orbit.  Now I understand that the current architecture does make the engines reusable, but as I understand it the need to completely rebuild the engines at every launch makes the re-usability hardly any better than the expendable one.
...
The engines are also not "completely rebuilt". 
     Nowadays they may not be, but earlier in the program they were wrestling with e.g. cracked turbopump turbine blades. SSME saw a lot of redesign work over the past thirty years to get them to this stage, with the most recent upgrades even in 2007.
     
    DarkenedOne, you may find "The Space Shuttle Decision" illuminating http://history.nasa.gov/SP-4221/sp4221.htm
 
    There were indeed earlier proposals with large internal fuel tankage, then (IIRC?) just the LOX tank interior and the ET holding LH2, before arriving at the final configuration.

   -Alex
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/01/2011 08:38 pm
     Nowadays they may not be, but earlier in the program they were wrestling with e.g. cracked turbopump turbine blades. SSME saw a lot of redesign work over the past thirty years to get them to this stage, with the most recent upgrades even in 2007.
     
 

That doesn't mean the engines were "completely rebuilt".  I'm not suggesting there isn't maintenance, inspections, etc. 

There have been a lot of redesigns/upgrades/improvements over the years across the entire vehicle.  SSME is not unique to this. 
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 03/01/2011 09:09 pm
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

No,

Even though PR shots always show the vehicle uncovered, in real life, the shuttle is always covered.

It is uncovered only a few times during a mission.
1.  rollout
2.  APU hot fire
3.  Payload installation into the PCR
4. launch

Only 1 & 4 happen every mission.  The other two happen occasionally and only for a day
The RSS is also extended for a tanking test, which STS-134 is scheduled to perform, immediately followed by pyld installation, so there will be a couple of days where the RSS will be extended.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/02/2011 03:08 am
I would very much like to get a photo of my ( now 6 month old ) son with a shuttle stack behind him. I'm thinking probably not until STS-135 Atlantis as he's still fussy on long car rides. The question is is there a reliable opportunity to get such photos without the RSS blocking the view?

No,

Even though PR shots always show the vehicle uncovered, in real life, the shuttle is always covered.

It is uncovered only a few times during a mission.
1.  rollout
2.  APU hot fire
3.  Payload installation into the PCR
4. launch

Only 1 & 4 happen every mission.  The other two happen occasionally and only for a day
The RSS is also extended for a tanking test, which STS-134 is scheduled to perform, immediately followed by pyld installation, so there will be a couple of days where the RSS will be extended.

Even so, the angle from the viewing gantry is not great. The open RSS would still block your view of the orbiter
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 03/02/2011 03:29 am
One of the ladies on ISS during STS-133 (couldn't tell which one) just said something really odd to me during the daily highlights.  They were equalizing the pressure between ISS and the PMM and there was a lot of flow audible.

What she said was, "it smells like....space".  Another crew member said "yep" to that.  What does that mean?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/02/2011 10:44 am
One of the ladies on ISS during STS-133 (couldn't tell which one) just said something really odd to me during the daily highlights.  They were equalizing the pressure between ISS and the PMM and there was a lot of flow audible.

What she said was, "it smells like....space".  Another crew member said "yep" to that.  What does that mean?

They smell the same thing when returning EVA crewmembers enter the station.  The vacuum/atomic oxygen causes a unique smell.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/02/2011 02:22 pm

http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html

"Well, it has been 24 years since the last time a software problem required an on-orbit fix during a mission. In the last 12 years, only three software errors have appeared during a flight. But perhaps the most meaningful statistic is that a software error has never endangered the crew, shuttle or a mission's success."

I am looking for more information / details regarding the on-orbit fix and the three software errors.

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 03/02/2011 05:16 pm
What do the numbers "19" and "20" mean on the WVS from the EVAers helmet cams?  For many missions, the numbers were "16" and "18."  What are the numbers' significance, and why did they change?
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 03/02/2011 09:00 pm
One of the ladies on ISS during STS-133 (couldn't tell which one) just said something really odd to me during the daily highlights.  They were equalizing the pressure between ISS and the PMM and there was a lot of flow audible.

What she said was, "it smells like....space".  Another crew member said "yep" to that.  What does that mean?

See these:-

http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles4.html (http://spaceflight.nasa.gov/station/crew/exp6/spacechronicles4.html)

http://articles.cnn.com/2002-11-08/tech/station.interview_1_valery-korzun-smell-international-space-station?_s=PM:TECH (http://articles.cnn.com/2002-11-08/tech/station.interview_1_valery-korzun-smell-international-space-station?_s=PM:TECH)

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 03/02/2011 09:49 pm
One of the ladies on ISS during STS-133 (couldn't tell which one) just said something really odd to me during the daily highlights.  They were equalizing the pressure between ISS and the PMM and there was a lot of flow audible.

What she said was, "it smells like....space".  Another crew member said "yep" to that.  What does that mean?

They smell the same thing when returning EVA crewmembers enter the station.  The vacuum/atomic oxygen causes a unique smell.

Interesting. One of the posts from Martin said it smelled like Ozone.  I wonder if it really is Ozone (atomic Oxygen joining with O2).

Thanks to both of you.
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 03/03/2011 02:12 am
Ozone seems more likely; surely at one atmosphere atomic oxygen would combine to form molecular oxygen virtually instantaneously.

Grouchy pet peeve:  chemical elements are not capitalized, thus "oxygen" (and "ozone") rather than "Oxygen", please.  :):)
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 03/03/2011 04:53 am
They smell the same thing when returning EVA crewmembers enter the station.  The vacuum/atomic oxygen causes a unique smell.
Ozone seems more likely; surely at one atmosphere atomic oxygen would combine to form molecular oxygen virtually instantaneously.
     Jim may not be referring to the smell of atomic oxygen any more than the "smell" of vacuum, but rather the effects that the free radicals have on e.g. organic materials.
      -Alex
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/04/2011 04:49 pm
What exactly is this fitting sticking out of the side of the aft compartment used for?

I used to think that it was for a jack stand to support the aft end in the OPF (like the fore end is) but I found out that they use the main landing gear or the ET salad bowls for that, so that isn't what its for.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/04/2011 05:18 pm
What exactly is this fitting sticking out of the side of the aft compartment used for?

I used to think that it was for a jack stand to support the aft end in the OPF (like the fore end is) but I found out that they use the main landing gear or the ET salad bowls for that, so that isn't what its for.
That's the vent port of Flash Evaporator#2. The vent port for Flash Evaporator#1 is on the port side.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 03/04/2011 05:38 pm
So what will happen with the SRB casings that were recovered after Discovery's launch last week since now the final 2 remaining flights already have thier SRBs prepped? And what will happen to the ones from Endevour and Atlantis since they would have no reason to refurb them
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/04/2011 05:45 pm
So what will happen with the SRB casings that were recovered after Discovery's launch last week since now the final 2 remaining flights already have thier SRBs prepped? And what will happen to the ones from Endevour and Atlantis since they would have no reason to refurb them

All of the current plans for a followup to the shuttle (SLS, Direct, even Ares (RIP)) envision using some version of the SRBs including re-using the current stock of hardware. The cases will be post flight processed as normal and then stored until they are needed again.
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 03/04/2011 08:35 pm
What exactly is this fitting sticking out of the side of the aft compartment used for?

I used to think that it was for a jack stand to support the aft end in the OPF (like the fore end is) but I found out that they use the main landing gear or the ET salad bowls for that, so that isn't what its for.
That's the vent port of Flash Evaporator#2. The vent port for Flash Evaporator#1 is on the port side.
More specifically, it's the FES starboard topping duct nozzle plug with a desiccant attached to it.  The port topping duct nozzle plug is opposite and fwd of that (close to the 50-1 door) is the FES hi load duct nozzle plug.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/04/2011 11:34 pm
What exactly is this fitting sticking out of the side of the aft compartment used for?

I used to think that it was for a jack stand to support the aft end in the OPF (like the fore end is) but I found out that they use the main landing gear or the ET salad bowls for that, so that isn't what its for.
That's the vent port of Flash Evaporator#2. The vent port for Flash Evaporator#1 is on the port side.
More specifically, it's the FES starboard topping duct nozzle plug with a desiccant attached to it.  The port topping duct nozzle plug is opposite and fwd of that (close to the 50-1 door) is the FES hi load duct nozzle plug.
Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 03/05/2011 03:27 pm
I wondered what that small metal tube was sticking out of side of the aft fuselage near the body flap. Thanks fellas for clearing that up. :)

Why were Columbia's wings given the extra black tiles on the top of the wings and the other orbiters didn't? I'm also curious as to why she wasn't given a total AFRSI cover like OV-103, 104, and 105? She still had the old tiles covering the forward fuselage.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/05/2011 03:32 pm
I wondered what that small metal tube was sticking out of side of the aft fuselage near the body flap. Thanks fellas for clearing that up. :)

Why were Columbia's wings given the extra black tiles on the top of the wings and the other orbiters didn't? I'm also curious as to why she wasn't given a total AFRSI cover like OV-103, 104, and 105? She still had the old tiles covering the forward fuselage.
On the black upper wing chines: Not tiles exactly. That was just a thermal coating paint applied to already existing LRSI and FRSI TPS while she was still OPF1 prior to the first flight.

Some analysis showed that it was necessary but subsequent flights showed the analysis was wrong and none of the subsequent orbiters had it applied.

I think they were planning to do the tile to blanket transition in stages to minimize orbiter down time between missions.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 03/06/2011 12:23 pm
I see. Hmm, my guess is had Columbia's accident not happened, she would look somewhat similar to the other orbiters.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/06/2011 12:56 pm
I see. Hmm, my guess is had Columbia's accident not happened, she would look somewhat similar to the other orbiters.



She wasvalways different in that aspect and there was no plan to change the paint.  The tlles would only  be changed for repair
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/07/2011 03:04 pm
I see. Hmm, my guess is had Columbia's accident not happened, she would look somewhat similar to the other orbiters.

Actually, there has been almost no "cosmetic" work done on the orbiters over the years. The one big exception was the repainting done as part of Goldin's famous banning of the "worm". If you look at close up photos of the various rescue lables and instructions painted around the exterior of the cabin, you'll notice that the wording is almost illegible after all these years since they have never been redone since the orbiter's were first assembled.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/07/2011 06:49 pm
In this STS-123 launch video clip from inside the cabin;

http://www.youtube.com/watch?v=doT6OcGULNo&feature=related

"bias in the PC booster" 1:47

what does that mean?

whats with the counting right after liftoff?

also, is that a C&W alarm going off at 3:09 ?

also, compared to the handful of cabin vids ive seen this crew seems more vocal about their emotions ("i love you guys"), and more excited in their tone of voice (engine ig and liftoff) than others.


Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/07/2011 08:01 pm
Great video.  Thanks for posting.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/07/2011 08:14 pm
In this STS-123 launch video clip from inside the cabin;

http://www.youtube.com/watch?v=doT6OcGULNo&feature=related

"bias in the PC booster" 1:47

what does that mean?

PC 'ducer, not booster. PC means "chamber pressure" and 'ducer is short for transducer. Bias means the 'ducer is reading differently than it should.

Quote
whats with the counting right after liftoff?

Counting up to roll program, I think, but I'm not an ascent guy.

Quote
also, is that a C&W alarm going off at 3:09 ?

Yes, class 2 C&W siren.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/07/2011 10:20 pm
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

From what I heard they are not considerably cheaper.  Ares I seems to confirm this as its estimated operational cost was over a billion per flight.  I also seems like the rest of the rocket industry does not seem interested in reusable solid boosters.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/07/2011 10:27 pm
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

The costs are pretty much a wash. The rationale for continuing to recover them is more postflight analysis for safety trends than economics.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/07/2011 10:35 pm
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

The costs are pretty much a wash. The rationale for continuing to recover them is more postflight analysis for safety trends than economics.

Why is that necessary especially after a decent number have flown? 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/07/2011 11:03 pm
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

The costs are pretty much a wash. The rationale for continuing to recover them is more postflight analysis for safety trends than economics.

Why is that necessary especially after a decent number have flown? 

1) To serve as an end-check of process integrity and prevent "escapes".
2) Define "decent number". The number of shuttle flights to date (133) would not even suffice for a flight-test program for a typical airliner or military plane. It is still very much an experimental vehicle.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/08/2011 12:27 am
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

The costs are pretty much a wash. The rationale for continuing to recover them is more postflight analysis for safety trends than economics.

Why is that necessary especially after a decent number have flown? 

1) To serve as an end-check of process integrity and prevent "escapes".
2) Define "decent number". The number of shuttle flights to date (133) would not even suffice for a flight-test program for a typical airliner or military plane. It is still very much an experimental vehicle.

Well by airliner standards it was experimental, but as far as space vehicles go few vehicles have a longer track record.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/08/2011 12:34 am
Hey guys I was just wondering if anybody could tell me whether or not the reusable solid rocket boosters used by the Shuttle were any cheaper than expendable ones. 

The costs are pretty much a wash. The rationale for continuing to recover them is more postflight analysis for safety trends than economics.

Why is that necessary especially after a decent number have flown? 

1) To serve as an end-check of process integrity and prevent "escapes".
2) Define "decent number". The number of shuttle flights to date (133) would not even suffice for a flight-test program for a typical airliner or military plane. It is still very much an experimental vehicle.

Well by airliner standards it was experimental, but as far as space vehicles go few vehicles have a longer track record.

NASA managers fooled themselves into thinking that, too. Got slapped pretty hard by both accident investigation boards for it. Both accident reports emphatically recommended NASA treat the shuttle as experimental. And gathering forensic data after each flight is one thing you do on experimental vehicles.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/08/2011 12:36 am

Great video.  Thanks for posting.
Sounds like you haven't seen it before. I would have thought full members would have seen it by now. :) Glad to see i havent rehashed something. :)

PC 'ducer, not booster. PC means "chamber pressure" and 'ducer is short for transducer. Bias means the 'ducer is reading differently than it should.
So in this case, PC should have been 0 since it was pre-ignition?
I'm guessing that this is a known "signature" and therefore doesnt mandate a scrub / troubleshooting? Is there a limit to where a bias would raise eyebrows?

Quote
Counting up to roll program, I think, but I'm not an ascent guy.
I thought that as well.... just wondering why I havent seen it done on other launches.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/08/2011 01:16 am
PC 'ducer, not booster. PC means "chamber pressure" and 'ducer is short for transducer. Bias means the 'ducer is reading differently than it should.
So in this case, PC should have been 0 since it was pre-ignition?

I *think* the ducer in question returns psia, not psig, so it should have been reading around 14.7 since the nozzle was exposed to ambient pressure.

Quote
I'm guessing that this is a known "signature" and therefore doesnt mandate a scrub / troubleshooting? Is there a limit to where a bias would raise eyebrows?

Yes.

Quote
Quote
Counting up to roll program, I think, but I'm not an ascent guy.
I thought that as well.... just wondering why I havent seen it done on other launches.


If mkirk was still around he might have been able to answer that.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 03/08/2011 01:34 am
Well by airliner standards it was experimental, but as far as space vehicles go few vehicles have a longer track record.

Just because it's a space vehicle doesn't make it inherently safer and thus certifiable in a shorter time frame.  Quite the contrary, in fact.

http://787flighttest.com/

3103 flight hours and 1065 flights so far, and still not certified.  Imagine what it would take to fully certify a vehicle that carries 1000 times more energy and has far fewer intact failure and abort options.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/08/2011 02:41 am
Quick question for you guys. 

Why is it that NASA never bothered to place a flight data recorder in the space shuttles?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/08/2011 02:44 am
Quick question for you guys. 

Why is it that NASA never bothered to place a flight data recorder in the space shuttles?

Downlinked telemetry.  There is also MADS which records some measurements that aren't down listed
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/08/2011 02:49 am
Quick question for you guys. 

Why is it that NASA never bothered to place a flight data recorder in the space shuttles?

Downlinked telemetry.  There is also MADS which records some measurements that aren't down listed

There is also the OPS recorders, since replaced with solid state recorders.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 03/09/2011 09:41 am
Was wondering what the out lined plan is when Discovery comes home today, and she is rolled back to the OPF today, what steps and time frame will it take for her to be decommissioned and how much of her internals will she actually loose? After seeing pictures of how enterprise was gutted, I'd hate to see the orbiters have it happen to
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 03/09/2011 09:43 am
Was wondering what the out lined plan is when Discovery comes home today, and she is rolled back to the OPF today, what steps and time frame will it take for her to be decommissioned and how much of her internals will she actually loose? After seeing pictures of how enterprise was gutted, I'd hate to see the orbiters have it happen to

Fully outlined in L2. I'll be writing an article on the process post mission.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/09/2011 02:21 pm
...After seeing pictures of how enterprise was gutted, I'd hate to see the orbiters have it happen to

The interior apperance of OV-101 is a result of a combination of the facts that it wasn't ever fitted out completely to begin with and they removed everything that they could use as spares for the rest of the fleet or was dangerous to keep in the orbiter (like pyros). The rest of the fleet will have parts of the MPS including the entire SMEs removed (to be used for testing of future designs) and the hazardous systems will be removed or inerted and that is about it.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/09/2011 02:49 pm
...After seeing pictures of how enterprise was gutted,
where can these pictures be found?

thanks!
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/09/2011 04:52 pm
...After seeing pictures of how enterprise was gutted,
where can these pictures be found?

thanks!


There's some in Jenkins. You might try googling "enterprise" + " crew cabin" or "payload bay"
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/09/2011 05:37 pm

There's some in Jenkins. You might try googling "enterprise" + " crew cabin" or "payload bay"

thanks... please disregard though.... i was reading enterprise, but thinking endeavour... i said to myself, "they have already gutted her!??".

Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/09/2011 05:40 pm
has any data from the protuberance tests been released and if so, where can it be found?

thanks

Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/09/2011 06:08 pm
has any data from the protuberance tests been released and if so, where can it be found?

thanks

Here's a couple of papers I'm aware of covering the tile protuberance experiments (DTO 900):

Boundary Layer Transition Flight Experiment Overview and In-Situ Measurements
Thermal and Fluids Analysis Workshop 2010; 16-20 Aug. 2010; Houston, TX
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100030598_2010032987.pdf

HYTHIRM Radiance Modeling and Image Analyses in Support of STS-119, STS-125 and STS-128 Space Shuttle Hypersonic Re-entries
48th AIAA Aerospace Sciences Meeting; 4-7 Jan. 2010; Orlando, FL
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100026009_2010025699.pdf
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/09/2011 09:12 pm
Joe Engle mentioned that the experimental entry maneuvers of STS-2 heated up the wings a little extra and reduced the total number of flights that Columbia would be allowed to make.  Do we know the number of flights a shuttle could make before its structure would be considered too fatigued?  Just wondering how the number 39 (for Discovery) compares to that number.

The vehicle, 102 included, is certified for 100 missions each.  Obviously there are inspections performed every flow and more detailed inspections during OMDP.  However, from a structure and system standpoint, there has been and is nothing suggesting that number is less.

Columbia was also still certified for 100 missions at the time of her loss. 
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 03/09/2011 10:51 pm
What was used to simulate the tiles for Enterprise? I know from the CAIB report that the RCC is made from fiberglass.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/10/2011 12:11 am
What was used to simulate the tiles for Enterprise? I know from the CAIB report that the RCC is made from fiberglass.
Polystyrene foam
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 12:14 am
Joe Engle mentioned that the experimental entry maneuvers of STS-2 heated up the wings a little extra and reduced the total number of flights that Columbia would be allowed to make.  Do we know the number of flights a shuttle could make before its structure would be considered too fatigued?  Just wondering how the number 39 (for Discovery) compares to that number.

The vehicle, 102 included, is certified for 100 missions each.  Obviously there are inspections performed every flow and more detailed inspections during OMDP.  However, from a structure and system standpoint, there has been and is nothing suggesting that number is less.

Columbia was also still certified for 100 missions at the time of her loss. 


Only 39 out of 100 possible is sadder than I thought.  Still at the top of her game, as they keep saying.

Absolutely.  There are very intersting metrics that show the number of IPRs, PRs, IFAs, etc down considerably in a very smooth curved trend. 

Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/10/2011 12:17 am
Only 39 out of 100 possible is sadder than I thought.  Still at the top of her game, as they keep saying.

But if they had made the originaly projected flight rate, she would have probably hit 100 missions by now. Anyway you look at it, she had a remarkable and complete career.
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 03/10/2011 03:35 am
When they were being designed, the original 'life' of an orbiter was expected to be less than 10 years (having flown 100 times in less than that timeframe)..

The B-52 has been flying longer than that, but it has needed re-certifying a few times now in its history, again because of its age.

Although they haven't flown as often as originally foreseen, and are still in great condition, the three remaining orbiter's airframes are still quite a bit older than the design was originally intended to last (Discovery was fast approaching 3 times its original design intent).  So the same basic re-certification is just needed for the Orbiter fleet, purely because of their age.   CAIB were simply bringing this need to NASA's attention, if they wanted to use Shuttle much beyond 2010.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 03/10/2011 12:02 pm
Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.

Am I pulling this out of my bum, or did it actually happen?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/10/2011 01:01 pm
Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.

Am I pulling this out of my bum, or did it actually happen?

They were available STS-2
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 01:13 pm
When they were being designed, the original 'life' of an orbiter was expected to be less than 10 years (having flown 100 times in less than that timeframe)..

The B-52 has been flying longer than that, but it has needed re-certifying a few times now in its history, again because of its age.

Although they haven't flown as often as originally foreseen, and are still in great condition, the three remaining orbiter's airframes are still quite a bit older than the design was originally intended to last (Discovery was fast approaching 3 times its original design intent).  So the same basic re-certification is just needed for the Orbiter fleet, purely because of their age.   CAIB were simply bringing this need to NASA's attention, if they wanted to use Shuttle much beyond 2010.

Ross.

Well that's not exactly correct.  The original certs, the paperwork, stated 100 missions or 10 years, whichever came first.  The time limit was really just a line pulled from the air.  The specific systems, etc were not designed to go belly up and expire at 10 years plus one day. 

Eventually, and long before the loss of Columbia, we had essentially removed most of the "10 year" comments from the certifications.

During RTF, we had a program known as "Mid-Life Certification Review".  This was in work prior to the release of the CAIB report.  It's intent was to verify, after these number of years, that the systems and components are "flown like we tested" and if not what should be done to "test and/or analyze like we fly".

The spreadsheets and specific things we looked at were rather intense.  There were a few "pokeouts" where we performed some limited testing here or there and/or analysis to update some certifications.  The good news is nothing major was found.

This "recertification" today is complete and given the cert testing performed initially, the rigor we have placed in the review process and other certs done over the years, the maintenance performed, the inspection history, etc I'm confident the fleet is in great shape and certainly capable of flying some more beyond the current NASA manifest. 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 03/10/2011 01:23 pm
Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.

Am I pulling this out of my bum, or did it actually happen?

They were available STS-2

Thanks Jim. Was I right with my story about it being developed in the sim by one of the crew, though? Any ideas who?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/10/2011 01:56 pm
Can somebody please tell me when TAL aborts were first developed/invented for use? I seem to remember they weren't an option for every single flight (as in, they weren't there from STS-1), and for some reason I'm seeing "STS-8" and "Joe Engle" in my head, I remember reading about an astronaut, could have been him, developing it in a simulator and then they did more work on it and it became an official option.

Am I pulling this out of my bum, or did it actually happen?

They were available STS-2

Thanks Jim. Was I right with my story about it being developed in the sim by one of the crew, though? Any ideas who?
IIRC, I read somewhere that the STS-2 crew worked on the "abort to Rota" prior to STS-1; however, it wasn't a certified abort mode at that point.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 03/10/2011 02:37 pm
That's what I remember reading too.
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 03/10/2011 03:30 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/10/2011 03:32 pm
During Discovery's STS-133 return the following was radioed up to the crew;

"9% adjust on the speed brake"

what does that mean?

Also, I'm probably imagining things, but did the pitch angle of the orbiter at touchdown seem higher than previous landings?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 03:35 pm
During Discovery's STS-133 return the following was radioed up to the crew;

"9% adjust on the speed brake"

what does that mean?

Also, I'm probably imagining things, but did the pitch angle of the orbiter at touchdown seem higher than previous landings?

Thanks

The speed brake is the "fins" that come out of the vertical stabilizer. 

Pitch angle was normal. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/10/2011 05:55 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?

STS-1 was shaped to work without TAL.
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 03/10/2011 06:01 pm
Thanks, Jim. Just to clarify: does that mean that after STS-1 it was expected that TAL would be a certified abort mode, so it was designed as a unique ascent trajectory? Or was the STS-1 ascent supposed to be the "normal" one, but instead things were changed to allow TAL aborts? Just trying to get the historical perspective on what was planned and when things changed.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/10/2011 06:57 pm

The speed brake is the "fins" that come out of the vertical stabilizer. 
yes, yes.. that i know... and i understand what the values mean when MCC says "spreadbreak 15%. However, this is the first time ive heard the term "x% adjust on the speedbreak" in the same call up.


that is what im asking about....

thanks!
Title: Re: Shuttle Q&A Part 5
Post by: ksc_houston on 03/10/2011 07:16 pm
Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 07:17 pm

The speed brake is the "fins" that come out of the vertical stabilizer. 
yes, yes.. that i know... and i understand what the values mean when MCC says "spreadbreak 15%. However, this is the first time ive heard the term "x% adjust on the speedbreak" in the same call up.


that is what im asking about....

thanks!


It's a call to set the speed break to that percent open. 
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 07:19 pm
Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks

No idea since it is not accurate.  May have been the press reacting in a typical fashion to something we were studying with the COPVs.  That concern has been addressed and is no longer a factor. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/10/2011 07:33 pm
Thanks, Jim. Just to clarify: does that mean that after STS-1 it was expected that TAL would be a certified abort mode, so it was designed as a unique ascent trajectory? Or was the STS-1 ascent supposed to be the "normal" one, but instead things were changed to allow TAL aborts? Just trying to get the historical perspective on what was planned and when things changed.

TAL was added to increase performance by covering a "black zone"
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 03/10/2011 07:51 pm
Gotcha. Thanks again, Jim.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/10/2011 08:36 pm
Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks

I remember what you're talking about.  They were helium tanks that were old, and spares were not available.  One analysis found that they would burst before they leaked, which would be catastrophic.  Another analysis found that they would leak before they burst.  That's all I remember.

Additionally, the tanks are now pressurized in a stepped fashion to 80% and than up to 100%.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/10/2011 08:50 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?

STS-1 was shaped to work without TAL.
IIRC, something like this was done again on STS-26, to reduce the "exposure" to TAL.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/10/2011 09:06 pm
Question:
I saw a couple of years ago an article about Atlantis that said her retirement should be urged, because of a problem with her aging tanks(cryo tanks?). Can someone clarify that for me?
Thanks

I remember what you're talking about.  They were helium tanks that were old, and spares were not available.  One analysis found that they would burst before they leaked, which would be catastrophic.  Another analysis found that they would leak before they burst.  That's all I remember.

Additionally, the tanks are now pressurized in a stepped fashion to 80% and than up to 100%.

Which are the COPVs I was referring to
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 03/11/2011 01:50 pm
Will there be a smaller than usual closeout crew for STS-135 considering there won't be anyone on the mid deck.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/11/2011 02:12 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
STS-1 was shaped to work without TAL.
And even so, an engine failure that forces a TAL abort does not equate to "eject right now". They would have gotten the vehicle thru re-entry and into a steady state glide and then ejected when the conditions were right.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/11/2011 04:51 pm
On the speed brake adjust.  If I recall, close to landing the speed brake is set at one altitude then adjusted later.  Both are done fairly low and are done automatically.  Maybe someone else can confirm this.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/11/2011 05:01 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
STS-1 was shaped to work without TAL.
And even so, an engine failure that forces a TAL abort does not equate to "eject right now". They would have gotten the vehicle thru re-entry and into a steady state glide and then ejected when the conditions were right.

I have never heard of a TAL that results in an ejection on the entry side.  All TALs result in a landing.  If TAL weather is bad, the launch is scrubed.
Title: Re: Shuttle Q&A Part 5
Post by: racshot65 on 03/11/2011 05:33 pm
I have a question from the STS 133 launch

What is drainback hold ?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/11/2011 05:52 pm
I have a question from the STS 133 launch

What is drainback hold ?

Amount of LOX placed in the tank to give maximum performance without carrying "extra".  Given LOX boils off, there is only "so long" (and it depends on the mission) that we can wait before we no longer have enough (with a slight margin) to meet the nominal and planned MECO. 
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/11/2011 08:41 pm
Since I believe there are parts of ascent where the only abort option is TAL, what would have been done if an engine failed during that time on STS-1? Would they have been within the ejection seat envelope at that time?
STS-1 was shaped to work without TAL.
And even so, an engine failure that forces a TAL abort does not equate to "eject right now". They would have gotten the vehicle thru re-entry and into a steady state glide and then ejected when the conditions were right.
I have never heard of a TAL that results in an ejection on the entry side.  All TALs result in a landing.  If TAL weather is bad, the launch is scrubed.
True, but I was addressing his question about the ejection seat envelope. Theoreticaly, if there had been an abort on STS-1 between the RTLS and the AOA zones (I know Jim, they designed the ascent to avoid that condition) They would have ended up in gliding decent with no place to land. Then they would have ejected.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 03/12/2011 12:51 am
On the speed brake adjust.  If I recall, close to landing the speed brake is set at one altitude then adjusted later.  Both are done fairly low and are done automatically.  Maybe someone else can confirm this.

You are correct Danny, retract is at 3000 feet and adjust is at 500 feet.  The "adjust" is at 500 feet because from a time perspective 500 occurs half between 3000 feet and touchdown.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/13/2011 12:51 am
On the speed brake adjust.  If I recall, close to landing the speed brake is set at one altitude then adjusted later.  Both are done fairly low and are done automatically.  Maybe someone else can confirm this.

You are correct Danny, retract is at 3000 feet and adjust is at 500 feet.  The "adjust" is at 500 feet because from a time perspective 500 occurs half between 3000 feet and touchdown.

Mark Kirkman

thank you all who replied on this.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/13/2011 12:54 am
Here's a couple of papers I'm aware of covering the tile protuberance experiments (DTO 900):
thank you
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/13/2011 12:56 am
PC 'ducer, not booster. PC means "chamber pressure" and 'ducer is short for transducer. Bias means the 'ducer is reading differently than it should.

I *think* the ducer in question returns psia, not psig, so it should have been reading around 14.7 since the nozzle was exposed to ambient pressure.
thank you



Title: Re: Shuttle Q&A Part 5
Post by: Gary on 03/13/2011 01:14 pm
What's the bank angle of the shuttle in the HAC and is this variable dependant on energy levels?
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/13/2011 03:45 pm
What's the bank angle of the shuttle in the HAC and is this variable dependant on energy levels?


It is about 45 degrees.  The big variable is wind.  Tail wind increases to angle while headwinds decrease the bank angle.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 03/14/2011 08:52 pm
Which mission had the OBSS used as part on an EVA? 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/14/2011 09:05 pm
Which mission had the OBSS used as part on an EVA? 

STS-121 (structural dynamics test to validate use of OBSS as an EVA platform)
STS-120 (P6 SAW blanket repair)
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 03/15/2011 05:06 pm
how do the sparklers  when shoot the tail service masts
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 03/15/2011 05:10 pm
how do the sparklers  when shoot the tail service masts

Try that one again, it didn't translate very well...
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 03/15/2011 05:12 pm
i am talking about the hydrogen burnoff system that is activated at
T-10 seconds
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/15/2011 05:16 pm
But there is no question or at least people aren't understanding.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/15/2011 05:49 pm
i am talking about the hydrogen burnoff system that is activated at
T-10 seconds
They are pyrotechnics (fireworks).
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 03/15/2011 05:50 pm
how are they produced
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/15/2011 05:56 pm
how are they produced

pyros.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/15/2011 06:53 pm
how are they produced

pyros.

Yeah, Basically a roman candle with no delay between the stars.
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 03/15/2011 09:40 pm
Are there any closeup photos of the actual hardware and installation? All I've ever seen is them burning.

(can you imagine having one of those to set off in your backyard on July 4?)
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 03/15/2011 11:41 pm
That would be cool seeing some detail of the HBS (hydrogen burn off system) on the MLP. I've been curious about those and how they work.

You're right DMeader, one awesome display for fireworks. :)

What do they use anyway? The same material as sparklers or something else? 

I noticed in some videos there are four of these that go off prior to SME start. the two directly below the engines and two more at the back end of each TSM.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/16/2011 12:04 am
What do they use anyway? The same material as sparklers or something else? 
I don't know exactly what they use in these, but the stars used in most fireworks are mostly potassium perchlorate as a combusting agent mixed with a binding agent and various salts for color.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/16/2011 12:17 am
I have a question from the STS 133 launch

What is drainback hold ?

Scroll on back a few pages in this very thread for a detailed answer to this question when it was asked right after the launch of STS-133.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/16/2011 01:30 am
I have a question from the STS 133 launch

What is drainback hold ?

Scroll on back a few pages in this very thread for a detailed answer to this question when it was asked right after the launch of STS-133.
IMO, the best answer on this was referred to in those posts a few pages back, which was Mark's (mkirk):
http://forum.nasaspaceflight.com/index.php?topic=625.msg23596#msg23596

The frightening thing is that was five years ago and it doesn't seem that long ago. :)

And it's still complicated enough (particularly with these station rendezvous windows) that I had to have it explained to me (yet again) when I asked about it during the mission.  (Name dropping omitted. ;D )
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/16/2011 10:55 am
What do they use anyway? The same material as sparklers or something else? 
I don't know exactly what they use in these, but the stars used in most fireworks are mostly potassium perchlorate as a combusting agent mixed with a binding agent and various salts for color.

Found this small snippet in a tech report during a quick search:

"A ROFI is, in effect, a small rocket motor filled with zirconium pellets. These pellets flood the area between the SSME nozzles and the duct entrance with small (550-micron), extremely hot zirconium sparklers."
Title: Re: Shuttle Q&A Part 5
Post by: gomorrha on 03/16/2011 12:37 pm
What would happen to the Shuttle if it were in space for more than 30 days undocked to the ISS or some other external power source?

Just discussing this question with a friend of mine because we´ve heard, that the Soyoz TMA-M can stay in space for up to 1 year.

We´re just interested in what happens to the shuttle (we assume no staff on board).

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 03/16/2011 12:41 pm
It would run out of power and shut down.
Title: Re: Shuttle Q&A Part 5
Post by: gomorrha on 03/16/2011 12:57 pm
I think that's been asked before. the limiting docked time for the shuttle is the ability of the fuel cells to provide power. Shutting them down and running all shuttle systems from SSPTS is not an option so eventually your fuel cells run out of a power.


So if the shuttle is complete out of power is there also the radiation cooling (payload bay) affected?
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 03/17/2011 12:23 am
Has the shuttle ever done a FD4 rendezvous to the ISS?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/17/2011 12:42 am
Has the shuttle ever done a FD4 rendezvous to the ISS?

Yes, on STS-88 (Node 1 installation on the ODS required the extra day).
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/17/2011 12:45 am
I think that's been asked before. the limiting docked time for the shuttle is the ability of the fuel cells to provide power. Shutting them down and running all shuttle systems from SSPTS is not an option so eventually your fuel cells run out of a power.


So if the shuttle is complete out of power is there also the radiation cooling (payload bay) affected?

Yes, with no power the Freon pumps and heat exchangers cannot run, so no circulation through the radiators.
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 03/17/2011 01:07 am
Not shuttle directly but what is the bay in the back of the VAB used for. I know it had Saturn V's roll out of it in years past I believe but not sure now. Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/17/2011 01:13 am
Not shuttle directly but what is the bay in the back of the VAB used for. I know it had Saturn V's roll out of it in years past I believe but not sure now. Thanks

that is where the ET's are processed and a contingency shelter for a shuttle stack
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/17/2011 02:31 am
Not shuttle directly but what is the bay in the back of the VAB used for. I know it had Saturn V's roll out of it in years past I believe but not sure now. Thanks

that is where the ET's are processed and a contingency shelter for a shuttle stack

FYI, high bay 2 was only used for stacking a vehicle once, for SA-513 (the Skylab station). While they were stacking it, high bay 1 was occupied by Apollo 17 and high bay 3 by ML-1 that was being modified for the Saturn IB. High bay 4 was never used for stacking a vehicle, but they have used it at times for horizontal storage of an orbiter.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/17/2011 02:37 am
Not shuttle directly but what is the bay in the back of the VAB used for. I know it had Saturn V's roll out of it in years past I believe but not sure now. Thanks

that is where the ET's are processed and a contingency shelter for a shuttle stack

To add, right now, the non-stacking High Bays (High Bays 2 and 4) are used for the following:

High Bay 2: ET-138 checkout and pre-SRB mating ops for STS-135; contingency shelter for a Shuttle stack if both HBs 1 and 3 are unavailable.

High Bay 4: Recently used for receiving, inspection, and initial integration of Ares I-X; will be used in April/May 2011 as temporary storage location for orbiter Discovery and later in 2011 for temporary storage of orbiter Endeavour.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/17/2011 02:40 am
And pre RPSF construction, the SRB pre stacking ops were done in High Bays 2 and 4
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/17/2011 04:33 pm
Is there any layman's explanation for what LOX drainback is all about, specifically re: the STS-133 launch hold.  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/17/2011 04:38 pm
Is there any layman's explanation for what LOX drainback is all about, specifically re: the STS-133 launch hold.  Thanks!
It's getting more attention; some posts in the last few pages here, and I highlighted Mark Kirkman's primer several posts back:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg709924#msg709924

Maybe not a layman's explanation, but I'd still encourage Shuttle geeks to read it.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/17/2011 05:05 pm
Is there any layman's explanation for what LOX drainback is all about, specifically re: the STS-133 launch hold.  Thanks!
It's getting more attention; some posts in the last few pages here, and I highlighted Mark Kirkman's primer several posts back:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg709924#msg709924

Maybe not a layman's explanation, but I'd still encourage Shuttle geeks to read it.


Thanks Phil, that'll work! I'll boil it down from there.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/17/2011 07:14 pm
Is there any layman's explanation for what LOX drainback is all about, specifically re: the STS-133 launch hold.  Thanks!
It's getting more attention; some posts in the last few pages here, and I highlighted Mark Kirkman's primer several posts back:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg709924#msg709924

Maybe not a layman's explanation, but I'd still encourage Shuttle geeks to read it.


Thanks Phil, that'll work! I'll boil it down from there.

Right here:
http://forum.nasaspaceflight.com/index.php?topic=17437.1620
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 03/18/2011 03:21 am
Has the shuttle ever done a FD4 rendezvous to the ISS?

Yes, on STS-88 (Node 1 installation on the ODS required the extra day).

Interesting.  That's kind of a unique scenario though.  Was STS-88 the only time?
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 03/18/2011 04:50 am
STS-74 docked to Mir on FD 4 for the same reason involving the Mir Docking Module.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 03/19/2011 10:46 pm
What I'm driving at is this: Was there ever a time when the shuttle launched on a day when both FD3/FD4 rendezvouses were possible, intending to rendezvous on FD3, but for whatever reason rendezvoused on FD4 instead?
Title: Re: Shuttle Q&A Part 5
Post by: The-Hammer on 03/20/2011 12:52 am
No.
Title: Re: Shuttle Q&A Part 5
Post by: Jason1701 on 03/21/2011 12:12 am
Is it possible that NASA could take a picture with all three shuttles together before Discovery leaves? I'd love to see them in a line abreast, in a file in order of seniority, and with their noses together.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 03/21/2011 06:33 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 03/21/2011 06:41 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

STS-95. I'm not for sure on the other questions. I'm pretty sure there has never been a failure... I'll let the experts weigh in.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/21/2011 06:55 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 
Title: Re: Shuttle Q&A Part 5
Post by: kirghizstan on 03/21/2011 07:02 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 

What was the chute's condition post flight?
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 03/21/2011 07:51 pm
Thanks OV!
More info and vid links from a previous Q&A thread too of that helps.
http://forum.nasaspaceflight.com/index.php?topic=17437.msg629381#msg629381
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/21/2011 08:16 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 

What was the chute's condition post flight?

It was fine.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 03/21/2011 08:20 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 
Thank you!
Is that chute compartment door hinged, or does it usually pop off on a nominal chute deploy?
What was the reason that it fell off?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/21/2011 09:01 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 
Thank you!
Is that chute compartment door hinged, or does it usually pop off on a nominal chute deploy?
What was the reason that it fell off?

It's not hinged but fastened.  It always comes off on chute deploy a little "cannon ball" ejects out the back and blows it off. 

I wasn't involved at all in this at the time (was still very much a "fresh out" working another system) but as I recall it had something to do with the frame. 
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 03/21/2011 09:08 pm
@OV-106: Thanks a lot for your detailed answers!
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/21/2011 09:08 pm
No problem. 
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/22/2011 01:35 am
I think the usual term for the "cannon ball" is a mortar.  They are very common in chute deploy design.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/22/2011 01:45 am
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 

Didn't the door cause an SSME nozzle leak?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/22/2011 06:52 am
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned above it was STS-95.  The door fell off during SSME start.  There was some analysis and concern that the chute could have been damaged from the various thermal environments and so it was not used. 

There aren't any other missions that I can recall where we just didn't use the chute and there have been no failures of the system as a whole (maybe some tears hear and there). 

Didn't the door cause an SSME nozzle leak?
No. That would have been impossible since all it did was briefly contact a hatband on SSME#1.

With a SSME nozzle leak you're probably thinking of STS-93 where a LOX post pin in SSME#3 was ejected at ignition, scraping against three nozzle coolant tubes which burst when they saw a increase in pressure.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/22/2011 03:22 pm
I used to love nozzle leaks in training sims.  Hundreds of feet per sec of performance loss that couldn't be modelled in the abort region determenator (ARD).
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 03/22/2011 04:03 pm
I seem to recall that on one Shuttle mission, the Orbiter's drag chute was not deployed on landing, as it had been decided against it, because a cover (or something similar) had fallen off earlier during the mission.
Which mission was this?
Had there also been other missions, where the drag chute was not deployed (on those missions equipped with a chute, of course)?
Has there ever been a failure of the drag chute?

As mentioned, STS-95. IIRC, the following mission (STS-88) had the drag chute disabled while the problem was investigated.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/22/2011 04:20 pm
...Has there ever been a failure of the drag chute?

IIRC there was a flight a couple of years ago where a reefing line cutter fired prematurely and caused a couple of risers to fail and the reefing line hardware to become detached from the canopy. I can't remember the flight number though.
Title: Re: Shuttle Q&A Part 5
Post by: Jason1701 on 03/22/2011 11:55 pm
How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 03/23/2011 12:03 am
How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.

First digit - planned year of flight (4 = 1984, for example), second digit = 1 for Florida and 2 for Vandenberg (you'll notice the 2 was never used as that site was decommissioned after Challenger), then the flights were "numbered" within each year by letter (A, B, C, .....).

This wasn't a particularly popular approach.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 03/23/2011 12:33 am
How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.

First digit - planned year of flight (4 = 1984, for example), second digit = 1 for Florida and 2 for Vandenberg (you'll notice the 2 was never used as that site was decommissioned after Challenger), then the flights were "numbered" within each year by letter (A, B, C, .....).

This wasn't a particularly popular approach.

True and I believe it was fiscal year not calander year.  Also STS-1 through 9 were numbered just how it is done now. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/23/2011 02:22 am
How were STS flights numbered before Challenger? I'm confused with all the -D, -L, etc. designations.

Done purely to avoid having an STS-13, by all accounts (known to me anyway).

If they had kept that numbering system, I wonder what they would have done in 1994 when the single-digit fiscal years would have begun producing duplicate flight numbers.  Maybe they anticipated that the system would not outlive the incumbent Administrator who requested it?

No, they would have avoided that issue by rolling over from STS-91x in FY89 to STS-101x in FY90.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 03/24/2011 04:10 am
I was wondering if anyone had explored the idea of creating a new shuttle orbiter that would interface with the current systems.

There has been a great deal of advancement in the past 34 years, since the last space shuttle was built.  We have entirely new aerospace materials that are being widely used now including lithium aluminium and carbon fiber.  We have far better computers and monitors with fiber optic communications.  We have new materials for heat shields.  We have more advanced sensor systems for detecting problems. 

I also heard from an engineer that worked on the shuttle that the technology exists that would eliminate the necessity of disassembling the SSME after every flight thus reducing labor considerably. 

I am not saying we should spend the money to do it, but it is an intellectual curiosity of mine.
Title: Re: Shuttle Q&A Part 5
Post by: pathfinder_01 on 03/24/2011 01:03 pm
I was wondering if anyone had explored the idea of creating a new shuttle orbiter that would interface with the current systems.

There has been a great deal of advancement in the past 34 years, since the last space shuttle was built.  We have entirely new aerospace materials that are being widely used now including lithium aluminium and carbon fiber.  We have far better computers and monitors with fiber optic communications.  We have new materials for heat shields.  We have more advanced sensor systems for detecting problems. 

I also heard from an engineer that worked on the shuttle that the technology exists that would eliminate the necessity of disassembling the SSME after every flight thus reducing labor considerably. 

I am not saying we should spend the money to do it, but it is an intellectual curiosity of mine.

There was an OV200 concept in the 90ies(or very early 2000). They would have either built new Orbiters or done a major upgrade on them.

The APU's which are very costly and dangerous would have been replaced by batteries and some of the shuttles hydraulics would have been replaced by electrical motors.

If  a composite frame where used the shuttle's payload would have increased greatly.

The idea got no traction and after the Columbia accident NASA spun off in a different direction.

Major upgrades that did happen to the shuttle are:

1. Replacing the Original cockpit instruments with a glass cockpit saving both mass and electrical power. The Seats were lighted in that upgrade ET fuel tank was also lightened several times over the years.

2. Computer upgrades in the 90ies to bring the shuttle on par with a 486 computer.

3. Addition of Parachutes for landing.

4. A Orbiter extended duration kit that increased the amount of time the shuttle could stay in space. Originally Endeavor had it but it was removed from Endeavor and installed in Columbia(and later lost with it).They moved it to increase Endeavor's payload mass that it could carry to the station and gave it to Columbia because Columbia could not carry as much to the station as her sisters. In fact without the upgrades she received before her lost she could not have gotten to the ISS at all. Columbia for the most part would have focused on non ISS missions if not for the disaster but it could do a crew rotation and was planned to visit the ISS before her loss. Columbia could carry cargo to the ISS but it would have to be something small.

5. Plus an upgrade to the life support to use a regenerative CO2 removal to reduce the amount of LIOH cartridges needed(so the shuttle could stay more time in space with the same number of cartages).

6. A space station power system was also installed in all but Atlantis that allows the shuttle to us the ISS's power to extend the amount of time it can stay in space docked for a day or two.

7. Even in terms of Mass if built Enterprise would have been the heaviest shuttle. Columbia was the Heaviest, Challenger was a few hundred pounds lighter than Columbia and Discovery and Atlantis are about 2,000 pounds lighter than Columbia(when built). Some of the lightness was due to the use of Thermal blankets(in some areas) instead of all tile(like Columbia) and some structural changes.(Challenger as a test bed(OV99) showed some areas where over built).
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/24/2011 11:22 pm
I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/25/2011 01:45 am
I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
It's called the Remote Orbiter Kit. It is esentialy a cable bundle. One end connects to the racks in AV bay 3 on the mid deck. The other end connects directly to the switches that the crew would otherwise have to manually throw. The astronauts would physically open up the panels and directly connect the wires to the contacts on the back of the switches. The cable is stored on the ISS. It connects to the controls for the Payload Bay Doors, startup and shutdown of the APUs, deployment of the air data probes, deployment of the landing gear and deployment and jetison of the drag chute. I believe (but I can't confirm) that they would have to upload a special version of PASS to use it.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/25/2011 02:04 am
I think there is a kit made to wire up the shuttle to do all of the manual only switch throws and button pushes.  Lowering the gear is probably number one on this list.
It's called the Remote Orbiter Kit.

Actually called Remote Controlled Orbiter (RCO).

Quote
It is esentialy a cable bundle. One end connects to the racks in AV bay 3 on the mid deck.

Specifically to the GCIL, which is the interface for ground commands.

Quote
The other end connects directly to the switches that the crew would otherwise have to manually throw. The astronauts would physically open up the panels and directly connect the wires to the contacts on the back of the switches. The cable is stored on the ISS. It connects to the controls for the Payload Bay Doors, startup and shutdown of the APUs, deployment of the air data probes, deployment of the landing gear and deployment and jetison of the drag chute.

Don't think it controls the payload bay doors - those can be commanded through the crew displays (and therefore via DEU-equivalent commands from the ground). But it also controls the fuel cell reactant valves.

The key point to get across, though, is that RCO only allows remote commanding of the particular switches required for an unmanned deorbit/landing. It is not a general purpose tool to allow an entire shuttle mission to be performed unmanned, just a Macgyver-esque hack to allow a shuttle crew stranded at ISS to attempt to return a damaged orbiter to allow the rescue orbiter to dock.

Quote
I believe (but I can't confirm) that they would have to upload a special version of PASS to use it.

Used to. I think OI-32 fixed that.
Title: Re: Shuttle Q&A Part 5
Post by: Nomadd on 03/25/2011 10:55 am
 I take it the unmanned shuttle would have landed at Edwards?
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 03/25/2011 11:08 am
The only time RCO would be used was if the shuttle TPS would be ruled not safe for landing. In that case the most likely scenario is that the shuttle would be deorbited upside down and burn up in the atmosphere.
Title: Re: Shuttle Q&A Part 5
Post by: rdale on 03/25/2011 11:31 am
I take it the unmanned shuttle would have landed at Edwards?

Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/25/2011 11:56 am
I take it the unmanned shuttle would have landed at Edwards?

Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.

My understanding was that Vandenberg was the preferred landing site (if there was to be one), having the lowest risk to the public or ground resources.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/25/2011 02:39 pm
I take it the unmanned shuttle would have landed at Edwards?

Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.

My understanding was that Vandenberg was the preferred landing site (if there was to be one), having the lowest risk to the public or ground resources.

I don't think Vandenberg has a MSBLS anymore, so they couldn't use the autoland there. Plus, they wouldn't have braking or nose wheel steering so keeping it on the runway durring rollout might be interesting.
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 03/25/2011 07:45 pm
Chris Bergin, in today's article on the STS-134 process flow you state:

"The operation to transport the payload down the crawlerway to the pad and into the PCR all proceeded normally, allowing the RSS to extend back into the mate position on Thursday for the installation operation."

However, is looking in the image embedded in the article adjacent to this text, it sure appears as if the payload caravan is NOT using the crawlerway, but rather a paved road, perhaps adjacent to the crushed stone crawlerway.  I can see where this might be the case, as the payload will certainly weigh no where near the CT/MLP and shuttle stack.  So my question (to anyone); is the crawlerway being used here or an adjecent, paved road?  Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 03/25/2011 11:21 pm
It's a paved road that runs along the crawlerway. Most wheeled vehicles would get stuck trying to drive on the crawlerway, as someone usually finds out here at the pad when the orbiter rolls out. They plow rock across the road for the crawler to run on and someone usually tries to drive over it and sinks right in, especially since they replaced all of the rock recently. Those fresh stones are quite slippery!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/26/2011 11:18 am
I take it the unmanned shuttle would have landed at Edwards?

Correct, that's what the plan has in it. But there also is plenty of talk that it'd be safer just to let it burn up over the Pacific this late in the game.

My understanding was that Vandenberg was the preferred landing site (if there was to be one), having the lowest risk to the public or ground resources.

I don't think Vandenberg has a MSBLS anymore, so they couldn't use the autoland there. Plus, they wouldn't have braking or nose wheel steering so keeping it on the runway durring rollout might be interesting.
For the folks who asked, the RCO capability has been discussed here frequently:
http://forum.nasaspaceflight.com/index.php?topic=6156.msg165683#msg165683

http://forum.nasaspaceflight.com/index.php?topic=10600.msg411433#msg411433

The feasibility of fully automating an OFT in 1980-1982 is another question.
Title: Re: Shuttle Q&A Part 5
Post by: parham55 on 03/30/2011 06:32 pm
1. With regard to the MMU retirement was it deemed too risky after Challenger because of known problems or was its retirement due to more of a general change in NASA culture becoming more risk averse? 

2.Have there been any serious thoughts of bringing the MMU out of retirement during the Shuttle program?

3.Any opinion and elaboration is appreciated. 
 
Please move if this is too off topic for Shuttle Q&A.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/30/2011 06:58 pm
1. With regard to the MMU retirement was it deemed too risky after Challenger because of known problems or was its retirement due to more of a general change in NASA culture becoming more risk averse? 

2.Have there been any serious thoughts of bringing the MMU out of retirement during the Shuttle program?

3.Any opinion and elaboration is appreciated. 
.

It was retired because there is no known use for it, not for any safety or risk reasons.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/30/2011 07:53 pm
1. With regard to the MMU retirement was it deemed too risky after Challenger because of known problems or was its retirement due to more of a general change in NASA culture becoming more risk averse? 

2.Have there been any serious thoughts of bringing the MMU out of retirement during the Shuttle program?

3.Any opinion and elaboration is appreciated. 
.

It was retired because there is no known use for it, not for any safety or risk reasons.

To elaborate, the MMU was originally deemed necessary because the orbiter was thought to be too cumbersome to maneuver in close proximity to spacecraft not specifically designed for it. The orbiter turns out to be more nimble than that, and all missions for the MMU *that were actually funded* could be done by a combination of maneuvering the orbiter and EVA astronauts in foot restraints (either on the tip of the RMS or, as we saw on STS-49 and 87, on the payload bay sill).

If there was ever a chance the MMU could have been revived, it would have been at the start of the ISS era when the issue of rescue during ISS stage EVAs was addressed. But the MMU was deemed too expensive for that role and the cheaper SAFER was developed instead.

Other than that, revival of the MMU has not been seriously considered.
Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 03/30/2011 08:00 pm
1. With regard to the MMU retirement was it deemed too risky after Challenger because of known problems or was its retirement due to more of a general change in NASA culture becoming more risk averse? 

2.Have there been any serious thoughts of bringing the MMU out of retirement during the Shuttle program?

3.Any opinion and elaboration is appreciated. 
.

It was retired because there is no known use for it, not for any safety or risk reasons.

To elaborate, the MMU was originally deemed necessary because the orbiter was thought to be too cumbersome to maneuver in close proximity to spacecraft not specifically designed for it. The orbiter turns out to be more nimble than that, and all missions for the MMU *that were actually funded* could be done by a combination of maneuvering the orbiter and EVA astronauts in foot restraints (either on the tip of the RMS or, as we saw on STS-49 and 87, on the payload bay sill).

If there was ever a chance the MMU could have been revived, it would have been at the start of the ISS era when the issue of rescue during ISS stage EVAs was addressed. But the MMU was deemed too expensive for that role and the cheaper SAFER was developed instead.

Other than that, revival of the MMU has not been seriously considered.
I realize this is off-topic, but has there been any thought given about using the MMU for a mission to an asteroid? Walking wouldn't be terribly practical.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/30/2011 08:08 pm

If there was ever a chance the MMU could have been revived, it would have been at the start of the ISS era when the issue of rescue during ISS stage EVAs was addressed. But the MMU was deemed too expensive for that role

And  too cumbersome also, I believe.
Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 03/30/2011 08:27 pm
Quote from: Robotbeat link=topic=17437.msg715827#msg715827
I realize this is off-topic, but has there been any thought given about using the MMU for a mission to an asteroid? Walking wouldn't be terribly practical.

Huh? Are you talking about a single person strapped in an MMU and blasting off to an asteroid or an MMU being used to explore an asteroid?

If it's the former the MMU doesn't have the Delta-V - If it's the latter this scenario was depicted in a Constellation mission video.

Certainly the latter. Was this Constellation mission video merely an artist's rendering, or was the MMU seriously analyzed for this purpose?
Title: Re: Shuttle Q&A Part 5
Post by: HIPAR on 03/31/2011 04:23 pm
What percentage of NASA occupied floor space at KSC is shuttle specific? After the last shuttle flight,  fixtures for shuttle processing will obviously become superfluous.  Will they be scraped?  Will the scaffolding in the vertical assembly building be dismantled and scraped? 

---  CHAS 
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/15/2011 03:01 am
If the O-ring leak on 51L had occurred in a different location such that it didn't burn through the strut, it was still going to cause an underspeed due to the loss of pressure.  My question is, what would have been the result of that underspeed?  ATO?  AOA?  TAL?  I'm asking because I have a vague memory of reading about this but endless searching hasn't turned up anything and I want to know if I'm just imagining it.
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 04/15/2011 10:26 am
what they should have done was goto the bolted joints by aerojet alot safer than the current design
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/15/2011 01:08 pm
what they should have done was goto the bolted joints by aerojet alot safer than the current design

I fail to see how that answer has any relation at all to the question I posed.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 04/15/2011 02:06 pm
If the O-ring leak on 51L had occurred in a different location such that it didn't burn through the strut, it was still going to cause an underspeed due to the loss of pressure.  My question is, what would have been the result of that underspeed?  ATO?  AOA?  TAL?  I'm asking because I have a vague memory of reading about this but endless searching hasn't turned up anything and I want to know if I'm just imagining it.

As I recall, the delta P between the motors was still very small at LOS. That would imply that the motor was still generatating most of the thrust it was supposed to. Your question is one of magnitude and has a lot of unknown variables (would the leak keep getting worse and the presure in the case drop more or not? where would the vehicle be at staging in reguards to where it was supposed to be?) Without knowing those things, I don't think there is a way to determine what the final outcome would have been.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/15/2011 02:36 pm
If the O-ring leak on 51L had occurred in a different location such that it didn't burn through the strut, it was still going to cause an underspeed due to the loss of pressure.  My question is, what would have been the result of that underspeed?  ATO?  AOA?  TAL?  I'm asking because I have a vague memory of reading about this but endless searching hasn't turned up anything and I want to know if I'm just imagining it.

As I recall, the delta P between the motors was still very small at LOS. That would imply that the motor was still generatating most of the thrust it was supposed to. Your question is one of magnitude and has a lot of unknown variables (would the leak keep getting worse and the presure in the case drop more or not? where would the vehicle be at staging in reguards to where it was supposed to be?) Without knowing those things, I don't think there is a way to determine what the final outcome would have been.

I finally found the post that might have been vague in my memory and it was from Jorge saying it might have resulted in ATO, indicating as you said that it wasn't a massive thrust difference.  Of course, you are correct that we'll never know what would have happened for sure.

http://www.spacekb.com/Uwe/Forum.aspx/space-history/2411/STS51L-Accident-Questions

Quote
It would not be far off course. The side force was not that great compared
to the thrust of the SRBs; the issues were that 1) the torque from the side
force could have exceeded control authority, and 2) there could have been
enough underspeed at SRB sep that the SSMEs alone couldn't make it up
during second stage, resulting in an ATO.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/18/2011 03:24 am
Next, realize that the ascending and descending nodes are around 12 hours apart.  So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
The principle is correct, but ascending and descending nodes are ~6 hours apart.


Okay, I've thought about this all day, and I don't understand why these are 6 hours apart and not 12.  Can someone help me please?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/18/2011 03:35 am
Next, realize that the ascending and descending nodes are around 12 hours apart.  So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
The principle is correct, but ascending and descending nodes are ~6 hours apart.


Okay, I've thought about this all day, and I don't understand why these are 6 hours apart and not 12.  Can someone help me please?

They would be 12 hours apart if the landing site was on the equator. But because the landing site is around 30 degrees north latitude, it doesn't take as long for the Earth to rotate from the ascending to the descending opportunity. So about 6 hours from ascending opportunity to descending opportunity, then about 18 hours until the next ascending opportunity (and actually not even that simple, since the shuttle's crossrange capability usually allows multiple opportunities both ascending and descending).

It's a lot easier to show this with a globe and a hula hoop than to describe it verbally.
Title: Re: Shuttle Q&A Part 5
Post by: wally on 04/18/2011 10:32 am
Recently, while praising the shuttle, I keep hearing that she has two million moving parts. I wonder if this is true. Of course, the whole orbiter plus boosters and main tank are moving during lift-off, but I'm curios if the orbiter itself holds (around) two million moving parts relative to its center of mass (valves, relays, pistons, etc) - I won't call the windows or the wings moving parts although they clearly move during liftoff, orbital maneuvers and re-entry in respect to Earth. So, does the orbiter itself hold two million moving parts or it's just to far fetched statement?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/18/2011 12:51 pm
Next, realize that the ascending and descending nodes are around 12 hours apart.  So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
The principle is correct, but ascending and descending nodes are ~6 hours apart.


Okay, I've thought about this all day, and I don't understand why these are 6 hours apart and not 12.  Can someone help me please?

They would be 12 hours apart if the landing site was on the equator.

While I was lying in bed late last night, I was wondering if that might be the case.

Let me try to paraphrase to see if I've got this.  The ascending node is going to move largely from South-West to North-East while the descending node is going to move largely from West to East.  This means the descending node is going to travel a lot farther East from initiation than the ascending node is, and this is because of the latitude of the landing site and because of the inclination of the orbit.  So, to extremely simplify, the ascending node is going from the bottom of the sine wave to the top (looking on a flat map instead of a globe), while the descending node is going from a little left of the top peak of the sine wave to a little right of the top peak.

As always, thanks for the help, Jorge.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 04/18/2011 03:20 pm
Next, realize that the ascending and descending nodes are around 12 hours apart.  So, in one case you might have to sleep-shift a bit forward (earlier) during the mission to meet that timeline, in the other case you might have to sleep-shift later (by a total of up to a maximum of 12 hours), thus "earning" some extra time in the mission because you are living 25 hour days or so during the mission.
The principle is correct, but ascending and descending nodes are ~6 hours apart.


Okay, I've thought about this all day, and I don't understand why these are 6 hours apart and not 12.  Can someone help me please?

They would be 12 hours apart if the landing site was on the equator.

Let me try to paraphrase to see if I've got this.  The ascending node is going to move largely from South-West to North-East while the descending node is going to move largely from West to East.  This means the descending node is going to travel a lot farther East from initiation than the ascending node is, and this is because of the latitude of the landing site and because of the inclination of the orbit.  So, to extremely simplify, the ascending node is going from the bottom of the sine wave to the top (looking on a flat map instead of a globe), while the descending node is going from a little left of the top peak of the sine wave to a little right of the top peak.

Basically, yes -- though the exact locations on the since curves are a little off.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 04/18/2011 03:22 pm
As I watch LC39B coming down in pieces, I am wondering about the initial construction of the two FSS towers.

I have read the FSS were the tops of two of the three towers from the MLP's in the Saturn era.  What I am wondering about is the process they used to get them off the MLP and onto the ground.

I doesn't seem likely they could have lifted the whole thing off the MLP in one chunk.  How many sections did they have to cut it into?  Comparable to the sections they are lobbing off the top of 39B right now?

If anyone has any historical links to the Shuttle pad transition from Saturn to Shuttle, I would appreciate it.  Thanks.

This is the best historical information, but the text is in French. The photos give you a good idea what was done.

http://www.capcomespace.net/dossiers/espace_US/shuttle/index.htm

On the left pane, scroll down to the 1976 section and click on the "le Pad 39" link. Scrool to the bottom of the page and click on the "Launch Complex 39 Historie" link.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/18/2011 04:04 pm
Basically, yes -- though the exact locations on the since curves are a little off.

Just to closeout my own question, here are the long-range entry ground tracks for STS-131 (descending node) and STS-132 (ascending node):

(http://www.nasa.gov/images/content/445731main_KSC237_long.gif)
(http://www.nasa.gov/images/content/457217main_sts132_ksc186_long.gif)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 04/18/2011 04:21 pm
This is the quickest plot I could find of most/all the daily orbits for a high inclination orbit, not ISS, but close enough to that inclination to illustrate...taken from this paper:
http://space.au.af.mil/documents/orbital_dynamics.pdf

Maybe it helps, maybe not...but it does show the ascending (like orbits 1 and 2, for example) and descending nodes (orbits 6 and 7, for example) together.  :)
Title: Re: Shuttle Q&A Part 5
Post by: kaphonius on 04/19/2011 02:51 am
I've searched online and have found many dead ends and conjecture to this question. I hope this is the right place to ask. What is the Space Shuttle return cargo payload mass?

I ask because I don't see any replacement capability since Bush's 'I see a picture in the stars' aka Constellation debacle. What happens if an ISS module gets damaged and needs repair beyond a spacewalk? Anyone else see an issue here?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/19/2011 02:55 am
I've searched online and have found many dead ends and conjecture to this question. I hope this is the right place to ask. What is the Space Shuttle return cargo payload mass?

No simple answer, since the landing weight limits are a function of both weight and CG location.

Quote
What happens if an ISS module gets damaged and needs repair beyond a spacewalk?

Same thing that happened with Spektr on Mir.

Quote
Anyone else see an issue here?

Yes, many people have, and have been saying so for years. Nevertheless, the capability will not be retained, because it is deemed too expensive.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 04/19/2011 02:59 am
Welcome to the NSF forum.

In the future, you can use the Q&A section and put questions into the appropriate thread in that forum.

The downmass (and volume) capabilities of the planned replacement vehicle don't allow the return of an ISS module.  However, I'm not all that sure that Shuttle would have been particularly suited to that either, not because it couldn't do it, but because ISS is now very interconnected and it would be quite difficult to separate a module and prep it for return.

The bigger downmass issue is that there are parts on ISS that can be returned practically on Shuttle that can't be practically returned on other vehicles.  These are much smaller than a whole module but still too large for Dragon, Orion/MPCV or Soyuz.  They're cramming all they can into the last few flights but I'm sure this will eventually cause issues.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/19/2011 11:29 am
What happens if an ISS module gets damaged and needs repair beyond a spacewalk? Anyone else see an issue here?

Not really an issue.  Even if the shuttle was available, most of the modules can't be removed from the ISS.  Node 1 &2 and the Lab are permanent fixtures as well as most of the truss.  There is no way to remove these without disrupting the whole ISS. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/19/2011 11:31 am
The design max return mass was 32Klbs.    Abort return masses were higher, but then again, they were aborts.
Title: Re: Shuttle Q&A Part 5
Post by: jsmjr on 04/20/2011 11:12 pm
Found this which pretty much answers it.... http://www.savethelut.org/MLDocs/ML_History.html

As I watch LC39B coming down in pieces, I am wondering about the initial construction of the two FSS towers.

I have read the FSS were the tops of two of the three towers from the MLP's in the Saturn era.  What I am wondering about is the process they used to get them off the MLP and onto the ground.

I doesn't seem likely they could have lifted the whole thing off the MLP in one chunk.  How many sections did they have to cut it into?  Comparable to the sections they are lobbing off the top of 39B right now?

If anyone has any historical links to the Shuttle pad transition from Saturn to Shuttle, I would appreciate it.  Thanks.

Any chance the LC 39 Observation Gantry is also a remnant of the Apollo LUTs?  As far as I can tell it serves no current purpose other than a viewing site for tour groups (http://www.kennedyspacecenter.com/lc-39-observation-gantry.aspx) but I've wondered if it ever did something more meaningful.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/20/2011 11:30 pm
Found this which pretty much answers it.... http://www.savethelut.org/MLDocs/ML_History.html

As I watch LC39B coming down in pieces, I am wondering about the initial construction of the two FSS towers.

I have read the FSS were the tops of two of the three towers from the MLP's in the Saturn era.  What I am wondering about is the process they used to get them off the MLP and onto the ground.

I doesn't seem likely they could have lifted the whole thing off the MLP in one chunk.  How many sections did they have to cut it into?  Comparable to the sections they are lobbing off the top of 39B right now?

If anyone has any historical links to the Shuttle pad transition from Saturn to Shuttle, I would appreciate it.  Thanks.

Any chance the LC 39 Observation Gantry is also a remnant of the Apollo LUTs?  As far as I can tell it serves no current purpose other than a viewing site for tour groups (http://www.kennedyspacecenter.com/lc-39-observation-gantry.aspx) but I've wondered if it ever did something more meaningful.
Nope. Not a LUT remnant. The design is very different to the LUTs. The LUT levels were made up of upside down "V" struts and the LC 39 Observation Gantry doesn't have them.
Title: Re: Shuttle Q&A Part 5
Post by: jsmjr on 04/21/2011 08:02 pm
Found this which pretty much answers it.... http://www.savethelut.org/MLDocs/ML_History.html

As I watch LC39B coming down in pieces, I am wondering about the initial construction of the two FSS towers.

I have read the FSS were the tops of two of the three towers from the MLP's in the Saturn era.  What I am wondering about is the process they used to get them off the MLP and onto the ground.

I doesn't seem likely they could have lifted the whole thing off the MLP in one chunk.  How many sections did they have to cut it into?  Comparable to the sections they are lobbing off the top of 39B right now?

If anyone has any historical links to the Shuttle pad transition from Saturn to Shuttle, I would appreciate it.  Thanks.

Any chance the LC 39 Observation Gantry is also a remnant of the Apollo LUTs?  As far as I can tell it serves no current purpose other than a viewing site for tour groups (http://www.kennedyspacecenter.com/lc-39-observation-gantry.aspx) but I've wondered if it ever did something more meaningful.
Nope. Not a LUT remnant. The design is very different to the LUTs. The LUT levels were made up of upside down "V" struts and the LC 39 Observation Gantry doesn't have them.

Yep, looks like LC 39 was built in 1997, wholly as a visitor amenity, by Delaware North Park Services (operator of the KSC VC) following the completion of their excellent Apollo-Saturn V center.  See http://www-pao.ksc.nasa.gov/kscpao/release/1997/64-97.htm and attached Spaceport News for April 25, 1997 (which also describes the arrival of the ET at the visitors center (apparently the one now on display with attached SRBs).

Title: Re: Shuttle Q&A Part 5
Post by: Mvossman on 04/25/2011 03:55 am
First post!

1) When viewing the reentry videos, cabin view, the orange occasionally, about every 2 or 3 seconds, flickers brightly. Why is that? Random turbulence causing momentary increase in plasma density?

2) I read someplace that STS-1 was the one flight where the SRBs were lit after T-0. True? If so, what is the reason, to allow a little more time for SSME problems to appear on the pad rather than after launch commit? Cannot find anything online here or elsewhere. The STS-1 video does indeed give a sense that the engines ran longer before SRB ignition.

Mitch
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 04/25/2011 04:08 am
With regard to SRB ignition.

http://www.youtube.com/watch?v=ExfjSuJxOP8

The off center thrust of the SSME forces the entire shuttle stack to "twang".
When the stack flexes back to it's original vertical position the SRB's are ignited.

I do not think there is much leeway on SRB ignition relative to the "Twang".

This twang does not entirely settle down. The vehicle has a slight lateral resonance of about 5hz IIRC.

This specific frequency was also noted on the Challenger accident because the SRB leak at the moment of ignition (and for a few seconds after lift off) had puffs of smoke coming from the SRB joint at the same frequency.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/25/2011 11:44 am

2) I read someplace that STS-1 was the one flight where the SRBs were lit after T-0. True? If so, what is the reason, to allow a little more time for SSME problems to appear on the pad rather than after launch commit? Cannot find anything online here or elsewhere. The STS-1 video does indeed give a sense that the engines ran longer before SRB ignition.

Mitch

2.  For STS-1, main engine start was at T-3 and SRB ignition was at T+3.  The extra 3 seconds was for the SRB twang to dampen out.  Countdown was adjusted to account for this on STS-2.
Title: Re: Shuttle Q&A Part 5
Post by: Mvossman on 04/25/2011 05:15 pm

2) I read someplace that STS-1 was the one flight where the SRBs were lit after T-0. True? If so, what is the reason, to allow a little more time for SSME problems to appear on the pad rather than after launch commit? Cannot find anything online here or elsewhere. The STS-1 video does indeed give a sense that the engines ran longer before SRB ignition.

Mitch

2.  For STS-1, main engine start was at T-3 and SRB ignition was at T+3.  The extra 3 seconds was for the SRB twang to dampen out.  Countdown was adjusted to account for this on STS-2.

So does this mean: the STS-1 SSMEs started sequentially around T-3, that they would have been ready for liftoff at T-0 except for wating for the twang to dampen? And the reason for liftoff not being defined as T-0.00 is that the exact time required for twang to dampen was not known with encough certainty to have a specific SRB ignition time but rather the twang was empirically observed until it was dampened enough for SRB ignition and that period turned out to be an extra 3 seconds? No doubt the twang had some terrific predictions, mechanically, but perhaps just enough uncertainty in the period of oscillation and severity existed to merit waiting a variable period? Sort of a "mini-hold"?

And after that, this observed requirement for approx. 6 seconds from first SSME to SRB igntion was embraced from STS-2 forward, with the entire countdown slid backward those empirically derived approx. 6 seconds so liftoff is defined as T-0.00?

If this is all incorrect, and in fact the STS-1 countdown was defined and configured for a planned T+3 liftoff, I fail to understand why that is important - 6 seconds from T-6 to T-0 vs. T-3 to T+3 is six seconds either way.

Which raises two interesting questions. 1) If my interpretation is correct, was the twang watched on STS-1 by a human with his finger poised over a button or was there an automatic observation, perhaps accelerometer at the top of the ET, that triggered the continued countdown? 2) Currently, is SRB ignition and liftoff subject to any kind of extra delay for anything, such as excessive twang or other factors (aside from a cutoff obviously)?

Anyway, the reason I am so interested in this is I dropped everything this week, I am fulfilling a lifelong goal of seeing a launch on Friday (we all hope)- flying there myself to Titusville. Been a space buff from Apollo to STS-1 and to here. My heart rate may have been greater than Crippen and Young that morning and love it to this day. I think it may be a mistake to abandon reuseable, glideable spacecraft entirely.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/25/2011 05:25 pm

1.  So does this mean: the STS-1 SSMEs started sequentially around T-3, that they would have been ready for liftoff at T-0 except for wating for the twang to dampen?

2.  And the reason for liftoff not being defined as T-0.00 is that the exact time required for twang to dampen was not known with encough certainty to have a specific SRB ignition time but rather the twang was empirically observed until it was dampened enough for SRB ignition and that period turned out to be an extra 3 seconds? No doubt the twang had some terrific predictions, mechanically, but perhaps just enough uncertainty in the period of oscillation and severity existed to merit waiting a variable period? Sort of a "mini-hold"?

3.  And after that, this observed requirement for approx. 6 seconds from first SSME to SRB igntion was embraced from STS-2 forward, with the entire countdown slid backward those empirically derived approx. 6 seconds so liftoff is defined as T-0.00?

4.  If this is all incorrect, and in fact the STS-1 countdown was defined and configured for a planned T+3 liftoff, I fail to understand why that is important - 6 seconds from T-6 to T-0 vs. T-3 to T+3 is six seconds either way.

5.  Which raises two interesting questions. 1) If my interpretation is correct, was the twang watched on STS-1 by a human with his finger poised over a button or was there an automatic observation, perhaps accelerometer at the top of the ET, that triggered the continued countdown?

 6) Currently, is SRB ignition and liftoff subject to any kind of extra delay for anything, such as excessive twang or other factors (aside from a cutoff obviously)?


1.  Not just for STS-1 but for all missions

2.  No, the countdown hadn't accounted for it at the time and they didn't want to change things for STS-1.

3. No, it was slid back only 3 seconds, since SSME start was around T-3 seconds.

4. So that liftoff occurs at T-0/T+0.  It is easier for event planning to key off of liftoff.

5.  Neither, it was a fixed interval in the countdown

6.  no, it is fixed.
Title: Re: Shuttle Q&A Part 5
Post by: Mvossman on 04/25/2011 05:39 pm

1.  So does this mean: the STS-1 SSMEs started sequentially around T-3, that they would have been ready for liftoff at T-0 except for wating for the twang to dampen?

2.  And the reason for liftoff not being defined as T-0.00 is that the exact time required for twang to dampen was not known with encough certainty to have a specific SRB ignition time but rather the twang was empirically observed until it was dampened enough for SRB ignition and that period turned out to be an extra 3 seconds? No doubt the twang had some terrific predictions, mechanically, but perhaps just enough uncertainty in the period of oscillation and severity existed to merit waiting a variable period? Sort of a "mini-hold"?

3.  And after that, this observed requirement for approx. 6 seconds from first SSME to SRB igntion was embraced from STS-2 forward, with the entire countdown slid backward those empirically derived approx. 6 seconds so liftoff is defined as T-0.00?

4.  If this is all incorrect, and in fact the STS-1 countdown was defined and configured for a planned T+3 liftoff, I fail to understand why that is important - 6 seconds from T-6 to T-0 vs. T-3 to T+3 is six seconds either way.

5.  Which raises two interesting questions. 1) If my interpretation is correct, was the twang watched on STS-1 by a human with his finger poised over a button or was there an automatic observation, perhaps accelerometer at the top of the ET, that triggered the continued countdown?

 6) Currently, is SRB ignition and liftoff subject to any kind of extra delay for anything, such as excessive twang or other factors (aside from a cutoff obviously)?


1.  Not just for STS-1 but for all missions

2.  No, the countdown hadn't accounted for it at the time and they didn't want to change things for STS-1.

3. No, it was slid back only 3 seconds, since SSME start was around T-3 seconds.

4. So that liftoff occurs at T-0/T+0.  It is easier for event planning to key off of liftoff.

5.  Neither, it was a fixed interval in the countdown

6.  no, it is fixed.

1. Got it.
2. See below.
3. Roger that.
4. Of course it is better to T-0 as liftoff as a very important event... but see below.
5. Roger.
6. Roger.

Regarding answer #2 - I get it now, tell me if this is it. The countdown was designed for STS-1 to have SRB ignition at T-0, based upon time required for SSMEs to be ready (and perhaps other factors?). However, at some late date close enough to the earliest possible launch date that it would be inconvenient to renumber the countdown, someone realized it was necessary to wait for an extra 3 seconds twang to dampen so rather than an inconvenient re-write of the entire countdown backsliding it 3 seconds, an extra 3 seconds was tacked on and SRB ingition/liftoff took place at T+3.

Fascinating, I picture a desk surrounded with folks when someone raises his hand and says "hey, we forgot to allow enough time for twang to dampen. Our simulations show approx. 6 seconds are needed even though the SSMEs require only 3 to be ready!" And people drop their pencils.

Which raises an interesting couple points. 1) 3 more seconds of propellant are "wasted", did that make a meaningful impact on useful payload capacity? 2) Why is it necessary for twang to subside? I would think (hazardous activity to think intuitively of course) that it would result in more lateral translation in a favorable direction, toward the ET, as all launches do anyway.

Mitch
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 04/25/2011 06:09 pm
If SRB ignition was made before the stack returned to vertical you would have too much lateral drift (among other things).

Minimizing lift-off drift is a good idea (even for wear and tear on the MLP).

The 3 seconds of "wasted" propellant could be factored into the perfomance margin.

Does anyone have the link to mkirk's explanation of the performance margin? It was in one of these Shuttle Q&A forums.


Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/25/2011 06:33 pm
The countdown people and the dynamicists are completely different groups.  The countdown people were probably aware of it and see the following.  The shuttle stack (Enterprise, inert SRB's and an ET) were subject to a MGVT (mated ground vibration test) at Marshall. This is how the vibe modes were determined/verified.   Also, Columbia performed an FRF early in the year before its first flight and this would have provided an actual period of oscillation.  I believe that this why the countdown was developed the way it was.  The countdown could be developed independent of the actual delay, since everything is ready at T-0 and the length of the delay could just be tacked on. 

Yes, the extra three seconds does "waste" propellant and did have an impact on payload to orbit.  They did look at eliminating it, see below.   The reason for waiting for the twang to "subside" is the amount of energy that is "stored" in the structure when it is bent over (not lateral drift).  Look at any cantilevered load and what would happen if the base were released.  The moment at the base of the SRB's never goes back to zero since the SSME's are burning but it is at a minimum when the bolts are fired. 

When they tried to eliminate the delay, they looked at the moment as it built up from SSME's start up.  The time in the SSME start sequence where the moment was equivalent to the moment after delay was too early in the start sequence to verify that the SSME's were ok.
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 04/25/2011 06:59 pm
Thanks for the clarification Jim.

P.S. Are you back to shooting from the hip?

Here is an STS-1 question for you.

I have read that the body flap on Columbia was forced past the allowable operational limits at SRB ignition due to the acoustic over-pressure on STS-1. (no water deluge)


My question is: how close to failure of the actuation mechanism (hydraulics) for the body flap was this over-pressure load?

No control of the body flap on re-entry means LOC/LOV, right?

What kind of margins are built into that "unauthorised" movement for the mechanism that moves/controls the body flap.

Given that surfaces like these are software/computer controlled. If the flap on STS-1 (or any flight) needed to be "recalibrated", does the software now how to extrapolate new values to dynamically (on the fly) recalibrate itself for the duration of the flight until physical "recalibration" could be done in the OPF?



Also in slight relation to the body flap (on re-entry) didn't STS 1 have an issue on re-entry in that the re-entry software had been programmed with upper atmospheric oxygen being di-atomic instead of single molecule resulting in errors with side slip?

 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/25/2011 07:16 pm
Thanks for the clarification Jim.

P.S. Are you back to shooting from the hip?

Here is an STS-1 question for you.

 

Nope and somebody else will have to answer those questions, but yes it would be an LOW/LOC and there were other aerosurfaces that were over stressed.

As for the "unauthorised" movement,

1.  was it ever stated that the surfaces didn't return to preflight positions?
2.  Most feedback is based on the actual position (actuator stroke length or rotation)and the software would see the "new" position.
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 04/26/2011 06:45 am
Jim is apparently feeling loquacious ;)


Is the twang video real time, ie true 1:1?

-Alex
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 04/26/2011 02:07 pm
Jim is apparently feeling loquacious ;)


Is the twang video real time, ie true 1:1?

-Alex

It's not 1:1. More like 1.5:1
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 04/26/2011 08:30 pm
Are the hard attach points on the Orbiter for the fuel and oxidiser lines from the ET positioned at (or sufficiently close to) the Orbiter's center of gravity (center of mass)?

Are payloads situated within the payload bay to help define/balance this point (at least for ascent)?







Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/26/2011 09:14 pm
Are the hard attach points on the Orbiter for the fuel and oxidiser lines from the ET positioned at (or sufficiently close to) the Orbiter's center of gravity (center of mass)?

Are payloads situated within the payload bay to help define/balance this point (at least for ascent)?


The position of the payloads in the bay is more important for entry and landing.  The orbiter/ET attach points are aft of the landing gear, just forward of the elevon hinge line.  Which is certainly aft of the orbiter CG.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 04/28/2011 02:41 am
On STS-88, Endeavour had the airlock tunnel adapter installed as well as the External airlock/ODS. Now as I understand it, the previous year she had her internal airlock removed meaning the tunnel adapter was not needed for the ODS. Now on her previous flight, STS-89 she flew in the same condition except with a SpaceHab module attached to the ODS airlock, so the tunnel makes sense for EVA access but on STS-88 there was nothing covering up the ODS EVA hatch.  Thinking logically, the best theory I could come up with was the need for more clearance due to the fact that she docked "upside down" to the PMA-2 relative to what is done today.  Is that correct?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/28/2011 12:33 pm
No, it was known early as I stated in MGVT. 
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 04/28/2011 06:41 pm
Orbiter CG is around Xo1120 - Xo1135 depending on the payload mass.  P/L bay aft bulkhead is Xo1307, and the Orbiter/ET aft hardpoints are around Xo1317 (The Orbiter nose is around Xo235).

UPDATE - The LO2 and LH2 feedline centers are at Xo1330.5


Are the hard attach points on the Orbiter for the fuel and oxidiser lines from the ET positioned at (or sufficiently close to) the Orbiter's center of gravity (center of mass)?

Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 05/04/2011 01:26 pm
Has a Shuttle launch ever been filmed by a camera mounted in one of the overhead windows of the aft flight deck station? Looks like that would be a pretty spectacular view. Searching here I find nothing.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/04/2011 01:29 pm
Has a Shuttle launch ever been filmed by a camera mounted in one of the overhead windows of the aft flight deck station? Looks like that would be a pretty spectacular view. Searching here I find nothing.
Couple of times that I can think of (with a video camera) -- STS-93 and STS-102...first one was night-time and for the dawn 102 launch after roll to heads down, it's mostly water.  The STS-102 video is around online, I believe.
Title: Re: Shuttle Q&A Part 5
Post by: Space Invaders on 05/04/2011 01:51 pm
Is there an estimate of the costs incurred for each day a Shuttle launch is delayed? (including only the "basic costs", i.e., without including any potential repairs).

I once read that delayed launches cost $28 million per day, but this figure seems way too high to me just to keep the Shuttle on the launchpad.
Title: Re: Shuttle Q&A Part 5
Post by: dninness on 05/04/2011 03:31 pm
FOD question.

In looking at the LCA replacement photos in the KSC Media Gallery (http://mediaarchive.ksc.nasa.gov/search.cfm?cat=4), I noted that the first few photos of the guys climbing around in the aft of Endeavor were wearing coveralls (not the full blown bunny suits with booties, but at least coveralls), whereas the later photos of the folks doing the R&R of the LCA were in jeans, sneakers (sorry, "trainers"..), etc. 

Having worked helicopter maintenance in my early years, I am cognizant of the hazard presented by items that are worn or found in pockets that become dropped items (tools, change, rings, ID badges, etc).   I can only imagine that working around the shuttle is 10x more complicated in the event that something were to get loose in the aft of the orbiter and do the old "ping-ding-boink-rattle-rattle-rattle" trip to the lowest point it can reach.   Imagine that IPR: "Joe's wedding ring found on #3 engine heatshield dome.  His wife will be happy."

My question is: what precautions are in place at the pad, and especially when working inside the orbiter, for FOD prevention? 

If you're doing maintenance in essentially "street clothes" are there provisions for removing FOD hazards from pockets, fingers, etc?  In one photo, one of the workers was definitely wearing a wedding ring (a no-no where I worked), and in another a wristwatch, so it *appears* (to me, the uninitiated outside observer) that there are very little FOD prevention measures in effect. 

What about things like FOD stuck in the tread of your sneakers, for example?

Thanks in advance!

Darin
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/04/2011 03:33 pm
Is there an estimate of the costs incurred for each day a Shuttle launch is delayed? (including only the "basic costs", i.e., without including any potential repairs).

I once read that delayed launches cost $28 million per day, but this figure seems way too high to me just to keep the Shuttle on the launchpad.

The $28 million is probably the cost of a scrubed attempt, not a per day cost. The cost of a shuttle sitting on the pad depends on how you want to calculte it. Assuming no actual material cost (nothing is being used up) then you are just talking about the saleries of the people involved who are getting paid anyways. Eventualy, if it sits out there long enough, some material costs will come into play to recharge batteries if nothing else.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 05/04/2011 03:39 pm
Is there an estimate of the costs incurred for each day a Shuttle launch is delayed? (including only the "basic costs", i.e., without including any potential repairs).

I once read that delayed launches cost $28 million per day, but this figure seems way too high to me just to keep the Shuttle on the launchpad.

The $28 million is probably the cost of a scrubed attempt, not a per day cost. The cost of a shuttle sitting on the pad depends on how you want to calculte it. Assuming no actual material cost (nothing is being used up) then you are just talking about the saleries of the people involved who are getting paid anyways. Eventualy, if it sits out there long enough, some material costs will come into play to recharge batteries if nothing else.

But where does the $28 million come from?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/04/2011 03:55 pm
FOD question.

1.  In looking at the LCA replacement photos in the KSC Media Gallery (http://mediaarchive.ksc.nasa.gov/search.cfm?cat=4), I noted that the first few photos of the guys climbing around in the aft of Endeavor were wearing coveralls (not the full blown bunny suits with booties, but at least coveralls), whereas the later photos of the folks doing the R&R of the LCA were in jeans, sneakers (sorry, "trainers"..), etc. 

2.  My question is: what precautions are in place at the pad, and especially when working inside the orbiter, for FOD prevention? 

3.  If you're doing maintenance in essentially "street clothes" are there provisions for removing FOD hazards from pockets, fingers, etc?  In one photo, one of the workers was definitely wearing a wedding ring (a no-no where I worked), and in another a wristwatch, so it *appears* (to me, the uninitiated outside observer) that there are very little FOD prevention measures in effect. 

4.  What about things like FOD stuck in the tread of your sneakers, for example?

Thanks in advance!

Darin

1.  Bunny suits are only required for payload bay or crew module access.  The rest of the orbiter is not a "clean" area

2.  same processes

3.  watches are allowed but either have to be taped or don't come completely apart.

4.  Tacky mats are used at the entrance.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/04/2011 04:36 pm
4.  What about things like FOD stuck in the tread of your sneakers, for example?
4.  Tacky mats are used at the entrance.

And if you look closely in those photos, everyone who is actually in the aft is wearing covers over their shoes.
Title: Re: Shuttle Q&A Part 5
Post by: dninness on 05/04/2011 04:43 pm
And if you look closely in those photos, everyone who is actually in the aft is wearing covers over their shoes.

Actually, not: http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=52363

Thats what sort of prompted the question.

It just seemed odd to me, especially considering, say, the issue with the emergency air pack that bounced around the aft (was that STS-133? I forget) that there was the potential for change, keys, "very small rocks," etc to wind up in the nether regions of the Shuttle.

Thanks for the info, guys! Very informative.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/04/2011 05:22 pm
And if you look closely in those photos, everyone who is actually in the aft is wearing covers over their shoes.

Actually, not: http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=52363

Actually, yes. The covers have a red sole with a white upper that covers about the bottom half of the shoes sides and the front half of the tongue area. You can see it better in the following picture of the same 2 people.
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=52362

I have also attached some blowups where I have outlined the covers.
Title: Re: Shuttle Q&A Part 5
Post by: dninness on 05/04/2011 06:31 pm
Oops, totally obvious now! Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 05/05/2011 05:26 pm
I've been in the aft once or twice. You have to clear your pockets and anything that you take into the aft (tools, paper, etc.) has to be inventoried before you go in and when you come out. I believe the crew cabin is the same, except you also have to wear bunny suits.
Title: Re: Shuttle Q&A Part 5
Post by: madscientist197 on 05/06/2011 09:16 am
Interesting that the crew cabin requires bunny suits. What's the rationale there?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 05/06/2011 11:10 am
They're more strict with tiny particles. I'm sure they don't want anything floating into the eyes of the Astros when they go weightless, like grains of sand.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/06/2011 09:33 pm
What color is the payload bay floodlights? I'm asking because there's some disagreements in various videos about the color.

For example, a shot from STS-114 of PLBD closing, shows it to be a white color while another this time from STS-130 shows it to be a yellow-green color.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/06/2011 10:50 pm
The lights are metal-halide which gives off a blue white light (above 5000 K) the greenish cast is what you get when a digital camera is balanced for sunlight but is shooting under a bluer light.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/06/2011 10:58 pm
The lights are halogen which gives off a blue white light (above 5000 K) the greenish cast is what you get when a digital camera is balanced for sunlight but is shooting under a bluer light.
OK, so the STS-114 shot is the more correct one?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/06/2011 11:21 pm
The lights are halogen which gives off a blue white light (above 5000 K) the greenish cast is what you get when a digital camera is balanced for sunlight but is shooting under a bluer light.

Are you sure?  First of all, Halogens are in the 2800-3400K range.  Second, that color cast is what you get when you image a single or dual phosphor fluorescent or metal halide when you are daylight balanced.  If you shoot a Halogen when you are daylight balanced, you'll get a yellow-orange cast.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/07/2011 12:35 am
The lights are halogen which gives off a blue white light (above 5000 K) the greenish cast is what you get when a digital camera is balanced for sunlight but is shooting under a bluer light.

Are you sure?  First of all, Halogens are in the 2800-3400K range.  Second, that color cast is what you get when you image a single or dual phosphor fluorescent or metal halide when you are daylight balanced.  If you shoot a Halogen when you are daylight balanced, you'll get a yellow-orange cast.

Sorry, miss typed in the first post. The lights are metal-halide.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/07/2011 01:37 am
The lights are halogen which gives off a blue white light (above 5000 K) the greenish cast is what you get when a digital camera is balanced for sunlight but is shooting under a bluer light.
OK, so the STS-114 shot is the more correct one?

If you mean properly white balanced, then yes.
Title: Re: Shuttle Q&A Part 5
Post by: msc on 05/10/2011 02:54 pm
I tried a search, but don't think I was crafty enough to come up with the right search terms.

When and how do they remove the shields over the windows?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/10/2011 03:25 pm
I tried a search, but don't think I was crafty enough to come up with the right search terms.

When and how do they remove the shields over the windows?

The soft covers are removed by hand during the T-11 hour hold before the RSS (rotating service structure) is retracted.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: msc on 05/11/2011 01:04 am
I tried a search, but don't think I was crafty enough to come up with the right search terms.

When and how do they remove the shields over the windows?

The soft covers are removed by hand during the T-11 hour hold before the RSS (rotating service structure) is retracted.

Mark Kirkman

Thanks.  that's what I figured, but I saw a picture of Endeavour with the the shields on, and I thought it was taken after the RSS retract.  Guess not. 
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 05/13/2011 01:55 pm
Maye have been when they retract the RSS for payload arrival to the pad
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/15/2011 04:59 pm
Hi all.

I was reading the other day this article regarding a clearance issue between the KU-Antenna and the OBSS. This problem was spotted first for STS-114 also if it appears that was there since the beginning since originally for the Shuttle it was thought to use to robotic arms.

My question is: how this issues has been handled? the article doesn't say anything else.

ps: the article is http://spaceflightnow.com/shuttle/sts114/050519tankingpre/

thanks very much.
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 05/15/2011 10:08 pm
My question is: how this issues has been handled? the article doesn't say anything else.

The Shuttle's robotic arm (SRMS) was designed to stored on the port side of the payload bay and the KU dish is in the starboard forward corner of the bay, so they didn't interfere with eachother.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/16/2011 05:23 am
Quote from: Mtakala24
The Shuttle's robotic arm (SRMS) was designed to stored on the port side of the payload bay and the KU dish is in the starboard forward corner of the bay, so they didn't interfere with eachother.

I was speaking about the KU antenna and the OBSS not the RMS. Originally they had tought to put a second arm on the same side of the Ku antenna, but apparently this clearance issue never come up until when for STS-114 they started to install the OBSS which uses the same mounting point designed for this second arm that was never added. Ku-antenna and OBSS are on the same side, the RMS is on the other side.

Title: Re: Shuttle Q&A Part 5
Post by: billshap on 05/16/2011 10:44 am
What is the "Air-Air" channel that is checked during the comm checks along with A/G1, A/G2, and UHF?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 05/16/2011 03:22 pm
Hi all.

I was reading the other day this article regarding a clearance issue between the KU-Antenna and the OBSS. This problem was spotted first for STS-114 also if it appears that was there since the beginning since originally for the Shuttle it was thought to use to robotic arms.

My question is: how this issues has been handled? the article doesn't say anything else.

ps: the article is http://spaceflightnow.com/shuttle/sts114/050519tankingpre/ (http://spaceflightnow.com/shuttle/sts114/050519tankingpre/)

thanks very much.

It was dealt with by confirming positive clearances and imposing a rule on antenna deployment.  The STS-114 Orbiter Flight Readiness Review (FRR) had the following note on the clearance issue:

○ Ku-Band Deployment Clearance

• As the Ku-Band is deployed with the OBSS in the stowed (or rolled in) position, the static clearance gets as close as 0.69”. There is a minimum of 2.6” of static clearance for the ascent/descent configuration of the Ku-Band and the OBSS.

• Worse case on-orbit thermal analysis of the 0.69” static condition has been completed (assumes re-entry thermal conditions) and positive clearance (0.30”) has been verified.  Dynamic clearance for ascent/decent phase was also completed and showed positive clearance.

• OCAD 730 has been put in place as an operational constraint so the KU-band will be deployed and stowed only when the OBSS is stowed and the MPM’s are rolled in.


------
OCAD - Operational Control Agreement Database
MPMs - Manipulator Positioning Mechanisms (supports for the SRMS and OBSS along the payload bay sills)
Rolled in = stowed position (MPMs are rotated inwards towards the payload bay by ~35 degrees from their deployed position to allow payload bay doors to close)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/16/2011 05:39 pm
Thanks AnalogMan that's exactly what I wanted to know. Where did you get the results of the FRR? is it here on the forum? L2 maybe? thanks again
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 05/16/2011 05:55 pm
Thanks AnalogMan that's exactly what I wanted to know. Where did you get the results of the FRR? is it here on the forum? L2 maybe? thanks again

With STS-114 being the Return to Flight (RTF) mission, quite a lot of internal documents are available in the public domain.  The one I quoted from can be found here:

http://www.hq.nasa.gov/pao/FOIA/FRRdocs/13_orbiter.pdf (http://www.hq.nasa.gov/pao/FOIA/FRRdocs/13_orbiter.pdf)

There's a section on the OBSS (pages 100 to 112) - the whole document is 168 pages long and ~8Mb.

Edit to add: If you copy and paste the following text into Google you will get a list of quite a few of these kinds of document:

"STS-114" site:http://www.hq.nasa.gov/pao/FOIA/FRRdocs filetype:pdf

Edit 2: This direct link is even better  :D
http://www.hq.nasa.gov/pao/FOIA/frrdocs.htm
Title: Re: Shuttle Q&A Part 5
Post by: wjbarnett on 05/16/2011 10:47 pm
During today's STS-134 launch, specifically during the MCC-H replay at ~16:40 here (http://www.youtube.com/watch?v=2fuaIEYEiLI&feature=share)
after throttling down to keep max of 3G and approaching MECO, there's a "henning up" call from either BOOSTER or FIDO. What does this mean?
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/16/2011 10:55 pm
Is there any photos or vide of an ET reentry? I saw a bit of one on a dvd I got of the shuttle program and it shows the ET explode during entry. It comes in like usual, bits peeling off then it explodes with fragments going all over the place.

Also in this video someone posted, do the SMEs always bend as they power up? Watch the center engine.

http://www.youtube.com/watch?v=hDCCBgppG4s&feature=related

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/17/2011 01:03 am
Yes, they always flex
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/17/2011 08:06 am
During today's STS-134 launch, specifically during the MCC-H replay at ~16:40 here (http://www.youtube.com/watch?v=2fuaIEYEiLI&feature=share)
after throttling down to keep max of 3G and approaching MECO, there's a "henning up" call from either BOOSTER or FIDO. What does this mean?

"Handing up" comm to TDRS (note the timing with respect to the previous TDRS call).
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/17/2011 08:39 am
During today's STS-134 launch, specifically during the MCC-H replay at ~16:40 [grl=http://www.youtube.com/watch?v=2fuaIEYEiLI&feature=share]here[/gurl]
after throttling down to keep max of 3G and approaching MECO, there's a "henning up" call from either BOOSTER or FIDO. What does this mean?

"Handing up" comm to TDRS (note the timing with respect to the previous TDRS call).
To (possibly) add, that's Ground Control (GC) making those calls (30 seconds to TDRS, handing up, on TDRS).

I haven't had a chance to watch the whole video, but from the parts I saw, you can hear the earlier calls for the different sources (like the MILA call I heard).

(Crippled the url for paging.)
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 05/17/2011 10:58 am
To answer previous page's question, Air to Air is UHF, I thought?
Title: Re: Shuttle Q&A Part 5
Post by: wjbarnett on 05/17/2011 11:32 am
During today's STS-134 launch, specifically during the MCC-H replay at ~16:40
after throttling down to keep max of 3G and approaching MECO, there's a "henning up" call from either BOOSTER or FIDO. What does this mean?

"Handing up" comm to TDRS (note the timing with respect to the previous TDRS call).
To (possibly) add, that's Ground Control (GC) making those calls (30 seconds to TDRS, handing up, on TDRS).

I haven't had a chance to watch the whole video, but from the parts I saw, you can hear the earlier calls for the different sources (like the MILA call I heard).

Thanks Jorge & Phillip - I mis-interpreted what was said and from whom. "Handing up" from GC makes sense.
Title: Re: Shuttle Q&A Part 5
Post by: Jason1701 on 05/17/2011 07:05 pm
Why do the shuttles have their flaps deployed while rolling over to the VAB?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/17/2011 07:19 pm
Why do the shuttles have their flaps deployed while rolling over to the VAB?

Not flaps but elevons.  They are down because there is no hydraulic power.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/17/2011 07:31 pm
STS-134 Ascent Team video;

At 1:28 - "Drop any non essential displays at this time"

Who said that (it doesnt appear to be FD) and what does it mean?

also shortly after;
"GC - enable FIDO and I early"

?

Finally;

After lift-off do the launch controllers have any required monitoring to do where in they might see something that requires their contribution to decision making during ascent?


Thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/17/2011 07:32 pm

After lift-off do the launch controllers have any required monitoring to do where in they might see something that requires their contribution to decision making during ascent?


They are involved with safing the pad and they don't see flight telemetry
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 05/17/2011 07:44 pm
To add to Jim's response:  the "bend" is referred to as start-up transients.  This is why you'll hear "main engines moved to the start position".  Start position has the engines spread apart to avoid nozzles hitting each other at start-up.  And of course start position is different than liftoff (as seen by the engines gimballing after start-up).

Edit:  I should add that this is one of the things I'll miss most when shuttle retires.  Having the liquid engines sitting up high where they can be seen through start-up and gimbal to lift-off position is unique in the rocket world--all other rockets (that I know of/have seen) have the engines buried in the launch pad infrastructure so we don't get such great views of this highly dynamic and exciting time.

Also in this video someone posted, do the SMEs always bend as they power up? Watch the center engine.

http://www.youtube.com/watch?v=hDCCBgppG4s&feature=related


Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 05/17/2011 08:05 pm

After lift-off do the launch controllers have any required monitoring to do where in they might see something that requires their contribution to decision making during ascent?


They are involved with safing the pad and they don't see flight telemetry

To add a little bit here, my understanding is that while we say control of the vehicle is handed off from the LCC to MCC at Launch Tower clear (~T+7secs), the reality is that MCC has control the moment the SRBs ignite.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/17/2011 10:45 pm
I heard something happened to one of the SMEs during STS-134's launch. What was the issue? I missed the press conference that mentioned it.
Title: Re: Shuttle Q&A Part 5
Post by: Rocket Science on 05/17/2011 11:00 pm
I heard something happened to one of the SMEs during STS-134's launch. What was the issue? I missed the press conference that mentioned it.
Q: Main engine sensor issue ? (Chris G)

A: It was on a sensor on low pressure fuel turbo pump B channel. It dropped off for a few milliseconds. So the computer threw it out. Its used for an internal calculation for internal flow through turbo pump. If both sensors failed they have a default flow rate value to fall back to.

Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/18/2011 04:57 am
I heard something happened to one of the SMEs during STS-134's launch. What was the issue? I missed the press conference that mentioned it.
Q: Main engine sensor issue ? (Chris G)

A: It was on a sensor on low pressure fuel turbo pump B channel. It dropped off for a few milliseconds. So the computer threw it out. Its used for an internal calculation for internal flow through turbo pump. If both sensors failed they have a default flow rate value to fall back to.


Couple of notes to add:

More details in the latest story:
http://www.nasaspaceflight.com/2011/05/endeavour-outstanding-shape-iss-for-docking/

And the call itself is in the video that NASA posted that was taken in the Shuttle flight control room before and during the ascent.
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 05/18/2011 04:16 pm
Yes, they always flex

Was it called a resonant nozzle? Or was the chamber? I remember that the RD-0120 had a completely different nozzle that might have been implemented for a possible RS-25E?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/18/2011 10:28 pm
Nozzles going through their normal (as in, structural dynamic "normal") modes as the engines come up to speed.
Title: Re: Shuttle Q&A Part 5
Post by: PeterAlt on 05/18/2011 10:30 pm
What is the current plan on what the fate will be for the two remaining MLPMs? Will they be reused for SLS, go to a museum, or is it undecided?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 05/19/2011 01:05 am
STS-134 Ascent Team video;

At 1:28 - "Drop any non essential displays at this time"

Who said that (it doesnt appear to be FD) and what does it mean?

It was GC. Some of the legacy displays on the MCC workstations are bandwidth hogs so during critical periods use of these displays is limited to those controllers that really need them.

Quote
also shortly after;
"GC - enable FIDO and I early"

?

Abort request pushbutton, which illuminates a light in the cockpit that the crew uses as one cue for an abort.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/19/2011 01:11 am
Abort request pushbutton, which illuminates a light in the cockpit that the crew uses as one cue for an abort.

This story may be interesting given this answer to the question:

http://waynehale.wordpress.com/2010/12/09/abort-request-command/
Title: Re: Shuttle Q&A Part 5
Post by: david1971 on 05/21/2011 12:20 am
I live about 6 hours from Edwards.  How far ahead of time do they decide where to land?  In other words, do I have to out-guess the weather folks and already be on the road before they officially decide to switch from KSC to California?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/21/2011 01:41 am
I live about 6 hours from Edwards.  How far ahead of time do they decide where to land?  In other words, do I have to out-guess the weather folks and already be on the road before they officially decide to switch from KSC to California?

I could barely make it from LA if it was the SSME orbit
Title: Re: Shuttle Q&A Part 5
Post by: Aobrien on 05/21/2011 02:47 am
You would also have to account for a LOT of traffic if I had to guess if it moved to Edwards
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 05/21/2011 04:08 am
Why did shuttle crews abandon wireless headsets for on-orbit comm?  They were used many years ago, but disappeared by the midpoint of the program.  With improvements in technology, wouldn't they be much better, much more comfortable, and most importantly, leave their hands free (other than a push-to-talk button)—not having to find/reach for the microphone or hold it while talking?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/21/2011 11:52 am
Why did shuttle crews abandon wireless headsets for on-orbit comm?  They were used many years ago, but disappeared by the midpoint of the program.  With improvements in technology, wouldn't they be much better, much more comfortable, and most importantly, leave their hands free (other than a push-to-talk button)—not having to find/reach for the microphone or hold it while talking?

battery management was a pain.  Because it still needed push to talk, there was no issue with holding one.  One microphone could be share vs many having headsets. 
It was one of those cases were an idea didn't pan out. 

Case in point, submariners don't use headsets.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/22/2011 01:21 pm
I saw on the astronaut Hall of Fame ceremony one of the crew told the story of how Discovery on 51-D did a flip when the crew tried to vent the leftover cryo from launch out of the T-0 umbilical.  Discovery went into a nose down pitch as a result. How did that happen?
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 05/22/2011 02:32 pm
I saw on the astronaut Hall of Fame ceremony one of the crew told the story of how Discovery on 51-D did a flip when the crew tried to vent the leftover cryo from launch out of the T-0 umbilical.  Discovery went into a nose down pitch as a result. How did that happen?

Maybe this? http://blogs.nasa.gov/cm/blog/waynehalesblog/posts/post_1233630956222.html

Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 05/22/2011 06:09 pm
I noticed in the STS-134 RPM images that the front landing gear doors are asymmetric, with one door being smaller than the other. What is the reason for this?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 05/23/2011 01:45 am
One has an edge to fit over the other when closed.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 05/23/2011 04:54 am
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?
Title: Re: Shuttle Q&A Part 5
Post by: sitharus on 05/23/2011 05:11 am
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?

Look closely at the shadows. On the right the black tiles overhang the white door, on the left it's reversed.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 05/23/2011 09:28 pm
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?

Padrat is correct. The overhanging door makes a more effective seal. The payload bay doors are built with the same principle in mind. The right door overlaps the left by almost 4 inches.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/23/2011 10:35 pm
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?

Padrat is correct. The overhanging door makes a more effective seal. The payload bay doors are built with the same principle in mind. The right door overlaps the left by almost 4 inches.
Speaking of the PLBDs: It's fairly well known during the SLC-6 on-pad trials with Enterprise the PLBDs blew open in the high winds and had to be secured using strings of some kind.

Was this ever a concern for Discovery or did Enterprise lack any of the PLBD latching systems(bulkhead/centerline) found on the operational orbiters?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 05/23/2011 10:48 pm
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?

Probably the same vehicle, from a slightly different angle.  Perhaps this makes the situation clear.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 05/24/2011 12:26 am
I suspected that might be the case, but I dismissed it due to this image (http://farm4.static.flickr.com/3637/3382986095_2a99d501da.jpg). Maybe the view isn't very good?

Here's a yet another view from a different angle - this of Discovery on the runway at the end of the STS-133 mission.  The overlap profiles are a little easier to see (click to enlarge).
Title: Re: Shuttle Q&A Part 5
Post by: treddie on 05/25/2011 08:42 am
Hey, this is a purely geeky question, but in ISS and Shuttle Mission Controls, you've probably noticed that everyone has a vertical orange-ish panel that sits off to either the far left or right of their particular stations.  They appear to be dedicated touch screens with a bunch of buttons on it.  Once in a very rare while, a controller will touch the screen.  Does anyone know what these are?
Title: Re: Shuttle Q&A Part 5
Post by: wjbarnett on 05/25/2011 11:29 am
Hey, this is a purely geeky question, but in ISS and Shuttle Mission Controls, you've probably noticed that everyone has a vertical orange-ish panel that sits off to either the far left or right of their particular stations.  They appear to be dedicated touch screens with a bunch of buttons on it.  Once in a very rare while, a controller will touch the screen.  Does anyone know what these are?
Answered a huge number of times in this and other threads. Nevertheless, those buttons select the various voice loops that the controller is listening to or able to speak into via their headset.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/25/2011 12:50 pm
I never noticed the overlap for the nose gear door. All the models of the shuttle have both doors the same size.

Speaking of which what is that hose connection port on the inside of the right nose gear door on Discovery? *points to above photo*
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/25/2011 05:47 pm
I never noticed the overlap for the nose gear door. All the models of the shuttle have both doors the same size.

Speaking of which what is that hose connection port on the inside of the right nose gear door on Discovery? *points to above photo*

That is the roller for the hook that holds the door closed. There is one at the front and rear ends of each NG door. The MLG doors each have 3 along the inboard edge.
Title: Re: Shuttle Q&A Part 5
Post by: Hungry4info3 on 05/25/2011 05:55 pm
Ahh okay, that helps clear it up. Very much appreciated.  :)
Title: Re: Shuttle Q&A Part 5
Post by: treddie on 05/25/2011 07:45 pm
Sorry about that Mission Control question popping up here...It got moved by the sys admin for some reason to this thread so it ended up off-topic from my point-of-view.  Thank you for the excellent reply, however.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/28/2011 11:17 pm
Why does the left SRB have additional stiffeners added to it?

This person's model of both boosters shows the difference.

http://i198.photobucket.com/albums/aa234/crowe-t/Space%20Shuttle%20build/IMG_3893.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/30/2011 02:27 am
How come STS-7's ET has the LH2 Gaseous line on the left side of the tank? Wasn't it discontinued after STS-5?

http://www.nasa.gov/images/content/2164main_sts7_et_lo.jpg
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/30/2011 04:17 am
Why does the left SRB have additional stiffeners added to it?

This person's model of both boosters shows the difference.

http://i198.photobucket.com/albums/aa234/crowe-t/Space%20Shuttle%20build/IMG_3893.jpg

I've never seen that in photos of actual SRBs. I believe the moldings of that model kit are in error. As far as I know, the only difference between the left and right SRBs, besides things that are symetricly opposite like the BSMs, is the black identification stripe on the forward skirt and frustrum of the left booster.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 05/30/2011 04:21 am
How come STS-7's ET has the LH2 Gaseous line on the left side of the tank? Wasn't it discontinued after STS-5?

http://www.nasa.gov/images/content/2164main_sts7_et_lo.jpg

STS-7 flew with a SWT (ET-6). STS-6 had debued the LWT (ET-8).
Title: Re: Shuttle Q&A Part 5
Post by: Phosphorus on 05/30/2011 12:53 pm
(Disclaimer -- I know search button is my friend, but couldn't find this topic covered)

At what point in the STS-134 timeline is STS-335 officially stood down? Logic says rescue is unavailable (and thus STS-335 is pointless) as soon as Endeavour is unable to return to ISS.

Thus, two questions:
1) what is the "point of no return to ISS" in Endeavour's post-undocking journey?
2) is there a formal stand-down time for STS-335?
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 05/30/2011 02:10 pm
Here is a pic to help with my question on the left SRB having extra fittings on it. The person's model photo shows the details more clearly.

This is a real one- http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/StackCloseups/KSC-99PP-1308_sts103.jpg That is the left SRB

The right SRB- http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/StackCloseups/STS-101-00pp0411.jpg

Why does the left booster have these extra straps on parts of it?  Above shows the left SRB compared to the right SRB.
Title: Re: Shuttle Q&A Part 5
Post by: SpaceAndrew25 on 05/30/2011 09:06 pm
I have always wondered how the orbiter stays attached to the ET during launch. The way the orbiter is oriented during launch has always scared me. How well do they bolt that thing to the external tank?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/30/2011 09:09 pm
There is a ball and socket arraignment for the aft attachments
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 05/31/2011 03:36 am
"Arrangement," perhaps?  Otherwise what crime are the aft attachments accused of? :)
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/01/2011 02:49 am
 Hi folks,

Two questions:

1) Why do they need to "hot fire" the RCS for landing when they just used them for the "fly around?

2) Why is this section of the tank(circled) a different color?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/01/2011 03:12 am
Hi folks,

Two questions:

1) Why do they need to "hot fire" the RCS for landing when they just used them for the "fly around?

2) Why is this section of the tank(circled) a different color?

1.  The aft RCS is used for entry until  around Mach 2

2.  That portion of the foam was applied at a different time and therefore had a shorter exposure to UV light.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/01/2011 04:01 am
Hi folks,

Two questions:

1) Why do they need to "hot fire" the RCS for landing when they just used them for the "fly around?


1.  The aft RCS is used for entry until  around Mach 2


And the flyaround is flown using the Orbit DAP, which prioritizes the RCS jets in each pod in each direction and only fires the highest priority jets when commanded to fire. The Aerojet DAP potentially uses all of them so we want to know if they're all available; the flyaround is not a good test of this.
Title: Re: Shuttle Q&A Part 5
Post by: Quaxo76 on 06/01/2011 07:36 am
I had already asked this question on the STS-134 landing thread, but it was "flooded" and went unnoticed, so I thought I'd repost it here...
During the final minutes before landing, the Shuttle trail is displayed on the screens of Mission Control. There is a solid line, and two red triangles moving in front of the solid line. The triangles are separated by quite a few miles. My question is: which is indicating the Shuttle's position? The first triangle, the second triangle or the beginning of the solid line?
And what do the two triangles represent exactly?

TIA,
Cristian
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/01/2011 07:37 am
Hi all.

I quick question for you. I know it's a silly questions, but I need to answer for a project I'm working on.

the questions is: people working in the OPF at the KSC, are NASA personnel or USA contractors?

thanks very much.

Davide
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 06/01/2011 07:54 am
Mostly USA and a few other assorted contractors. NASA supplies some engineering.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/01/2011 09:57 am
end of the solid line and the triangles are 30 and 60 second position predictions, I believe.  Search the Shuttle Q&A thread, where also, this question should be.
Title: Re: Shuttle Q&A Part 5
Post by: lucspace on 06/01/2011 10:51 am
Are there any photo's or illustrations of the sensors orbiters use to take the 'air data' late before landing?
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/01/2011 02:57 pm
Why was the AFRSI portion changed on the final 3 orbiters? For example you compare Discovery, Endeavour, and Atlantis from when the first flew to today, you notice the amount of AFRSI is less than what was there before. Why?
Title: Re: Shuttle Q&A Part 5
Post by: Skylab on 06/01/2011 02:58 pm
Are there any photo's or illustrations of the sensors orbiters use to take the 'air data' late before landing?
I guess the best ones may be here: http://historical.ha.com/c/item.zx?saleNo=6052&lotIdNo=50006 (http://historical.ha.com/c/item.zx?saleNo=6052&lotIdNo=50006) (hope the link lasts a while)
Title: Re: Shuttle Q&A Part 5
Post by: mcdavis941 on 06/01/2011 06:33 pm
What's the source of the bright white-orange light on the base of the vertical stabilizer than you see in night landings, like in this shot:

http://graphics8.nytimes.com/images/2011/06/01/science/space/01shuttle-b/01shuttle-b-popup.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 06/01/2011 06:46 pm
What's the source of the bright white-orange light on the base of the vertical stabilizer than you see in night landings, like in this shot:

http://graphics8.nytimes.com/images/2011/06/01/science/space/01shuttle-b/01shuttle-b-popup.jpg

That's the APU exhaust.
Title: Re: Shuttle Q&A Part 5
Post by: wedge on 06/01/2011 07:31 pm
Why was the AFRSI portion changed on the final 3 orbiters? For example you compare Discovery, Endeavour, and Atlantis from when the first flew to today, you notice the amount of AFRSI is less than what was there before. Why?

Well, the AFRSI did not perform so well in some locations, so we went back to tile in those areas.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 06/02/2011 12:03 am
Just out of curiosity, why did the orbiters land at Edwards for their first flights?  I understand that for Columbia and Challenger KSC was not open to landings yet, for Discovery only one KSC landing had taken place before, and for Atlantis there were still issues with the Tires/brakes, but by the time Endeavour flew KSC landings were a regular occurrence, yet she still landed at Edwards.  Is there any special reason?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/02/2011 12:08 am
Just out of curiosity, why did the orbiters land at Edwards for their first flights?  I understand that for Columbia and Challenger KSC was not open to landings yet, for Discovery only one KSC landing had taken place before, and for Atlantis there were still issues with the Tires/brakes, but by the time Endeavour flew KSC landings were a regular occurrence, yet she still landed at Edwards.  Is there any special reason?

Just being conservative with a new orbiter, it was a program rule.

BTW, KSC was available for  Columbia and Challenger, again just being cautious.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 06/02/2011 02:11 am
The redesigned brakes and wheels as well as the drag chute made KSC a better option.  Those old brakes gave NASA lots of problems.

And KSC was an option for STS-1.  It was needed for RTLS.
Title: Re: Shuttle Q&A Part 5
Post by: shuttlefanatic on 06/02/2011 03:26 am
Just out of curiosity, why did the orbiters land at Edwards for their first flights?  I understand that for Columbia and Challenger KSC was not open to landings yet, for Discovery only one KSC landing had taken place before, and for Atlantis there were still issues with the Tires/brakes, but by the time Endeavour flew KSC landings were a regular occurrence, yet she still landed at Edwards.  Is there any special reason?

Just being conservative with a new orbiter, it was a program rule.

BTW, KSC was available for  Columbia and Challenger, again just being cautious.
For comparison, the runway at the SLF is 15000' long.
The lakebed runway (17/35) they used at Edwards is currently charted as 39097' long, and I think was even a little longer back when the shuttle was using it.  Plus, it didn't really much matter if you wound up a little short or long or off to one side :)  (I think there's mention in Wayne Hale's blog, or somewhere here, of a lakebed shuttle landing that technically came in a tad bit short of the threshold.)
Title: Re: Shuttle Q&A Part 5
Post by: sitharus on 06/02/2011 04:41 am
For comparison, the runway at the SLF is 15000' long.
The lakebed runway (17/35) they used at Edwards is currently charted as 39097' long, and I think was even a little longer back when the shuttle was using it.  Plus, it didn't really much matter if you wound up a little short or long or off to one side :)  (I think there's mention in Wayne Hale's blog, or somewhere here, of a lakebed shuttle landing that technically came in a tad bit short of the threshold.)


I think this is the post you're thinking of: http://blogs.nasa.gov/cm/blog/waynehalesblog/posts/post_1216755480398.html
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/02/2011 01:05 pm
Endeavour's first landing was also the first use of the drag chute.
Title: Re: Shuttle Q&A Part 5
Post by: oxford750 on 06/02/2011 03:44 pm
Thanks Jim and Jorge.

oxford750
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/03/2011 11:25 pm
Why are Challenger's tiles around the crew hatch different from the other orbiters? 

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/04/2011 10:56 am
Why are Challenger's tiles around the crew hatch different from the other orbiters? 



AFRSI was added to the other orbiters.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/04/2011 02:10 pm
I was asking on the tile pattern  of the hatch, not the AFRSI. :)

Here is a decal sheet for shuttle models that shows both hatch tile patterns. The one on the left is with all the orbiters except Challenger, the one on the right is what Challenger has. She has extra black tiles. http://www.ninfinger.org/models/pix/rsmdecal.jpg

Why?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/04/2011 04:14 pm
I was asking on the tile pattern  of the hatch, not the AFRSI. :)

Here is a decal sheet for shuttle models that shows both hatch tile patterns. The one on the left is with all the orbiters except Challenger, the one on the right is what Challenger has. She has extra black tiles. http://www.ninfinger.org/models/pix/rsmdecal.jpg

Why?
Just a guess, but I would say there was some concern about thermal conditions around the hatch tunnel. It is the one place where the crew cabin structure approaches the outer mold line. Challenger's structure was somewhat different from the later vehicles.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/04/2011 05:13 pm
Why does the left SRB have additional stiffeners added to it?

This person's model of both boosters shows the difference.

http://i198.photobucket.com/albums/aa234/crowe-t/Space%20Shuttle%20build/IMG_3893.jpg

Here is a pic to help with my question on the left SRB having extra fittings on it. The person's model photo shows the details more clearly.

This is a real one- http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/StackCloseups/KSC-99PP-1308_sts103.jpg That is the left SRB

The right SRB- http://homepage.mac.com/georgegassaway/GRP/Scale/ShuttleData/StackCloseups/STS-101-00pp0411.jpg

Why does the left booster have these extra straps on parts of it?  Above shows the left SRB compared to the right SRB.   
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/05/2011 04:22 pm
Why does the left SRB have additional stiffeners added to it?...
Why does the left booster have these extra straps on parts of it?  Above shows the left SRB compared to the right SRB.   

The SRBs don't have "stiffeners" on the segments except for the lower segment. The rings are the joints between the various segments.

As far as the extras on the left SRB, those are covers over linear strain guage sensors used to measure bending and hoop stress'es in the segment cases durring firing. They are a lot fhinner than the segment joints themselves. I have included photos of the various items. The black ones are the factory segment joints and the thicker white ones are the field joints.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/05/2011 06:46 pm
I see. Though I do wonder why the left booster has more of these than the right one? Does the left booster being closer to the FSS get more strain from the shockwaves at launch?
Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 06/05/2011 08:29 pm
Is it true that one of the limitations of the Shuttle's wingspan design was the ability to fit through the transfer aisle during Lift/Mate??

TIA,

Steve
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/05/2011 08:33 pm
Is it true that one of the limitations of the Shuttle's wingspan design was the ability to fit through the transfer aisle during Lift/Mate??

TIA,

Steve


It turns sideways or the lift
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/05/2011 11:01 pm
Is it true that one of the limitations of the Shuttle's wingspan design was the ability to fit through the transfer aisle during Lift/Mate??

TIA,

Steve


Not really for lift/mate since they can swivel it once they have it vertical, but the width of the transfer aisle (95') was a constraint on the wingspan (78') since they roll the orbiter in horizontaly.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 06/05/2011 11:12 pm
what happens to "trash" that is brought down on the MPLM?  I understand that some of it is taken for engineering analysis especially if it is failed components, but WHat about things like shirts, pants and packing foam?  Is there a dumpster that they are thrown in beside the SSPF?  And in that case, how can I get a dumpster diving permit  ;)
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 06/05/2011 11:14 pm
I see. Though I do wonder why the left booster has more of these than the right one? Does the left booster being closer to the FSS get more strain from the shockwaves at launch?

I'm reading a book about the X-15... one side of the aircraft was heavily instrumented with thermocouples and pressure pick-off points, with very few on the other side. The thinking was that the aircraft was symmetrical, so the measurements on one side would be basically the same as the other side. Instrumenting only one side saved significantly in the areas of weight and complexity. I suspect the same thing goes here for the Shuttle stack.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/07/2011 12:29 am
*nods* Interesting.

Another question on the SRBs I have is how come on some of the early flights the boosters had this bolt pattern on some of the segments? As an example look at http://www.axmpaperspacescalemodels.com/images/stack1a.gif http://www.axmpaperspacescalemodels.com/images/stack1b.gif http://www.axmpaperspacescalemodels.com/images/stack2b.gif

and compare it to http://www.axmpaperspacescalemodels.com/images/stack6b.gif

Why was this done on those particular flights early in the shuttle program?
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 06/10/2011 06:22 pm
How fast can each of the individual joints on the RMS move? Also, what are the overall speed limits for the RMS? The RMS speed seems to be limited to 2.0 fps (according to the PDRS documents I've seen), but I'm wondering if this is due to mechanical constraints or just so it doesn't bump into anything.
Title: Re: Shuttle Q&A Part 5
Post by: simonbp on 06/13/2011 05:27 am
This has most certainly been covered before, but what is the contingency if one of the SRBs fails to ignite?
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 06/13/2011 05:31 am
I've asked; apparently there is none.  Somebody must be supremely confident that it won't happen.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/13/2011 05:37 am
I've asked; apparently there is none.

No, there is a contingency plan. Range Safety would order spectators to shelter in-place, and LCC and MCC would lock the doors and take steps to preserve data for the investigation.

Quote
Somebody must be supremely confident that it won't happen.

The pyros are extremely reliable, there are redundant pyros with multiple command paths.
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 06/13/2011 06:23 am
Well, that's not /much/ of a contingency plan, but it would seem to be all that could humanly be done.

A certain amount of work, IIRC, goes into the NASA Standard Initiator, in generating and maintaining supreme confidence that it will work on time, every time. IIRC, there was some question a while back about a recent manufacturing batch.
   -Alex
Title: Re: Shuttle Q&A Part 5
Post by: Nicolas PILLET on 06/13/2011 02:38 pm
When flying a shuttle mission to the ISS with external payloads, you can use an ICC or a LMC. What are the differences between these to platforms ? Why would you use one rather than the other ?

Altought ICC is well documented, it is very hard to find documentation on LMC. Someone has documents to share ?

Thanks !
Title: Re: Shuttle Q&A Part 5
Post by: simonbp on 06/13/2011 07:23 pm
No, there is a contingency plan. Range Safety would order spectators to shelter in-place, and LCC and MCC would lock the doors and take steps to preserve data for the investigation.

So, I assume that means that there is zero chance of the orbiter surviving in such a case?

Semi-related, but is there a public (or L2) list of Shuttle contingency plans?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 06/13/2011 07:46 pm
No, there is a contingency plan. Range Safety would order spectators to shelter in-place, and LCC and MCC would lock the doors and take steps to preserve data for the investigation.

So, I assume that means that there is zero chance of the orbiter surviving in such a case?

Correct.
Title: Re: Shuttle Q&A Part 5
Post by: sascha_l on 06/19/2011 05:15 pm
Does anyone know how the Orbiter's rudder/speedbrake actuators work?

Are there actuators for each surface (i.e. left and right side of the rudder), or are there separate actuators for opening/closing the speedbrake and for rotating the entire speedbrake assembly (i.e. both sides) for the rudder function?

The crew operations manual mentions different rate limits and different maximum deflection angles for the rudder and the speedbrake functions, which strongly suggests the latter, but I couldn't find a definite answer.

Thanks a lot!
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 06/19/2011 08:58 pm
So, I assume that means that there is zero chance of the orbiter surviving in such a case?
    There are hold down bolts, fractured at the moment the SRBs are lit, but if not blown the SRBs will comfortably tear through them anyways. Imagine what the stack will do as it rotates off the gantry. You can work out how many megajoules are in the tankage, but figure the stack is about two kilotons of mostly propellant. And a bit of a BLEVE.
     It would be interesting to see the ballistics calculations, but fatalities among the public on the causeway from SRB fragments would seem reasonable.

Quote
Semi-related, but is there a public (or L2) list of Shuttle contingency plans?
   Yes.  This: http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html
   ... is good reading, particularly the Intact Ascent Aborts and Contingency Aborts handbooks. Fascinating, and terrifying.
    -Alex
Title: Re: Shuttle Q&A Part 5
Post by: uapyro on 06/21/2011 09:11 pm
I remember hearing somewhere that "the sound from the space shuttle engines and SRB can kill at X distance."

Is that true? If so, what is that distance, or thought to be the distance?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 06/22/2011 02:18 pm
I remember hearing somewhere that "the sound from the space shuttle engines and SRB can kill at X distance."

Is that true? If so, what is that distance, or thought to be the distance?

I think I've heard somewhere around 1500-2000 ft
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 06/23/2011 04:43 pm
So, I assume that means that there is zero chance of the orbiter surviving in such a case?
    There are hold down bolts, fractured at the moment the SRBs are lit, but if not blown the SRBs will comfortably tear through them anyways. Imagine what the stack will do as it rotates off the gantry. You can work out how many megajoules are in the tankage, but figure the stack is about two kilotons of mostly propellant. And a bit of a BLEVE.

To get nit-picky here, the hold down bolts are actually blown about 0.3 seconds before SRB ignition.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/23/2011 06:47 pm
So, I assume that means that there is zero chance of the orbiter surviving in such a case?
    There are hold down bolts, fractured at the moment the SRBs are lit, but if not blown the SRBs will comfortably tear through them anyways. Imagine what the stack will do as it rotates off the gantry. You can work out how many megajoules are in the tankage, but figure the stack is about two kilotons of mostly propellant. And a bit of a BLEVE.

To get nit-picky here, the hold down bolts are actually blown about 0.3 seconds before SRB ignition.

This time-line says that they are initiated at the same instant:
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 06/24/2011 01:17 pm
What is the aerovent seen on the external tank's intertank used for? Also are there any diagrams or photos of it?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/24/2011 03:31 pm
What is the aerovent seen on the external tank's intertank used for? Also are there any diagrams or photos of it?

This is a description of the intertank pressure vents (snipped from the L2 ET Bible)

7.3.1 PRESSURE VENTS
 
Two vent openings, each with an area of six square inches, are provided at the forward end of the intertank for venting during preflight environmental conditioning and for equalization of internal/external pressures in flight. This 12.6 square-inch area is combined with other penetrations to provide a leak area varying from 54 to 63 square inches to maintain safe oxygen levels during high wind ground operations, and to maintain localized intertank pressures between -1.1 and +3.7 psig during flight. Indeterminate joint leakage is eliminated by sealers and foam insulation used to cover the entire intertank surface as a TPS requirement.
 
Each vent consists of an elliptical shaped tube. A flange is welded at the start of the bend, and the vent is installed on the intertank skin with the flange on the inside so that the tube extends, between two stringers and to the top surface of the TPS. The tube bend direction is positioned toward the L02 tank to prevent the entry of rain water during prelaunch operations.


There is also this description of the intertank conditioning during propellant load:

9.5.1 INTERTANK PURGE

The ET intertank is purged with dry, heated GN2 during propellant loading to prevent condensation of moisture, preclude air ingestion through the intertank vents, and to avert a buildup of hazardous gases and to provide temperature conditioning of the Range Safety System components and other electronics.


This simple graphic is the best I could quickly find.
Title: Re: Shuttle Q&A Part 5
Post by: Nikola on 06/29/2011 11:56 pm
Hi,

does anybody know what is the thickness of the ET thermal insulation foam?

Somehow, I always imagined that it is really tick.

Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 06/30/2011 12:01 am
Hi,

does anybody know what is the thickness of the ET thermal insulation foam?

Somehow, I always imagined that it is really tick.

Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?

Thanks.


The thickness varies for different parts of the tank.  Consistency I guess is harder to answer but the closest analogy I can think of right now is something like styrofoam, and yes it can be cut, shaved, etc. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/30/2011 11:51 am
Hi,

does anybody know what is the thickness of the ET thermal insulation foam?

Somehow, I always imagined that it is really tick.

Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?

Thanks.


It is very similar to this stuff

http://greatstuff.dow.com/

This even turns the same color when exposed to sunlight
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 06/30/2011 03:19 pm
Also, what is the consistency? Can you for example cut a chunk of foam with kitchen knife?

Thanks.


Back in 1995, woodpeckers pecked out nearly 100 holes in the STS-70 ET foam insulation. Needed rolled back to the VAB for repairs.
Title: Re: Shuttle Q&A Part 5
Post by: Nikola on 07/02/2011 10:33 pm
The thickness varies for different parts of the tank.  Consistency I guess is harder to answer but the closest analogy I can think of right now is something like styrofoam, and yes it can be cut, shaved, etc. 

Yes, I expected it probably varies.

But in what range is it? I mean is it 3 cm or 30cm.

I have another question. Is there any very high quality sound recording of a space shuttle launch? I guess HD video has good sound but it's optimized for video and not sound since it's HD *video*.

Title: Re: Shuttle Q&A Part 5
Post by: Jason1701 on 07/03/2011 12:01 am
This video is amazing.

http://www.youtube.com/watch?v=OnoNITE-CLc
Title: Re: Shuttle Q&A Part 5
Post by: kraisee on 07/03/2011 01:36 am
Nikola,
The SOFI varies across the entire structure of the tank.   Generally, it is between 0.25" to 1.52" thick on the cryogenic tanking structures.   The LH2 tank tends to have the thickest material, the LOX tank uses thinner.   The tank domes inside the Intertank are protected from airflow, so they are fairly thin.

The Intertank structure typically has the thinnest material, as thin as 0.15" thick.

The SLWT System Definition Handbook has precise details.   Its available in the L2 section.

Ross.
Title: Re: Shuttle Q&A Part 5
Post by: Nikola on 07/03/2011 12:39 pm
Thanks.

It's not a very tick layer. I mean from the appearance of the tank you could think is like 1m tick :)
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 07/05/2011 10:32 pm
How fast can each of the individual joints on the RMS move? Also, what are the overall speed limits for the RMS? The RMS speed seems to be limited to 2.0 fps (according to the PDRS documents I've seen), but I'm wondering if this is due to mechanical constraints or just so it doesn't bump into anything.

The rates are set by software based on the mass and inertias of the payload.  The 2 fps tip rate is for the unloaded arm.  The overriding consideration is that the system should be able to detect a failure and stop motion as long as the payload remains more than five feet from structure (the flight rule limit).  Heavy payloads will move much slower than the unloaded arm to protect this stopping distance constraint.

Individual joint rates scale down with the allowable tip rate.  If you take the 50 foot arm and figure out what rotational rate gives you 2 fps at the tip, you will be darn close to the shoulder joint rate for unloaded motion.
Title: Re: Shuttle Q&A Part 5
Post by: JLicklider on 07/08/2011 05:18 am
Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO.  I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but  it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info.  (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?

Joey


Title: Re: Shuttle Q&A Part 5
Post by: alexw on 07/08/2011 05:55 am
Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO.  I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but  it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info.  (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?
Try: http://spaceflightnow.com/shuttle/sts135/fdf/135ascent.html

Note that the times may not be exact to the second --- the precise launch window depends on recent updates of the station's position, and they target the center of the window. Although, this version says updated 8 July, so it should be about on the money.
     -Alex
Title: Re: Shuttle Q&A Part 5
Post by: JLicklider on 07/08/2011 06:04 am
Perfect! Thanks!

Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 07/08/2011 08:33 am
Im looking for a chart or list of the milestones, speeds, times, MCC calls etc. from T-0 to MECO.  I did a search and found the same question asked in the Shuttle Q&A thread number 2, the reply was to see http://science.ksc.nasa.gov/shuttle/countdown/count.html#T-01M00S but  it only goes to T-0. Clicking LIFTOFF on that page takes to a countdown clock but no launch info.  (Searching for "launch milestone" on a spaceflight forum returns quite a few results!)
Any ideas?
Try: http://spaceflightnow.com/shuttle/sts135/fdf/135ascent.html

Note that the times may not be exact to the second --- the precise launch window depends on recent updates of the station's position, and they target the center of the window. Although, this version says updated 8 July, so it should be about on the money.
     -Alex

Also, the abort boundary calls are made in real-time by Mission Control based on performance and other factors.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 07/08/2011 08:01 pm
with the shuttle fleet retiring, what becomes of the one remaining ET-94 left in Michoud? Will it be scrapped or put in an exhibit with Atlantis or the other orbiters?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 07/09/2011 06:48 pm
Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw.  Why is this?

Next- just after the roll program there always seems to a be slight roll back in the opposite direction. Is this because of the enormous forces involved in the roll that there will always be a need for a correction back?

Finally, I have noticed the following on prior launches, including this one; During ascent, if you use the shadows cast on the stack or the Earth as reference you will notice what appears to be slight rolling back and forth around the vertical axis. What causes this?

Thank you!


Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 07/09/2011 07:18 pm
Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw.  Why is this?

Quidance is open-loop during SRB firing (first stage) - that means that the flying follows a preset profile, not taking realtime things, such as performance variations, into account. Soon after separation, the computers calculate what needs to be done to achieve the pinpoint orbital targets, and actively start steering the shuttle there.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/10/2011 01:24 am
How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 07/10/2011 06:51 pm
How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?

Compare the values psloss provides to the preliminary values in the attachment to his post.  Non-trivial difference!

NC-4 burn updates:

Weight: 248252 lbs
TIG: 01/19:26:23.4 --> 10:55:27 GMT / 5:55:27 Central

TGT PEG7:

dVx: +143.9 (fps)
dVy: 0
dVz: +7.6

Lots of questions about that preliminary "PAD", BTW, like almost all the acronyms.  The math for {delta}VTOT is clear: sqrt((139^2) + (38.4^2)) = 144.2.  TGO must be burn duration?  But what are R, P, and Y for BURN ATT?  And TGT HA and HP?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 07/11/2011 12:04 am
1) Watching the STS-135 replays, about 8 seconds after SRB sep and just prior to OMS ignition that if you use the background of the earth as a reference you can see what appears to be a tail left / nose right yaw.  Why is this?

2) Next- just after the roll program there always seems to a be slight roll back in the opposite direction. Is this because of the enormous forces involved in the roll that there will always be a need for a correction back?

3) Finally, I have noticed the following on prior launches, including this one; During ascent, if you use the shadows cast on the stack or the Earth as reference you will notice what appears to be slight rolling back and forth around the vertical axis. What causes this?

Thank you!


1) Approximately 10 seconds prior to SRB separation, the Flight Computers initiate an "attitude hold" command to the SSMEs to hold the SSV stack in a 'rock-solid' attitude for SRB separation. When the SRBs separate, dispersions are induced onto the ET/Orbiter pair, changing their attitude ever-so-slightly. About 5 secs after SRB sep, the Flight Computers command the guidance programs to converge. This dampens out - or corrects - those attitude dispersions induced at SRB sep as well as begin to align the vehicle precisely with the mission's MECO targets.

2) Basically, yes.

3) If you are referring to the movement of shadows during SRB powered flight, the slight movement of the SSV stack is caused by aerodynamic and atmospheric forces (i.e. upper level winds) acting on the vehicle as it ascends through the dense lower atmosphere of Earth and the Thrust Vector Control system on the SRBs and the guidance system gimbaling of the SSMEs to correct the vehicle's attitude as it encounters these forces.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/11/2011 04:44 am
How much does a couple minute hold like we had on 135 affect the OMS 2 and NC burns?

Compare the values psloss provides to the preliminary values in the attachment to his post.  Non-trivial difference!

NC-4 burn updates:

Weight: 248252 lbs
TIG: 01/19:26:23.4 --> 10:55:27 GMT / 5:55:27 Central

TGT PEG7:

dVx: +143.9 (fps)
dVy: 0
dVz: +7.6

Lots of questions about that preliminary "PAD", BTW, like almost all the acronyms.  The math for {delta}VTOT is clear: sqrt((139^2) + (38.4^2)) = 144.2.

In this case, yes, because dVy was zero.

Quote
TGO must be burn duration?

Correct.

Quote
  But what are R, P, and Y for BURN ATT?

Roll, pitch, and yaw in inertial M50 coordinates.

Quote
  And TGT HA and HP?

Target height of apogee and perigee, in nautical miles.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 07/11/2011 05:56 pm
Sorry if this is the wrong place to post this, but I have a question about the net mass of the MPLM cargo on this mission.  The Flight Operations and Integration PDF on L2 lists the mass of the MPLM as 25,478 lbs up, and this page (http://mplm.msfc.nasa.gov/mission.html) indicates that the empty mass of an MPLM is 9000 lbs, so the cargo should be 16,478 lbs.  However this article (http://www.spaceflightnow.com/shuttle/sts135/110711fd4/index.html) says that the MPLM cargo came to 9,403 lbs.  Where is the discrepancy?
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 07/11/2011 06:49 pm
Wow, what a thread! :)

A pair of questions for people who might know the PASS...

First, I've read that early in Shuttle's life, the on-orbit autopilot would overuse the vernier RCS jets; was anything ever done about that? How are the vernier RCS jets selected now?

Second, why does (wow I can still say that, for just a little longer) the transitional autopilot not use a state estimator/kalman filter?

Thanks,
Title: Re: Shuttle Q&A Part 5
Post by: plomaris on 07/12/2011 05:33 pm
Does anyone have any details on the debris seen right after SRB Separation (at about 2:15)?  From the launch video ET camera view, it looks like an yellow/orange piece of cloth or tape that leaves the starboard side of the orbiter in the chine area and gets whirled back over the starboard wing (see pics).  It does not appear to strike the orbiter.

I've been listening to all the updates and haven't heard any mention of this event.  Normally after launch, all debris events are covered in news conferences, but I've heard no mention of this one.  I'm sure I'm not the only one to have seen it.

Just replay the launch video and watch in slow motion right after SRB sep.

Anyone else see it?

Tom
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/12/2011 05:35 pm
That's OMS assist ignition.
Title: Re: Shuttle Q&A Part 5
Post by: ugordan on 07/12/2011 05:35 pm
That just looks like an OMS assist start transient.
Title: Re: Shuttle Q&A Part 5
Post by: plomaris on 07/12/2011 05:41 pm
Thanks for the quick reply.  I guess I never paid such close attention before.
Title: Re: Shuttle Q&A Part 5
Post by: STS-134 on 07/12/2011 06:58 pm
Why do they always fire the OMS engines on the way up?  Aren't those only supposed to be for maneuvering once in orbit?  Why not just use up the SSME propellant (by pushing MECO back a bit) and save the OMS propellant for later?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/12/2011 07:09 pm
Why do they always fire the OMS engines on the way up?  Aren't those only supposed to be for maneuvering once in orbit?  Why not just use up the SSME propellant (by pushing MECO back a bit) and save the OMS propellant for later?

They know how much they need for each mission with margin and burn off the excess. There is a performance benefit by doing this.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/13/2011 08:41 am
I remember asking about this ages ago. I was surprised that they actually got such a good boost from the OMS engines, as opposed to just not loading that propellant in the first place.

Why do they always fire the OMS engines on the way up?  Aren't those only supposed to be for maneuvering once in orbit?  Why not just use up the SSME propellant (by pushing MECO back a bit) and save the OMS propellant for later?

They know how much they need for each mission with margin and burn off the excess. There is a performance benefit by doing this.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/13/2011 12:10 pm
I remember asking about this ages ago. I was surprised that they actually got such a good boost from the OMS engines, as opposed to just not loading that propellant in the first place.

Why do they always fire the OMS engines on the way up?  Aren't those only supposed to be for maneuvering once in orbit?  Why not just use up the SSME propellant (by pushing MECO back a bit) and save the OMS propellant for later?

They know how much they need for each mission with margin and burn off the excess. There is a performance benefit by doing this.


It isn't the thrust as much but the loss of mass.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 07/13/2011 10:00 pm
Does anybody have a list of all the acronyms used on the radio loop during the shuttle countdown.  There were so many I can't remember them all.  The ones I figured out (or think I did) were:

CDR - Commander
PLT - Pilot
MS1 - Mission Specialist 1
MS2 - Mission Specialist 2
MMT - Mission Management Team
SRO - Safety Range Officer (thought it was RSO)

But there were many others that I didn't catch or couldn't figure out like NTD.

Not that we'll ever hear a Shuttle countdown again but I was curious who all the acronyms referred to.
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 07/13/2011 10:04 pm
Does anybody have a list of all the acronyms used on the radio loop during the shuttle countdown.  There were so many I can't remember them all.  The ones I figured out (or think I did) were:

CDR - Commander
PLT - Pilot
MS1 - Mission Specialist 1
MS2 - Mission Specialist 2
MMT - Mission Management Team
SRO - Safety Range Officer (thought it was RSO)

But there were many others that I didn't catch or couldn't figure out like NTD.

Not that we'll ever hear a Shuttle countdown again but I was curious who all the acronyms referred to.

Someone doesn't read my articles then ;) NTD Is NASA Test Director (NTD). I've used that in about 100 articles.

Moving to Shuttle Q&A
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/13/2011 10:37 pm
Does anybody have a list of all the acronyms used on the radio loop during the shuttle countdown.  There were so many I can't remember them all.  The ones I figured out (or think I did) were:

CDR - Commander
PLT - Pilot
MS1 - Mission Specialist 1
MS2 - Mission Specialist 2
MMT - Mission Management Team
SRO - Safety Range Officer (thought it was RSO)

But there were many others that I didn't catch or couldn't figure out like NTD.

Not that we'll ever hear a Shuttle countdown again but I was curious who all the acronyms referred to.
SRO = Superintendent of Range Ops
NTD = NASA Test Director
LD = Launch Director
OTC = Orbiter Test Conductor
SPE = Shuttle Project Engineer
LRD = Landing/Recovery Director
BTC = Booster/Tank Test Conductor
PTC = Payload Test Conductor
LPS = Launch Processing System
STM = Site Test Manager
CGLS = Ground Launch Sequencer
OPE = Orbiter Project Engineer
CLHY = Liquid Hydrogen console
CLOX= Liquid Oxygen console
CAPU = Auxiliary Power Unit console
CMPS = Main Propulsion System console
CHYD = Orbiter(??) Hydraulics console
CHGD = Hazardous Gas Detection console

That's all that comes to mind right now but there are many more.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 07/13/2011 10:47 pm
Bumping my earlier question...

Sorry if this is the wrong place to post this, but I have a question about the net mass of the MPLM cargo on this mission.  The Flight Operations and Integration PDF on L2 lists the mass of the MPLM as 25,478 lbs up, and this page (http://mplm.msfc.nasa.gov/mission.html) indicates that the empty mass of an MPLM is 9000 lbs, so the cargo should be 16,478 lbs.  However this article (http://www.spaceflightnow.com/shuttle/sts135/110711fd4/index.html) says that the MPLM cargo came to 9,403 lbs.  Where is the discrepancy?
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/14/2011 09:41 am
Don't we have a document somewhere with a huuuuuge list of them in? I'm sure I've downloaded it from NSF before.

Also NASA have a list online on their public website somewhere.

Does anybody have a list of all the acronyms used on the radio loop during the shuttle countdown.  There were so many I can't remember them all.  The ones I figured out (or think I did) were:

CDR - Commander
PLT - Pilot
MS1 - Mission Specialist 1
MS2 - Mission Specialist 2
MMT - Mission Management Team
SRO - Safety Range Officer (thought it was RSO)

But there were many others that I didn't catch or couldn't figure out like NTD.

Not that we'll ever hear a Shuttle countdown again but I was curious who all the acronyms referred to.

Someone doesn't read my articles then ;) NTD Is NASA Test Director (NTD). I've used that in about 100 articles.

Moving to Shuttle Q&A
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 07/14/2011 02:29 pm
Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?

Is it just because they needed room to be able to gimble "down" (towards bottom of orbiter) without interference from the body flap or are there other reasons?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/14/2011 03:12 pm
Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/14/2011 06:36 pm
What happens after SRB and ET separation? It changes and so the orbiter has to make burns at a weird orientation?

Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/14/2011 06:39 pm
What happens after SRB and ET separation? It changes and so the orbiter has to make burns at a weird orientation?

Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 

The SSMEs gimbal to handle the transient at SRB sep. If you watch the ET camera you can see that it's small and controllable, not a "weird orientation" at all.

ET sep is not an issue since MECO occurs before then.
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 07/14/2011 07:29 pm
What happens after SRB and ET separation? It changes and so the orbiter has to make burns at a weird orientation?

Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 

The SSMEs gimbal to handle the transient at SRB sep. If you watch the ET camera you can see that it's small and controllable, not a "weird orientation" at all.

ET sep is not an issue since MECO occurs before then.

How much does the stack CG shift (1) during first stage, (2) at SRB sep, and (3) during second stage? Presumably most of the shift is in x as the LO2 and LH2 are depleted?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 07/14/2011 08:33 pm
Sorry if this is the wrong place to post this, but I have a question about the net mass of the MPLM cargo on this mission.  The Flight Operations and Integration PDF on L2 lists the mass of the MPLM as 25,478 lbs up, and this page (http://mplm.msfc.nasa.gov/mission.html) indicates that the empty mass of an MPLM is 9000 lbs, so the cargo should be 16,478 lbs.  However this article (http://www.spaceflightnow.com/shuttle/sts135/110711fd4/index.html) says that the MPLM cargo came to 9,403 lbs.  Where is the discrepancy?
[/quote]

My documentation shows 26700 lbm total, 16008 cargo + packing material, 10692 net cargo.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 07/14/2011 10:09 pm
Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 

So in that case is the direction of travel of the stack offset by an angle from the direction the nose is pointing?  If so are the wings creating "lift" pulling the orbiter away from the ET (although definitly not nearly as strong as the engines are pushing towards the ET)?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 07/15/2011 01:32 am
 
[/quote]

So in that case is the direction of travel of the stack offset by an angle from the direction the nose is pointing?  If so are the wings creating "lift" pulling the orbiter away from the ET (although definitly not nearly as strong as the engines are pushing towards the ET)?
[/quote]

If memory serves, the orbiter flies at a negative angle of attack during first stage specifically to keep the wings from generating lift.  All steering and trajectory control comes from the SSME and SRB thrust vector control.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 07/15/2011 08:35 am
Duh, of course.

I think I was getting confused with OMS, thanks :)

What happens after SRB and ET separation? It changes and so the orbiter has to make burns at a weird orientation?

Why is the "neutral" thrust vector of the SSMEs angled relative to the stack?  I've always wondered why they were set up to where they are sort of pushing the orbiter towards the ET.  I assume that because of this the stack doesn't travel exactly in the direction the nose is pointing?


they are pointed at the CG of the stack. 

The SSMEs gimbal to handle the transient at SRB sep. If you watch the ET camera you can see that it's small and controllable, not a "weird orientation" at all.

ET sep is not an issue since MECO occurs before then.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 07/15/2011 07:23 pm
When did Columbia get her AFRSI blankets installed and which flight did she fly with this new look?

What is that tiny hole for on the Forward  RCS? You see it in this photo http://upload.wikimedia.org/wikipedia/commons/8/8a/STS-135_Atlantis_port_side_view.jpg 

And here with rectangular cover over it. Look to the upper left of the green access panel cover. http://upload.wikimedia.org/wikipedia/commons/3/38/STS-135_Atlantis_Ready_to_Roll.jpg 

You see it between the edge of the FRCS module and the thruster nozzles.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 07/20/2011 02:00 am

What is that tiny hole for on the Forward  RCS? You see it in this photo http://upload.wikimedia.org/wikipedia/commons/8/8a/STS-135_Atlantis_port_side_view.jpg 

And here with rectangular cover over it. Look to the upper left of the green access panel cover. http://upload.wikimedia.org/wikipedia/commons/3/38/STS-135_Atlantis_Ready_to_Roll.jpg 

You see it between the edge of the FRCS module and the thruster nozzles.


It's a helium relief valve/burst disk overboard dump port for the FRCS fuel tank pressurization system. There is a mirror image port on the starboard side of the FRCS for the oxidizer tank system. And each OMS pod has two ports on the base heat shield arranged around the OMS engine cover. Again, one port for the fuel system and one for the oxidizer. The relief valve/burst disk assembly protects their systems from an overpressure caused by a failed pressure regulator.
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 07/20/2011 11:43 am
I've got a strange question and wonder if anyone knows: As the ET drains during the flight, the forward sections of the tanks are no longer in direct contact with the cryogenic fluids. So how much of a temperature difference do those forward sections see by the time the vehicle reaches MECO? I would imagine that a significant temperature change might cause quite a bit of thermal stress on the fwd sections.

-MG
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 07/20/2011 01:34 pm
I've got a strange question and wonder if anyone knows: As the ET drains during the flight, the forward sections of the tanks are no longer in direct contact with the cryogenic fluids. So how much of a temperature difference do those forward sections see by the time the vehicle reaches MECO? I would imagine that a significant temperature change might cause quite a bit of thermal stress on the fwd sections.

-MG

Not to mention the fact that, after main engine start, the ET tanks are pressurized with oxygen and hydrogen gas tapped off from the main engines. The hydrogen to pressurize the hydrogen tank comes from the flow that drives the LPFT turbopump which comes from the main combustion chamber cooling jacket. The oxygen tank is pressurized with gas from the heat exchanger in the HPOT turbine exhaust which comes from the oxidizer pre-burner. My point is, both of those sources produce what is probably pretty hot gas.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 07/20/2011 10:04 pm
I would imagine that a significant temperature change might cause quite a bit of thermal stress on the fwd sections.

-MG

It does and is suspected to contribute to the foam loss issues.  Liquid air which collects in cracks or voids expands rapidly when the underlying aluminum heats up, and blows off chunks of foam - this is 'cryopumping'.  Charts were shown at one of the MMTs during this mission with graphs of the fluid interface position vs time and how it correlated to foam loss.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 07/20/2011 10:38 pm
Does this helium dump port  have a door to cover it? As it looks like a place  heat could enter.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/21/2011 01:37 pm


So in that case is the direction of travel of the stack offset by an angle from the direction the nose is pointing?  If so are the wings creating "lift" pulling the orbiter away from the ET (although definitly not nearly as strong as the engines are pushing towards the ET)?
[/quote]

If memory serves, the orbiter flies at a negative angle of attack during first stage specifically to keep the wings from generating lift.  All steering and trajectory control comes from the SSME and SRB thrust vector control.
[/quote]

You are correct.  It flies at about minus 4 degrees.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 07/21/2011 02:37 pm
Here's a bit of perspective for you. During fueling, when the ECO sensors in the bottom of the LH2 tank go wet, it's still reading 70-80 degrees at the top of the LH2 tank. Quite a bit of distance between the two.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 07/22/2011 02:21 pm
What will become of the sims?

Is the source code for the GPC's PASS available to the public? My limited knowledge of the GPC's is that their memory and storage space is significantly less than today's PC's (and that isn't to knock how great they are / specialized for flight) and that compared to today's software out there I'd imagine the source code wouldnt be as big. Also, since this isn't private sector (ala microsoft) and was paid for by tax dollars and not a national security secret (or is it?) I would think that it should be available?

Thanks


Title: Re: Shuttle Q&A Part 5
Post by: JayP on 07/22/2011 02:28 pm
What will become of the sims?

Is the source code for the GPC's PASS available to the public? My limited knowledge of the GPC's is that their memory and storage space is significantly less than today's PC's (and that isn't to knock how great they are / specialized for flight) and that compared to today's software out there I'd imagine the source code wouldnt be as big. Also, since this isn't private sector (ala microsoft) and was paid for by tax dollars and not a national security secret (or is it?) I would think that it should be available?

Thanks

First, It very much is a national security secret. Any goverment sponsered sofware dealing with the guidence of rockets in flight is by definition.

Second, Even if the code was available, It's written in a unique language called HAL/S. You'd need a special compiler just to read it.
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 07/22/2011 02:34 pm
The HAL/S source code is, if you're a programmer, not too difficult to figure out (at a high level, anyway). It was designed to be a readable language, for the 60's anyway, so that non-programmers like GNC guys can go read GNC code and make sure it does what they want it to.

But, you're absolutely correct that it will almost certainly never be released. The Apollo LM code is out there, though, all in assembly, just released a few years ago. If you ever see the PASS source code in public, it'll likely be a long time from now.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 07/22/2011 05:54 pm

First, It very much is a national security secret. Any goverment sponsered sofware dealing with the guidence of rockets in flight is by definition.

Second, Even if the code was available, It's written in a unique language called HAL/S. You'd need a special compiler just to read it.

Just so I understand.

The shuttle launches, and goes through the roll program.

In all the documentation / resources on here- we don't know how the gimballing is commanded and how the computers maintain control? Thats the secret?

Ok, so redact anything to do with guidance. Or just leave out the launch and ascent. I'd be happy with re-entry and landing.

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/22/2011 06:12 pm


In all the documentation / resources on here- we don't know how the gimballing is commanded and how the computers maintain control? Thats the secret?

Ok, so redact anything to do with guidance. Or just leave out the launch and ascent. I'd be happy with re-entry and landing.



The issue is knowing what it does but how it does it.
Entry and landing is also guidance driven.
Entry control is also ITAR material.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 07/23/2011 03:13 pm
In this article;

http://www.nasaspaceflight.com/2011/07/atlantis-down-processing-mer-review-notes-flawless-return/

 “performed flawless, bar typical GPC (General Purpose Computer) errors during rollout.”


What are these errors, causes and where can I find out more about this?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: DansSLK on 07/23/2011 08:22 pm
What will become of the sims?

Is the source code for the GPC's PASS available to the public? My limited knowledge of the GPC's is that their memory and storage space is significantly less than today's PC's (and that isn't to knock how great they are / specialized for flight) and that compared to today's software out there I'd imagine the source code wouldnt be as big. Also, since this isn't private sector (ala microsoft) and was paid for by tax dollars and not a national security secret (or is it?) I would think that it should be available?

Thanks




You'll find a plethora of HAL/S specifications online along with the entry guidance and PEG algorithms, including from NASA direct.

As for the source code itself, ITAR i'm afriad, illogical huh!
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 07/26/2011 01:37 am
Sorry if this is the wrong place to post this, but I have a question about the net mass of the MPLM cargo on this mission.  The Flight Operations and Integration PDF on L2 lists the mass of the MPLM as 25,478 lbs up, and this page (http://mplm.msfc.nasa.gov/mission.html) indicates that the empty mass of an MPLM is 9000 lbs, so the cargo should be 16,478 lbs.  However this article (http://www.spaceflightnow.com/shuttle/sts135/110711fd4/index.html) says that the MPLM cargo came to 9,403 lbs.  Where is the discrepancy?

My documentation shows 26700 lbm total, 16008 cargo + packing material, 10692 net cargo.

Thanks for the response and sorry for the delayed follow-up.  This comes close, but it doesn't resolve the entire discrepancy, as there is still 1,289 pounds of difference between 10,692 and 9,403.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 07/26/2011 01:23 pm
Looking at the post-landing convoy photos, I've always wondered what are the trucks tailing the orbiter doing? They have those long hoses attached to the sides, I think three red ones on one side and a white one on the other.
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 07/26/2011 01:31 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/26/2011 01:32 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Yup...

http://www.nasa.gov/mission_pages/shuttle/flyout/flyout_convoy.html
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2011 02:01 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 07/26/2011 02:06 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.

Makes sense. I keep forgetting that Shuttle is chock full of 70's era solid state electronics - it's a water heater! :)

Why does the orbiter need to stay powered up all the way back to the OPF? Because it still contains APU and RCS fuels? Does someone actually sit on the flight deck during the towback?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/26/2011 02:16 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.

That's what I thought too, but that link I posted had this:

"We have to hook up within 30 minutes. It's very important to maintain cooling, maintain power in the orbiter,"

To what was he referring?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/26/2011 02:22 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.

That's what I thought too, but that link I posted had this:

"We have to hook up within 30 minutes. It's very important to maintain cooling, maintain power in the orbiter,"

To what was he referring?
Probably that if sufficient cooling can't be maintained, you have to start turning more and more things off prematurely.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 07/26/2011 02:23 pm
Makes sense. I keep forgetting that Shuttle is chock full of 70's era solid state electronics - it's a water heater! :)

Why does the orbiter need to stay powered up all the way back to the OPF? Because it still contains APU and RCS fuels? Does someone actually sit on the flight deck during the towback?

Yes, there a couple of people in the cabin all the way back. After the 135 landing last week, they left Atlantis parked outside the OPF for a few hours while they had the employee and press event. The airstair truck was parked off to the side and the hatch was secured. You could see the people inside thru the cockpit windows. We were chuckling about it wondering who they got to volunter for that duty.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2011 03:03 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.

That's what I thought too, but that link I posted had this:

"We have to hook up within 30 minutes. It's very important to maintain cooling, maintain power in the orbiter,"

To what was he referring?

The fuel cells are supplying power and producing heat.  If the heat cant be removed, then the fuel cells would have to shut down.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/26/2011 03:04 pm
I think one gives the orbiter power, one cools the inside and one I think purges the vapors.

Not power.  Purge and cooling.

Makes sense. I keep forgetting that Shuttle is chock full of 70's era solid state electronics - it's a water heater! :)

Why does the orbiter need to stay powered up all the way back to the OPF? Because it still contains APU and RCS fuels? Does someone actually sit on the flight deck during the towback?

To monitor systems
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 07/26/2011 03:08 pm
The fuel cells are supplying power and producing heat.  If the heat cant be removed, then the fuel cells would have to shut down.

Okay, so they're not actually supplying power, they're just allowing the orbiter to continue to supply its own power.  That statement just confused me.  Thanks for clearing that up.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 07/26/2011 10:15 pm
On STS-135 there was a hold at T-31 seconds.  After verifying that the GVA had retracted SPE was GO and it sounded like the NTD was about to tell CGLS to pick up the count when SPE said they needed concurrence with CGLS and ASP to clear the hold.  Considering SPE and LD were both GO at this time, why was there this additional delay?  I'm sure there wasa a very good reason but had there been less LOX drainback hold time then it could have resulted in a scrub.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/26/2011 10:30 pm
On STS-135 there was a hold at T-31 seconds.  After verifying that the GVA had retracted SPE was GO and it sounded like the NTD was about to tell CGLS to pick up the count when SPE said they needed concurrence with CGLS and ASP to clear the hold.  Considering SPE and LD were both GO at this time, why was there this additional delay?  I'm sure there wasa a very good reason but had there been less LOX drainback hold time then it could have resulted in a scrub.
jcopella elaborated on launch day:
http://forum.nasaspaceflight.com/index.php?topic=25871.msg769415#msg769415

(It wasn't 'ASP', I'll have to go back and get the exact words, but I think that was 'mask'.)
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 07/26/2011 11:34 pm

Yes, there a couple of people in the cabin all the way back. After the 135 landing last week, they left Atlantis parked outside the OPF for a few hours while they had the employee and press event. The airstair truck was parked off to the side and the hatch was secured. You could see the people inside thru the cockpit windows. We were chuckling about it wondering who they got to volunter for that duty.

One of the personnel inside also performed the same duty on STS-1.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 07/27/2011 02:40 pm
There was a video of Atlantis post landing from STS-132 that showed what goes on after the crew leave. I can't find the video though. It showed the ground crew in the cabin checking the flight computers, etc. The hatch being shut prior to tow back and opened once near the OPF.
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 07/27/2011 09:12 pm
Regarding the shuttle airlock prior to iss. Did the astronauts need to prebreathe for Eva as well?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 07/27/2011 09:17 pm
Regarding the shuttle airlock prior to iss. Did the astronauts need to prebreathe for Eva as well?
Yes, Anytime you drop from 14.7 psi O2/N2 directly to 4 psi 100% O2 you are going to need to scrub the nitrogen from your blood stream first or else you'll get the bends.
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 07/27/2011 10:11 pm
Great thanks for the answer!
Title: Re: Shuttle Q&A Part 5
Post by: Zamzara on 07/29/2011 05:40 pm
Hi, sorry if this has been answered but I could not find it in a search:

What do the colours mean in contingency abort modes? E.g. "two out blue"?
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 07/30/2011 04:11 am
I remember reading a while back that Dick Scobee was part of the crew that flew the 747 / Enterprise from the Paris Air Show back to the United States.
Can anyone here confirm that?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/30/2011 01:51 pm
Hi, sorry if this has been answered but I could not find it in a search:

What do the colours mean in contingency abort modes? E.g. "two out blue"?

The color is a label on the manuver to be flown between abort start and ET seperartion.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/30/2011 06:24 pm
Hi, sorry if this has been answered but I could not find it in a search:

What do the colours mean in contingency abort modes? E.g. "two out blue"?

The color is a label on the manuver to be flown between abort start and ET seperartion.

Right, my understanding was it was just a color-coding scheme on the cue card, and the colors themselves didn't have any physical significance.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 07/30/2011 11:10 pm
Hi, sorry if this has been answered but I could not find it in a search:

What do the colours mean in contingency abort modes? E.g. "two out blue"?

The color is a label on the manuver to be flown between abort start and ET seperartion.

Right, my understanding was it was just a color-coding scheme on the cue card, and the colors themselves didn't have any physical significance.

You understand correctly
Title: Re: Shuttle Q&A Part 5
Post by: John Duncan on 07/31/2011 10:23 pm
I've searched high and low on NSF and through google to no avail.  Are there any proper line drawings of the shuttle mold lines with cross sections available?  I was looking to get the shape of the OMS pods correct but the only drawings I can find are not very helpful.

NASA has nothing that I've been able to find and a search here only turns up images from 135.

Any ideas guys?
Title: Re: Shuttle Q&A Part 5
Post by: ZANL188 on 07/31/2011 10:35 pm
I remember reading a while back that Dick Scobee was part of the crew that flew the 747 / Enterprise from the Paris Air Show back to the United States.
Can anyone here confirm that?
Thank you.

Yes, he was on the SCA when they stopped at Wright-Patterson on the way over.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 08/02/2011 10:07 pm
I remember reading a while back that Dick Scobee was part of the crew that flew the 747 / Enterprise from the Paris Air Show back to the United States.
Can anyone here confirm that?
Thank you.

Yes, he was on the SCA when they stopped at Wright-Patterson on the way over.

Thanks very much for that info!
Title: Re: Shuttle Q&A Part 5
Post by: Zamzara on 08/03/2011 01:34 pm
The color is a label on the manuver to be flown between abort start and ET seperartion.

Right, my understanding was it was just a color-coding scheme on the cue card, and the colors themselves didn't have any physical significance.

You understand correctly

Thanks for the information. Is there a list of the contingency modes available anywhere, and in what situations they would have been used?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/03/2011 01:42 pm
The color is a label on the manuver to be flown between abort start and ET seperartion.

Right, my understanding was it was just a color-coding scheme on the cue card, and the colors themselves didn't have any physical significance.

You understand correctly

Thanks for the information. Is there a list of the contingency modes available anywhere, and in what situations they would have been used?
Probably flight-specific, but if you haven't looked at the workbooks here, then it's a good place to continue:
http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html

In the "Workbooks / Training Manuals" section there are ones for intact and contingency aborts.

That page also has flight-specific (mission-specific) data; if you look in the Ascent Checklist for STS-135, in the Cue Card section, you'll see specific information on things like that.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/04/2011 09:36 pm
Sorry if there is an SSME QA thread, but...

What altitude are the engine bells optimized for? They clearly show overexpanded flow at sea level.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/05/2011 12:57 pm
The color is a label on the manuver to be flown between abort start and ET seperartion.

Right, my understanding was it was just a color-coding scheme on the cue card, and the colors themselves didn't have any physical significance.

You understand correctly

Thanks for the information. Is there a list of the contingency modes available anywhere, and in what situations they would have been used?

They are used for 2 or 3 engine failures on ascent.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/06/2011 02:25 pm
Why was rollout done at night?  From pictures it looks like at one time there were rollouts during the day but for the last bunch of missions it was always at night.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/06/2011 03:05 pm
Why was rollout done at night?  From pictures it looks like at one time there were rollouts during the day but for the last bunch of missions it was always at night.

weather was calmer at night
Title: Re: Shuttle Q&A Part 5
Post by: flying finn on 08/07/2011 10:05 am
Prior to the Challenger disaster, pilot astronauts would fly only once as PLT before becoming CDR for their second and subsequent missions.

After 1986, this appeared to change and pilot astronauts would, in most cases, fly TWO missions as PLT before becoming CDR:

So -
1) Why the change?
2) Even post-1986, some astronauts did become CDR after just one mission, so how was this decided?
3) Was there some sort of a "command check" for a new CDR?
4) Towards the end of the Shuttle, PLTs started to become CDR after just one mission again?  Why?  To get everyone at least one flight?

Interested to hear your thoughts, so thanks in advance!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/07/2011 01:32 pm
Prior to the Challenger disaster, pilot astronauts would fly only once as PLT before becoming CDR for their second and subsequent missions.

After 1986, this appeared to change and pilot astronauts would, in most cases, fly TWO missions as PLT before becoming CDR:

So -
1) Why the change?
2) Even post-1986, some astronauts did become CDR after just one mission, so how was this decided?
3) Was there some sort of a "command check" for a new CDR?
4) Towards the end of the Shuttle, PLTs started to become CDR after just one mission again?  Why?  To get everyone at least one flight?

Interested to hear your thoughts, so thanks in advance!


Since you are new, there is one rule about astronaut mission selection that you need to know:  There is no logic involved.
With that, the change for pilots to make two missions was that they needed to maintain a group of pilots, so that they wouldn't have all chiefs and no Indians.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/07/2011 03:43 pm
Which aerosurface on the orbiter is used for the post-MLG touchdown derotation?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/07/2011 08:35 pm
Which aerosurface on the orbiter is used for the post-MLG touchdown derotation?
The elevons.
Title: Re: Shuttle Q&A Part 5
Post by: Urvabara on 08/08/2011 06:40 am
For how long does it take after the liftoff before a Space Shuttle achieves the orbital velocity (orbit)? What is the distance (tangent) between the observer at the launch pad and the Space Shuttle during the orbital velocity (orbit) is achieved?

For how long does it take after the liftoff before a Space Shuttle is behind the horizon?
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 08/08/2011 07:11 am
The real meat of your questions is the type of stuff that is always worth a good 'think'.

This link may help.

http://www.haydenplanetarium.org/blog/joerao/2009/03/09/shuttle-launch-visible-along-east-coast

Launch windows and trajectories are particularly fascinating.

Check out the Apollo launch window with respect to the Saturn V flying through the keyhole of the Moon's antipode on ascent.

http://history.nasa.gov/afj/launchwindow/lw1.html



Title: Re: Shuttle Q&A Part 5
Post by: clevelas on 08/08/2011 09:50 pm
I've read through all five FAQ threads and came up with a question that I don't think has been answered (though there was an overwhelming amount of information).

There are four primary GPCs and one running backup flight software (BFS).  My understanding is this computer is running completely different software.  Is it an older version of the primary software?  If not, is it written by the same group?  What are the requirements for ensuring it will function if there's a bug in the primary system (how different is different)?  How much of the functionality of the primary system is duplicated in the backup software?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/08/2011 10:02 pm
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/09/2011 12:24 am
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

To add, PASS and BFS remained under separate groups to the end. PASS ended up with USA and BFS with Boeing.

BFS supported only ascent/entry and basic orbit coast (i.e. no rendezvous or prox ops). It did not support all modes during ascent/entry either. Ascent BFS was auto only (no manual takeover capability) while entry BFS was manual only (no auto flight control). Until very close to the end of the program BFS did not support the HUD, or any approach/landing guidance below 1500'.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/09/2011 08:41 am
Why was that, Jorge? Why were those things left till late in the program to change?
Title: Re: Shuttle Q&A Part 5
Post by: clevelas on 08/10/2011 03:09 pm
Thanks Jim and Jorge.  Great information.  Sounds like it was kept pretty simple and just intended to give you a chance to make it back home.

The more in-depth I get with orbiter operations, the more I'm amazed at how much the commander really has to know his/her stuff.  A lot of 'if we're in this mode, do this.  if in that mode, do that'.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/10/2011 09:09 pm
Does anybody have any recollection of the following or know what the proposal actually was?  When I was a kid (I'm pretty sure before Challenger) I saw a magazine with drawing that from memory was additional engines at the bottom of the ET.  It almost looked like the Ares V/SLS but with the orbiter still there.  I know I saw it, the only question in my mind was if this was something real or a mistake made by the magazine that confused some kind of Shuttle Derived vehicle?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/10/2011 09:53 pm
Does anybody have any recollection of the following or know what the proposal actually was?  When I was a kid (I'm pretty sure before Challenger) I saw a magazine with drawing that from memory was additional engines at the bottom of the ET.  It almost looked like the Ares V/SLS but with the orbiter still there.  I know I saw it, the only question in my mind was if this was something real or a mistake made by the magazine that confused some kind of Shuttle Derived vehicle?
That sort of sounds like the Sigma EDIN05 concept.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/10/2011 10:57 pm
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

The shuttle never actually flew on BFS, right?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/10/2011 11:37 pm
Does anybody have any recollection of the following or know what the proposal actually was?  When I was a kid (I'm pretty sure before Challenger) I saw a magazine with drawing that from memory was additional engines at the bottom of the ET.  It almost looked like the Ares V/SLS but with the orbiter still there.  I know I saw it, the only question in my mind was if this was something real or a mistake made by the magazine that confused some kind of Shuttle Derived vehicle?

That was the LBM (Liquid Boost Module).  It was replaced by filament wound cases for VAFB.

If you have L2, it is here

http://forum.nasaspaceflight.com/index.php?topic=20427.0
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 08/11/2011 08:46 am
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

The shuttle never actually flew on BFS, right?

Never been engaged in flight, but it's always active. It's used for ascent and (i think) landing for monitoring certain parameters up/down hill.
Title: Re: Shuttle Q&A Part 5
Post by: DansSLK on 08/11/2011 08:38 pm
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

The shuttle never actually flew on BFS, right?

BFS performs SM functions with PASS in 4 GPC RS GNC
Title: Re: Shuttle Q&A Part 5
Post by: Naito on 08/11/2011 08:43 pm
Which aerosurface on the orbiter is used for the post-MLG touchdown derotation?
The elevons.

Specifically I believe they use the elevon TRIM control to de-rotate, because doing it the other way was too finicky and resulted in the Columbia wheelie on STS-3
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/11/2011 09:50 pm
Which aerosurface on the orbiter is used for the post-MLG touchdown derotation?
The elevons.

Specifically I believe they use the elevon TRIM control to de-rotate, because doing it the other way was too finicky and resulted in the Columbia wheelie on STS-3


The elevons don't have trim tabs like a conventional aircraft. They are the only "aerosurfaces" on the wings.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/12/2011 12:23 am
Which aerosurface on the orbiter is used for the post-MLG touchdown derotation?
The elevons.

Specifically I believe they use the elevon TRIM control to de-rotate, because doing it the other way was too finicky and resulted in the Columbia wheelie on STS-3


The elevons don't have trim tabs like a conventional aircraft. They are the only "aerosurfaces" on the wings.

However there is a 'trim control' on the rotational hand controller, "beep trim", that could be used to derotate.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/12/2011 12:30 am
Apologize in advance if this has been answered.  I did some searching and didn't find it.

Is there a comprehensive, detailed history of all shuttle ferry flights out there somewhere?  By "detailed" I mean where they stopped to overnight and when. 

Thanks,
S-I
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/12/2011 01:44 pm
Apologize in advance if this has been answered.  I did some searching and didn't find it.

Is there a comprehensive, detailed history of all shuttle ferry flights out there somewhere?  By "detailed" I mean where they stopped to overnight and when. 

Thanks,
S-I

Logbooks for the STA aircraft, maybe? Good luck compiling it, though. I'll bet there were lots of stops, since STA can't fly through weather, can't fly above 10,000 ft and burns jet fuel like crazy. So any precipitation or headwinds would have forced lots of unplanned stops over the years.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/12/2011 04:01 pm
Two questions today...

1) I remember during the weather uncertainty lead up to STS-135, the weather officer mentioned that no flight through precipitation was a shuttle specific launch constraint.  Why can other rockets fly through precip but the shuttle couldn't?  Was it that hitting rain at high speed could damage the TPS tiles?

2) Why is the SSME "flame" almost clear and cone shaped while other LH2/LOX engines like the one's on Delta IV have long orange/purple exhaust flames.  Is it different exhaust temperature?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/12/2011 04:39 pm
1.  Yes, precip would erode the tiles.   

2.  Delta IV uses an ablative nozzle and that material colors the exhaust.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 08/12/2011 08:39 pm
1.  Yes, precip would erode the tiles.   

And to add on to this, as the last flight tile erosion would not have been as big of an issue as there was not a need to turn around.  The big issue was energy for landing, as tiles would absorb moisture increasing the weight of the orbiter, and therefore also robbing momentum to get to the runway. Obviously it was felt that the risks were protected, and they launched.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 08/13/2011 02:21 pm
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

The shuttle never actually flew on BFS, right?

BFS was never used.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/13/2011 02:28 pm
Orginally, PASS was written by IBM and BFS by Rockwell. It is completely different and only handles the primary flight regimes

The shuttle never actually flew on BFS, right?

BFS was never used.

Actually - not quite right. 

BFS - Originally designed just for ALT flights then expanded to include OFT (STS-1 through STS-4) and then kept for the rest of the program (I left out a few steps).

BFS was running and active for all launches and landings (as stated above).  It had SM functions (including s-band antenna pointing) and until the 2000s contained some ascent displays that provided additional data above what was displayed on the primary displays.  This was called "Listen Mode" and did not allow for active control of the vehicle steering functions (GN&C, more accurately). "Engaged Mode" took over full control from the primary computers.

BFS was *never* engaged.  But, it was used multiple times to close the payload bay doors after a landing wave-off.  This was done with BFS since it was a faster procedural method than using PASS.  While the doors moved at the same rate whether PASS or BFS, there were less steps required to let BFS close the doors.  The faster the doors closed, the less time was used with our entry cooling capabilities, which were going to be needed again the next day.

A DTO was planned, early in the program, to try BFS after OMS-2.  But, no one could justify why that was needed in-flight since all of the similators showed no problems with engaging BFS.


Andy
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 08/14/2011 10:13 pm
How come the flag on the side of Endeavour is closer to the United States logo than on Discovery? As an example look at http://www-pao.ksc.nasa.gov/kscpao/images/large/2011-6405.jpg and Discovery at http://www-pao.ksc.nasa.gov/kscpao/images/large/2011-6418.jpg  http://www-pao.ksc.nasa.gov/kscpao/images/large/2011-6399.jpg

My other question is are there any pre flight photos of Challenger on STS-51L?
Title: Re: Shuttle Q&A Part 5
Post by: saturnapollo on 08/14/2011 10:31 pm
Mark

You are not comparing like with like. These are on opposite sides of the orbiters. It was perhaps decided that there should be a bigger space before the capital U for aesthetic purposes. It might even be a rule used by printers.

Keith
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/14/2011 10:56 pm
Can someone remind of the difference(s) between an IPR and a PR?
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 08/15/2011 12:20 am
I apologies for that. Thanks for clearing up my question there. :)

On my Challenger question please. Are there such pre launch photos of the 51L stack before launch?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/15/2011 12:59 am
Can someone remind of the difference(s) between an IPR and a PR?

They are the same.  one is just interim.
Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 08/15/2011 01:22 am
Can someone remind of the difference(s) between an IPR and a PR?

They are the same.  one is just interim.
Not at all.  Generally, a PR is a discrepancy taken against a known component, which then can be resolved (i.e. a broken wire).  An IPR is a discrepancy in which the cause has not been isolated (i.e. the valve didn't open when commanded) to one component.  Usually troubleshooting is required to isolate the problem, at which time the IPR would be upgraded to a PR.  At least that was the way it used to be done . . .
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/15/2011 01:30 am

My other question is are there any pre flight photos of Challenger on STS-51L?

Google NASA Image Exchange and then search on that page (NIX) for Challenger.  You'll get plenty of pictures but not hi res.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/15/2011 02:16 am
Can someone remind of the difference(s) between an IPR and a PR?

They are the same.  one is just interim.
Not at all.  Generally, a PR is a discrepancy taken against a known component, which then can be resolved (i.e. a broken wire).  An IPR is a discrepancy in which the cause has not been isolated (i.e. the valve didn't open when commanded) to one component.  Usually troubleshooting is required to isolate the problem, at which time the IPR would be upgraded to a PR.  At least that was the way it used to be done . . .

When one becomes the other, they are the same.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/15/2011 05:38 pm
I understand that Columbia was some 8,000 lbs heavier than her sister ships. Exactly where was this extra weight and what was it made up of (ie - airframe, engine mounts, etc)? Did she have extra hardware that the other orbiters did not?
Title: Re: Shuttle Q&A Part 5
Post by: jnc on 08/15/2011 05:46 pm
I understand that Columbia was some 8,000 lbs heavier than her sister ships. Exactly where was this extra weight and what was it made up of (ie - airframe, engine mounts, etc)? Did she have extra hardware that the other orbiters did not?

Columbia, as the first orbiter, had extra diagnostic gear (e.g. strain gauges) built into her, which her later sisters lacked. That, plus the wiring to connect them up, etc was part of the extra weight. More details here (http://en.wikipedia.org/wiki/Space_Shuttle_Columbia#Prototype_orbiter).

Noel
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 08/15/2011 05:58 pm
Plus Columbia has extra tiles on her wing chines and tail that were covered with thermal blankets on other orbiters.  Not much difference, but the tiles did weigh more than the blankets
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/15/2011 07:48 pm
I understand that Columbia was some 8,000 lbs heavier than her sister ships. Exactly where was this extra weight and what was it made up of (ie - airframe, engine mounts, etc)? Did she have extra hardware that the other orbiters did not?

The structure (mostly wings)was made stronger than was needed
Title: Re: Shuttle Q&A Part 5
Post by: gfagley on 08/15/2011 08:28 pm
How come the flag on the side of Endeavour is closer to the United States logo than on Discovery?
there is more space between letters on Endeavour than on Discovery.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 08/15/2011 08:33 pm
I see.

On the Challenger question. I did look, but mostly all I found are crew training and launch photos, as well as the destruction of the vehicle. Nothing pre launch of the vehicle, save for the one photo of the ice on the FSS. I only saw one pre launch photo, and that was on a video about the disaster.

Title: Re: Shuttle Q&A Part 5
Post by: 10W29 on 08/15/2011 10:09 pm
Can someone remind of the difference(s) between an IPR and a PR?

They are the same.  one is just interim.
Not at all.  Generally, a PR is a discrepancy taken against a known component, which then can be resolved (i.e. a broken wire).  An IPR is a discrepancy in which the cause has not been isolated (i.e. the valve didn't open when commanded) to one component.  Usually troubleshooting is required to isolate the problem, at which time the IPR would be upgraded to a PR.  At least that was the way it used to be done . . .

When one becomes the other, they are the same.
The original question asked for the differences, not the similarities.
Not all IPR's became PR's and the vast majority if PR's did not start off as IPR's.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/16/2011 12:05 am
What is the circular white indentation that is in front of the port side front window in the white area between the cockpit and the RCS.  It can be seen just above the right side of the orbiter access arm in this photo.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=25488.0;attach=307518;image (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=25488.0;attach=307518;image)
Title: Re: Shuttle Q&A Part 5
Post by: subisnack on 08/16/2011 12:16 am
I believe what you are referring to is one of the star tracker doors.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 08/16/2011 12:17 am
What is the circular white indentation that is in front of the port side front window in the white area between the cockpit and the RCS.  It can be seen just above the right side of the orbiter access arm in this photo.

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=25488.0;attach=307518;image (http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=25488.0;attach=307518;image)

Star tracker, I think.

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-gnnc.html#sts-star-tracker

"Each star tracker has a door to protect it during ascent and entry. The doors are opened on orbit to permit use of the star trackers."
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 08/16/2011 12:29 am
Star tracker, I think.


Yes.
Title: Re: Shuttle Q&A Part 5
Post by: jnc on 08/16/2011 03:23 am
Plus Columbia has extra tiles on her wing chines and tail that were covered with thermal blankets on other orbiters.  Not much difference, but the tiles did weigh more than the blankets

A fair number of the tiles on Columbia's upper side were replaced with thermal blankets during one of her refurbishments (for weight savings purposes), not sure if that included those areas.

Noel
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 08/16/2011 03:41 am

A fair number of the tiles on Columbia's upper side were replaced with thermal blankets during one of her refurbishments (for weight savings purposes), not sure if that included those areas.

Noel


The chine areas remained covered with extra black tiles for her entire life, and extra black tiles were added in support of the SILTS experiment on the tail after STS-9.  Columbia did replace areas of her LRSI tiles with AFRSI, but the distinctive HRSI chines were never replaced.

But of course the spars and test equipment were the main contributors to her extra weight.  Attached an image of Columbia rolling out for STS-107 to shot the tail and chines still covered in HRSI.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/16/2011 12:23 pm

The chine areas remained covered with extra black tiles for her entire life, and extra black tiles were added in support of the SILTS experiment on the tail after STS-9.  Columbia did replace areas of her LRSI tiles with AFRSI, but the distinctive HRSI chines were never replaced.

But of course the spars and test equipment were the main contributors to her extra weight.  Attached an image of Columbia rolling out for STS-107 to shot the tail and chines still covered in HRSI.

And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?

What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 08/16/2011 12:50 pm

And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?

What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.

The question was raised after the Challenger accident but it was decided it was cheaper to build Endeavour than refit Enterprise
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/16/2011 01:01 pm


And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?

What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.

No, Enterprise (OV-101) was an even earlier airframe than Columbia (OV-102).  Columbia's had another year of structures analysis to benefit from prior to construction.

Yes, modernizing OV-101 into a space-rated vehicle was thoroughly looked at prior to the decision to turn the structural test article into Challenger (OV-099).  At that point it was found to be easier (time and money) to turn an empty airframe into a real orbiter than to modify Enterprise.  The issue was again looked at after the Challenger accident.  Again, the answer was that it was cheaper to build Endeavour (OV-105) out of spare parts than it would be to turn Enterprise into an orbital vehicle.  The issue was *not* looked at after STS-107 because there were no plans to replace Columbia and OV-101 had sat outside under a essentially a tarp tent for about 10 years at Dulles Airport by that point (now OV-101 is thankfully in a beautiful building).

Again, Enterprise's drawings (engineering drawings) would have been unique to the fleet, even comared with Columbia.  Whereas Endeavour's drawings matched that of Discovery (OV-103) and Atlantis (OV-104).  Much easier to handle from an analysis standpoint (one analysis fits three of the vehicles).  Also, I've heard it said that Enterprise, even in pristine condition, would have cracked in half during entry because the structure was not strong enough in many places.  Fixing that would have required more weight and more "uniqueness".

Enterprise is missing most systems (most of the cockpit instrumentation was "donated" to OV-103 for its build).  Even the payload bay doors don't work, the thrust structure for the main engines isn't there, there is no fuel cell plumbing, and the list would go on for quite some time.  The last photo I have of Enterprise's interior shows that only a mechanical horizon instrument (unique to the ALT flights only) remains in the forward cockpit.  The rest is empty spaces where avionics boxes used to be for ALT.

So, bottom line is that Enterprise required lots of work to turn into an orbital vehicle and even if you did all of the work, the result would not have been able to carry as much payload as the sister ships and would have required lots of special analysis because the configuration would have been different than the sister ships.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/16/2011 02:16 pm


And Enterprise's airframe was the same as Columbia's, which is why she was never retrofitted for spaceflight? Same heavier construction?

What did Enterprise lack other than TPS? I assume it had (has) fuel cells, APU's, etc? Was there ever any thought post STS-107 of fitting her out? I'm guessing not.

No, Enterprise (OV-101) was an even earlier airframe than Columbia (OV-102).  Columbia's had another year of structures analysis to benefit from prior to construction.

Yes, modernizing OV-101 into a space-rated vehicle was thoroughly looked at prior to the decision to turn the structural test article into Challenger (OV-099).  At that point it was found to be easier (time and money) to turn an empty airframe into a real orbiter than to modify Enterprise.  The issue was again looked at after the Challenger accident.  Again, the answer was that it was cheaper to build Endeavour (OV-105) out of spare parts than it would be to turn Enterprise into an orbital vehicle.  The issue was *not* looked at after STS-107 because there were no plans to replace Columbia and OV-101 had sat outside under a essentially a tarp tent for about 10 years at Dulles Airport by that point (now OV-101 is thankfully in a beautiful building).

Again, Enterprise's drawings (engineering drawings) would have been unique to the fleet, even comared with Columbia.  Whereas Endeavour's drawings matched that of Discovery (OV-103) and Atlantis (OV-104).  Much easier to handle from an analysis standpoint (one analysis fits three of the vehicles).  Also, I've heard it said that Enterprise, even in pristine condition, would have cracked in half during entry because the structure was not strong enough in many places.  Fixing that would have required more weight and more "uniqueness".

Enterprise is missing most systems (most of the cockpit instrumentation was "donated" to OV-103 for its build).  Even the payload bay doors don't work, the thrust structure for the main engines isn't there, there is no fuel cell plumbing, and the list would go on for quite some time.  The last photo I have of Enterprise's interior shows that only a mechanical horizon instrument (unique to the ALT flights only) remains in the forward cockpit.  The rest is empty spaces where avionics boxes used to be for ALT.

So, bottom line is that Enterprise required lots of work to turn into an orbital vehicle and even if you did all of the work, the result would not have been able to carry as much payload as the sister ships and would have required lots of special analysis because the configuration would have been different than the sister ships.

Andy

Thanks, I was wondering how different it actually was. Sounds like a lot more than TPS! Would love to see flight deck photos, though!
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/16/2011 02:40 pm

Quote

Thanks, I was wondering how different it actually was. Sounds like a lot more than TPS! Would love to see flight deck photos, though!

Here's a link to a flight deck photo (probably originally from NIX):
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/226195_2315242044504_1353041163_2727932_2837615_n.jpg

There were also no OMS/RCS systems in Enterprise.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/16/2011 06:43 pm
Hi all.

My question for today is: why the POGO suppresion system on the SSME has been installed only on the oxygen feed line and not on the fuel line (or both?). Could this have to do with the fact that oxygen is denser then hydrogen and therefore more capable of dampening the oscillations in flow?

thanks
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/16/2011 06:54 pm
Yes and I believe LH2 is not susceptible to pogo
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/16/2011 08:29 pm
Quote from: Jim
Yes and I believe LH2 is not susceptible to pogo

Thanks Jim.

I was also wondering another things: since there are three main engines and since each one of them as its own pogo suppression system, are somehow the three pogo systems connected to each other? I mean, does each pogo suppression system get some kind of feedback from the two other systems so that to regulate its action on the engine? because I suppose the pogo vibrations of the three engines should somehow coupled with each other.

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Wepush on 08/16/2011 09:06 pm
There is no feedback and no interaction from one engine's pogo system to another.  They operate independently.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/16/2011 10:06 pm
Quote from: Jim
Yes and I believe LH2 is not susceptible to pogo

Thanks Jim.

I was also wondering another things: since there are three main engines and since each one of them as its own pogo suppression system, are somehow the three pogo systems connected to each other? I mean, does each pogo suppression system get some kind of feedback from the two other systems so that to regulate its action on the engine? because I suppose the pogo vibrations of the three engines should somehow coupled with each other.

Thanks

Davide

It isnt an active system.  The system is just basically a damper
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/16/2011 11:35 pm
The dots in the boxes on the photo, are they part part of the Space Vision System(SVS)?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/17/2011 05:02 am
This is great information. Is there a formal PDF or other type of study document that lists the various problems with making Enterprise space worthy?

Cheers.


I never saw one come across my desk.  But most of the work would have been before the Internet was in general use and even before the PC (or TRS-80 for that matter).  It may have been studied but I would think it would have been such an obvious answer in the late 1970s and mid-1980s that the detail might not have been required.  More likely it was just someone comparing the engineering drawings between OV-101 and noting differences with the later orbiters.

Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 08/17/2011 12:53 pm
Regarding Columbia, I was under the impression that the black chine areas were actually paint and not tiles.  When Columbia arrived at KSC, and rolled over, the chine area wasnt black, however on rollout, it was.  I was always told that it was due to engineers thinking that that area might experience more heat and it was treated with a black "paint".

I could be totally wrong, but just something I read somewhere.....

Please correct me if I am wrong.

Thanks!!

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/17/2011 01:02 pm
I understand that Columbia was some 8,000 lbs heavier than her sister ships. Exactly where was this extra weight and what was it made up of (ie - airframe, engine mounts, etc)? Did she have extra hardware that the other orbiters did not?

The structure (mostly wings)was made stronger than was needed

And the opposite happened with OV-103 and OV-104, their wings were made too weak and the shuttle had to fly lofted trajectories, which reduced performance.   The wings were eventually reinforced and it bought back the performance.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 08/17/2011 06:12 pm


Thanks, I was wondering how different it actually was. Sounds like a lot more than TPS! Would love to see flight deck photos, though!

http://www.capcomespace.net/dossiers/espace_US/shuttle/sts/orbiter_avionique.htm

This has comparison photos of OV-101's forward flight deck and the flight orbiters' cockpits. Enterprise's panels are noticibly different.

I can't find an online version, but Jenkins' book has a photo of Enterprise's cockpit from the 1990s gutted of everything.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/17/2011 06:22 pm
Keep in mind that the photo of "les cockpit de l' Enterprise" shows Enterprise as it no longer exists.  I know that when it was turned over to the Smithsonian in the mid-1980s, that cockpit was already gutted (except for the mechanical horizon).

The Enterprise layout was not *that* much different from Columbia's first version.  What you are missing are the gauges and switches needed for ascent - hadn't been invented yet.  Also the MEDS Phase 1 drawing never existed beyond paper.  Only the final MEDS version was actually implemented.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/18/2011 01:26 pm
[quote author=alk3997 link=topic=17437.msg794430#msg794430
The Enterprise layout was not *that* much different from Columbia's first version.  What you are missing are the gauges and switches needed for ascent - hadn't been invented yet.  Also the MEDS Phase 1 drawing never existed beyond paper.  Only the final MEDS version was actually implemented.
[/quote]

Opinions may vary, but I'd call it significantly different.  The GPC status matrix was in front of the pilot instead of CDR, the fuel cell purge controls were on the upper front panel, the left and right overhead panels of switches were completely missing, panel R1 has three steam gauges on it, there is a ?backup? 'artificial horizon' on the fwd panels, most of the steam gauges are missing off the upper front panel....
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 08/19/2011 04:43 pm
I noticed in a video that on the STS-91 landing, the main gear touchdown, then it rises up again, maybe a foot or two at most, then settles down again..
was this because of certain conditions (wind?) or was there no reason, just happened? Certainly wasn't a major issue, just was curious,, never seen it happen before.
Title: Re: Shuttle Q&A Part 5
Post by: kch on 08/19/2011 05:42 pm
I noticed in a video that on the STS-91 landing, the main gear touchdown, then it rises up again, maybe a foot or two at most, then settles down again..
was this because of certain conditions (wind?) or was there no reason, just happened? Certainly wasn't a major issue, just was curious,, never seen it happen before.

I take it you don't remember this:

http://www.youtube.com/watch?v=DDkfFkNHqpE

:)
Title: Re: Shuttle Q&A Part 5
Post by: kevin-rf on 08/19/2011 06:27 pm
Wasn't that PIO (Pilot Induced Oscillation)?

btw YouTube has a similar video of STS-3
http://www.youtube.com/watch?v=O8fnUY2IFAw

Didn't Prince Charles manage to do something similar on a NASA simulator?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/19/2011 07:12 pm
FWIW, winds approaching the HAC were 070 at 8 knots gusting to 13, which was pretty much a straight crosswind, and they performed the crosswind landing performance DTO (DTO 805).  On final, they were updated to 070 at 7 gusting to 11.
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 08/19/2011 08:50 pm
landing replay on youtube:

http://www.youtube.com/watch?v=4o2K6PaDkd0&t=14m44s  at 14min 44s mark.

although not shot from a good angle; the actual landing only from HUD camera.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/19/2011 09:35 pm
landing replay on youtube:

http://www.youtube.com/watch?v=4o2K6PaDkd0&t=14m44s  at 14min 44s mark.

although not shot from a good angle; the actual landing only from HUD camera.
Also some excerpts of the live landing coverage I posted on L2; you can find that from the mission tag:
http://forum.nasaspaceflight.com/index.php?action=tags&tags=STS-91
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 08/20/2011 01:59 am
It didn't look like PIO.. more like just trying to make such a soft landing he brought it off the ground ever so slightly.. I didn't think it was major problem, or even a minor problem.. just noticed it and was wondering how/why it happened.
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/20/2011 09:09 pm
Hi,

I saw a post earlier in this thread asking about source code for PASS. While its dramatically unlikely we'll see that anytime soon, there is a small consolation prize -- the Approach and Landing Test System Software Design Specification _is_ available. It is a 1580 page PDF with complete flowcharts (1977 style flowcharts, with every conditional expression present) of the FCOS and some really interesting stuff on GPC redundancy.

Link here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770075091_1977075091.pdf

The document only covers the system software, not flight software, sadly. But it is still a great document.

Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 08/21/2011 12:17 am
Regarding Columbia, I was under the impression that the black chine areas were actually paint and not tiles.  When Columbia arrived at KSC, and rolled over, the chine area wasnt black, however on rollout, it was.  I was always told that it was due to engineers thinking that that area might experience more heat and it was treated with a black "paint".

I could be totally wrong, but just something I read somewhere.....

Please correct me if I am wrong.

Thanks!!



Partially correct. The black areas on the wing gloves were actually the original white tiles painted with a black thermal coating. We were told at the time it was to prevent the potential freezing of hydraulic lines in the mid fuselage.
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 08/21/2011 02:33 am
I saw a post earlier in this thread asking about source code for PASS. While its dramatically unlikely we'll see that anytime soon, there is a small consolation prize -- the Approach and Landing Test System Software Design Specification _is_ available. It is a 1580 page PDF with complete flowcharts (1977 style flowcharts, with every conditional expression present) of the FCOS and some really interesting stuff on GPC redundancy.
Link here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770075091_1977075091.pdf
The document only covers the system software, not flight software, sadly. But it is still a great document.
      It's enormous. Any particularly interesting or revealing bits you've found thus far?
     -Alex
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/21/2011 02:59 am
I saw a post earlier in this thread asking about source code for PASS. While its dramatically unlikely we'll see that anytime soon, there is a small consolation prize -- the Approach and Landing Test System Software Design Specification _is_ available. It is a 1580 page PDF with complete flowcharts (1977 style flowcharts, with every conditional expression present) of the FCOS and some really interesting stuff on GPC redundancy.
Link here: http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770075091_1977075091.pdf

The document only covers the system software, not flight software, sadly. But it is still a great document.
      It's enormous. Any particularly interesting or revealing bits you've found thus far?
     -Alex

Keep in mind many of the details changed before the first orbital flight.  I was always impressed that my colleagues were able to get a redundant set working for ALT, which was almost a decade before I got there.

And, SSW (system software) is part of FSW (flight software) as was GN&C (guidance navigation & control), VU (vehicle utility) and SM (systems management).  I believe the SSW folks would be upset to not be counted as FSW.  They were amazing folks who did amazing things with very little software!  They also had the ability to analyze GPC anomalies with amazing detail (when one of the very few GPC anomalies occurred).


Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/21/2011 03:10 am



Opinions may vary, but I'd call it significantly different.  The GPC status matrix was in front of the pilot instead of CDR, the fuel cell purge controls were on the upper front panel, the left and right overhead panels of switches were completely missing, panel R1 has three steam gauges on it, there is a ?backup? 'artificial horizon' on the fwd panels, most of the steam gauges are missing off the upper front panel....

By my comment, I meant that I could take someone trained on the later original orbital cockpit and put them in Enterprise's original cockpit and they would be able to fly approach and landing without almost any training.  The stick is in the same place, the CRTs are the same vintage and location, the keyboards are in the same place, the electromechanical entry/landing tapes are the same, the ADI the same, the HSI the same, and the landing phase lights are the same place they were with Columbia's first flight.  Yes, a few things are moved about and a lot is missing, but the basic layout design is the same.  Most of what you mention as missing was missing because it wasn't needed yet (ascent or orbital items).

There was also an earlier question on the Enterprise (OV-101) differences.  While Enterprise had fuel cells, they were different than the orbital system,

"The Electrical Power System (EPS) includes three fuel cells to provide electrical power for OV-101; however, high pressure bottles of gaseous oxygen and hydrogen will replace cryogenics for the fuel cell supply. Sufficient gaseous oxygen and hydrogen will be carried to allow for 208 minutes of EPS operation at the presently baselined power profile (59.9 kilowatt hours)."

Andy
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/21/2011 05:31 am
      It's enormous. Any particularly interesting or revealing bits you've found thus far?
     -Alex

Depends on what you're looking for -- section 3.1.1.4 (FPMDISP) looks more or less like its analogue in any modern operating system, which is pretty cool!

Section 3.1.2 has a nice description of timers and events in the system. The design of TQEs (timer queue events) looks like something you'd see in software today. There was a watchdog timer -- not called that then, I suppose? Timers were interesting in that they were associated with Processes, so they were removed if a process was cancelled.

Section 3.1.3.3 describes a routine that is often subtle -- FPMSIGNAL -- set an event, allow it to wake sleeping processes, and then reset it. The Event Evaluator logic is pretty clever, more complex than most systems use today. It could probably be used to filter types of events coming in on a common event variable?

The GPC Synchronization flowcharts seem to be incomplete (marked "to be provided"); that's really unfortunate, GPC sync would have been one of the most difficult challenges for any operating system, even now. I wonder if there is a later version of this document that covers them, but probably not. The Approach and Landing tests themselves were Feb 1977 - Oct 1977. Maybe the GPC synchronization work wasn't available till later?

I mostly do operating systems work these days; from a modern perspective, this work seems heroic. On paper, there are flowcharts of every routine, every supervisor call, callers, and conditions worked out. All in 1977 (and earlier).

If you're familiar with modern avionics operating systems, particular ARINC653 compliant ones, you'll see a lot that is familiar; this work is a bit of a forerunner then.

The document doesn't have anything on stuff I wanted to see most, namely how the DAPs worked, though... :\. That would be elsewhere...

Keep in mind many of the details changed before the first orbital flight.  I was always impressed that my colleagues were able to get a redundant set working for ALT, which was almost a decade before I got there.

And, SSW (system software) is part of FSW (flight software) as was GN&C (guidance navigation & control), VU (vehicle utility) and SM (systems management).  I believe the SSW folks would be upset to not be counted as FSW.  They were amazing folks who did amazing things with very little software!  They also had the ability to analyze GPC anomalies with amazing detail (when one of the very few GPC anomalies occurred).

Andy

Did many details of the FCOS change between ALT and the orbiter flights?

Sorry, didn't mean to slight them! I'm used to 'flight software' not covering system software; however it'd be very rare in a modern design for system software to be developed afresh for a project.

Would be pretty great to have some of them share memories of ALT or shuttle work :)

Thanks,
-- vs
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/21/2011 03:20 pm
Yes, many of the details continued to change between ALT and OFT (orbital flight tests - STS-1 through STS-4).  The ALT FCOS was good enough to handle take-off from the ground on the 747, separating from the 747, approach & landing and then post-landing shutdown.  It wasn't ready for orbital flights yet, which included OPS overlays and a lot longer run time, among other major items.  So, yes, there was much to go and other changes even after OFT - GPS caused changes, for instance.

Keep in mind the idea of just *having* four flight computers and a digital databus on an aerospace vehicle was very new in the late 1970s and early 1980s.  The idea of synchronizing them in this scheme was even more unusual.  It would have been impossible to create a finished product for ALT.  The Shuttle's flight computer system really did push the state-of-the-art at the time.

The FCOS operating system was first created in the 1970s and maintained throughout the next thirty years of flights.  BOS for BFS was also also created specifically for the Shuttle program. 

While you may not do that now for cost reasons, we had the advantage that if there was a question about the O/S, the people just down the hall knew everything about your O/S.  You didn't have to go far for an answer.

You might also want to read this, if you haven't already...
http://klabs.org/DEI/Processor/shuttle/shuttle_primary_computer_system.pdf

Some of it was a little dated, such as the quality metrics which were even better towards the middle-to-end of the program and the company name, of course.  But, there are some good factoids in that paper.

And, yes, GPC sync was definitely working for ALT.  Watch the NASA video on the ALT flights ("Go For Sep") and you'll see GPC 2 being voted out of the redundant set right after separation on the first ALT free flight.  Can't be voted out if you don't have a synchronization scheme.  Just don't consider the document you found to be a final version of (well) anything.  When the program ended we were flying OI-34 - lots of time for changes.

Besides the operating system we also maintained (and modified) the compiler, as well.  One stop shopping...

Andy
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/21/2011 06:07 pm
You might also want to read this, if you haven't already...
http://klabs.org/DEI/Processor/shuttle/shuttle_primary_computer_system.pdf

Some of it was a little dated, such as the quality metrics which were even better towards the middle-to-end of the program and the company name, of course.  But, there are some good factoids in that paper.


Yep, it was an interesting read! I'd actually had some questions about it though...

The article described a high-priority process that would be scheduled every 40 mS; the process would switch on cycle # to determine what to do.
Is there any reason it was designed that way? Rather than having each subset of things to do in a separate cyclic process executed at its true rate?

Also, I seem to remember hearing that the RCS jets couldn't be commanded at 40 mS, there was some problem with pressure waves in the feed lines or something to that effect that required them to be commanded at 80mS; was the high-priority process constrained to only command the RCS jets every other cycle?

Something I was wondering about, how did the system report when a cyclic process couldn't be run at its scheduled time? I suspect there'll be an answer in the ALT FCOS, but I haven't found it yet...

And, yes, GPC sync was definitely working for ALT.  Watch the NASA video on the ALT flights ("Go For Sep") and you'll see GPC 2 being voted out of the redundant set right after separation on the first ALT free flight.  Can't be voted out if you don't have a synchronization scheme.  Just don't consider the document you found to be a final version of (well) anything.  When the program ended we were flying OI-34 - lots of time for changes.

I'd never seen that video before; thanks very much!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/21/2011 08:08 pm
Also, I seem to remember hearing that the RCS jets couldn't be commanded at 40 mS, there was some problem with pressure waves in the feed lines or something to that effect that required them to be commanded at 80mS; was the high-priority process constrained to only command the RCS jets every other cycle?

The constraint was in the DAP rather than the high-frequency executive. To respect the 80 ms limitation, the DAP was only scheduled to run every other HFE cycle.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/21/2011 08:32 pm
Remember PASS was designed to handle processes asynchronously unlike BFS which was synchronous and had definite scheduling.  In PASS, processes were handled in a priority manner so that the high priority items would run and we made sure there was enough margin to handle all of those processes.  If we didn't have time to handle a high priority process, a GPC cycle overrun error would be annunicated.   Again, though there was much done to make sure we didn't get those "errors" (although there were some circumstances that one would occur and it was analyzed to death when they happened).  BTW, in all of those cases the delayed process would complete in the next cycle and the system was designed that way.



Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/21/2011 08:51 pm
Also, I seem to remember hearing that the RCS jets couldn't be commanded at 40 mS, there was some problem with pressure waves in the feed lines or something to that effect that required them to be commanded at 80mS; was the high-priority process constrained to only command the RCS jets every other cycle?

The constraint was in the DAP rather than the high-frequency executive. To respect the 80 ms limitation, the DAP was only scheduled to run every other HFE cycle.

Sorry, the DAP was a separate process? The klabs document only listed the high frequency executive, the guidance process (160 ms), navigation, and keyboards/displays, though they did say there were many more.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/21/2011 08:58 pm
Everything was a separate process (or multiple processes) in one way or another.  Remember they had to fit in their chunks of time, so you had different processes for different activities such as sequencers.  Very complicated and required a real-time O/S to handle it 100% (or at least many many 9s) reliably.

This reference is probably a much higher level than you want but it provides an overview of the computing power on the vehicles,

http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/22/2011 12:24 am
Everything was a separate process (or multiple processes) in one way or another.  Remember they had to fit in their chunks of time, so you had different processes for different activities such as sequencers.  Very complicated and required a real-time O/S to handle it 100% (or at least many many 9s) reliably.

This reference is probably a much higher level than you want but it provides an overview of the computing power on the vehicles,

http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html

Andy

Right, as I understood it, the system SW had the HFE, MFE, and LFE, and all the application SW processes ran at an integer multiple of one of those three executives.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/22/2011 01:37 am
Everything was a separate process (or multiple processes) in one way or another.  Remember they had to fit in their chunks of time, so you had different processes for different activities such as sequencers.  Very complicated and required a real-time O/S to handle it 100% (or at least many many 9s) reliably.

This reference is probably a much higher level than you want but it provides an overview of the computing power on the vehicles,

http://www.nasa.gov/mission_pages/shuttle/flyout/flyfeature_shuttlecomputers.html

Andy

Right, as I understood it, the system SW had the HFE, MFE, and LFE, and all the application SW processes ran at an integer multiple of one of those three executives.

Yes.  LFE was for the lowest priority items, such as display updates.  Of course we're talking about GN&C OPS modes - SM & VU had different processes.  I have to admit I never really understood how the OPS 9 (ground) processes were scheduled (didn't really need to).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 08/22/2011 12:24 pm
What was the purpose of the black markings on the SRB nose cones and frustum seen in the later half of the 80s and early to mid 90s? For example This is what they look like now http://upload.wikimedia.org/wikipedia/commons/e/ed/STS-135_SRB_right_and_left_forward_assemblies.jpg compared to back in the decades prior http://enterfiringroom.ksc.nasa.gov/Images/Gallery/STS26R.jpg http://www.friends-partners.org/mwade/graphics/s/sts.jpg

 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2011 12:37 pm
Camera tracking, to help differentiate the boosters.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/22/2011 01:15 pm
Hi all.

This time a question about the SSME: how did they get built? I meant, which is the process flow for which they are finally assembled? How long does it last?

Any idea where I can get good information on this? Maybe Rocketdyne itself?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 08/22/2011 03:02 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2011 03:23 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.
Title: Re: Shuttle Q&A Part 5
Post by: Wepush on 08/22/2011 03:38 pm
Build of the engine components takes years, five or six for some.
Engine assembly, after all the parts are built, can be completed in as little as a month, but usually happened over something closer to six months, while other work was being done too.
Title: Re: Shuttle Q&A Part 5
Post by: DarkenedOne on 08/22/2011 05:01 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

Why is the inspection necessary.  Practically all other rockets seem to do fine without it.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/22/2011 05:25 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

Why is the inspection necessary.  Practically all other rockets seem to do fine without it.

Because it is manrated and post flight inspection is one of the ways to ensure that there are no bad trends.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/22/2011 07:18 pm
[quote+Webpush]Build of the engine components takes years, five or six for some.
Engine assembly, after all the parts are built, can be completed in as little as a month, but usually happened over something closer to six months, while other work was being done too. [/quote]

Hi webpush. Thanks for the reply. I was also interested in knowing, roughly the assembly sequence, from the first two elements assembled together to the last one at engine completion. Is there any document around about this?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/23/2011 05:00 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

If the flight manifest had ever achieved anywhere near the original goal of 50 flights per year, then recovery was the best option. Cheaper to refurbish a rotating set of, say, 12 booster pairs than to buy 100 of them each year. Of course, that never happened.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/23/2011 05:10 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

If the flight manifest had ever achieved anywhere near the original goal of 50 flights per year, then recovery was the best option. Cheaper to refurbish a rotating set of, say, 12 booster pairs than to buy 100 of them each year. Of course, that never happened.
Actually, it's the opposite. With a higher flight rate, The per flight recovery costs (SRB ship opperations, disassembly and shipping the segments, refurbishing them, etc.) would be the same, but the cost of producing segments from scratch would decrease somewhat as economies of scale began to apply. Reusability as a cost saver was always a misguided concept.
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 08/23/2011 05:21 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

If the flight manifest had ever achieved anywhere near the original goal of 50 flights per year, then recovery was the best option. Cheaper to refurbish a rotating set of, say, 12 booster pairs than to buy 100 of them each year. Of course, that never happened.

If post flight inspection was a fundamental requirement of human rating, and if those where the big cost of recovery, I would be tempted to think that it couldn't be lowered by bigger scale of production as easily as manufacturing. May be someone could enlighten me?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/23/2011 05:36 pm
If post flight inspection was a fundamental requirement of human rating, and if those where the big cost of recovery, I would be tempted to think that it couldn't be lowered by bigger scale of production as easily as manufacturing. May be someone could enlighten me?
Post flight inspection was never a "fundamental requirement of human rating" of a launch vehicle. In the case of the STS SRBs, they were originally designed for recovery. Analysis done after several years of flying showed that the cost of recovering and refurbishing was about the same as building new hardware for flight and had the ADDED benefit of providing an opportunity to study hardware that had flown to establish a family history(especially since the hardware in question had experienced a catostrophic failure - This was after 51L). Given that, the question of paying for redesigning and recertificating the booster as expendables was not viable.
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 08/23/2011 05:42 pm
If post flight inspection was a fundamental requirement of human rating, and if those where the big cost of recovery, I would be tempted to think that it couldn't be lowered by bigger scale of production as easily as manufacturing. May be someone could enlighten me?
Post flight inspection was never a "fundamental requirement of human rating" of a launch vehicle. In the case of the STS SRBs, they were originally designed for recovery. Analysis done after several years of flying showed that the cost of recovering and refurbishing was about the same as building new hardware for flight and had the ADDED benefit of providing an opportunity to study hardware that had flown to establish a family history(especially since the hardware in question had experienced a catostrophic failure - This was after 51L). Given that, the question of paying for redesigning and recertificating the booster as expendables was not viable.

Is any public documentation available on this subject?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/23/2011 05:45 pm
The Shuttle uses SRB that are recoverable.  The Ares I and V were to use extended versions of these SRBs.  What I have been wondering is whether or not recovery of these SRB is cost effective?  Are it cheaper to recover them than it is to simply use expendables, and if so how much cheaper?  Lastly if it is more cost-effective than why are they not used by any other launch vehicles today?


This question has been asked before, so feel free to just give me a link if you do not want to fully explain it to me. 



Recovery is not for cost but for post flight inspection.

If the flight manifest had ever achieved anywhere near the original goal of 50 flights per year, then recovery was the best option. Cheaper to refurbish a rotating set of, say, 12 booster pairs than to buy 100 of them each year. Of course, that never happened.

If post flight inspection was a fundamental requirement of human rating, and if those where the big cost of recovery, I would be tempted to think that it couldn't be lowered by bigger scale of production as easily as manufacturing. May be someone could enlighten me?

If post flight inspection were a requirement of human rating, then the darn things should have been decertified in 1984! Ignoring the blowby evidence shows that that wasn't the case.

IMO, an edict from on high that never again shall solids be used in human spaceflight would be a good thing. Maybe we could get some funding for stacking the remaining casings and letting RSO have some fun on the 4th of July! :):):)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/23/2011 06:58 pm
Post flight inspection was never a "fundamental requirement of human rating" of a launch vehicle.

It is for segmented solids
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/23/2011 10:17 pm
...

If post flight inspection were a requirement of human rating, then the darn things should have been decertified in 1984! Ignoring the blowby evidence shows that that wasn't the case.

IMO, an edict from on high that never again shall solids be used in human spaceflight would be a good thing. Maybe we could get some funding for stacking the remaining casings and letting RSO have some fun on the 4th of July! :):):)

You realize, of course, that the RSRMs were one of the most reliable part of the vehicle by retirement?  It's really an engineering question - would you rather have a part that has less chance of failure but if it fails there are no benign modes (most catastrophic).  Or, would you rather have a part that has more chance of failure but the failure modes range from benign to catastrophic.  Liquids engines have many more moving parts and many more ways of failing than segmented solids.

Of course, cost factors into this discussion as well.  Environmental also factors in (those who have been "lucky" enough to breathe the air around 39A/B after a launch can tell you what SRB exhaust mixed with water is like).  But, a blanket statement condemming solids doesn't do anyone any good.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/23/2011 10:57 pm
In one of the ALT videos, the one where GPC 2 sync is lost, what is 'Go for mode 203'?

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/24/2011 12:38 am
What is the distance between each "bay" of the orbiter payload bay?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/24/2011 01:17 am
...

If post flight inspection were a requirement of human rating, then the darn things should have been decertified in 1984! Ignoring the blowby evidence shows that that wasn't the case.

IMO, an edict from on high that never again shall solids be used in human spaceflight would be a good thing. Maybe we could get some funding for stacking the remaining casings and letting RSO have some fun on the 4th of July! :):):)

You realize, of course, that the RSRMs were one of the most reliable part of the vehicle by retirement?  It's really an engineering question - would you rather have a part that has less chance of failure but if it fails there are no benign modes (most catastrophic).  Or, would you rather have a part that has more chance of failure but the failure modes range from benign to catastrophic.  Liquids engines have many more moving parts and many more ways of failing than segmented solids.

Of course, cost factors into this discussion as well.  Environmental also factors in (those who have been "lucky" enough to breathe the air around 39A/B after a launch can tell you what SRB exhaust mixed with water is like).  But, a blanket statement condemming solids doesn't do anyone any good.

Andy

A bit sour? ;)

Liquids are proven, and can be shut down prior to failure by well designed avionics software. Solids are awesome for cargo into LEO. I just wouldn't use them for HSF. A failing solid is a bomb. A failing liquid is probably only going to send turbopump shrapnel tangentially away from its axis of rotation.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/24/2011 01:55 am
...

If post flight inspection were a requirement of human rating, then the darn things should have been decertified in 1984! Ignoring the blowby evidence shows that that wasn't the case.

IMO, an edict from on high that never again shall solids be used in human spaceflight would be a good thing. Maybe we could get some funding for stacking the remaining casings and letting RSO have some fun on the 4th of July! :):):)

You realize, of course, that the RSRMs were one of the most reliable part of the vehicle by retirement?  It's really an engineering question - would you rather have a part that has less chance of failure but if it fails there are no benign modes (most catastrophic).  Or, would you rather have a part that has more chance of failure but the failure modes range from benign to catastrophic.  Liquids engines have many more moving parts and many more ways of failing than segmented solids.

Of course, cost factors into this discussion as well.  Environmental also factors in (those who have been "lucky" enough to breathe the air around 39A/B after a launch can tell you what SRB exhaust mixed with water is like).  But, a blanket statement condemming solids doesn't do anyone any good.

Andy

A bit sour? ;)

Liquids are proven, and can be shut down prior to failure by well designed avionics software. Solids are awesome for cargo into LEO. I just wouldn't use them for HSF. A failing solid is a bomb. A failing liquid is probably only going to send turbopump shrapnel tangentially away from its axis of rotation.

Not sour one bit - I don't have a pony in this race. 

However, you might want to go back and look at the history of liquid engine failures before stating that they fail benignly.  There are many examples of one engine taking out another.  Either type of engine/motor (solid or liquid) carries risk or else we would have never needed to put in many of the Shuttle contingency modes.  To dismiss one type without analyzing the risk of the other is not good program management or engineering.  I'd also point out that we had 5 pad aborts and 1 ATO, each of which was caused by a shutdown of an SSME (contained SSME failure - even if it was just a sensor).  There were hazards with each abort but crew and vehicle survived.  There was 1 failure of the SRM (prior to being redesigned) and obviously we know that result.  However, the 51F ATO could have easily ended up as a loss of vehicle had a second engine also shutdown (which it came very close to doing).

There are some liquid engine failures that occur so fast that not even the best avionics can prevent the issue (such as a fuel manifold that ruptures very quickly).

Again, if you would like to dismiss an entire technology because of one (yes catastrophic) failure 25 years ago, then you're dismissing a valuable booster.  Seems silly to me, but that's your choice.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/24/2011 02:51 am
Liquids do fail benignly.  They give enough notice to abort.
As for valuable technology, SRB is not, we can do without.

The rest of your points are actually in favor of liquids and especially, your use of 51-F.  The engine "failure" was benign.  And if there was another engine shutdown, crew loss would not be due to the engines, but to the program for not having an intact abort system.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/24/2011 04:57 am
Liquids do fail benignly.  They give enough notice to abort.
As for valuable technology, SRB is not, we can do without.

The rest of your points are actually in favor of liquids and especially, your use of 51-F.  The engine "failure" was benign.  And if there was another engine shutdown, crew loss would not be due to the engines, but to the program for not having an intact abort system.

Actually I'm not in favor or against either.  I am however against throwing out one technology without due studying. 

There were plenty of SSME failure modes that would not be so benign.  It was one of the reasons for putting the AHMS on the SSME.  Monitoring the freqencies of the engine vibrations wasn't cheap but it did provide additional safe-guards which wouldn't be necessary if all liquid engines gave plenty of warning of an upcoming failure.  I suppose we could start with the AJ-26 as an example of a catastrophic engine failure that luckily occurred on the test stand.  Even on the test stand that wasn't caught in time.

Solids have advantages as do liquids - certainly the ability to throttle a liquid can be an advantage, although the failure mode of getting stuck in the bucket can't occur with a solid.

I really don't see this as cut 'n' dry either way.  A liquid booster back in the early days of Shuttle would have had some interesting effects, including development budget.  It also would have generated many more abort mode possibilities (ways to do aborts) and also generated many more ways of getting into aborts (intact and contingency).

And could you explain this better? - "And if there was another engine shutdown, crew loss would not be due to the engines, but to the program for not having an intact abort system"

Vehicle loss (I didn't say crew although that was probable) would have been because of lack of energy to reach a TAL site.  I can't see that as a program problem but rather a physics problem.  At that time, the program had not put in as much contingency abort work as we had at the end of the program and even then it would have been "dicey" to reach a site.
Andy
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/24/2011 12:29 pm
Not sour one bit - I don't have a pony in this race. 

However, you might want to go back and look at the history of liquid engine failures before stating that they fail benignly.  There are many examples of one engine taking out another.  Either type of engine/motor (solid or liquid) carries risk or else we would have never needed to put in many of the Shuttle contingency modes.  To dismiss one type without analyzing the risk of the other is not good program management or engineering.  I'd also point out that we had 5 pad aborts and 1 ATO, each of which was caused by a shutdown of an SSME (contained SSME failure - even if it was just a sensor).  There were hazards with each abort but crew and vehicle survived.  There was 1 failure of the SRM (prior to being redesigned) and obviously we know that result.  However, the 51F ATO could have easily ended up as a loss of vehicle had a second engine also shutdown (which it came very close to doing).

There are some liquid engine failures that occur so fast that not even the best avionics can prevent the issue (such as a fuel manifold that ruptures very quickly).

Again, if you would like to dismiss an entire technology because of one (yes catastrophic) failure 25 years ago, then you're dismissing a valuable booster.  Seems silly to me, but that's your choice.


Lol! No, I meant the booster exhaust probably tasted a bit sour! Like HCl sour.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/24/2011 12:38 pm
Not sour one bit - I don't have a pony in this race. 

However, you might want to go back and look at the history of liquid engine failures before stating that they fail benignly.  There are many examples of one engine taking out another.  Either type of engine/motor (solid or liquid) carries risk or else we would have never needed to put in many of the Shuttle contingency modes.  To dismiss one type without analyzing the risk of the other is not good program management or engineering.  I'd also point out that we had 5 pad aborts and 1 ATO, each of which was caused by a shutdown of an SSME (contained SSME failure - even if it was just a sensor).  There were hazards with each abort but crew and vehicle survived.  There was 1 failure of the SRM (prior to being redesigned) and obviously we know that result.  However, the 51F ATO could have easily ended up as a loss of vehicle had a second engine also shutdown (which it came very close to doing).

There are some liquid engine failures that occur so fast that not even the best avionics can prevent the issue (such as a fuel manifold that ruptures very quickly).

Again, if you would like to dismiss an entire technology because of one (yes catastrophic) failure 25 years ago, then you're dismissing a valuable booster.  Seems silly to me, but that's your choice.


Lol! No, I meant the booster exhaust probably tasted a bit sour! Like HCl sour.

Ah!  Sorry about that.  The smell was much like you walked into chemistry class after the hydrochloric acid lab.  The only way out of class was to go back to your van.  Maybe more burning than sour but only slightly irritating by the time we got there.

The launches that were at 2AM-ish, meant we were back out there around 5AM, so we would get the morning dew combined with the acid smell (and the SRB exhaust had already been combined with H2O from the SSME exhaust).

When it dried, it left tan-dirt-colored residue spots that were really bad for car finishes (and camera lenses).
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/24/2011 02:44 pm
In one of the ALT videos, the one where GPC 2 sync is lost, what is 'Go for mode 203'?



In the operational FSW, the ops modes are 1xx for ascent, 2xx for orbit, 3xx for entry, etc.  Sounds like they may have been using 2xx for ALT.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 08/24/2011 02:50 pm
What is the distance between each "bay" of the orbiter payload bay?

The payload bay is 60 x 15 feet.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 08/24/2011 02:56 pm
What is the distance between each "bay" of the orbiter payload bay?

Approximately 5 feet.  Each bay is divided by a bulkhead. 
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/24/2011 02:58 pm
Why is the aft exterior of the engine compartment covered in black tiles? Does that area experience high heat on re-entry? High heat on ascent? Or is it there to accomodate an RTLS abort mode where the vehicle would fly backwards into its own exhaust for a period of time?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/24/2011 03:03 pm
Why is the aft exterior of the engine compartment covered in black tiles? Does that area experience high heat on re-entry? High heat on ascent? Or is it there to accomodate an RTLS abort mode where the vehicle would fly backwards into its own exhaust for a period of time?
Radiant heating from the SSMEs on ascent.
Title: Re: Shuttle Q&A Part 5
Post by: butters on 08/24/2011 05:08 pm
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/24/2011 05:13 pm
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?

Depends on the payload mass.  It could be an ATO. 
You can't do a comparison between vehicles like this.  It is apples to oranges.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/24/2011 05:14 pm
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?
Probably mission-dependent, situation-dependent, performance-dependent; I think that would probably be near a single-engine ATO/TAL boundary.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/24/2011 05:16 pm
If Shuttle had a single-engine cutoff at T+325s (like the Soyuz-U today) headed to the ISS, would that have been a TAL abort?

Would have been an ATO on STS-134 or 135.

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/24/2011 06:59 pm
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.

I think I might know the answer - PASS source code. Classified! :)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/24/2011 07:14 pm
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.

I think I might know the answer - PASS source code. Classified! :)


No, it is an inertial measurement like all launch vehicles.

The inertial platform is kept aligned during the countdown.  Drift is not a factor for launch vehicles since the flight duration is short.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/25/2011 04:51 am
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.

I think I might know the answer - PASS source code. Classified! :)

Don't forget flight path angle as well.

PASS (and BFS) source wasn't classified.  However it is also not on the ITAR list of things that can be disseminated publicly with foreign nationals present (from a U.S. perspective).  It's actually a very big distinction in how you can work on something.

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/25/2011 12:34 pm
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.

I think I might know the answer - PASS source code. Classified! :)


No, it is an inertial measurement like all launch vehicles.

The inertial platform is kept aligned during the countdown.  Drift is not a factor for launch vehicles since the flight duration is short.


Doesn't the orbiter use fiber optic gyroscopes? I've never been sure how those can drift. The mechanical gyro drift makes sense - friction will drag it ever so slightly in the direction of travel so it gradually loses its inertial frame of reference. But a laser? I know it happens, just been a while since physics! :)
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/25/2011 12:39 pm
How does the Orbiter compute its velocity on ascent? Is it all inertial measurement? The MECO time seems like a very precise calculation of +X velocity and desired orbital plane. I suppose you need to know your mass, thrust (acceleration) and local gravity and you compute from that. Orbital plane I suppose could be an inertial measurement if the gyro drift is small enough during ascent.


I think I might know the answer - PASS source code. Classified! :)


No, it is an inertial measurement like all launch vehicles.

The inertial platform is kept aligned during the countdown.  Drift is not a factor for launch vehicles since the flight duration is short.


Doesn't the orbiter use fiber optic gyroscopes? I've never been sure how those can drift. The mechanical gyro drift makes sense - friction will drag it ever so slightly in the direction of travel so it gradually loses its inertial frame of reference. But a laser? I know it happens, just been a while since physics! :)

No laser gyros.  Sorry.  Shuttle IMUs were last upgraded in the early-1990s.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/25/2011 01:56 pm
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around. :)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/25/2011 02:11 pm
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around. :)
The SRM segments are stored in the two Surge facilities north of the VAB once they have completed processing in the Rotation, Processing and Surge Facility(RPSF).

This photo shows right aft segment for STS-121 being transported from one of the Surge facilities to the VAB for stacking: http://www-pao.ksc.nasa.gov/kscpao/images/large/06pd0108.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/25/2011 02:34 pm
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around. :)

RPSF, which is north of VAB.  The segments are moved from there to the VAB on a Kamag transporter.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/25/2011 02:56 pm
STS-135's boosters were a couple of years old, right? Where are the segments stored? At KSC? How did they get to the VAB? I figure a segment has to weigh roughly 1/3 of the total, so say 400,000 lbs? I don't see rail lines leading to the VAB. And, no offense to Mike Rowe, but I don't think the F-150 is going to tow that around. :)
The SRM segments are stored in the two Surge facilities north of the VAB once they have completed processing in the Rotation, Processing and Surge Facility(RPSF).

This photo shows right aft segment for STS-121 being transported from one of the Surge facilities to the VAB for stacking: http://www-pao.ksc.nasa.gov/kscpao/images/large/06pd0108.jpg

This building (green arrow)? I think I can see the yellow/orange transporter platforms parked there. I'm guessing the building only holds one pair of boosters, right?

http://maps.google.com/maps?f=q&source=s_q&hl=en&geocode=&q=28%C2%B035'35.02%22N,+80%C2%B039'12.30%22W&aq=&sll=37.0625,-95.677068&sspn=64.241198,134.912109&vpsrc=6&ie=UTF8&ll=28.591371,-80.651053&spn=0.008874,0.016469&t=h&z=17
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/25/2011 03:00 pm
The other surge building is to the left, above the "A" and the RPSF is to the left, above "Launcher Road"
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/25/2011 03:11 pm
The other surge building is to the left, above the "A" and the RPSF is to the left, above "Launcher Road"

Got it. So you can have 4 boosters (2 pair) on site at once?

The RPSF has the rail lines running through it, right? What work gets done at KSC versus elsewhere? Elsewhere was out west, wasn't it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/25/2011 03:16 pm

1.  Got it. So you can have 4 boosters (2 pair) on site at once?

2.  The RPSF has the rail lines running through it, right? What work gets done at KSC versus elsewhere? Elsewhere was out west, wasn't it?

1.  more, the RPSF can store some

2.  All the SRB assembly work is at KSC.
Title: Re: Shuttle Q&A Part 5
Post by: VB94 on 08/29/2011 11:49 am
Two linguistic questions...

1)What is the actual definition of the term "close-out"? Does it refer to the final preparations done in a specific part of the orbiter (e.g. aft or crew compartment) before it is closed for flight?

2)Why are key members of the launch team called "test conductors" even though they do a lot more than just supervising tests?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 08/29/2011 12:34 pm
Two linguistic questions...

1)What is the actual definition of the term "close-out"? Does it refer to the final preparations done in a specific part of the orbiter (e.g. aft or crew compartment) before it is closed for flight?

2)Why are key members of the launch team called "test conductors" even though they do a lot more than just supervising tests?

Thanks!


1.  Essentially, that is the correct definition

2.  OTCs (Orbiter Test Conductors) essentially run the operations being performed on the vehicle.  In a way, you can correlate their role to that of Flight Director in Mission Control. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/29/2011 01:09 pm
Two linguistic questions...

1)What is the actual definition of the term "close-out"? Does it refer to the final preparations done in a specific part of the orbiter (e.g. aft or crew compartment) before it is closed for flight?

2)Why are key members of the launch team called "test conductors" even though they do a lot more than just supervising tests?

Thanks!


1.  It is applicable to any spacecraft or launch vehicle

2.  It goes back to the days when all work done on space vehicles were performed via "test" procedures.  For ELV's, test conductors become launch conductors on launch day.  Spacecraft always have test conductors because they supervise electric testing.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 08/29/2011 03:01 pm
Two linguistic questions...
1)What is the actual definition of the term "close-out"? Does it refer to the final preparations done in a specific part of the orbiter (e.g. aft or crew compartment) before it is closed for flight?
1.  Essentially, that is the correct definition
In addition "close out" also refers to the fact that there is no more access allowed to that system or area. For instance, the close out procedure for the orbiters wings include placing kapton tape strips across the access openings in the wing spars so that no one can crawl thru them without removing the tape. That way, they know that nothing in there has changed on launch day.
Title: Re: Shuttle Q&A Part 5
Post by: VB94 on 08/29/2011 05:23 pm
Thanks to all of you for your answers!  :)
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/31/2011 01:39 am
If I understand correctly, the Shuttle had an autoland system that was meant to be tested on STS53, but wasn't. Was it ever used?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/31/2011 02:06 am
If I understand correctly, the Shuttle had an autoland system that was meant to be tested on STS53, but wasn't. Was it ever used?


No.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/31/2011 04:14 am
If I understand correctly, the Shuttle had an autoland system that was meant to be tested on STS53, but wasn't. Was it ever used?


I almost wanted to write, "yes, every flight", since every flight the autoland was run in SAIL (OV-095) and the other simulators.  PASS had an autoland capability but BFS did not.  The PASS capability was available since STS-1.  Autoland was used down to 300 feet on STS-3 (I believe the crew flew around the HAC and then went back to auto and then back to CSS at 300 feet).

For STS-53 a detailed test objective (DTO) was written and temporarily approved.  The DTO would have had the crew fly both auto and CSS around the HAC and then let the vehicle fly itself to a landing.  Braking would have been applied by the crew (because there was no auto-braking available) with brakes and drag chute.  Landing would have been at Edwards on a dry lakebed runway.

A special hand-hold was built for the CDR, so he could rest his hand right next to the rotational hand controller (the stick) in case an immediate take-over was needed.

My memory is that we made it to about a month before flight before the inevitible occurred and the DTO was cancelled.  The funny thing was that when STS-53 landed, it was diverted to Edwards and clouds blocked the view of the runway down to around 5,000 feet.  So, the crew flew guidance all the way around and really didn't have a view of the runway until below the deck.  All autoland would have done was to automatically follow guidance rather than the crew doing it.

The Autoland DTO never came up again.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 08/31/2011 04:34 am
Oh cool! I didn't realize SAIL still existed. What is its fate post-SSP?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/31/2011 04:57 am
Oh cool! I didn't realize SAIL still existed. What is its fate post-SSP?

Undecided. I'm hearing abandon-in-place is a leading candidate, since it would be expensive to either move or demolish. If so, it would be the only major shuttle artifact that JSC gets to keep.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/31/2011 05:00 am
If I understand correctly, the Shuttle had an autoland system that was meant to be tested on STS53, but wasn't. Was it ever used?


I almost wanted to write, "yes, every flight", since every flight the autoland was run in SAIL (OV-095) and the other simulators.

I was tempted to write the same thing for a different reason - autoland guidance was used to drive the HUD flight director symbol and the ADI error needles, even when the DAP was in CSS and the crew was manually flying.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/31/2011 09:47 am
If I understand correctly, the Shuttle had an autoland system that was meant to be tested on STS53, but wasn't. Was it ever used?


I almost wanted to write, "yes, every flight", since every flight the autoland was run in SAIL (OV-095) and the other simulators.

I was tempted to write the same thing for a different reason - autoland guidance was used to drive the HUD flight director symbol and the ADI error needles, even when the DAP was in CSS and the crew was manually flying.

Not just the HUD but all of the instrumentation.  So as long as the crew was flying the guidance needles, they were essentially flying autoland guidance but with the crew providing the control inputs (and the GPCs interpreting the stick movements the same as if guidance had sent control inputs).

And, yes, a (mostly) non-functioning SAIL going to Space Center Houston was the leading candidate last I heard.


Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/31/2011 01:10 pm

I almost wanted to write, "yes, every flight", since every flight the autoland was run in SAIL (OV-095) and the other simulators. 

I have to ask this...

Were any of you around when Iron Maiden came to JSC? http://www.collectspace.com/ubb/Forum3/HTML/004178.html

Did Bruce (he is an airline transport pilot) fly an approach and landing? How did he do? Did he splash an orbiter or not? :)

Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/05/2011 12:00 pm
Hi all. A question about the AHMS. I was wondering why it came up on line so late in the program (STS-118 in active mode on all 2 SSMEs)? It seems it was a quite important piece of equipment for the safety of the engines, so why so late.

I was reading an interview with George Hopson from the JSC oral history project and he says that the reason for developping the AHMS was that the previous engine controller wasn't able to tell apart noise (not acustic but the electric noise in the wires) from the real patter of the pump vibrations and therefore was it be in active mode we would have seen many engines shut down during ascent. For this reason the control on the vibrations was never flown in active mode. So once again I'm wondering why they didn't solve this problem earlier?

thanks

Davide

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/05/2011 01:46 pm
Hi all. A question about the AHMS. I was wondering why it came up on line so late in the program (STS-118 in active mode on all 2 SSMEs)? It seems it was a quite important piece of equipment for the safety of the engines, so why so late.

I was reading an interview with George Hopson from the JSC oral history project and he says that the reason for developping the AHMS was that the previous engine controller wasn't able to tell apart noise (not acustic but the electric noise in the wires) from the real patter of the pump vibrations and therefore was it be in active mode we would have seen many engines shut down during ascent. For this reason the control on the vibrations was never flown in active mode. So once again I'm wondering why they didn't solve this problem earlier?

thanks

Davide



Three reasons - one, the technology didn't exist much earlier than the late 1990s (high speed DSP chips that could withstand sitting on top of an SSME).  The software also takes time to create, which is after the requirements are made and approved.

Two, we didn't want to fly anything that we weren't sure about how it would work.  Testing takes time.

Adding AHMS and having it shutdown a perfectly good engine would have been very bad.  So, the software was developed and tested on the bench, then tested on the test stand, then tested while riding on the SSME but unable to control, then tested while able do some control and then finally full active mode.  It took a lot of iterations before it flew actively.

And, three, getting the money allocated to create AHMS.  Money comes from Congress and allocating money also takes time.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/05/2011 06:43 pm
So once again I'm wondering why they didn't solve this problem earlier?

It wasn't for lack of trying.  Columbia had a VIB SHUT DOWN ENABLE/INHIBIT switch on the center console but as you say the system was never used in active mode.  Later there was FASCOS (maybe FASCOS II?) for Flight Accelerometer Safety Cut-Off System but again, never used in active mode.  As Andy said, finally technology and funding caught up with the requirements.  AHMS does near real time fast Fourier transforms to distinguish real problems from noise.  None of the precursor systems were that smart and the chance of a 'false alarm' shutdown was deemed too great.
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 09/05/2011 07:33 pm
What sort of DSPs were used in AHMS?

What was the system looking for? Changes in vibrational frequencies of the pumps?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/05/2011 11:18 pm
Quote
What was the system looking for? Changes in vibrational frequencies of the pumps?

From the interview reported with George Hopson reported in the JSC Oral history project this is the explanation:

Quote
The AHMS [advanced health management system], the big difference between it and the first vibration shut down system was that the first system used composite vibration. In other words the old system used the whole spectrum of frequencies, so any noise was considered along with real vibration. The AHMS only considered synchronous vibration. The pump turns X number of rpm [revolutions per minute]. If you have a vibration that matches the speed that the pump is turning, then that’s synchronous. And if it’s synchronous it’s real.

hope this help in answering your question

Davide
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/06/2011 11:43 am
Hi all.

I was reading that the guidance during the first part of the ascent (up to SRM sep) is open loop. The guidance has in its memory a pre loaded set of attitude positions the orbiter has to have when it reaches a given velocity.

I was wondering why is the guidance control logic up to SRM sep, open loop type? This exclude the possibility to correct any large deviations from a nominal attitude due to some for example some strong gust of wind. Since up to SRB sep the shuttle is still in the lower portion of the atmosphere where the winds are stronger, it would have made sense to use a closed-loop control logic. What have I missed?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/06/2011 12:08 pm
Hi all.

I was reading that the guidance during the first part of the ascent (up to SRM sep) is open loop. The guidance has in its memory a pre loaded set of attitude positions the orbiter has to have when it reaches a given velocity.

I was wondering why is the guidance control logic up to SRM sep, open loop type? This exclude the possibility to correct any large deviations from a nominal attitude due to some for example some strong gust of wind. Since up to SRB sep the shuttle is still in the lower portion of the atmosphere where the winds are stronger, it would have made sense to use a closed-loop control logic. What have I missed?

thanks

Davide

In first stage there is also feedback from the lateral accelerometers that react to off nominal winds.  So there is a response to winds in first stage.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/06/2011 01:14 pm
Quote
In first stage there is also feedback from the lateral accelerometers that react to off nominal winds.  So there is a response to winds in first stage

but how this information is put into the open loop? if you have this kind of feedback the guidance is not anymore open loop.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/06/2011 01:23 pm
This exclude the possibility to correct any large deviations from a nominal attitude due to some for example some strong gust of wind.

yes
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/06/2011 01:37 pm
But it is safe not being able to make corrections due to winds up to SRB sep? which is the reason for having chosen to adopt this kind of guidance?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/06/2011 01:37 pm
Hi all.

I was reading that the guidance during the first part of the ascent (up to SRM sep) is open loop. The guidance has in its memory a pre loaded set of attitude positions the orbiter has to have when it reaches a given velocity.

I was wondering why is the guidance control logic up to SRM sep, open loop type? This exclude the possibility to correct any large deviations from a nominal attitude due to some for example some strong gust of wind. Since up to SRB sep the shuttle is still in the lower portion of the atmosphere where the winds are stronger, it would have made sense to use a closed-loop control logic. What have I missed?

thanks

Davide

First, here's a publicly available paper on first stage guidance,

http://www.allmanpc.com/papers_presentations/SpaceShuttleSimplex.pdf

1st stage is open loop.  Corrections for wind were made pre-launch using the DOLILU II system.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/06/2011 02:02 pm
But it is safe not being able to make corrections due to winds up to SRB sep? which is the reason for having chosen to adopt this kind of guidance?

I would think fine control using the rock and tilt actuators in the SRBs would be impossible. The stack is doing its best to just fly a compass heading and proper alpha angle so as not to tear the wings off during first stage. Second stage is another 6 minutes of flight well out of the thick air - plenty of time to fine tune where the vehicle is headed.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 09/06/2011 02:08 pm
Quote
In first stage there is also feedback from the lateral accelerometers that react to off nominal winds.  So there is a response to winds in first stage

but how this information is put into the open loop? if you have this kind of feedback the guidance is not anymore open loop.

Then I guess guidance is not 100% open loop.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/06/2011 02:19 pm
Quote
In first stage there is also feedback from the lateral accelerometers that react to off nominal winds.  So there is a response to winds in first stage

but how this information is put into the open loop? if you have this kind of feedback the guidance is not anymore open loop.

Then I guess guidance is not 100% open loop.

...or 100% open loop, unless "the loop" includes the prelaunch wind calculations.
Title: Re: Shuttle Q&A Part 5
Post by: mmeijeri on 09/06/2011 02:24 pm
From that paper it looks as if open-loop means they are sticking to a fixed velocity-attitude profile that is unaffected by previous deviations, not that there is no feedback at all. Inside that open-loop profile there is apparently another control system that does use feedback. Otherwise you wouldn't need sensors and they'd be playing back actuator commands. As I understand it, PEG does find the best way to get to the desired final conditions based on the current conditions, not on the conditions in the reference profile at the same point in time. In other words open-loop guidance uses feedback to steer the vehicle towards a reference velocity-attitude profile whereas PEG uses feedback to steer it towards the desired final conditions.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/06/2011 02:31 pm
PEG was second stage.  The vehicle had to know its current attitude, even in first stage. 

Here's a JSC article on DOLILU I and how it was used to accomodate differening winds:
http://www.jsc.nasa.gov/jscfeatures/articles/000001006.html

Here's an open source on DOLILU II:
http://www.space-explorations.com/abort-region-determinator/dol-iload-update-dolilu-ii-procedures.html
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/06/2011 03:34 pm
But it is safe not being able to make corrections due to winds up to SRB sep? which is the reason for having chosen to adopt this kind of guidance?

Most launch vehicles use open loop for their lower stages.
Title: Re: Shuttle Q&A Part 5
Post by: DansSLK on 09/06/2011 09:00 pm
From that paper it looks as if open-loop means they are sticking to a fixed velocity-attitude profile that is unaffected by previous deviations, not that there is no feedback at all. Inside that open-loop profile there is apparently another control system that does use feedback. Otherwise you wouldn't need sensors and they'd be playing back actuator commands. As I understand it, PEG does find the best way to get to the desired final conditions based on the current conditions, not on the conditions in the reference profile at the same point in time. In other words open-loop guidance uses feedback to steer the vehicle towards a reference velocity-attitude profile whereas PEG uses feedback to steer it towards the desired final conditions.
That is my understanding of ascent guidance.
First stage guidance is closed-loop in the sense that the vehicle will try its best to meet the I-Loaded targets while minimizing stress on the airframe and 'making the most of what it's got' profile wise and open-loop in that the targets are initalized loaded (DOLILU) and not computed on-the-fly with an end goal in mind (that would be PEG)
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/06/2011 09:05 pm

Most launch vehicles use open loop for their lower stages.

Jim's correct.  The DOLILU team held fairly regular working group meetings with teams that performed similar functions for other launch vehicles.  The process of "analyze the wind of the day, then design the trajectory based on that and the vehicle's load constraints" seemed to me to be consistent (at a high level) across all the vehicles.  The EELV folks had the advantage of better technology in their analysis tools but the basic idea was the same.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/06/2011 09:21 pm
The bottom line to all of this is what would you use to "look ahead" at the wind in the upcoming atmosphere in real-time that would fit on a vehicle and be enough of a look-ahead that the vehicle could compensate effectively?  Much easier to do that on the ground and the winds aloft don't change that rapidly (normally) compared to using balloon data.  And, if the winds are changing that rapidly you probably don't want to launch.  I always thought it was best to keep the wings attached to the vehicle...

Andy

Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/06/2011 10:56 pm
Hi all.

thanks very much for your answers and for the links...very interesting....i'm now understing.

I've now another question for you. Always during the first part of the ascent, I read the elevons are moved for stress relief during Max q. So I'm wondering in which way are they moved? is again something set in pre-launch loaded tables or is based on a closed loop? I would guess it's the first one (the preloaded table).

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/06/2011 11:11 pm
Pre-loaded and purely for load relief (no steering) and prior to max-q.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/07/2011 10:17 am
but exactly how are the elevons moved? My guess is that they are moved in order to reduce the lift created on the wings but I'm not sure.

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/07/2011 01:15 pm
but exactly how are the elevons moved? My guess is that they are moved in order to reduce the lift created on the wings but I'm not sure.


The angle of attack vs altitude is known, so the elevons are moved to reduce the loads.  The AOA is negative so it is actually a down force on the wings that they are trying to reduce.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/07/2011 01:18 pm
Pre-loaded and purely for load relief (no steering) and prior to max-q.

Andy

It's closed loop at least in the sense that it only happens if needed.  I'm looking at an MMT pitch from STS-130 (the ascent performance quick-look) and it states "no elevon load relief".  From what I remember the 2 big things that could change in real time were presence/absence of load relief and the throttle bucket settings.  I remember the throttle bucket changing a few times but I never remember load relief happening.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/07/2011 01:26 pm
but exactly how are the elevons moved? My guess is that they are moved in order to reduce the lift created on the wings but I'm not sure.


The angle of attack vs altitude is known, so the elevons are moved to reduce the loads.  The AOA is negative so it is actually a down force on the wings that they are trying to reduce.


If I recall correctly, the wing zero lift angle of attack for the Orbiter is about -7, and during high q the alpha target is -4, transitioning to +2 after Mach 2 ish.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/07/2011 01:37 pm
Quote from: Specifically Impulsive
It's closed loop at least in the sense that it only happens if needed.  I'm looking at an MMT pitch from STS-130 (the ascent performance quick-look) and it states "no elevon load relief".  From what I remember the 2 big things that could change in real time were presence/absence of load relief and the throttle bucket settings.  I remember the throttle bucket changing a few times but I never remember load relief happening.

very interesting...what do you mean for throttle buckt changing? The throttling was always done isn't?

where can I find these performance quick-looks?

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/07/2011 01:41 pm
Quote from: Specifically Impulsive
It's closed loop at least in the sense that it only happens if needed.  I'm looking at an MMT pitch from STS-130 (the ascent performance quick-look) and it states "no elevon load relief".  From what I remember the 2 big things that could change in real time were presence/absence of load relief and the throttle bucket settings.  I remember the throttle bucket changing a few times but I never remember load relief happening.

very interesting...what do you mean for throttle buckt changing? The throttling was always done isn't?

where can I find these performance quick-looks?

Davide

The throttling was always done and the min throttle and duration of the bucket was planned out preflight.  But, if the SRBs were more powerful than planned, the SSMEs would throttle down more, or vice versa if the SRBs were less powerful than planned.

I don't know where the MMT pitches are publicly available.  Maybe on L2?  Chris seems to have a pipeline to the MMT.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/07/2011 02:23 pm
Remember so-called adaptive guidance was purely an attempt to match the vehicles actual velocity at a given time versus what it was expected to be.  The engines (SSMEs) could then be throttled an additional amount if the vehicle was going faster than expected (hotter SRBs).  It was not closed-loop guidance in a 2nd stage sort of way by any means.  First stage remained opened loop - it has to given our present abilities to measure winds in real-time.

For accuracy, the Adaptive Guidance and Throttling (AGT) test was at a pre-loaded velocity and then time was computed and compared.  A very simple method.  You can see a short discussion of this in one paragraph of the following article from this actual website,

http://www.nasaspaceflight.com/2011/07/sts-135-ascent-reviews-point-superb-launch-performance-atlantis/

Andy
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/08/2011 12:20 am
Hi all.

Again another question about the ascent. Before STA-87, the orbiter didn't perform the roll head up towards the end of the ascent. So I was the maneuver for ET sep? being in an head-down attitude, how could the orbiter avoid colliding with the ET that was just "over" it?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/08/2011 12:31 am
Hi all.

Again another question about the ascent. Before STA-87, the orbiter didn't perform the roll head up towards the end of the ascent. So I was the maneuver for ET sep?

Same maneuver, 4 fps -Z RCS with an optional +X RCS for ET photography.

Quote
being in an head-down attitude, how could the orbiter avoid colliding with the ET that was just "over" it?

The orbiter is no more likely to collide with the ET in a heads-down vs a heads-up orientation.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 09/08/2011 01:46 am
Ah, so that was "Go for the plus x" -- positioning for ET photos.  And "Go for the pitch?"
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/08/2011 02:10 am
Ah, so that was "Go for the plus x" -- positioning for ET photos.

Right, from the ET umbilical well cameras. Doing a +X allows more of the tank to pass below the cameras while they're still close enough to get good resolution.

Quote
  And "Go for the pitch?"

That's for ET photography from the overhead windows.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2011 03:36 am
Including the ribs and radiator panels, how thick are the PLBDs(average thickness if the thickness is not uniform)?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/08/2011 01:26 pm
Hi all.

Again another question about the ascent. Before STA-87, the orbiter didn't perform the roll head up towards the end of the ascent. So I was the maneuver for ET sep?

Same maneuver, 4 fps -Z RCS with an optional +X RCS for ET photography.

Quote
being in an head-down attitude, how could the orbiter avoid colliding with the ET that was just "over" it?

The orbiter is no more likely to collide with the ET in a heads-down vs a heads-up orientation.

Is there any impulse provided for ET sep, or is the RCS required to perform the separation? In other words, does residual tank pressure or something similar serve to "pop" it loose once the disconnect is made?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/08/2011 01:40 pm
Quote from: wolfpack link=topic=17437.msg803833#msg803833

Is there any impulse provided for ET sep, or is the RCS required to perform the separation? In other words, does residual tank pressure or something similar serve to "pop" it loose once the disconnect is made?

The jets were used.  Residual pressure in the feedlines would have been bad, leading to a pitching moment on the tank while it was in close proximity to the orbiter.  In fact, if the valves isolating the orbiter from the tank did not all indicate closed, the separation was inhibited until enough time had passed for the tank to vent down. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/08/2011 02:04 pm

Is there any impulse provided for ET sep, or is the RCS required to perform the separation? In other words, does residual tank pressure or something similar serve to "pop" it loose once the disconnect is made?

The tension in the bolts also provides a small impulse
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/08/2011 05:13 pm
Quote from: wolfpack link=topic=17437.msg803833#msg803833

Is there any impulse provided for ET sep, or is the RCS required to perform the separation? In other words, does residual tank pressure or something similar serve to "pop" it loose once the disconnect is made?

The jets were used.  Residual pressure in the feedlines would have been bad, leading to a pitching moment on the tank while it was in close proximity to the orbiter.  In fact, if the valves isolating the orbiter from the tank did not all indicate closed, the separation was inhibited until enough time had passed for the tank to vent down. 

The jets would have been even more critical during ET Sep in an RTLS scenario.  Luckily we never got to try one of those out...

Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/09/2011 11:23 am
The PLBD skins are 4-ply graphite/epoxy face sheets over a honeycomb core.  I'll have to look for my Rockwell/Tulsa PLBD briefing to find the thicknesses, and the rib dimensions.  Can't remember if it talked about the radiators too.
F=ma

Including the ribs and radiator panels, how thick are the PLBDs(average thickness if the thickness is not uniform)?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/11/2011 04:41 am
Interesting paper on the ascent loads relief discussed earlier...
http://www.aiaa.org/pdf/industry/Why_the_Wings_Stay_On.pdf

So here's what I found on the PLBD structures:

Each PLBD has 4@~15ft,1@~2ft sections connected at expansion joints by shear pins. 
Skins - Al wire mesh screen on OML for lightning protection.  Mostly 3 ply, tape/fabric/tape gr-ep FS (16-22 mil thick) over 0.6 in.-thick Nomex HC cores.
Hingelines has [90/0/±45/0/90]t laminate w/ 0.3-in core.
Frames – 4.41 in. deep x 1.125 in. wide, spaced at 22.5 inches.  0/±45 tape/fabric caps and flats, ±45 fabric webs. 
Radiator panels - 11-mil Al FS over 0.5-0.9 in. thk Al HC cores.

Refs: NASA TM 107793 (avail NTRS); Rockwell/Tulsa govt/industry briefing on PLBDs

Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/14/2011 11:46 am
Quote from: fequalsma
Interesting paper on the ascent loads relief discussed earlier...
http://www.aiaa.org/pdf/industry/Why_the_Wings_Stay_On.pdf

very interesting paper indeed...thanks very much...but just out of curiosity: how did you find it? if I just use the following addresss www.aiaa.org/pdf I can't get any access. Are there papers from AIAA freely available?

now the question of the day: for the ascent the pilots can see the information regarding the progress of the ascent on three different displays, which are ASCENT TRJ 1 (used up to SRB sep), ASCENT TRJ 2 (used up to ET sep) and ASCENT TRJ (it displays the whole ascent). This is at least what I've understood from what I've been reading lately. My question is: when the ASCENT TRJ is used? Also are the ASCENT TRJ 1 and 2 generated by the PASS or by the BFS?

thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 09/14/2011 01:14 pm
very interesting paper indeed...thanks very much...but just out of curiosity: how did you find it? if I just use the following addresss www.aiaa.org/pdf (http://www.aiaa.org/pdf) I can't get any access. Are there papers from AIAA freely available?

A bit off-topic, but try pasting the following into google:

site:aiaa.org/pdf   filetype:pdf

You should get a list of ~1200 pdf files, some of which are academic papers and briefings.  Bit of a blunderbuss method though!
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/15/2011 10:19 am
During the roll for placing the orbiter in the head up attitute halfway the ascent, is there any kind of sideslip deviation from the nominal trajectory path? I mean, does the orbiter stay centered on the nominal trajectory or it jsut goes a bit sideaways for then recenter itself on the ascen path?

I hope the question is clear enough.

Best regards

Davide
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 09/15/2011 05:58 pm
Not sure how about trajectory error, but IIRC there was a small performance penalty with the rolling heads up vs. staying heads down.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/16/2011 02:23 pm
Quote
now the question of the day: for the ascent the pilots can see the information regarding the progress of the ascent on three different displays, which are ASCENT TRJ 1 (used up to SRB sep), ASCENT TRJ 2 (used up to ET sep) and ASCENT TRJ (it displays the whole ascent). This is at least what I've understood from what I've been reading lately. My question is: when the ASCENT TRJ is used? Also are the ASCENT TRJ 1 and 2 generated by the PASS or by the BFS?

Hi all.

no answer about this? I really need to understand this thing.

thanks very much for your help

Davide
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 09/17/2011 05:16 pm
Originally, the PASS used a single display for both first stage and second stage called ASCENT TRAJ. AIUI, this was intended to help fly an RTLS, and its usefulness after Negative Return was limited. BFS used one display for first stage and a different display for second stage (ASCENT TRAJ 1 and 2).

For the OI-32 (I believe) software release, the PASS displays were changed to more closely resemble the BFS displays.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/18/2011 08:10 pm
[quoteHelixSpiral]Originally, the PASS used a single display for both first stage and second stage called ASCENT TRAJ. AIUI, this was intended to help fly an RTLS, and its usefulness after Negative Return was limited. BFS used one display for first stage and a different display for second stage (ASCENT TRAJ 1 and 2).

For the OI-32 (I believe) software release, the PASS displays were changed to more closely resemble the BFS displays. [/quote]

Interesting to know, but basically now which displayes are displayed during the different ascent phases?

And just to know, what OI-32 stands for?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 09/19/2011 12:22 pm
Operational Increment 32, essentially version 32 of the flight software (I think!)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/20/2011 06:43 am
why is it important for the pilots, during ascent to view the horizon in front of them? this is one of the reason for which the roll program is executed.

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/20/2011 06:54 am
I've been away for a little bit, so let me catch-up and give you a bit of detail.

First on your question about the ascent traj displays, there is a good account of that in Part 4 of the Shuttle Q&A (MKirk I believe appended).  One should always check the archives before asking new questions.

Yes for many years BFS had a much better first stage ascent traj display and a better second stage ascent traj display than PASS.  The 6X Traj upgrade for OI-32, did indeed update the PASS displays into a much more usable format.  6X stands for the XXXXXX in front of the Traj on the display title.  These can be changed to different abort modes such as RTLS, as well.  So your question about whether these are 1 or 2 is actually irrelevent - they were three or one depending upon how you look at a different display format.  The transitions were done automatically, so from a pilot stand-point I think one format with different options may be a good way to look at it.  From a requirements standpoint, each format had its own requirements.  So, you can choose your own answer.

Keep in mind that the crew had a good number of displays to choose from during ascent.  Of course my favorite for the last two OIs being the Bearing Display (see Shuttle flight software paper topic in the historic spaceflight forum - http://forum.nasaspaceflight.com/index.php?topic=26630.0) which provided two maps spanning the U.S. east coast to Europe as well as orbiter velocity and position indications overlayed on the map.  There were also a number of systems displays.

http://www.unitedspacealliancenewsroom.com/usa-in-the-news/news-releases/sts-126-launches-with-new-software-that-enhances-astronaut-safety/

OI-32 is indeed Operational Increment but it wasn't the 32nd version of the flight software.  We skipped numbers (some were "test" OIs) and also occasionally used a letter after the OI number (OI-26B for instance).  However the final OI was OI-34.

And, seeing the horizon was not the reason for the roll program.  The roll program was there because the launch pad could only face one way (tail to the south).  To get to the proper azimuth at launch then required a roll.  Roll to heads down was primarily for load relief, after initial program studies showed less pressure on the wings heads down than heads up.  After a few flights, I'm told that using actual flight data made the different irrelevent but RTLS was easier to setup heads-down (work it out by "flying" RTLS with your hands).

So, why did you "really need" to know this in such a hurry?  I'm curious...

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/20/2011 07:54 am
OI-32 is indeed Operational Increment but it wasn't the 32nd version of the flight software.  We skipped numbers (some were "test" OIs) and also occasionally used a letter after the OI number (OI-26B for instance).  However the final OI was OI-34.

There was also a wholesale change in the numbering philosophy with, I think, OI-8D giving way directly to OI-20.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/20/2011 01:45 pm
OI-32 is indeed Operational Increment but it wasn't the 32nd version of the flight software.  We skipped numbers (some were "test" OIs) and also occasionally used a letter after the OI number (OI-26B for instance).  However the final OI was OI-34.

There was also a wholesale change in the numbering philosophy with, I think, OI-8D giving way directly to OI-20.


That's right.  When the then-new AP-101S computers started flying, we did some numbering tricks.  The flight sequence was OI-8D (AP-101B) to OI-8F (AP-101S using OI-8D application software but designed for the new GPC) and then OI-20 (starting to take advantage of the AP-101S).  So, the sequence went OI-8D, OI-8F and OI-20. 

The OI-12 line was for trying out things with the new computers as I recall.  There was also the Centaur OI (7C), the CAU OIs and a few other test systems along the way.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/20/2011 06:09 pm
One of the parameters computed by PEG during the second-stage guidance, is the reference thrust vector, which is defined as a unit vector in the direction of the velocity to be gained Vgo, indicating the constant thrust direction that would achieve the desired velocity.

Am I understing right that this is a vector fixed during all the ascent representing the thrust vector velocity at MECO? Also if I've understood well, aim of PEG is to rotate the real thrust vector in order to have its direction parallel to the reference thrust vector. Am I correct?

thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/23/2011 01:00 am
Whats the maximum length of time that the SRB retrieval ships can stay at sea for?

I couldn't find a time-frame but this reference shows a cruising range of 6,000 miles (assumed to be at 15 knots).

http://blogs.nasa.gov/cm/blog/sailing_with_nasa/posts/post_1255980355154.html

I suspect the crew compliment would have a lot to do with sea-time.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: joncz on 09/23/2011 02:08 pm

I suspect the crew compliment would have a lot to do with sea-time.

Andy

<Captain> Crew, you're a very nice crew.  It's a pleasure to work with you!
<Crew> Captain - thanks for the compliment!  We'll stay out another month with you for those nice words!

 ;D
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 09/23/2011 02:18 pm
The food probably has a lot to do with it as well.  ;)
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 09/23/2011 07:27 pm
Does anyone know what happened to the prototype SSME, the ISTB?
Title: Re: Shuttle Q&A Part 5
Post by: Wepush on 09/23/2011 09:04 pm
The ISTB tested for a long time, was rebuilt and tested some more.  The main parts were destroyed in a lox fire in ‘78.  The nozzle tested on another engine, but was eventually destroyed in a different incident in ‘85.  (You can read about both of these incidents in the Bob Biggs book on the SSME - see tests 901-120 (was actually 902-120) on engine 0101 and test 750-259 on Engine 2308.)
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/23/2011 09:05 pm

I suspect the crew compliment would have a lot to do with sea-time.

Andy

<Captain> Crew, you're a very nice crew.  It's a pleasure to work with you!
<Crew> Captain - thanks for the compliment!  We'll stay out another month with you for those nice words!

 ;D

Fair enough - I should have reminded myself about the complement and then you could have given me a compliment. 

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/24/2011 01:19 am
Do you have a citation or link for this book, Wepush?


 the Bob Biggs book on the SSME

Title: Re: Shuttle Q&A Part 5
Post by: GoForTLI on 09/24/2011 01:24 am
Do you have a citation or link for this book, Wepush?


 the Bob Biggs book on the SSME


Space Shuttle Main Engine
The First Ten Years
by Robert E. Biggs

http://www.enginehistory.org/ssme.shtml (http://www.enginehistory.org/ssme.shtml)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/24/2011 01:31 am
Thanks very much!
F=ma


Do you have a citation or link for this book, Wepush?


 the Bob Biggs book on the SSME


Space Shuttle Main Engine
The First Ten Years
by Robert E. Biggs

http://www.enginehistory.org/ssme.shtml (http://www.enginehistory.org/ssme.shtml)
Title: Re: Shuttle Q&A Part 5
Post by: Wepush on 09/24/2011 01:48 am
Even better:
Space Shuttle Main Engine: The First Twenty Years and Beyond. By Robert E. Biggs. San Diego, Calif.: American Astronautical Society, 2008 [AAS History Series, volume 29].
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/24/2011 05:35 am
Why were the sunshades on the early program Hughes sat deploys open before payload bay door opening?   
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/24/2011 02:10 pm
Why were the sunshades on the early program Hughes sat deploys open before payload bay door opening?   

So as to increase the clearances with the payload bay doors when the payload bay doors were closed.  The orbiter was launched with the sunshades open, as well.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 09/26/2011 06:25 am
Were the STA aircraft controlled by something like the Shuttle's DPS? Or were the avionics for them completely different?

Thanks,
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/27/2011 03:40 pm
2 questions:

1) Did any payload ever use the full length of the payload bay?

2) Why was parallel staging used?  Wouldn't it have been more efficient to use series staging so the 2nd stage tank would have been smaller/lighter and a lot of weight could be jettisoned with the first stage separation?  Wouldn't it have eliminated the need for SRBs if you had just a normal liquid first stage.  Probably would have looked wierd since you'd have the orbiter side mounted to a smaller ET sitting on top of a first stage.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2011 03:46 pm
2 questions:

1) Did any payload ever use the full length of the payload bay?

2) Why was parallel staging used?  Wouldn't it have been more efficient to use series staging so the 2nd stage tank would have been smaller/lighter and a lot of weight could be jettisoned with the first stage separation?  Wouldn't it have eliminated the need for SRBs if you had just a normal liquid first stage.  Probably would have looked wierd since you'd have the orbiter side mounted to a smaller ET sitting on top of a first stage.

1.  See AXAF

2.  No quick answer.  See history of shuttle documents or books.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/27/2011 04:10 pm
2 questions:

1) Did any payload ever use the full length of the payload bay?

2) Why was parallel staging used?  Wouldn't it have been more efficient to use series staging so the 2nd stage tank would have been smaller/lighter and a lot of weight could be jettisoned with the first stage separation?  Wouldn't it have eliminated the need for SRBs if you had just a normal liquid first stage.  Probably would have looked wierd since you'd have the orbiter side mounted to a smaller ET sitting on top of a first stage.

1.  See AXAF

2.  No quick answer.  See history of shuttle documents or books.

For number 2 are there any books or documents in particular that focus on this design aspect that you would recommend?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/27/2011 04:19 pm
Were the STA aircraft controlled by something like the Shuttle's DPS? Or were the avionics for them completely different?

Thanks,

The left seat mimic'ed the Shuttle's controls, the right seat was a standard Gulfstream control system (mostly).  The Shuttle side was a simulation tied into the STA's flight control.  So, there were no GPCs on an STA.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/27/2011 04:23 pm
2 questions:

1) Did any payload ever use the full length of the payload bay?

2) Why was parallel staging used?  Wouldn't it have been more efficient to use series staging so the 2nd stage tank would have been smaller/lighter and a lot of weight could be jettisoned with the first stage separation?  Wouldn't it have eliminated the need for SRBs if you had just a normal liquid first stage.  Probably would have looked wierd since you'd have the orbiter side mounted to a smaller ET sitting on top of a first stage.

AXAF isn't a bad answer, but there were still some clearances needed for launch vibrations and thermal expansion.  This amounted to a few inches.  Some of the Spacelab flights, if you include the tunnel to Spacelab (not Hab) and the external pallet (or EDO pallet) could be considered to use the entire payload bay.

A lot of configurations were studied in the late 1960s and early 1970s.  The SSMEs were under development when the configuration was selected, so a lot had to do with SSME capabilities (as then planned), including any air-start capability.  Three SSMEs alone were not powerful enough to get the vehicle off the pad.  So, some time of launch boost was needed.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2011 04:36 pm
AXAF isn't a bad answer, but there were still some clearances needed for launch vibrations and thermal expansion.  This amounted to a few inches.

It was the only one I could give on this forum.

As for clearances, that was already accounted for in the 15' dia and 60" length.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2011 04:39 pm
  Some of the Spacelab flights, if you include the tunnel to Spacelab


The tunnel was only there to move the Spacelab to the back of the payload bay for CG considerations.  It wasn't a requirement of the payload. 
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/27/2011 05:35 pm
  Some of the Spacelab flights, if you include the tunnel to Spacelab


The tunnel was only there to move the Spacelab to the back of the payload bay for CG considerations.  It wasn't a requirement of the payload. 

No tunnel, no Spacelab (the tunnel also included the Spacelab EVA airlock hatch).  *If* the tunnel was chargable to the payload then it was considered payload.  Now, I just have to find out whether it was charged to payload or not.



Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2011 06:16 pm
  Some of the Spacelab flights, if you include the tunnel to Spacelab


The tunnel was only there to move the Spacelab to the back of the payload bay for CG considerations.  It wasn't a requirement of the payload. 

No tunnel, no Spacelab (the tunnel also included the Spacelab EVA airlock hatch).  *If* the tunnel was chargable to the payload then it was considered payload.  Now, I just have to find out whether it was charged to payload or not.

It was charged to the payload.   

My point that Spacelab did not need the whole length of payload bay, which is what the original question was about.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/28/2011 03:17 am
Anyone have any idea of the masses of the SpaceHab RDM and FREESTAR payloads flown on STS-107?
Title: Re: Shuttle Q&A Part 5
Post by: alexw on 09/28/2011 03:55 am
AXAF isn't a bad answer, but there were still some clearances needed for launch vibrations and thermal expansion.  This amounted to a few inches.
It was the only one I could give on this forum.
As for clearances, that was already accounted for in the 15' dia and 60" length.
    Are you suggesting there was a huge DOD payload?
              -Alex
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 09/28/2011 05:07 am
AXAF isn't a bad answer, but there were still some clearances needed for launch vibrations and thermal expansion.  This amounted to a few inches.

As for clearances, that was already accounted for in the 15' dia and 60" length.

Hubble was pretty close as well
Title: Re: Shuttle Q&A Part 5
Post by: brettreds2k on 09/28/2011 08:49 pm
What will NASA do with the Gulfstream Shuttle Training aircraft now? Its not like its fitted to be used as a regular plane especially with one side of the cockpit a replica shuttle cockpit
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/28/2011 09:24 pm
What will NASA do with the Gulfstream Shuttle Training aircraft now? Its not like its fitted to be used as a regular plane especially with one side of the cockpit a replica shuttle cockpit

sent to museums
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 09/29/2011 01:21 am
What will NASA do with the Gulfstream Shuttle Training aircraft now? Its not like its fitted to be used as a regular plane especially with one side of the cockpit a replica shuttle cockpit

sent to museums

One STA has already been sent to the Rick Husband Airport in Amarillo, TX. Don't know where the others are going.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/29/2011 10:11 pm
Anyone have any information on the velocities when the plasma begins to show and fade during entry?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 09/30/2011 07:12 pm
Hi all.

a question about re-entry. I was wondering if for re-entry there was something similar to DOLILU. I mean, before giving the go no go for deorbit burn, is there anybody designing (or optimizing) the re-entry trajectory based on the wind profile at the landing location? Something similar to what the DOLILU group did but done for re-entry rather then for the ascent.

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/01/2011 01:12 am
Hi all.

a question about re-entry. I was wondering if for re-entry there was something similar to DOLILU. I mean, before giving the go no go for deorbit burn, is there anybody designing (or optimizing) the re-entry trajectory based on the wind profile at the landing location? Something similar to what the DOLILU group did but done for re-entry rather then for the ascent.


Thanks

Davide

All computed onboard.  The deorbit burn was the only thing uplinked.  Winds were radioed to the CDR and PLT on the way down, but if autoland had been used, the autoland system would sense what the winds were doing to the vehicle and correct the winds out.  I phrased that the way I did so as to not give the impression that there was a "look ahead" capability.  Guidance that was displayed to the crew used the same algorithms.

The PGSC had a deorbit burn target program included so that *if* no communications were available with the ground, the crew could compute their own burn targets.  That was never used to compute the real targets.

From a terminology standpoint, we would in general break-up entry into deorbit (up to entry interface), entry, TAEM, HAC and then autoland guidance and then touchdown and rollout.

Now, to give the ground credit, the guidance algorithms were also simulated on the ground, so only a runway that had acceptable guidance solutions would be chosen.  So while very little was uplinked, the ground always made sure we would reach the runway with the actual conditions.


Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/01/2011 01:18 am
Anyone have any information on the velocities when the plasma begins to show and fade during entry?

Depened upon the entry, but somewhere around the first roll reversal.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/02/2011 11:38 pm
How is the maneuver to entry attitude accomplished? Through ITEM 27 on MM303?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/03/2011 02:57 am
How is the maneuver to entry attitude accomplished? Through ITEM 27 on MM303?

Yes.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 10/03/2011 07:27 pm
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/03/2011 09:56 pm
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2011 01:53 am
On page 3-14 of the Entry FDF it mentions the De-orbit burn cue card. Where can one find this cue card?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/04/2011 02:35 am
On page 3-14 of the Entry FDF it mentions the De-orbit burn cue card. Where can one find this cue card?

Page CC 8-8.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/04/2011 03:31 am
On page 3-14 of the Entry FDF it mentions the De-orbit burn cue card. Where can one find this cue card?

Page CC 8-8.
Thanks. Another that has had me looking for ages now: The FDF/page that lists the camera pan/tilt angles used for elevon viewing during FCS C/O.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 10/04/2011 10:37 am
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy

Rgr, thanks Andy!!!
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 10/05/2011 01:17 am
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy

How accurate was the pointing capability of the Shuttle, and how frequent were the thruster firings to accomplish it?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/05/2011 01:44 am
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy

How accurate was the pointing capability of the Shuttle, and how frequent were the thruster firings to accomplish it?

There's really multiple parts to the first question. First, how accurate was the shuttle's attitude determination? The shuttle used IMUs to maintain its attitude reference, and the IMU platforms slowly drifted over time. Flight Rules required the IMU misalignment be maintained <0.5 deg for safe entry, so to protect for extended loss of comm, an IMU alignment would be performed if the misalignment exceeded 0.25 deg. This was done using the star trackers. The star trackers were accurate within 1-2 hundredths of a degree. The original KT-70 IMUs required alignment about every 12 hours. The HAINS IMUs used at the end of the program could go 48 hours between alignments, and sometimes as much as 96.

Second, how precisely could the shuttle hold attitude? This was a function of the attitude deadband setting in the digital autopilot (DAP). Minimum attitude deadband was 0.033 deg using the vernier RCS thrusters. 0.5 deg for primary RCS, I think.

Obviously there is no simple answer to your second question; thruster firing frequency depended on the deadband width, which thrusters were used, and the environmental torques acting on the vehicle (which in turn were a function of attitude, mass properties, and altitude).
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/05/2011 01:29 pm
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy

How accurate was the pointing capability of the Shuttle, and how frequent were the thruster firings to accomplish it?

There's really multiple parts to the first question. First, how accurate was the shuttle's attitude determination? The shuttle used IMUs to maintain its attitude reference, and the IMU platforms slowly drifted over time. Flight Rules required the IMU misalignment be maintained <0.5 deg for safe entry, so to protect for extended loss of comm, an IMU alignment would be performed if the misalignment exceeded 0.25 deg. This was done using the star trackers. The star trackers were accurate within 1-2 hundredths of a degree. The original KT-70 IMUs required alignment about every 12 hours. The HAINS IMUs used at the end of the program could go 48 hours between alignments, and sometimes as much as 96.

Second, how precisely could the shuttle hold attitude? This was a function of the attitude deadband setting in the digital autopilot (DAP). Minimum attitude deadband was 0.033 deg using the vernier RCS thrusters. 0.5 deg for primary RCS, I think.

Obviously there is no simple answer to your second question; thruster firing frequency depended on the deadband width, which thrusters were used, and the environmental torques acting on the vehicle (which in turn were a function of attitude, mass properties, and altitude).

Excellent answer - the only thing I'd add is that if you made the deadband tighter, you would use more propellant.  So, there was a tradeoff for keeping the deadband too tight.  Also if you were running microgravity experiments, you might want a wider deadband to minimize the microgravity-disturbing jet firings.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 10/05/2011 03:07 pm
Quick question re: orbiter attitude, was the gravity gradient attitude SOP for all Spacelab/Spacehab research flights?

No, Spacelabs like Spacelab 2 were astronomy releated and had strict pointing requirements.  Usually microgravity experiments were gravity gradient.  Thermal requirements could have also been a reason for not using gravity gradient.

Andy

How accurate was the pointing capability of the Shuttle, and how frequent were the thruster firings to accomplish it?

There's really multiple parts to the first question. First, how accurate was the shuttle's attitude determination? The shuttle used IMUs to maintain its attitude reference, and the IMU platforms slowly drifted over time. Flight Rules required the IMU misalignment be maintained <0.5 deg for safe entry, so to protect for extended loss of comm, an IMU alignment would be performed if the misalignment exceeded 0.25 deg. This was done using the star trackers. The star trackers were accurate within 1-2 hundredths of a degree. The original KT-70 IMUs required alignment about every 12 hours. The HAINS IMUs used at the end of the program could go 48 hours between alignments, and sometimes as much as 96.

Second, how precisely could the shuttle hold attitude? This was a function of the attitude deadband setting in the digital autopilot (DAP). Minimum attitude deadband was 0.033 deg using the vernier RCS thrusters. 0.5 deg for primary RCS, I think.

Obviously there is no simple answer to your second question; thruster firing frequency depended on the deadband width, which thrusters were used, and the environmental torques acting on the vehicle (which in turn were a function of attitude, mass properties, and altitude).

Excellent answer - the only thing I'd add is that if you made the deadband tighter, you would use more propellant.  So, there was a tradeoff for keeping the deadband too tight.  Also if you were running microgravity experiments, you might want a wider deadband to minimize the microgravity-disturbing jet firings.

Andy

I guess that's one of the things I was getting at - Station uses CMGs to both keep precise pointing as well as microgravity. Shuttle doesn't have those, so could you do both astronomy-related experiments and microgravity work at the same time? Or would all the microgravity stuff have to wait until periods of free drift?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/05/2011 04:17 pm


I guess that's one of the things I was getting at - Station uses CMGs to both keep precise pointing as well as microgravity. Shuttle doesn't have those, so could you do both astronomy-related experiments and microgravity work at the same time? Or would all the microgravity stuff have to wait until periods of free drift?


It depends, but astronomy-related experiments and microgravity work were usually not manifested on the same mission, however, there were exceptions like STS-9/Spacelab-1.  The shuttle used gravity gradient for microgravity missions.  Astronomy payloads had their pointing systems so the orbiter didn't require to have tight deadbands.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 10/18/2011 02:27 am
Does anyone notice a difference in the appearance of the plume of STS 129's launch.
In this view from the VAB roof, it seems that the shuttles exhaust sort of curves to the north before straightening out (26 to 30 seconds into the video).
Anyone know if the wind was blowing from the south?

See clip:  http://www.youtube.com/watch?v=3siNkZu7VNE&feature=related
Title: Re: Shuttle Q&A Part 5
Post by: DDG40 on 10/18/2011 02:44 am
Does anyone notice a difference in the appearance of the plume of STS 129's launch.
In this view from the VAB roof, it seems that the shuttles exhaust sort of curves to the north before straightening out (26 to 30 seconds into the video).
Anyone know if the wind was blowing from the south?

See clip:  http://www.youtube.com/watch?v=3siNkZu7VNE&feature=related

Per weather undergrund winds were 12 mph NNW at launch time. I remember there was a low cloud ceiling the morning of the launch, But it cleared up around noon.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/18/2011 11:13 pm
Let me see if I can understand your question a bit better.  First, the tail of the orbiter faced south.  At the roll manuever, the orbiter turned at least 90 degrees (to the east in other words) and for ISS continued another approximately 21 degrees (total roll of 111 degrees apprx).  In other words the roll maneuver put the vehicle on a ENE direction.

Now given that, which direction and which plume did you mean (SSME or SRB)?  The SSME plume went south (mostly) and SRB plume went north (mostly).  If the ground wind was from the east, then the SSME plume would head south out of the flame duct and then the east wind would blow it towards the west.

The photographers who setup remote cameras would try to take into account which way the wind was predicted to blow when setting up remote cameras.  The cameras would have to be setup about a day before launch, so figuring out which way the wind *would* blow was important. 

Now if you are talking higher up during ascent, then that would be upper level winds (or winds aloft) and that would be a completely different subject.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 10/19/2011 01:52 am
Andy, I was referring to the plume created by the SRB's.
If you look at the video between 25 and 30 seconds in, you will see that the plume is not vertical as it appears in all othe shuttle launches...it actually curves to the north (left) and then straightens out.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 10/19/2011 02:09 am
Andy, I was referring to the plume created by the SRB's.
If you look at the video between 25 and 30 seconds in, you will see that the plume is not vertical as it appears in all othe shuttle launches...it actually curves to the north (left) and then straightens out.


That's the roll program. You're wrong, it happens every launch. The camera angle is not always optimal for seeing the effect of the roll on the plume.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/19/2011 02:19 am
Yes, it's exactly what Jorge said.  The SRB and SSME nozzles gimbaled to allow the vehicle to steer.  Those were the only steering mechanisms during ascent.  So, if a change in the attitude of the vehicle was needed, the GPCs would command the proper nozzle movement to make the desired attitude change.  As you might expect the roll maneuver caused a significant attitude change.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 10/19/2011 02:59 pm
Where exactly does the ET bipod attach the orbiter? The aft attachments are with the fuel and oxidizer feedlines, which have umbilical doors. Where was the forward one, and how was it protected thermally? I don't remember ever seeing another door near the nose gear.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/19/2011 03:25 pm
Where exactly does the ET bipod attach the orbiter? The aft attachments are with the fuel and oxidizer feedlines, which have umbilical doors. Where was the forward one, and how was it protected thermally? I don't remember ever seeing another door near the nose gear.

It is below the "skinline" of the TPS.  It is just a "hole" for a stud to pass through.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/21/2011 04:08 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 10/21/2011 04:19 pm
Where exactly does the ET bipod attach the orbiter? The aft attachments are with the fuel and oxidizer feedlines, which have umbilical doors. Where was the forward one, and how was it protected thermally? I don't remember ever seeing another door near the nose gear.

It is below the "skinline" of the TPS.  It is just a "hole" for a stud to pass through.

The arrowhead is also made of RCC
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 10/21/2011 04:19 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?

If I understand your question correctly, it is essentially 180 degrees.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 10/21/2011 04:28 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?

I may not be clear on exactly what you are asking but a quick look in the KU Ops Workbook shows 113 degrees to the deployed state.  Should also be a diagram in the SCOM (Comm Section) if you don't have a copy of that workbook.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/21/2011 04:33 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?

I may not be clear on exactly what you are asking but a quick look in the KU Ops Workbook shows 113 degrees to the deployed state.  Should also be a diagram in the SCOM if you don't have a copy of that workbook

Mark Kirkman

Not sure where I grabbed this from, but its probably the diagram referred to.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/21/2011 04:35 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?

I may not be clear on exactly what you are asking but a quick look in the KU Ops Workbook shows 113 degrees to the deployed state.  Should also be a diagram in the SCOM if you don't have a copy of that workbook

Mark Kirkman
Yes, I have seen that figure but it is measured from alpha gimbal-stowed to alpha gimbal-deployed, not around the hinge itself, which is what I'm looking for.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 10/25/2011 10:11 pm
Does anyone know how many degrees the orbiter Ku band DA rotates around its hinge attachment to the payload bay to the deployed position?

I may not be clear on exactly what you are asking but a quick look in the KU Ops Workbook shows 113 degrees to the deployed state.  Should also be a diagram in the SCOM if you don't have a copy of that workbook

Mark Kirkman
Yes, I have seen that figure but it is measured from alpha gimbal-stowed to alpha gimbal-deployed, not around the hinge itself, which is what I'm looking for.

Is this any help?


"a/b Gimbal
The beta gimbal is mounted on the alpha gimbal housing, which, in turn, is mounted on the frame into which the DEA (Deployed Electronics Assembly) fits. Both dc gimbal motors are identical but the beta, or inner, gimbal is limited in its motion from -85° to +75°. The alpha, or outer, gimbal motion is from -206° to +154°. The antenna coordinate system 0,0 reference is up the minus Z body axis. Two drive signals (1 and 2) are provided from the gimbal servodrive
circuits in the Interface and Control Unit and provide for positive or negative motion about the gimbal axis. An encoder disc is mounted on each motor shaft and provides motor position information. The digital output (0.088° resolution) resets a storage buffer in the Interface and Control Unit every time a Master Index Pulse (MIP) is encountered. There is one MIP on each gimbal encoder."


I found it in the INCO Sys Briefs.  My only other suggestion would be to ask someone to look in the SSSH (space shuttle systems handbook) for you - I'm almost certain there is a diagram of it in there.  I only have a paper copy of the SSSH and that is at home (a place I wont see for at least 2 or 3 more weeks).  However, anyone with internal web access should be able to look at the electronic version.

I'm sorry I can't be much more help but I am woefully ignorant of the comm system details - I was always content with knowing "panel command" when it came to shuttle comm.  ;)

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 11/02/2011 02:48 pm
Why is Atlantis stacked in this shot during 1987 without SSME's?

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-27/html/s87-31470.html

Quote
(13 March 1987) --- The Space Shuttle Atlantis is transferred from the giant Vehicle Assembly Building's high bay 1 to high bay 3 as preparations for de-stacking of the orbiter begin. The orbited will be separated from its solid rocket boosters and external fuel tank before being taken to the Orbiter Processing Facility. Once there, it will begin an extended processing flow to undergo return-to-flight modifications and other preparations for the STS-27 mission next year.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 11/02/2011 02:58 pm
Why is Atlantis stacked in this shot during 1987 without SSME's?

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-27/html/s87-31470.html

Quote
(13 March 1987) --- The Space Shuttle Atlantis is transferred from the giant Vehicle Assembly Building's high bay 1 to high bay 3 as preparations for de-stacking of the orbiter begin. The orbited will be separated from its solid rocket boosters and external fuel tank before being taken to the Orbiter Processing Facility. Once there, it will begin an extended processing flow to undergo return-to-flight modifications and other preparations for the STS-27 mission next year.
This was during the stand down after Challenger. They had stacked the orbiter and rolled it out to 39B to fit check the new weather protection system that had been installed and do some tests of the emergency egress procedures.
Title: Re: Shuttle Q&A Part 5
Post by: TFGQ on 11/03/2011 05:37 pm
got a picture of it at pad 39-B?
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 11/03/2011 06:51 pm
got a picture of it at pad 39-B?

THere is this one, but due to the angle cannot really see the lack of SSME's:

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-27/html/s86-38627.html

Quote
The Space Shuttle Atlantis is rolled out to Launch Pad 39-B in the early morning of Oct. 9, 1986. Atlantis is scheduled to remain at Pad B for seven weeks where it will support checkout of new weather protection structures, a variety of special measurements, launch team proficiency exercises and emergency egress simulations. The 4.2 mile journey from the Vehicle Assembly Building to the launch pad is the first for the shuttle fleet since the Space Shuttle Challenger accident in January of this year.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 11/05/2011 03:00 pm
Folks, I'm looking for the start and stop times for STS-57's single EVA.  I know the total elapsed time was 5 hours, 50 minutes, but I cannot for the life of me find when it started or stopped (GMT or MET).  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 11/05/2011 08:58 pm
Folks, I'm looking for the start and stop times for STS-57's single EVA.  I know the total elapsed time was 5 hours, 50 minutes, but I cannot for the life of me find when it started or stopped (GMT or MET).  Thanks!

Started EVA at 3:23:59:51 MET
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 11/05/2011 10:42 pm
Folks, I'm looking for the start and stop times for STS-57's single EVA.  I know the total elapsed time was 5 hours, 50 minutes, but I cannot for the life of me find when it started or stopped (GMT or MET).  Thanks!

Started EVA at 3:23:59:51 MET

Thanks!!!
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/05/2011 11:16 pm
Why is Atlantis stacked in this shot during 1987 without SSME's?

http://spaceflight.nasa.gov/gallery/images/shuttle/sts-27/html/s87-31470.html

Quote
(13 March 1987) --- The Space Shuttle Atlantis is transferred from the giant Vehicle Assembly Building's high bay 1 to high bay 3 as preparations for de-stacking of the orbiter begin. The orbited will be separated from its solid rocket boosters and external fuel tank before being taken to the Orbiter Processing Facility. Once there, it will begin an extended processing flow to undergo return-to-flight modifications and other preparations for the STS-27 mission next year.

also, i remember there was a "discussion" about if the sharp turn out to 39B might have caused the stack to shift slightly and open up the o-rings on 51-L....i think this was more "what-if" but i thought i was worth mentioning.....
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 11/16/2011 09:45 pm
Hi all.

this kind I have kind of "silly" question. I find quite curiuos the software for the shuttle was written in a language called HAL/S running on IBM computers. As it's known HAL is the name of the computer on 2001: A Space Odyssey and it's an implict reference to IBM (every letter in HAL is the letter soon after each letter in IBM).

I'd like to know is there is any particular reason for which language for the shuttle software was named HAL.

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 11/16/2011 10:16 pm
Hi all.

this kind I have kind of "silly" question. I find quite curiuos the software for the shuttle was written in a language called HAL/S running on IBM computers. As it's known HAL is the name of the computer on 2001: A Space Odyssey and it's an implict reference to IBM (every letter in HAL is the letter soon after each letter in IBM).

I'd like to know is there is any particular reason for which language for the shuttle software was named HAL.

It was named as a tribute to Dr. J Halcombe "Hal" Laning.

Advanced Vehicle Automation and Computers
Aboard the Shuttle

Dennis Jenkins

"A variation of a the HAL language, called HAL/S, was created specifically for the Shuttle project by Intermetrics, Incorporated, a Massachusetts company founded in 1969 by five M.I.T. programmers who had worked on developing software for Apollo. The name was a tribute to computer pioneer J. Halcombe Laning, who had invented an algebraic compiler in 1952 that ran on the M.I.T. Whirlwind—the first real-rime computer. The ‘S’ appended to the name has been variously explained as meaning “subset” (of what is unclear) or "Shuttle," and it is left to the reader to determine which is most fitting."

http://history.nasa.gov/sts1/pages/computer.html
Title: Re: Shuttle Q&A Part 5
Post by: MarsMethanogen on 11/16/2011 11:01 pm
Hi all.

this kind I have kind of "silly" question. I find quite curiuos the software for the shuttle was written in a language called HAL/S running on IBM computers. As it's known HAL is the name of the computer on 2001: A Space Odyssey and it's an implict reference to IBM (every letter in HAL is the letter soon after each letter in IBM).

I'd like to know is there is any particular reason for which language for the shuttle software was named HAL.

Thanks very much

Davide

Regarding your "implicit reference to IBM" statement.  Quickly off-topic, but both Kubrick and Clarke, before they passed on, said that in creating the HAL acronym, such a relationship never occurred to them, and that it was purely coincidental.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/17/2011 01:30 am
Hi all.

this kind I have kind of "silly" question. I find quite curiuos the software for the shuttle was written in a language called HAL/S running on IBM computers. As it's known HAL is the name of the computer on 2001: A Space Odyssey and it's an implict reference to IBM (every letter in HAL is the letter soon after each letter in IBM).

I'd like to know is there is any particular reason for which language for the shuttle software was named HAL.

Thanks very much

Davide

Regarding your "implicit reference to IBM" statement.  Quickly off-topic, but both Kubrick and Clarke, before they passed on, said that in creating the HAL acronym, such a relationship never occurred to them, and that it was purely coincidental.

Clarke even joked about it in the 2010 novel.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/17/2011 01:37 am
Hi all.

this kind I have kind of "silly" question. I find quite curiuos the software for the shuttle was written in a language called HAL/S running on IBM computers. As it's known HAL is the name of the computer on 2001: A Space Odyssey and it's an implict reference to IBM (every letter in HAL is the letter soon after each letter in IBM).

I'd like to know is there is any particular reason for which language for the shuttle software was named HAL.

Thanks very much

Davide

What AnalogMan wrote is accurate.  The language was named in the early 1970s timeframe.  The name fit very well in so many ways.

What you have to remember is at the time, the languages were named Cobol and Fortran and Pascal.  The big deal with HAL was that it was high order but still allowed for easy bit-manipulation.  So, that it started with high-order (H) made sense.  That there was still assembly language (AL) is a reference to the bit-manipulations available.  I guess is could have been HOAL but HOAL wouldn't have been asked about 40 years later.

The funny thing is that within the program, the reasons for HAL being named HAL was often different depending upon who you asked.

It may have been a case of the acronym coming before the definition, but I think the reasoning for the name has been lost to history.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/19/2011 03:09 am
So here are a couple of questions for all you rocketeers out there:

1/  In the recent IMAX movie "Hubble 3D", they show several excellent sequences of the Shuttle launching.  However, I noticed that the water bags across the SRB flame holes were not there in one of these shots.  I thought these were installed on every launch after STS-1.  So what's the story? 

2/  The Shuttle's SRBs/SRMs were modified shortly after STS-1 (and before STS-51L) to reduce weight and improve performance.  What mods were made?  Does anyone have references? 

v/r,
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/19/2011 05:13 am
So here are a couple of questions for all you rocketeers out there:


2/  The Shuttle's SRBs/SRMs were shortly after STS-1 (and before STS-51L) to reduce weight and improve performance.  What mods were made?  Does anyone have references? 

v/r,
F=ma


Did you mean the External Tank or the SRBs for weight reduction?  The standard ET was indeed reduced to the lightweight tank (and then the superlightweight tank).  Each pound of Tank reduction was roughly equal to a pound more that could be carried into orbit.

The SRB equation is not quite as good since the SRBs only made the first 2 minutes and 4 seconds of the journey.  So a pound of SRB weight reduction resulted in a fraction of a pound into orbit.

I know some instrumentation was removed but I'd have to defer to the KSC folks for any real SRB weight reductions after STS-1.  Considering the SRMs were reusable, that would mean the pre-existing cases would have to be modified for any weight reduction (or the old cases tossed) or the forward cone or nozzle assembly/aft weights were reduced.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/19/2011 01:33 pm
I did mean the early, pre-Challenger SRB mods.  I seem to recall reading somewhere that these 2nd-gen shell walls were ~0.45 inches thick, vs the original 0.50 inches. 

From http://choo.fis.utoronto.ca/FIS/Courses/LIS2102/DM.case.html:
"During 1983, the SRBs were modified to use thinner walls, narrower nozzles, and more powerful fuel..."

 I do realize that the "gear ratio" for the SRBs is ~10:1, where a 10 lb reduction in the SRBs => 1 lb to LEO.  Obviously, the Orbiter and ET have better gear ratios (~1:1), but you takes your performance gains wherever you can, I guess...

Of course, if you have any documentation on the original Standard-Weight Tank, I'd also like to see that!  Is there a Systems Definition Handbook for the SWT out there, somewhere?

Cheers,
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 11/19/2011 02:27 pm
I did mean the early, pre-Challenger SRB mods.  I seem to recall reading somewhere that these 2nd-gen shell walls were ~0.45 inches thick, vs the original 0.50 inches. 

From http://choo.fis.utoronto.ca/FIS/Courses/LIS2102/DM.case.html (http://choo.fis.utoronto.ca/FIS/Courses/LIS2102/DM.case.html):
During 1983, the SRBs were modified to use thinner walls, narrower nozzles, and more powerful fuel..."

There is this note from the ATK SRB Bible regarding wall thicknesses (on L2)

Cylinders are classified according to the membrane thickness requirements:

• Lightweight cylinder thickness are 0.450 to 0.499 in.
• Standard weight cylinder thickness are 0.477 to 0.526 in.
• Early SRM configuration used standard weight cylinders only
• HPM design increased pressure (950 to 1,000 psia) and reduced thickness
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/20/2011 07:01 pm
During STS-135, GLS and OTC were both female...however, in years past, they voices always sounded the same to me, so I thought it was one person....However, for 135, it was obviously two different females.   Anyone know who CGLS and the OTC were for STS-135.  I am assuming it was Roberta Wyrick as OTC.

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/20/2011 07:51 pm
During STS-135, GLS and OTC were both female...however, in years past, they voices always sounded the same to me, so I thought it was one person....However, for 135, it was obviously two different females.   Anyone know who CGLS and the OTC were for STS-135.  I am assuming it was Roberta Wyrick as OTC.
Different positions, never one person.  Ms. Wyrick was OTC and Janine Pape was GLS; both were noted in the launch day thread.

(And elsewhere (http://www.cfnews13.com/article/news/2011/july/276612/Atlantis-gets-special-sendoff-from-United-Space-Alliance).)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 11/20/2011 10:12 pm
Hi all.

Question on the avionics system. I understand the way in which the redundant set works, however I don't understand if in case of need, both ascent and reentry could be flown with just one GPC in GNC mode running PASS.

Obviously with just on GPC you loose all the FO/FS condition, but would it be theoretically possible flying with just one GPCs? My guess is no, is not possible. Since you should have at least two GPCs for commanding two different strings, otherwise maneuvering with the RCS wouldn't be possible (for example).

which are your thoughts?

thanks

Davide


Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/20/2011 10:16 pm
Hi all.

Question on the avionics system. I understand the way in which the redundant set works, however I don't understand if in case of need, both ascent and reentry could be flown with just one GPC in GNC mode running PASS.

Obviously with just on GPC you loose all the FO/FS condition, but would it be theoretically possible flying with just one GPCs? My guess is no, is not possible. Since you should have at least two GPCs for commanding two different strings, otherwise maneuvering with the RCS wouldn't be possible (for example).

which are your thoughts?

thanks

Davide




It is possible for one PASS GPC to control all four strings. Not particularly wise, but it is possible.
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/21/2011 02:34 pm
Hi everyone, quick question regarding SSMEs - I've read that they are referred to from an engineering standpoint mostly as RS-25 engines, but that RS-24 is an alternate designation - is this correct, and, if so, what is the difference between the two models, please?

In addition, I'm aware that the last half or so of the programme used Block II engines, but were the preceding models all Block I standard or were there other variants thereof?

Finally, I've seen the SLS engines being referred to as RS-25D/E - does this mean that they are RS-25D and RS-25E and there is a distinction between the two, or simply that the SLS engines are actually designated as D/E variants?

Many thanks in advance!
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 11/21/2011 02:44 pm
Hi everyone, quick question regarding SSMEs - I've read that they are referred to from an engineering standpoint mostly as RS-25 engines, but that RS-24 is an alternate designation - is this correct, and, if so, what is the difference between the two models, please?

In addition, I'm aware that the last half or so of the programme used Block II engines, but were the preceding models all Block I standard or were there other variants thereof?

Finally, I've seen the SLS engines being referred to as RS-25D/E - does this mean that they are RS-25D and RS-25E and there is a distinction between the two, or simply that the SLS engines are actually designated as D/E variants?

Many thanks in advance!

I think the RS-25E is the expendable version. Basically less rugged turbopump design as no need for reuse. RS-25D is what they have sitting in a building now at KSC since they've gutted the Orbiter's MPS for SLS. There are something like 15 of them IIRC.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/21/2011 03:55 pm
Here's a good reference for the other half of your question...

http://history.msfc.nasa.gov/shuttle/documents/space_shuttle_main_engine_30_years_innovation.pdf


Basically, Original --> Phase II --> Block I --> Block IIA --> Block II

My memory is that when possible we flew a single SSME of the new type with two of the earlier type and basically phased in each upgrade in case there was a surprise.  One engine out was survivable (assuming it didn't take another engine with it), two engines out was possibly survivable.  So, there was a big advantage to trying a change out with a single engine first.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/21/2011 04:05 pm
Hi all.

Question on the avionics system. I understand the way in which the redundant set works, however I don't understand if in case of need, both ascent and reentry could be flown with just one GPC in GNC mode running PASS.

Obviously with just on GPC you loose all the FO/FS condition, but would it be theoretically possible flying with just one GPCs? My guess is no, is not possible. Since you should have at least two GPCs for commanding two different strings, otherwise maneuvering with the RCS wouldn't be possible (for example).

which are your thoughts?

thanks

Davide




Not wise but certainly do-able.  When we were testing application software (such as ascent guidance), the majority of all the FEID testing (where the flight software was tested and verified) was done in single string (which is what flying with one GPC is called).  From an applicaion program standpoint, the system didn't know the difference between one GPC and four GPCs flying the system.  All strings are assigned to the single GPC with the NBAT, so all databus strings are still being commanded - just by one GPC.  All of the GPCs listened to all of the busses, so that didn't change no matter how many GPCs were in the set.

Now that's great for on the ground application testing, but I wouldn't bet my life on a single GPC working through ascent and entry over 30 years -- even the AP-101S.  The groundrules were basically to fly dynamic flight with four GPCs and then if you lost one you were OK.  If you had two GPCs left and then another failed, you probably were on the BFS at that point because you might not know which of the two that failed was the good one (both would likely indicate the other was bad).

Bottom line - a very flexible O/S and redunancy management system did allow for single string ops that were pretty much the same as any other combo of GPCs, as long as there were no failures that would knock-out that remaining GPC.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/21/2011 04:28 pm
Brilliant, thanks very much! Two things I'm still unsure about - what is an RS-24, and what differentiates an RS-25D from a Block II SSME? Cheers!
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/21/2011 04:50 pm
Here's the best reference I could find on what the engine designations mean.  But basically an RS-25D = SSME (Block II or otherwise)

http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=space&id=news/asd/2011/10/24/06.xml

The RS-24 designation is a bit confusing to me.  We just called them SSMEs in my part of the program and in the official documentation (along with Block II or whatever mod level we were at).  So, the terms RS-24 and RS-25 were not used.  We had SSMEs.

I can find no reasonably official reference to an SSME being called RS-24.  Rocketdyne refers to the SSME as an RS-25D.
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/21/2011 05:08 pm
Cheers, much appreciated! :-)
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/21/2011 05:19 pm
On a not-totally-unrelated note, I'm slightly confused by this chart from P&W: http://collectspace.com/review/sts133_ssmechart-lg.jpg - weirdly, engines 2012, 2018 and 2109 were all used on '25', then were flown again on 27 and 32? Unless I'm missing something, isn't that impossible? :-S
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/21/2011 05:25 pm
Remember KSC had a different numbering scheme since they didn't go by the ##L designation.  So KSC used just numbers for the flights up until 51L.  So, the 25 you see isn't for 51L.

After return to flight, the R was put after the number on the KSC numbering to designate a flight number that had already been used prior to 51L.  After that KSC and the rest of the program all used the same numbering system for flights.

Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/21/2011 05:28 pm
Ah, fair enough, thanks - any idea which of them is 51L by any chance?
Title: Re: Shuttle Q&A Part 5
Post by: anik on 11/21/2011 05:45 pm
any idea which of them is 51L by any chance?

33.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/21/2011 05:58 pm
Ah, fair enough, thanks - any idea which of them is 51L by any chance?

Dennis Jenkins has an excellent table on page 300 of the 1997 edition of "Space Shuttle - The History of Developing the NSTS".

The 25th Space Shuttle flight was STS-33 at KSC and STS-51L elsewhere

The 18th Space Shuttle flight was STS-25 at KSC and STS-51G elsewhere

Andy
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 11/21/2011 08:57 pm

RS-25D is what they have sitting in a building now at KSC since they've gutted the Orbiter's MPS for SLS. There are something like 15 of them IIRC.

Worth noting that they have not yet started gutting Endeavour's and Atlantis's MPSs.

Also, yes, there are 15 SSMEs sitting at KSC now.
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/22/2011 07:00 am
Also, yes, there are 15 SSMEs sitting at KSC now.

Which are those? I can count only 14 on P&W's chart?
http://collectspace.com/review/sts133_ssmechart-lg.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Galactic Penguin SST on 11/22/2011 07:29 am
Also, yes, there are 15 SSMEs sitting at KSC now.

Which are those? I can count only 14 on P&W's chart?
http://collectspace.com/review/sts133_ssmechart-lg.jpg

I believe P&W produced a spare SSME (s/n 2062) some time around 2009, which was never intended to be used on the last shuttle missions.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 11/22/2011 11:25 am
Also, yes, there are 15 SSMEs sitting at KSC now.

Which are those? I can count only 14 on P&W's chart?
http://collectspace.com/review/sts133_ssmechart-lg.jpg (http://collectspace.com/review/sts133_ssmechart-lg.jpg)

I believe P&W produced a spare SSME (s/n 2062) some time around 2009, which was never intended to be used on the last shuttle missions.

That agrees with my own notes.   Last info I had was from a long-term planning document from April 2009 which noted that SSME 2062 was due to be tested Jan 2010.  I never heard if the test was completed.
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/22/2011 03:35 pm
...well, ladies and gentlemen, with many thanks, here's my updated version of the P&W chart, free for anyone to use! Thanks again for the help! :-)

http://commons.wikimedia.org/wiki/File:SSME_Flight_History.png
Title: Re: Shuttle Q&A Part 5
Post by: Wepush on 11/22/2011 03:57 pm
Engine 2062 has never been tested.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/22/2011 05:42 pm
There were a lot of skills retention exercises going on towards the end of the program.  In other words, if you don't use the skills, you lose the skills.  I suspect that building 2062 was one of those exercises.

The parts of ET-139, ET-140 and ET-141 that were made was the result of skills retention.  Nearly every project within the program had something of that nature going on.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/23/2011 12:52 pm
By the way folks, further to my earlier question about RS-24/25, does anyone know what exactly an RS-24 is? Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: kch on 11/23/2011 01:11 pm
By the way folks, further to my earlier question about RS-24/25, does anyone know what exactly an RS-24 is? Thanks.

Two (rather different) possibilities:

http://en.wikipedia.org/wiki/RS-24

http://en.wikipedia.org/wiki/Space_Shuttle_main_engine

:D
Title: Re: Shuttle Q&A Part 5
Post by: arkaska on 11/23/2011 01:17 pm

Two (rather different) possibilities:

http://en.wikipedia.org/wiki/RS-24

http://en.wikipedia.org/wiki/Space_Shuttle_main_engine

:D

It is for Wikipedia that Colds7ream needs the info so I don't think that's a good source ;)
Title: Re: Shuttle Q&A Part 5
Post by: Colds7ream on 11/23/2011 01:28 pm
It is for Wikipedia that Colds7ream needs the info so I don't think that's a good source ;)

Exactly! I can't find any other reference to RS-24 as an SSME designation, so I'm fairly sure its erroneous, wanting to check. :-)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/27/2011 09:39 pm
I was watching the STS-39 post-flight presentation video and noticed that a white rod hanging down from the port PLBD. Any idea what it might have been?
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 11/29/2011 12:34 am
What's the long-term plan for archival of all the Shuttle program electronic documentation and software? Is it going to be accessible for FOIA requests, etc. in the future? (For the stuff that isn't ITAR'd, of course.) Is the archival plan different for different centers/projects/offices/contracts, or is there going to be one massive set of tapes labeled "Shuttle" somewhere?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/29/2011 01:12 am
What's the long-term plan for archival of all the Shuttle program electronic documentation and software? Is it going to be accessible for FOIA requests, etc. in the future? (For the stuff that isn't ITAR'd, of course.) Is the archival plan different for different centers/projects/offices/contracts, or is there going to be one massive set of tapes labeled "Shuttle" somewhere?

Any shuttle document that fits the definition of a "federal record" will go to the National Archives. It will all be electronic; any paper-only documents will be scanned first.

There was a parallel "knowledge capture" exercise, on an organization-by-organization basis, where key documents were archived locally along with lessons to help educate the workforce on future programs.

Beyond that, what got archived was an organization-by-organization decision. Many organizations are saving the last full backups from internal servers, but that doesn't necessarily mean the data will be easily accessible.

Archiving doesn't change FOIA status; any document that was exempt from FOIA (e.g. due to ITAR or other export-control laws) during the shuttle program will remain exempt.
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 11/29/2011 12:39 pm
Hi,

This morning's topic is AHMS!

Is there any reason there is (was?) no shaft-speed sensor on the HPOTP? Did searching the wider frequency-band (as compared to the HPFTP) work out well? {Did it ever workout better? The wider search conceivably could...}

Did the flight version of the AHMS hardware have the two PowerPC chips for the System Control/Linear Engine Model? Or was that only on the ground version?

Will any of the AHMS work (or Phase II stuff that was discussed, such as engine throttling in the face of unexpected vibration) find its way into any current/near-current rockets?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: vsrinivas on 11/29/2011 02:36 pm
Also slightly related, was the OPAD system ever flown?
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/29/2011 07:56 pm
HELP!!

There is either a post launch or post landing news conference in which Mike Moses comments that "it is easy to go high and easy to go fast, it is hard to go high AND fast". 

He makes this comment when answering a question about how private industry will look to experienced NASA engineers to solve the commercial human spaceflight puzzle. 

Does anyone know which news conference that was.  Like I said, it was either a post launch or post landing...I just don't know which and I don't know what mission it was on.

Any help would be GREATLY appreciated!!!!

Thanks!!!

Jeff
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/29/2011 08:03 pm
What's the long-term plan for archival of all the Shuttle program electronic documentation and software? Is it going to be accessible for FOIA requests, etc. in the future? (For the stuff that isn't ITAR'd, of course.) Is the archival plan different for different centers/projects/offices/contracts, or is there going to be one massive set of tapes labeled "Shuttle" somewhere?

Still being archived last I heard.  But the knowledge capture is obviously long done. 

Bottom line is any government record will be officially archived.  Delivered software was a government record.  Non-government records were not saved.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 11/29/2011 08:06 pm
Also slightly related, was the OPAD system ever flown?

Not to my knowledge.  Mounting something on the nozzle would have had a lot of reviews.  You would have needed a long certification period to prove that the system wouldn't shutdown an engine accidentally.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 11/29/2011 09:07 pm
HELP!!

There is either a post launch or post landing news conference in which Mike Moses comments that "it is easy to go high and easy to go fast, it is hard to go high AND fast". 

He makes this comment when answering a question about how private industry will look to experienced NASA engineers to solve the commercial human spaceflight puzzle. 

Does anyone know which news conference that was.  Like I said, it was either a post launch or post landing...I just don't know which and I don't know what mission it was on.

Any help would be GREATLY appreciated!!!!

Thanks!!!

Jeff

The most I can help you with is that it was a conference I was at personally. I'm thinking it was an STS-131 or STS-132 presser.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/29/2011 10:44 pm
Thanks Chris....you think it was post launch or post landing?
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 11/29/2011 11:40 pm
I found it!

STS-130 Post Launch Presser at 33:17

thanks everyone!
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 12/01/2011 03:30 am
It seems every Shuttle maneuver resulted in "good burn, no trim required"...at least over the last 20-plus missions.  Were there burns which weren't good and did require trim?  If so, how was this done?  What would cause a deficient burn?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/01/2011 04:31 am
It seems every Shuttle maneuver resulted in "good burn, no trim required"...at least over the last 20-plus missions.  Were there burns which weren't good and did require trim?

There were many. Usually CAPCOM would hold the call until after the trim was completed, then the call would be worded "good burn, no further trim required".

Quote
  If so, how was this done?

Depended on the phase of flight. For rendezvous burns, which had the most stringent trim limits, the CDR would perform an RCS trim by deflecting the THC, axis-by-axis, according to the displayed VGOs. The order in which the axes were trimmed was selected to minimize cross-coupling effects: if VGO Z was negative, the order would be Z-X-Y, otherwise X-Y-Z. If any VGO was greater than 1 fps magnitude, the CDR would select NORM in that axis and hold the THC out of detent until the VGO was less than 1, then select PULSE and pulse the THC, at 0.1 fps per pulse, until the VGO was less than the trim limit (0.2 fps).

Quote
  What would cause a deficient burn?

Slight OMS gimbal biases, mass property biases, slight differences in Isp, etc. could cause burn residuals even in a normally functioning system, when combined with the "fine count" (last 6 seconds) period where the guidance software went open-loop to prevent large attitude maneuvers at the end of the burn. Then there's outright malfunctions (which thankfully never happened) such as OMS gimbal failure, prop failure, engine failure, GPC/MDM failure, IMU failure, etc.
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 12/02/2011 01:23 am
Great insight, Jorge.  Thanks for the prompt response and expert insight.  I didn't realize that burns were trimmed onboard before hearing from the ground.
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 12/03/2011 03:30 am
Any chance you could post those mission designations?
I'd heard STS-51L was STS-33 internally.. was there a STS-22?




Dennis Jenkins has an excellent table on page 300 of the 1997 edition of "Space Shuttle - The History of Developing the NSTS".

The 25th Space Shuttle flight was STS-33 at KSC and STS-51L elsewhere

The 18th Space Shuttle flight was STS-25 at KSC and STS-51G elsewhere

Andy
[/quote]
Title: Re: Shuttle Q&A Part 5
Post by: Galactic Penguin SST on 12/03/2011 03:43 am
Quote

Dennis Jenkins has an excellent table on page 300 of the 1997 edition of "Space Shuttle - The History of Developing the NSTS".

The 25th Space Shuttle flight was STS-33 at KSC and STS-51L elsewhere

The 18th Space Shuttle flight was STS-25 at KSC and STS-51G elsewhere

Andy

Any chance you could post those mission designations?
I'd heard STS-51L was STS-33 internally.. was there a STS-22?


See here: http://forum.nasaspaceflight.com/index.php?topic=8941.msg164022#msg164022 (http://forum.nasaspaceflight.com/index.php?topic=8941.msg164022#msg164022)
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/06/2011 12:46 pm
Was their ever any planning EARLY in the program (pre 51-L) to have simultaneous shuttle missions (ie - two orbiters, maybe practicing rendevous maneuvers)? Or would that have been overload for MCC in Houston? I know post STS-107 there were the STS-3XX contingency missions - that's not what I'm thinking about.
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 12/06/2011 03:26 pm
A space shuttle version of the Gemini 6/7 mission would have been cool. :)

Are there any old photos of the orbiters when they were at Rockwell's Palmdale plant? For example Atlantis when she looked like this? http://www.capcomespace.net/dossiers/espace_US/shuttle/1996-2005/1997%20KSC-97PC-1663.jpg

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/06/2011 05:40 pm
Was their ever any planning EARLY in the program (pre 51-L) to have simultaneous shuttle missions (ie - two orbiters, maybe practicing rendevous maneuvers)? Or would that have been overload for MCC in Houston? I know post STS-107 there were the STS-3XX contingency missions - that's not what I'm thinking about.

We discussed this a while back but basically my belief is that since the MCC only had one of many of the backrooms (MER for instance), it would have been very difficult to do two missions at the same time.  One flight would have had attention and the other pretty much left to their own, which is not the way MCC usually operates.

I think Jim had discussed that the original Galileo / Ulysses missions might have overlapped if there had been a launch slip.  My memory was that the second mission would also have been delayed but I can't find anything that backs-up my statement.

It would have been a completely different thing if a station had been there and one orbiter was docked.  But two free-flying orbiters is a different story (luckily we didn't have to find out with an STS-400).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Prober on 12/11/2011 06:36 pm
Payload schedule question

The X-37 was scheduled to fly inside the payload bay of STS-120.    This is schedule was back in 2001.   What file name should I be looking for back from 2001 with this schedule?    Each piece of the puzzle pulls more files and details of the program.    Is there a program code for this payload that I might track and follow the history up to the cancellation?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/11/2011 06:47 pm
Payload schedule question

The X-37 was scheduled to fly inside the payload bay of STS-120.    This is schedule was back in 2001.   What file name should I be looking for back from 2001 with this schedule?    Each piece of the puzzle pulls more files and details of the program.    Is there a program code for this payload that I might track and follow the history up to the cancellation?


x-37 is program name
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/12/2011 02:21 pm
Payload schedule question

The X-37 was scheduled to fly inside the payload bay of STS-120.    This is schedule was back in 2001.   What file name should I be looking for back from 2001 with this schedule?    Each piece of the puzzle pulls more files and details of the program.    Is there a program code for this payload that I might track and follow the history up to the cancellation?


It was NASA funded at that time (along with the X-33 orbital and X-34 Mach 10-14 demonstrator).  I'd check the NASA budgets at that time.

This is an MSFC press release in the 2003 timeframe (after the ELV shift):
http://www.nasa.gov/centers/marshall/pdf/100427main_x37-facts.pdf
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 12/16/2011 01:55 pm
I just saw and read in the KSC Media Gallery that Atlantis's robot arm will be  eventually used in future spaceflights.

What could the shuttle's RMS be used for without the shuttle?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/16/2011 08:01 pm
I just saw and read in the KSC Media Gallery that Atlantis's robot arm will be  eventually used in future spaceflights.

What could the shuttle's RMS be used for without the shuttle?
The operative word in the Media Gallery captions was "possible," which means that while the hardware will be protected/preserved, presumably there are no definite (funded) plans to fly it again right now. 
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/19/2011 11:14 am
I may be remembering it wrong, but I seem to recall hearing that the roll rate for the roll program after liftoff changed (increased) beginning with STS-9 (first high-inclination mission)...anyone know what the roll rates were before and after?  (And did they change again?)

Thanks.

(Sorry if repeating this.)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 12/19/2011 06:27 pm
I all.

I'm getting a bit confused: what's the purpurse of the C&W system when both PASS and SM have fauld detection alarm capabilities? is the C&W something "embedded" in PASS and SM or it is something on its own? If I understand well the C&W system is separated from both PASS and SM.

Thanks a mil

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/21/2011 03:20 am
I may be remembering it wrong, but I seem to recall hearing that the roll rate for the roll program after liftoff changed (increased) beginning with STS-9 (first high-inclination mission)...anyone know what the roll rates were before and after?  (And did they change again?)

Thanks.

(Sorry if repeating this.)


My memory must be fading.  But, remember the rates are a combined (RSS) of roll, pitch and yaw not to exceed 15 deg / sec (if my memory is still good enough for that number).  I don't remember the individual gains changing but that was before my time.  The roll did last a lot longer (obviously).
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/21/2011 03:23 am
I all.

I'm getting a bit confused: what's the purpurse of the C&W system when both PASS and SM have fauld detection alarm capabilities? is the C&W something "embedded" in PASS and SM or it is something on its own? If I understand well the C&W system is separated from both PASS and SM.

Thanks a mil

Davide

My memory is better in this area.  Don't confuse hardware C&W with fault annunciation in the software.  There was a hardware C&W matrix that components could light up.  But to confuse matters more, there was also C&W embedded in the software and so a Class 2 or Class 3 alarm was software triggered.  A Class 4 (tone) was also software generated by the software and then sent to the audio annunciation unit.

Remember this was the late 1970s when this system was designed and so software was not to be trusted and so a hardware solution was used as well as a software solution.

Also remember SM is part of PASS (SM OPS 2, for instance).  PASS and BFS had separate SM functions.  But fault detection and annunciation were part of GN&C as well (SSME failures came from GN&C).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 12/21/2011 09:00 am
I think one of the (now publically accessible) training/documents you can download from NASA.gov is a brilliant overview of C&W. If not there then it's on L2 probably :)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 12/21/2011 08:53 pm
Quote from: alk3997
Also remember SM is part of PASS (SM OPS 2, for instance).  PASS and BFS had separate SM functions.  But fault detection and annunciation were part of GN&C as well (SSME failures came from GN&C).

Hi Andy! thanks for the clarification...I tripped my fingers on the keyboard  ;D I meant SM and GNC.

I was reading on the SCOM the chapter about the C/W system and I think that now I've got how the whole thing works. Basically there are paramenters that are controlled by hardware only and in case of limit violation, the alarm goes off (like for Class 1 and Class 2 Primary alarms).

Class 2 primary alarms are shown on the C/W annunciation matrix on panel F7 along with aural warnings. The parameters that drive the matrix are 120 and can be set/read via manual inputs on panel R13U.

Class 2 backup alarms are instead triggered by SM software computations but are shown an dedicated display page on the MEDS monitors, and the parameters controlling the alarms can be set/read via SPEC 60 SM TABLE MAINTENANCE page. Regarding these last types of alarms what it gets me a bit confused is the word backup. Why is it called backup? I mean if I've understood well this type of alarms are triggered only by computations of the SM software and don't involve the same parameters that trigger the matrix on panel F7.

Basically it seems to me that the for Class 2 primary and backup alarms there are two different sets of parameters. Especially considering that the Class 2 backup alarms involves also violations of limits from GNC.

Furthermore it looks to me that the paramaters controlling the Class 2 backup alarms can be modified more deeply that the parameters for Class 2 primary alarms.

So bottom line my question is: why Class 2 backup alarms are called "backup"? Backup seems something that is there in case of primary system fails, but in this instance it looks to me that these alarms are quite complementary of Class 2 Primary ones. I mean it seems to me that Class 2 primary and backup alarms go side by side rather then as a emergency plan in case the primary fails.

Where am I right and where wrong?

Thanks very much

Davide

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/22/2011 04:32 pm
What could have been done in a scenario where the ET failed to separate? Would it be possible to extend the OMS burn and carry it into some sort of stable(ish) orbit, thus buying time to work the problem? Did crews train for that sort of thing?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/22/2011 08:11 pm
What could have been done in a scenario where the ET failed to separate? Would it be possible to extend the OMS burn and carry it into some sort of stable(ish) orbit, thus buying time to work the problem? Did crews train for that sort of thing?

I believe it was a LOC event.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/22/2011 10:00 pm
Because OMS doesn't have enough delta-v to raise the perigee of that combined mass high enough? I recall reading studies about orbiting an ET. Would that have been done by extending MECO by a few seconds?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/23/2011 02:28 am
Quote from: alk3997
Also remember SM is part of PASS (SM OPS 2, for instance).  PASS and BFS had separate SM functions.  But fault detection and annunciation were part of GN&C as well (SSME failures came from GN&C).

Hi Andy! thanks for the clarification...I tripped my fingers on the keyboard  ;D I meant SM and GNC.

I was reading on the SCOM the chapter about the C/W system and I think that now I've got how the whole thing works. Basically there are paramenters that are controlled by hardware only and in case of limit violation, the alarm goes off (like for Class 1 and Class 2 Primary alarms).

Class 2 primary alarms are shown on the C/W annunciation matrix on panel F7 along with aural warnings. The parameters that drive the matrix are 120 and can be set/read via manual inputs on panel R13U.

Class 2 backup alarms are instead triggered by SM software computations but are shown an dedicated display page on the MEDS monitors, and the parameters controlling the alarms can be set/read via SPEC 60 SM TABLE MAINTENANCE page. Regarding these last types of alarms what it gets me a bit confused is the word backup. Why is it called backup? I mean if I've understood well this type of alarms are triggered only by computations of the SM software and don't involve the same parameters that trigger the matrix on panel F7.

Basically it seems to me that the for Class 2 primary and backup alarms there are two different sets of parameters. Especially considering that the Class 2 backup alarms involves also violations of limits from GNC.

Furthermore it looks to me that the paramaters controlling the Class 2 backup alarms can be modified more deeply that the parameters for Class 2 primary alarms.

So bottom line my question is: why Class 2 backup alarms are called "backup"? Backup seems something that is there in case of primary system fails, but in this instance it looks to me that these alarms are quite complementary of Class 2 Primary ones. I mean it seems to me that Class 2 primary and backup alarms go side by side rather then as a emergency plan in case the primary fails.

Where am I right and where wrong?

Thanks very much

Davide



Davide, a quick reply right now then more later.  It's called backup C&W because it was a backup to the hardware panel.  Remember in the late-1970s the whole concept of software doing C&W was new.  So the hardware system was primary and the software was the secondary or backup system.

Over the years, the reliance on the software side grew more and more.  There were plans for an enhanced C&W but those went away when the decision to end the program in 2010 (actually 2011, of course) was made.  The enhanced system would have provided the crew more information based on multiple C&W indications.

Also be careful of confusing the MEDS built-in fault line with the GN&C or SM fault summary displays and message line.  The GPC's fault summary displays (SM and GN&C) were the same whether the old MCDS or MEDS displays were used.  Those displays were generated by the GPCs and sent to the MCDS/MEDS.  The MEDS IDPs could also indicate internal faults and indicate those faults separately from the GPC displays on the MEDS fault line (since the GPC might not "know" about the MEDS faults).  I know that's confusing and is one of the reaons the crews were interested in improving the display system onboard the orbiters (more information, less data).

I'm not sure I answered all your questions - let me know if you have more.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/23/2011 02:35 am
What could have been done in a scenario where the ET failed to separate? Would it be possible to extend the OMS burn and carry it into some sort of stable(ish) orbit, thus buying time to work the problem? Did crews train for that sort of thing?

Let see...a dry external tank was about 58,000 lbs.  So this would be the equivalent of hanging a 58,000 lbs payload over the black-side of the orbiter.  The mass would have been well-off the normal cg and been about 1/4 to 1/5 of the total system mass, so I doubt the OMS would have been able to burn optimally. 

I'd have to work out how much orbital improvement 23,000 lbs of OMS would have provided with 58,000 lbs of additional mass.  Off the top of my head, even if you could get into orbit, you would not have enough to get back out of orbit.  That assumes the cg could even be managed.  Also the tank would still have residual propellant in it, so the weight figure I used was probably too low, anyway.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 12/23/2011 07:00 am
What could have been done in a scenario where the ET failed to separate? Would it be possible to extend the OMS burn and carry it into some sort of stable(ish) orbit, thus buying time to work the problem? Did crews train for that sort of thing?

Let see...a dry external tank was about 58,000 lbs.  So this would be the equivalent of hanging a 58,000 lbs payload over the black-side of the orbiter.  The mass would have been well-off the normal cg and been about 1/4 to 1/5 of the total system mass, so I doubt the OMS would have been able to burn optimally. 

I'd have to work out how much orbital improvement 23,000 lbs of OMS would have provided with 58,000 lbs of additional mass.  Off the top of my head, even if you could get into orbit, you would not have enough to get back out of orbit.  That assumes the cg could even be managed.  Also the tank would still have residual propellant in it, so the weight figure I used was probably too low, anyway.

Andy

Realistically, this scenario is very remote probability due to the high reliability of the pyros and multiple redundancy. There were no published procedures for it, nor any crew training, nor (to my knowledge) did we ever sim it. Therefore what follows is just informed speculation on my part on what would have been *tried* had this happened.

I'd expect them to go ahead and attempt OMS-2 to buy time. I'd expect high RCS activity during OMS burns due to not being able to trim the OMS gimbals through the c.g.. Probably not much that could be done about it for OMS-2. Once in OPS2, I'd expect GNC to develop and uplink a DAP mass properties update which would improve control response a bit, but attitude control would still be sloppy (and involve high RCS usage).

(If this were to happen on a Hubble mission the crew would be hozed already since OMS-2 nominally uses half the OMS prop and deorbit uses the other half. The higher usage for OMS-2 with the ET attached alone would preclude deorbit. And of course they could not reach ISS.)

I'd expect the flight control team to conclude that a standalone EVA would be highly unlikely to fix the problem and that the only hope for the crew would be safe haven at ISS. In this scenario the orbiter is written off anyway, so the fact that there wouldn't be enough prop for deorbit is not a showstopper.

The big challenge would be prox ops and docking to ISS, since the off-center c.g. would cause increased cross-coupling from translational firings. Control would be sloppy, perhaps to the point of being uncontrollable, and both RCS usage and plume impingement loads on ISS would be increased. In particular, +/-Y axis translation (side-to-side) would couple into -Z translation (toward ISS), even worse than what normally happens using Low Z DAP, requiring frequent braking to prevent excessive closure rate.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/23/2011 12:35 pm
What could have been done in a scenario where the ET failed to separate? Would it be possible to extend the OMS burn and carry it into some sort of stable(ish) orbit, thus buying time to work the problem? Did crews train for that sort of thing?

Let see...a dry external tank was about 58,000 lbs.  So this would be the equivalent of hanging a 58,000 lbs payload over the black-side of the orbiter.  The mass would have been well-off the normal cg and been about 1/4 to 1/5 of the total system mass, so I doubt the OMS would have been able to burn optimally. 

I'd have to work out how much orbital improvement 23,000 lbs of OMS would have provided with 58,000 lbs of additional mass.  Off the top of my head, even if you could get into orbit, you would not have enough to get back out of orbit.  That assumes the cg could even be managed.  Also the tank would still have residual propellant in it, so the weight figure I used was probably too low, anyway.

Andy

Realistically, this scenario is very remote probability due to the high reliability of the pyros and multiple redundancy. There were no published procedures for it, nor any crew training, nor (to my knowledge) did we ever sim it. Therefore what follows is just informed speculation on my part on what would have been *tried* had this happened.

I'd expect them to go ahead and attempt OMS-2 to buy time. I'd expect high RCS activity during OMS burns due to not being able to trim the OMS gimbals through the c.g.. Probably not much that could be done about it for OMS-2. Once in OPS2, I'd expect GNC to develop and uplink a DAP mass properties update which would improve control response a bit, but attitude control would still be sloppy (and involve high RCS usage).

(If this were to happen on a Hubble mission the crew would be hozed already since OMS-2 nominally uses half the OMS prop and deorbit uses the other half. The higher usage for OMS-2 with the ET attached alone would preclude deorbit. And of course they could not reach ISS.)

I'd expect the flight control team to conclude that a standalone EVA would be highly unlikely to fix the problem and that the only hope for the crew would be safe haven at ISS. In this scenario the orbiter is written off anyway, so the fact that there wouldn't be enough prop for deorbit is not a showstopper.

The big challenge would be prox ops and docking to ISS, since the off-center c.g. would cause increased cross-coupling from translational firings. Control would be sloppy, perhaps to the point of being uncontrollable, and both RCS usage and plume impingement loads on ISS would be increased. In particular, +/-Y axis translation (side-to-side) would couple into -Z translation (toward ISS), even worse than what normally happens using Low Z DAP, requiring frequent braking to prevent excessive closure rate.

Ok. Scary stuff!

How would the plans for intentionally orbiting an ET have worked then? If you extend MECO a bit, you can raise the perigee of a direct ascent Orbit high enough that it won't reenter? But then how to circularize the tank's orbit? I remember reading something about it (probably back when I had L2, need it again. Santa? :))
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/23/2011 01:01 pm
Ok. Scary stuff!

How would the plans for intentionally orbiting an ET have worked then? If you extend MECO a bit, you can raise the perigee of a direct ascent Orbit high enough that it won't reenter? But then how to circularize the tank's orbit?
It's in Jorge's answer if you also take into account that you wouldn't know there was an ET sep problem until after MECO.

Excerpt:
I'd expect them to go ahead and attempt OMS-2 to buy time. I'd expect high RCS activity during OMS burns due to not being able to trim the OMS gimbals through the c.g.. Probably not much that could be done about it for OMS-2. Once in OPS2, I'd expect GNC to develop and uplink a DAP mass properties update which would improve control response a bit, but attitude control would still be sloppy (and involve high RCS usage).
Title: Re: Shuttle Q&A Part 5
Post by: CrudBasher on 12/23/2011 02:34 pm
I tried searching for this but didn't find anything.

I noticed when the orbiters started their retirement flow one of the first things removed was the TPS tiles around the windows. Does anyone know why they were removed? Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 12/26/2011 10:03 pm
I used the search and actually believe I've read all shuttle Q&A responses and couldn't find an answer to this. Is there an engineering or other reason the shuttle side hatch opens the direction it does? It seems to me that when the orbiter it horizontal, up would be fighting gravity and left would be fighting gravity when the orbiter is vertical. That leaves down (the configuration chosen) or right when the orbiter is horizontal. Anyone know why down was chosen over right? Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/26/2011 11:49 pm
I used the search and actually believe I've read all shuttle Q&A responses and couldn't find an answer to this. Is there an engineering or other reason the shuttle side hatch opens the direction it does? It seems to me that when the orbiter it horizontal, up would be fighting gravity and left would be fighting gravity when the orbiter is vertical. That leaves down (the configuration chosen) or right when the orbiter is horizontal. Anyone know why down was chosen over right? Thanks!

It opens down when the orbiter is horizontal, so the crew doesn't have to fight gravity during a post landing situation.
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 12/27/2011 12:58 pm
I used the search and actually believe I've read all shuttle Q&A responses and couldn't find an answer to this. Is there an engineering or other reason the shuttle side hatch opens the direction it does? It seems to me that when the orbiter it horizontal, up would be fighting gravity and left would be fighting gravity when the orbiter is vertical. That leaves down (the configuration chosen) or right when the orbiter is horizontal. Anyone know why down was chosen over right? Thanks!

It opens down when the orbiter is horizontal, so the crew doesn't have to fight gravity during a post landing situation.

That makes sense. Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: parham55 on 12/27/2011 03:10 pm
My search skills are lacking. Anyone care to help identify what turbine and/or provide some more context around this turbine blade? By context I mean a larger picture or explanation of this piece installed as ready for flight. Thanks.
Rob
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/27/2011 03:35 pm
My search skills are lacking. Anyone care to help identify what turbine and/or provide some more context around this turbine blade? By context I mean a larger picture or explanation of this piece installed as ready for flight. Thanks.
Rob

It is a flown turbine blade from an SSME.  It is just an artifact that has flown into space.  Unlike the patches and flags, this is a piece of operational hardware.

Major General Frank J. Simokaitis was commandant of the Air Force Institute of Technology and commandant of the Defense Institute of Security Assistance Management at Wright-Patterson Air Force Base, Ohio.

Don't know his post USAF career
Title: Re: Shuttle Q&A Part 5
Post by: parham55 on 12/27/2011 04:02 pm
Thank you, Jim. Is that a whole blade or just a piece? Any way to tell if it is from the fuel or oxidizer turbine? Is the ridged (bottom in the picture) end the portion that would be fit into the hub? Where is the leading edge of the blade?
I had dinner with General Simokaitis last night. Most of the time we were discussing his B-26 flying days. During training he belly landed in Texas after a prop sheered off the crank and the pilot bailed out after saying, "What are you going to do?"
Title: Re: Shuttle Q&A Part 5
Post by: kwan3217 on 12/27/2011 04:02 pm
The shuttle is famous for its four computers running the primary software simultaneously and a fifth running the backup flight software. Was this redundancy ever used? Did one of the four ever fail or disagree during a flight? Was the backup computer ever engaged as a backup?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/27/2011 04:21 pm
The shuttle is famous for its four computers running the primary software simultaneously and a fifth running the backup flight software. Was this redundancy ever used? Did one of the four ever fail or disagree during a flight? Was the backup computer ever engaged as a backup?

BFS was never engaged.  Look into STS-9 for failures.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 12/27/2011 06:12 pm
Question re: STS-67 Middeck Active Control Experiment (MACE), did MACE have any input into actual ISS hardware (e.g. the CMGs)?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/27/2011 08:26 pm
The shuttle is famous for its four computers running the primary software simultaneously and a fifth running the backup flight software. Was this redundancy ever used? Did one of the four ever fail or disagree during a flight? Was the backup computer ever engaged as a backup?

And, STS-7 for more failures and STS-30.  But those were on the older AP-101B computers not on the newer AP-101S.  The differences in MTBF were huge.  The AP-101B was measured in 1,000s of actual hours MTBF while the AP-101S computers were 10,000s of actual hours (close to 100,000 hours) MTBF.  If you work out how many hours of use per flight (including pre-launch and post-landing) you can see why the AP-101S GPC hardware didn't give us much trouble once it replaced the AP-101B.

I worked the STS-30 GPC failure in the MER when it occured which was frantic but the actually replacement of the GPC was slow and methodical.

Remember BFS also had SM capabilities that were not available in the PASS during ascent and entry.  So BFS was used every flight, but was never "engaged" - meaning it never took control from PASS.

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/07/2012 02:28 am
Anyone know what font is used for the MEDS displays like in the one attached?
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 01/07/2012 02:51 am
Well, for one thing, I think that's a regular old DEU, not a MEDS screen - but to answer your actual question... I don't know.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/07/2012 03:15 am
Well, for one thing, I think that's a regular old DEU, not a MEDS screen - but to answer your actual question... I don't know.

It's a MEDS MDU, specifically AFD1, which replaced the aft ADI. The old DUs had rectangular screens, not square ones, and had no edgekeys. Also, the old DUs had monochrome displays. The MDU is multicolor (with the DPS text in green, edgekey graphics in cyan).

The "font" used on the shuttle screens doesn't really have a name. The old DUs were vector displays and the DEUs would draw the characters stroke-by-stroke. MEDS emulated this behavior, with the IDPs sending vector drawing commands that were interpreted by the MDUs onto their raster displays.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 01/07/2012 04:59 am
Anyone know what font is used for the MEDS displays like in the one attached?

That's a MEDS aft display (MDU).  The font was referred to as the "DEU Font".  It basically emulated the original DEU's font.  The font was originally created by IBM and was very similar to the Tektronics fonts (exactly in many cases) of the era.

BTW, we added 32 characters to the font in 2008.  We added a bit that accessed an alternate character set that allowed us to add the Bearing Displays which required some additional characters.  We also ended up using color on these final DPS displays (as well as adding an option for entry traj bugs to be in color for three landing sites).  Despite adding some color to a few displays, the DPS displays were still referred to as "green screens".

Andy
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/12/2012 06:18 am
Hi all.

Question on the Orbital DAP, and in particular on the Manual TVC DAP mode. From what I've read till now, in this mode a deflection of the RHC up to the softstop causes to gimbal the OMS engine. If instead the RHC is deflected beyound the softstop, the RCS will be fired continuously.

What I don't understand is, if during this mode, while the RHC is before the softstop, the RCS jets are still fired for keeping the attitude or if instead the RHC deflections are only transformed in OMS engines gimbalining.

Said in other words: is this a mode in which OMS thrust vectoring is accomplished by manual inputs to the OMS engines only or also the RCS is used (I'm always speaking in the case in which the RHC is before the softstop).

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/12/2012 07:49 am
Hi all.

Question on the Orbital DAP, and in particular on the Manual TVC DAP mode. From what I've read till now, in this mode a deflection of the RHC up to the softstop causes to gimbal the OMS engine. If instead the RHC is deflected beyound the softstop, the RCS will be fired continuously.

What I don't understand is, if during this mode, while the RHC is before the softstop, the RCS jets are still fired for keeping the attitude or if instead the RHC deflections are only transformed in OMS engines gimbalining.

Said in other words: is this a mode in which OMS thrust vectoring is accomplished by manual inputs to the OMS engines only or also the RCS is used (I'm always speaking in the case in which the RHC is before the softstop).

Thanks

Davide

Can't believe how quickly I forget this stuff... had to look up the answer for this.

For 2-engine burns, RHC deflection within the softstop will use OMS steering in all three axes. For single-engine burns, THC deflection within the softstop uses OMS steering in pitch and yaw, RCS in roll. In both cases, if the OMS gimbals lack the control authority to maintain the commanded rate, RCS thrusters will be used to augment the gimbals. This is called RCS wraparound.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/12/2012 08:28 am
Quote from: Jorge
Can't believe how quickly I forget this stuff... had to look up the answer for this.

ah too bad Jorge! you can't forget this things ahah.

Quote
RHC deflection within the softstop will use OMS steering in all three axes

Ok so this means that basically the pilots could manually steer the OMS engines? Where did they get information about which direction they had to steer the OMS engines to? From the ADI?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/12/2012 02:45 pm
Quote from: Jorge
Can't believe how quickly I forget this stuff... had to look up the answer for this.

ah too bad Jorge! you can't forget this things ahah.

Quote
RHC deflection within the softstop will use OMS steering in all three axes

Ok so this means that basically the pilots could manually steer the OMS engines? Where did they get information about which direction they had to steer the OMS engines to? From the ADI?

Thanks

Davide


Either the ADI, or the VGOs on the MNVR EXEC display.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/13/2012 04:27 pm
Hi all.

Did the state vector propagation and scheme change when the IMUs where upgraded to the laser ring system?

If yes what changed?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/13/2012 04:35 pm
Hi all.

Did the state vector propagation and scheme change when the IMUs where upgraded to the laser ring system?

If yes what changed?

Thanks

Davide

The shuttle IMUs never used ring laser gyros.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/14/2012 07:25 am
Sorry i misread what i was reading. The gyros were replaced with the ring laser type.

Another question: which is the difference between the AUTO and INRTL mode for the DAP? I mean, in AUTO the DAP kept the attitude automatically without manual input from the crew, but is not equvalent to say that it maintained an inertial attitude?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/14/2012 07:43 am
Sorry i misread what i was reading. The gyros were replaced with the ring laser type.

Either you're still misreading or you're miswriting. The shuttle has never used ring laser gyros in the IMUs, nor the RGAs, nor the SRB RGAs. What's your source for this?

Quote
Another question: which is the difference between the AUTO and INRTL mode for the DAP? I mean, in AUTO the DAP kept the attitude automatically without manual input from the crew, but is not equvalent to say that it maintained an inertial attitude?

AUTO puts the universal pointing software in control, which can either maneuver to a designated inertial attitude, track a designated target with a designated body vector, or rotate about a designated body vector. That's in major mode 201. In major mode 202, AUTO enables the automatic maneuver to burn attitude.

INRTL simply snaps and holds the current inertial attitude. Similarly, the LVLH mode simply snaps and holds the current LVLH attitude.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/14/2012 11:16 am
Quote from: Jorge
Either you're still misreading or you're miswriting. The shuttle has never used ring laser gyros in the IMUs, nor the RGAs, nor the SRB RGAs. What's your source for this?

I was listening to the MIT Open Course Aircraft System lessons. This course is all about the Space Shuttle and every lesson tackle a different subject regarding the on board systems. I was listening the lesson about GNC and there I hear this thing that the IMUs were replaced with the ring laser system. But it's quite likely fault of mine, I must have understoond wrongly. All in all in the Astronaut Training Manual IMU available on L2, there is not mention at all of laser type IMUs.

Thanks very much for the explanations on the differences between AUTO and INRTL DAP modes. That's what I need to know.

Davide



Title: Re: Shuttle Q&A Part 5
Post by: Robotbeat on 01/17/2012 10:24 pm
Sivodave:
You need to edit your quote formatting.

In that MIT OpenCourseware course, at the end, they mentioned different ways that a next-generation Shuttle could be improved compared to the existing Shuttles as part of what the students had to do as part of their grade. It's possible the ring laser gyros were mentioned in that context.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 01/17/2012 11:30 pm
It didn't have to be a "next-generation" shuttle.  There were ample ideas and studies performed on many system upgrades and modifications that were never implimented.

The reasons varied of course, from the cost would have been prohibitive to sometimes changing things just to supposedly improve them (when more or less it was working fine or was understood) was not something the always fit within the other confines of the Program. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/18/2012 12:31 am
It didn't have to be a "next-generation" shuttle.  There were ample ideas and studies performed on many system upgrades and modifications that were never implimented.

The reasons varied of course, from the cost would have been prohibitive to sometimes changing things just to supposedly improve them (when more or less it was working fine or was understood) was not something the always fit within the other confines of the Program. 

I remember the proposed SIGI upgrade. Very slick... but the costs of modifying the FSW to work with SIGI caused a lot of people to freak out. The assumption of a stable-platform IMU was pretty deeply baked-into the software. Re-verifying it would have been a bear.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 01/18/2012 04:15 am
It didn't have to be a "next-generation" shuttle.  There were ample ideas and studies performed on many system upgrades and modifications that were never implimented.

The reasons varied of course, from the cost would have been prohibitive to sometimes changing things just to supposedly improve them (when more or less it was working fine or was understood) was not something the always fit within the other confines of the Program. 

I remember the proposed SIGI upgrade. Very slick... but the costs of modifying the FSW to work with SIGI caused a lot of people to freak out. The assumption of a stable-platform IMU was pretty deeply baked-into the software. Re-verifying it would have been a bear.

Prototype software had been made and we were actually "looking forward" to the challenge.  The SIGI was tested onboard using PGSCs to record the data (much as MAGR-S was tested).

SIGI was actually very important from the keep GPCs flying until 2025 plan.  We would have off-loaded displays first (CAU) and then off-loaded Nav.  This way there would have been enough memory available to keep upgrading GPC flight software through 2025 (if the plan to do that had materialized).  Much much cheaper than new GPCs (and software).
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/18/2012 06:13 am
It didn't have to be a "next-generation" shuttle.  There were ample ideas and studies performed on many system upgrades and modifications that were never implimented.

The reasons varied of course, from the cost would have been prohibitive to sometimes changing things just to supposedly improve them (when more or less it was working fine or was understood) was not something the always fit within the other confines of the Program. 

I remember the proposed SIGI upgrade. Very slick... but the costs of modifying the FSW to work with SIGI caused a lot of people to freak out. The assumption of a stable-platform IMU was pretty deeply baked-into the software. Re-verifying it would have been a bear.

Prototype software had been made and we were actually "looking forward" to the challenge.  The SIGI was tested onboard using PGSCs to record the data (much as MAGR-S was tested).

SIGI was actually very important from the keep GPCs flying until 2025 plan.  We would have off-loaded displays first (CAU) and then off-loaded Nav.  This way there would have been enough memory available to keep upgrading GPC flight software through 2025 (if the plan to do that had materialized).  Much much cheaper than new GPCs (and software).


I was really looking forward to CAU, especially after getting to do some display evals in the SMS. (Also made some design inputs on the Orbit PFD, Att Tgt, and Rndz Task displays). Some of the designs live on in the Orion displays.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/18/2012 06:45 am
Hi all.

A question regarding proximity operations with the ISS.

I'm reading that after the RPM the orbiter started a Twice Orbital Rate V Bar Approach (TORVA) to reas the V-Bar. In earlier missions to the ISS, like STS-88 it was instead used a Twice Orbital Rate R Bar Approach (TORRA).

Could you please explain me which is the meanig of these two maneuvers? and why they were adopted?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 01/18/2012 02:52 pm
"CDR, reconfigure heaters".......can anyone explain this call in the countdown?

thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 01/18/2012 03:06 pm
"CDR, reconfigure heaters".......can anyone explain this call in the countdown?

thanks!

Switching from one string to another, possibly turning them on/off, etc.  It just depends. 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/18/2012 03:10 pm
Hi all.

A question regarding proximity operations with the ISS.

I'm reading that after the RPM the orbiter started a Twice Orbital Rate V Bar Approach (TORVA) to reas the V-Bar. In earlier missions to the ISS, like STS-88 it was instead used a Twice Orbital Rate R Bar Approach (TORRA).

Could you please explain me which is the meanig of these two maneuvers? and why they were adopted?

Thanks very much

Davide

Long answer, think it's in here, if not I'll deal with it later:

http://forum.nasaspaceflight.com/index.php?topic=27598.0
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/18/2012 03:49 pm
"CDR, reconfigure heaters".......can anyone explain this call in the countdown?

thanks!

If your are talking about the call around T-5 minutes, then it is a call to have the commander turn off the flash evaporator feed line heaters.  Prior to this point in the count you had cryo loading of the external fuel tank (thru the aft compartment) and thermal conditioning of the MPS (main propulsion system) taking place - making the belly of the orbiter (located next to the extremely cold external tank) and the aft compartment of the orbiter, very cold.  The flash evaporator feed lines run under the payload bay (i.e. along the belly) and into the aft compartment.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 01/19/2012 10:15 am
Thanks Mark...i was hoping you would chime in!!!!

:)

Jeff
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 01/20/2012 03:34 am
I asked on the Historical thread re: STS-51C but maybe it's better to try here:
What was the bank limitation for the orbiter, coming around the hack? The commentator says on STS-51C landing coverage that Discovery is in a bank of 87 degrees at one point - I didn't think they ever went that far - was it a mistake, by the commentator, or was that the case? In the video, it does indeed look remarkably accurate...
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/20/2012 05:53 am
Quote from: Jorge
Long answer, think it's in here, if not I'll deal with it later:

http://forum.nasaspaceflight.com/index.php?topic=27598.0

Hi Jorge.

I've to say that I've found out about TORVA and TORRA just reading few days ago History of Space Shuttle Rendezvous...a very inspiring document I've to say...plenty of good description.

TORVA and TORRA are mentioned at page 137 where it says that twice orbital rate fly-arounds permitted faster transfers with lower propellant consuption and plume impingment. Also it says that the faster rate prevented the Sun from continously staying in the field of view of the crew.

So I'd like to have some more info about it. Why TORVA and TORRA are better and in what they exactly consists? I see from the diagrams in the quoted document that TORRA and TORVA are performed in the maneuver for passing from the +R bar to the +V bar.

Does the adjective "twice" simply mean that the the passage from +R bar to +V bar is just done at twice the speed than what was done before the maneuver was introduced? And which is the difference between orbital rate and velocity?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/20/2012 08:22 am
I asked on the Historical thread re: STS-51C but maybe it's better to try here:
What was the bank limitation for the orbiter, coming around the hack? The commentator says on STS-51C landing coverage that Discovery is in a bank of 87 degrees at one point - I didn't think they ever went that far - was it a mistake, by the commentator, or was that the case? In the video, it does indeed look remarkably accurate...

I'd have to see and hear the coverage you are talking about, but most likely he is referring to the (HTA) hac turn angle to go before the orbiter is lined up on final - in other words the number of degrees around the HAC circumference.

The orbiter's guidance system had specific constraints on roll angle in both the supersonic and subsonic phase of flight while on the HAC (ranging from 30 to 60 degrees) - these were intended to prevent the 1.8 G limit from be exceeded.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 01/21/2012 04:31 am
This is the transcript..

PAO: Approaching the Heading Alignment Circle, and Discovery will be beginning the sweeping left turn, coming around for runway 15… left bank 45 degrees now, 40.000 feet, on Heading Alignment Circle, normal energy… orbiter systems in good shape, 36,000 feet, .7 mach on the Heading Alignment Circle, bank 77 degrees… now 87 degrees… airspeed about 264 knots, range 8 miles… and they’ve reported the sonic boom at the Cape… on the Heading Alignment Circle airspeed 258, altitude 24,000 feet, range 9 miles…
Title: Re: Shuttle Q&A Part 5
Post by: starbird on 01/21/2012 06:34 am
I'm pretty sure he's talking about some turn angle, not bank. There are clips of the landing on youtube and none of them show any extreme bank angles.

Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/21/2012 07:42 am
Quote from: Jorge
Long answer, think it's in here, if not I'll deal with it later:

http://forum.nasaspaceflight.com/index.php?topic=27598.0

Hi Jorge.

I've to say that I've found out about TORVA and TORRA just reading few days ago History of Space Shuttle Rendezvous...a very inspiring document I've to say...plenty of good description.

TORVA and TORRA are mentioned at page 137 where it says that twice orbital rate fly-arounds permitted faster transfers with lower propellant consuption and plume impingment. Also it says that the faster rate prevented the Sun from continously staying in the field of view of the crew.

So I'd like to have some more info about it. Why TORVA and TORRA are better and in what they exactly consists?

I'm not sure what you are asking.

Quote
I see from the diagrams in the quoted document that TORRA and TORVA are performed in the maneuver for passing from the +R bar to the +V bar.

TORRA is a maneuver from the +Rbar to the -Rbar. TORVA is a maneuver from the +Rbar to the +Vbar.

Quote
Does the adjective "twice" simply mean that the the passage from +R bar to +V bar is just done at twice the speed than what was done before the maneuver was introduced?

Yes.

Quote
And which is the difference between orbital rate and velocity?

"Orbital rate" is angular velocity while "velocity", in this context, is tangential velocity. Tangential velocity is just the angular velocity times the range (omega cross r).
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/22/2012 11:55 am
Quote from: Jorge
Quote from: sivodave on 01/20/2012 06:53 AM

    Quote from: Jorge

        Long answer, think it's in here, if not I'll deal with it later:

        http://forum.nasaspaceflight.com/index.php?topic=27598.0


    Hi Jorge.

    I've to say that I've found out about TORVA and TORRA just reading few days ago History of Space Shuttle Rendezvous...a very inspiring document I've to say...plenty of good description.

    TORVA and TORRA are mentioned at page 137 where it says that twice orbital rate fly-arounds permitted faster transfers with lower propellant consuption and plume impingment. Also it says that the faster rate prevented the Sun from continously staying in the field of view of the crew.

    So I'd like to have some more info about it. Why TORVA and TORRA are better and in what they exactly consists?


I'm not sure what you are asking.

Hi Jorge

I read better the document and I've understood that TORVA and TORRA were used for all MIR and ISS missions. I had understood that this kind of approaches were implemented in the early docked missions to MIR or ISS. So my question has not reason of being! sorry about that.

Last thing: twice orbital rate/velocity, i suppose they refer to twice the orbital rate/velocity of the target (ie: ISS) or of the chaser (Shuttle)?

Thanks very much

Regards

Davide
 
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/22/2012 06:07 pm

Last thing: twice orbital rate/velocity, i suppose they refer to twice the orbital rate/velocity of the target (ie: ISS) or of the chaser (Shuttle)?

Doesn't matter. The value of twice orbital rate used (0.13 deg/sec) was rounded to the nearest hundredth. We're talking prox ops here. The difference in orbital rate between the two vehicles was far less than the margin of rounding.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/23/2012 08:29 am
This is the transcript..

PAO: Approaching the Heading Alignment Circle, and Discovery will be beginning the sweeping left turn, coming around for runway 15… left bank 45 degrees now, 40.000 feet, on Heading Alignment Circle, normal energy… orbiter systems in good shape, 36,000 feet, .7 mach on the Heading Alignment Circle, bank 77 degrees… now 87 degrees… airspeed about 264 knots, range 8 miles… and they’ve reported the sonic boom at the Cape… on the Heading Alignment Circle airspeed 258, altitude 24,000 feet, range 9 miles…

Yeah he definitely misspoke - I watched the video and my best "GUESS" is he read the numbers for the brake (as in speed brake which might have been opening to 77 percent)...I really have no idea, and I only know enough to make me very dangerous. ;)

As for your original question, the roll/bank during this part of the TAEM Guidance phase (subsonic, on the HAC, and not flying RTLS guidance limits) is ideally around 45 degrees with guidance limiting roll commands to a maximum of 60 degrees.

While normally bank on the HAC is around 45-ish degrees, high winds at altitude (such as a strong tail wind) may require a larger bank angle.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 01/23/2012 03:10 pm
OK thanks -
wouldn't be the first or last time PAO mis-spoke lol ..

Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 01/24/2012 09:40 pm
another random question, but does anyone know the launch that Rob Navias commented that the orbiter was "flying down hwy (XXX)"  (he was referring to the STS mission number as the "why").

completely random, but i can't find the flight commentary.

thanks!!!
Title: Re: Shuttle Q&A Part 5
Post by: catdlr on 01/24/2012 11:04 pm
another random question, but does anyone know the launch that Rob Navias commented that the orbiter was "flying down hwy (XXX)"  (he was referring to the STS mission number as the "why").

completely random, but i can't find the flight commentary.

thanks!!!

Steer to this location:
http://forum.nasaspaceflight.com/index.php?topic=19476.msg504345#msg504345

Here is the YouTube link.  The comment is made at 3:50 into the video.
http://www.youtube.com/watch?v=zsJpUCWfyPE
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 01/25/2012 12:19 am
THANKS!
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 01/26/2012 02:42 pm
This is the transcript..

PAO: Approaching the Heading Alignment Circle, and Discovery will be beginning the sweeping left turn, coming around for runway 15… left bank 45 degrees now, 40.000 feet, on Heading Alignment Circle, normal energy… orbiter systems in good shape, 36,000 feet, .7 mach on the Heading Alignment Circle, bank 77 degrees… now 87 degrees… airspeed about 264 knots, range 8 miles… and they’ve reported the sonic boom at the Cape… on the Heading Alignment Circle airspeed 258, altitude 24,000 feet, range 9 miles…

Yeah he definitely misspoke - I watched the video and my best "GUESS" is he read the numbers for the brake (as in speed brake which might have been opening to 77 percent)...I really have no idea, and I only know enough to make me very dangerous. ;)

As for your original question, the roll/bank during this part of the TAEM Guidance phase (subsonic, on the HAC, and not flying RTLS guidance limits) is ideally around 45 degrees with guidance limiting roll commands to a maximum of 60 degrees.

While normally bank on the HAC is around 45-ish degrees, high winds at altitude (such as a strong tail wind) may require a larger bank angle.

Mark Kirkman

As Mark said, it was PAO's interpretation of the little bit of information that they had at that time.  Remember 51C was in the old MCC and all they had were single TV channels with columns of data (and not always the most useful data).  Also it was a DOD flight which limited what could be shown (even during landing). The MCC that we were familiar with at the end of the program had the ability to choose from a lot of data.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 01/26/2012 02:44 pm
another random question, but does anyone know the launch that Rob Navias commented that the orbiter was "flying down hwy (XXX)"  (he was referring to the STS mission number as the "why").

completely random, but i can't find the flight commentary.

thanks!!!

Steer to this location:
http://forum.nasaspaceflight.com/index.php?topic=19476.msg504345#msg504345

Here is the YouTube link.  The comment is made at 3:50 into the video.


Rob has a proclivity for annunciating words that add to the flavor of the moment.  In other words, he was just trying to make it sound different than any other launch.  And, apparently he succeeded.

During one of the launches, a NASA PAO (I shall leave the name out) said "oh, shoot" in the middle of ascent (I think, first stage ascent) when a different PAO's words got tangled.  That was one I always remember and a good reminder of the value of a excellent commentator like Rob Navias.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 01/28/2012 08:06 pm
I looked at a photo of SSME 0003 and the shape of the bell of the engine looks very different from that of the current SMEs that have flown. Why? I also recall in a documentary this engine or a similar early version identical to 0003 exploded during a test.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/28/2012 08:15 pm
I looked at a photo of SSME 0003 and the shape of the bell of the engine looks very different from that of the current SMEs that have flown. Why? I also recall in a documentary this engine or a similar early version identical to 0003 exploded during a test.

Was it from the MPTA days? Some of those tests used lower expansion ratio nozzles. Less stress on the engine that way (less thrust, too).
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 01/29/2012 11:31 pm
Yep.  The engine is painted white in the photo and video of the test.

I guess the nozzle needed to be bigger as that engine design was never used when the shuttle first flew.

It also explains now why Revell has the old 0003 design on it's 1/72 scale model kits of the orbiter.

Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 02/01/2012 02:59 am
Not sure if this goes here, but what the heck is the Reusable Launch Vehicle Hangar ? 

Also what was the purpose of the OMRCF before it was converted to and OPF, and did NASA intentionally design the facility to be converted to an OPF in the future?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/01/2012 03:06 am
Not sure if this goes here, but what the heck is the Reusable Launch Vehicle Hangar ? 

Also what was the purpose of the OMRCF before it was converted to and OPF, and did NASA intentionally design the facility to be converted to an OPF in the future?

It was built for X-34 type testing
OMRCF was non mission work, such as what became OMDP.   Any "hangar" that was large enough to hold an Orbiter and with the ability to support some work on the Orbiter could be OPF.  The fact that OMCF GSE became available made it easy.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 02/03/2012 06:13 pm
Is November 19, 1985 the correct date for OV-101's arrival at Dulles?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/04/2012 08:04 pm
Is November 19, 1985 the correct date for OV-101's arrival at Dulles?

November 18, 1985 was when OV-101 left KSC for Dulles according to one source.  NASM has OV-101 arriving at Dulles on November 16, 1985 and being lowered to the tarmac on November 17, 1985.  While NASA has OV-101 departing KSC on a one day flight on November 18, 1985.  No references to November 19th were found.

http://blog.nasm.si.edu/2011/06/06/getting-enterprise-ready-for-prime-time/
http://www-pao.ksc.nasa.gov/shuttle/resources/orbiters/enterprise.html

Who to believe?  Well I believe a one day trip for an empty airframe from KSC to Dulles is well within the 747's capabilities.  The NASM article includes the date of demate.  So, I'd lean towards the NASM work, but maybe a call to NASM would be in order if this is more than a curiousity.

Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/05/2012 06:53 pm
Hi all.

Question about the star trackers. I know that two different types were used, namely the solid state start tracker and the image dissector tube star tracker.

I'd like to know the advantage of the one type respect the other. Which
one was better? could an orbiter have both types at the same time?

Thanks very much

Regards

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 02/06/2012 12:59 am
Hi all.

Question about the star trackers. I know that two different types were used, namely the solid state start tracker and the image dissector tube star tracker.

I'd like to know the advantage of the one type respect the other. Which
one was better? could an orbiter have both types at the same time?

Thanks very much

Regards

Davide

Yes, the two types could be used interchangeably and mixed on the same flight. I suspect the older ones were simply becoming unsupportable due to their age.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 02/07/2012 02:00 am
Hubble servicing question, on STS-125 the APAS/Docking tunnel was removed from Atlantis' external airlock, yet when Discovery visited on STS-103 (SM-3A) she still had the full docking system. Was this due to the addition of the OBSS on SM-4, or was there more to the story?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/07/2012 04:23 pm
I may be remembering it wrong, but I seem to recall hearing that the roll rate for the roll program after liftoff changed (increased) beginning with STS-9 (first high-inclination mission)...anyone know what the roll rates were before and after?  (And did they change again?)

Thanks.

(Sorry if repeating this.)


My memory must be fading.  But, remember the rates are a combined (RSS) of roll, pitch and yaw not to exceed 15 deg / sec (if my memory is still good enough for that number).  I don't remember the individual gains changing but that was before my time.  The roll did last a lot longer (obviously).
Now that my STS-9 recording is no longer imprisoned on Betamax tape, I found a reasonable source for the change at that time.  Richard Covey, who was providing astronaut 'color' for CNN during STS-9, noted on launch day that the roll rate was changed from 10 deg/sec to 15.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/08/2012 09:06 am
Quote
Quote
Quote from: sivodave on 02/05/2012 07:53 PMHi all.

Question about the star trackers. I know that two different types were used, namely the solid state start tracker and the image dissector tube star tracker.

I'd like to know the advantage of the one type respect the other. Which
one was better? could an orbiter have both types at the same time?

Thanks very much

Regards

Davide

Yes, the two types could be used interchangeably and mixed on the same flight. I suspect the older ones were simply becoming unsupportable due to their age.

Thanks DMeader. Just another question: in what sense the only ones became unsupportable? Unsupportable from a software point of view or maintenance? If they were unsupportable, why they flew with both type together?

Thanks very much

Regards

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 02/08/2012 02:37 pm
On Columbia, OV-102. Why was she the only one to get the extra black tiles on the wing chines while the rest of the fleet didn't? What purpose did it serve? 
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 02/08/2012 02:41 pm
On Columbia, OV-102. Why was she the only one to get the extra black tiles on the wing chines while the rest of the fleet didn't? What purpose did it serve? 

Initial thermal analysis showed the chine area to be warmer than it actually turned out to be.  Columbia had the black FRSI for this reason. 

When it was determined it wasn't really needed, there was no real reason to change the vehicle and it gave the "flagship" a distinctive look as well.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/08/2012 02:42 pm
On Columbia, OV-102. Why was she the only one to get the extra black tiles on the wing chines while the rest of the fleet didn't? What purpose did it serve? 

Early preflight data indicted it was needed and it was found that it wasn't
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 02/08/2012 02:42 pm
On Columbia, OV-102. Why was she the only one to get the extra black tiles on the wing chines while the rest of the fleet didn't? What purpose did it serve? 

I believe that was black paint over the lower temperature white tiles, not the high temperature black tiles. The reason was for some early on "guestimates" at heating, turned out to be unnecessary but was kept anyway, making 102 stand out from the rest of the fleet. 102 had plenty of other distinctive markings as well (SILTS pod and black tiles atop the vertical stabilizer being the 2nd most noticeable difference).
Title: Re: Shuttle Q&A Part 5
Post by: Wayne Hale on 02/08/2012 09:00 pm
The black chine areas on Columbia were to minimize on-orbit thermal stresses on the underlying structure; later vehicles incorporated structural changes that made the extra thermal absorption unnecessary.
Title: Re: Shuttle Q&A Part 5
Post by: Zpoxy on 02/09/2012 09:55 pm
On Columbia, OV-102. Why was she the only one to get the extra black tiles on the wing chines while the rest of the fleet didn't? What purpose did it serve? 

I believe that was black paint over the lower temperature white tiles, not the high temperature black tiles. The reason was for some early on "guestimates" at heating, turned out to be unnecessary but was kept anyway, making 102 stand out from the rest of the fleet. 102 had plenty of other distinctive markings as well (SILTS pod and black tiles atop the vertical stabilizer being the 2nd most noticeable difference).

Correct, I watched it being applied. At the time we were told it was to protect the midbody hydraulic lines. But there aren't any hydraulic lines in that part of the wing. So I would guess that Mr. Hale's explanation is correct.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/12/2012 08:56 am
Hi all.

Question about the ET. Apart the changes to the ligth version and then superlight version, have there been other changes in the ET structure or systems before the Columbia accident?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/12/2012 06:27 pm
Quote
Quote
Quote from: sivodave on 02/05/2012 07:53 PMHi all.

Question about the star trackers. I know that two different types were used, namely the solid state start tracker and the image dissector tube star tracker. 

I'd like to know the advantage of the one type respect the other. Which
one was better? could an orbiter have both types at the same time?

Thanks very much

Regards

Davide

Yes, the two types could be used interchangeably and mixed on the same flight. I suspect the older ones were simply becoming unsupportable due to their age.

Thanks DMeader. Just another question: in what sense the only ones became unsupportable? Unsupportable from a software point of view or maintenance? If they were unsupportable, why they flew with both type together?

Thanks very much

Regards

Davide

The software didn't "know" which type of star tracker was being flown.  There were a lot of pieces of equipment we had to know which type was being used, but not the star trackers.  For the other equipment, the selection was usually done with an I-Load (or TMBU update), so it wasn't that difficult as long as there wasn't a late change.

Usually aging equipment that needs to be replaced was due to the inability to find spare parts.  I suspect that the image dissector tube was not a very common part and is probably no longer made.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/14/2012 11:41 pm
I've been looking at the launch attempts for all shuttle missions and have noticed a few examples of recycles back to T-20 minutes for another launch attempt on the same day.  The question is, was there ever one of these that actually launched?  As all of these missions were in the early days there isn't much information available and the examples I have read about ended up getting scrubbed in the end, for example STS-1 (I beleive) and STS-61-C.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/14/2012 11:59 pm
I've been looking at the launch attempts for all shuttle missions and have noticed a few examples of recycles back to T-20 minutes for another launch attempt on the same day.  The question is, was there ever one of these that actually launched?  As all of these missions were in the early days there isn't much information available and the examples I have read about ended up getting scrubbed in the end, for example STS-1 (I beleive) and STS-61-C.
Off the top of my head, 51-F is one.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/15/2012 01:50 pm
I've been looking at the launch attempts for all shuttle missions and have noticed a few examples of recycles back to T-20 minutes for another launch attempt on the same day.  The question is, was there ever one of these that actually launched?  As all of these missions were in the early days there isn't much information available and the examples I have read about ended up getting scrubbed in the end, for example STS-1 (I beleive) and STS-61-C.

The reason that was possible at that time was there were 4-hour launch windows.  So, there was enough time to go back to 20 minutes, work a problem and restart at the transition to OPS 1.  Once the orange pumpkin suits were added, the window was reduced to 2.5 hours.  If a rendezvous was required, then the window was (much) shorter (from a little over an hour down to 5 minutes).  So there was no time to recycle to 20 minutes.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/16/2012 01:37 am
Some interesting reading on this subject in the S0007 volume 2 recycle control sequence.  One strange procedure I noticed is that it says that if a cutoff has occurred after T-16 seconds and the launch is not going to be scrubbed then the sound surpression water tank is to be refilled.  From reading previous threads I thought the rule was that if you went below T-31 seconds then you had to scrub so why does S0007 contain procedures for same day launch attempt when the countdown is as low as T-16 seconds?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/16/2012 03:24 am
Some interesting reading on this subject in the S0007 volume 2 recycle control sequence.  One strange procedure I noticed is that it says that if a cutoff has occurred after T-16 seconds and the launch is not going to be scrubbed then the sound surpression water tank is to be refilled.  From reading previous threads I thought the rule was that if you went below T-31 seconds then you had to scrub so why does S0007 contain procedures for same day launch attempt when the countdown is as low as T-16 seconds?

I don't remember any rule that said you had to scrub after a T-31 hold.  The time limit for scrubbing was T-6.6 seconds when the SSMEs started.  I forget if the H2 igniters (the sparklers) had a second cartridge or not, which would have allowed for a second attempt if the hold was between T-11 seconds and T-6 seconds.

Kind of irrelevent later in the program because of the limited duration windows.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/16/2012 04:12 am
http://forum.nasaspaceflight.com/index.php?topic=10600.950

It was discussed back in 2008 and the suggestion there was that it would take more than a day before another attempt could be made due to the SRB HPUs.  STS-93 for example had a 48 hour turnaround  I do see reference in the S0007 to a "manifold refill" if second launch attempt is to be made so it does seem that there is a procedure for this. 

Out of interest, how long would it have taken to get from a GLS cutoff to resuming the count at T-20 minutes in an STS-93 situation where the issue could have been quickly resolved?  It says 1 hour 30 minutes in the S0007 where it says to refill the sound surpression water tank although I'm not sure if this is referring to the time it would take to refill the tank before the count could be resumed.  Obsviously this would never be an option for an ISS mission like STS-93 but would be intersted to know if it could have been done within the later 2.5 hour launch windows.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/16/2012 11:54 am
It was discussed back in 2008 and the suggestion there was that it would take more than a day before another attempt could be made due to the SRB HPUs.
That was specific to that 61-C cutoff, which was due to an indication of a HPU overspeed.  This would be one of the topics in the case of any cutoff after T-31 -- whatever was "wrong" might be worth analyzing/discussing overnight.  And if something appeared to be broken (as with the HPU), then scrub might be the only option.

Out of interest, how long would it have taken to get from a GLS cutoff to resuming the count at T-20 minutes in an STS-93 situation where the issue could have been quickly resolved?  It says 1 hour 30 minutes in the S0007 where it says to refill the sound surpression water tank although I'm not sure if this is referring to the time it would take to refill the tank before the count could be resumed. 
Kind of an interesting topic; there are multiple references to IMU alignment unplanned hold time in the 90 minute range back in the 80s contributing to the length of recycles (51-F on 29 July 1985, 61-C on 6 January 1986, etc.)

Subsequently, there were a few launch attempts later in the program that were delayed for long periods at T-9 minutes...would be interesting to see whether the unplanned hold time was extended for the original KT-70 units and/or the HAINS units.  Or maybe that coupled with other software and procedural changes.  After the crew-on-back limits were more strictly enforced, there were a couple of cases in the late 80s and early/mid 90s with long-ish holds that ran close to 90 minutes or a bit longer.  The last long one I can think of was with STS-64 in September, 1994.

Obsviously this would never be an option for an ISS mission like STS-93 but would be intersted to know if it could have been done within the later 2.5 hour launch windows.
Nit: STS-93 was the last Shuttle IUS deploy mission; it had a longer window than Mir or ISS rendezvous/docking missions.  Probably in the 60 minute range (which was exhausted on the second attempt, due to weather).
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/16/2012 12:25 pm
Quote from: psloss
That was specific to that 61-C cutoff, which was due to an indication of a HPU overspeed.  This would be one of the topics in the case of any cutoff after T-31 -- whatever was "wrong" might be worth analyzing/discussing overnight.  And if something appeared to be broken (as with the HPU), then scrub might be the only option.
I was referring to mkirk's comments that said you were done for the day once you go past T-31 seconds and that there was a rule about this before STS-61-C was mentioned in that converstation.  Having been reading these threads since then I always thought that would be the case until I discovered the S0007 recycle control sequence that contained procedures for a second launch attempt even if there was a cutoff after T-31 seconds.  For the December launch attempt though of STS-61-C I note http://www.space-shuttle.com/challenger2.htm says that the countdown was recycled to T-20 minutes but it was hopeless so it would seem that they didn't immediately scrub after the cutoff at T-14 seconds although this could of course just be referring to the fact that the countdown has to be recycled to T-20 minutes after a cutoff regardless of it there is going to be a scrub or not.


Quote
Kind of an interesting topic; there are multiple references to IMU alignment unplanned hold time in the 90 minute range back in the 80s contributing to the length of recycles (51-F on 29 July 1985, 61-C on 6 January 1986, etc.)
According to the "Some Trust in Chariots" book about Challenger, there was also a recycle on January 7 although exactly why they had to recycle to T-20 minutes and count back down to T-9 minutes when they could have just waited at T-9 minutes until the end of the window is not clear.

Quote
After the crew-on-back limits were more strictly enforced, there were a couple of cases in the late 80s and early/mid 90s with long-ish holds that ran close to 90 minutes or a bit longer.  The last long one I can think of was with STS-64 in September, 1994.
Would these have just been long holds though rather than recycles?  Even for STS-51-F I have seen it just referred to as a long hold even though in this case there was a recycle.

Also even though it wasn never going to launch, I believe there was a recycle during a tanking test for STS-114.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/16/2012 08:05 pm
Quote from: psloss
That was specific to that 61-C cutoff, which was due to an indication of a HPU overspeed.  This would be one of the topics in the case of any cutoff after T-31 -- whatever was "wrong" might be worth analyzing/discussing overnight.  And if something appeared to be broken (as with the HPU), then scrub might be the only option.
I was referring to mkirk's comments that said you were done for the day once you go past T-31 seconds and that there was a rule about this before STS-61-C was mentioned in that converstation.  Having been reading these threads since then I always thought that would be the case until I discovered the S0007 recycle control sequence that contained procedures for a second launch attempt even if there was a cutoff after T-31 seconds.
My point was that whatever caused the cutoff inside the "go for auto sequence start" GLS milestone might preclude use of any hypothetical capability to recycle.  So in the case of the December, 1985, attempt -- or the STS-51 attempt in July, 1993 -- even if there had been an unlimited launch window, the failure that caused the cutoff was also going to require a lengthy R&R (multiple days).

For the December launch attempt though of STS-61-C I note http://www.space-shuttle.com/challenger2.htm says that the countdown was recycled to T-20 minutes but it was hopeless so it would seem that they didn't immediately scrub after the cutoff at T-14 seconds although this could of course just be referring to the fact that the countdown has to be recycled to T-20 minutes after a cutoff regardless of it there is going to be a scrub or not.
It might not have been immediately announced, but it might also have taken longer to review the data back then to see what caused the cutoff.  It wasn't long after it was reported the problem was a HPU overspeed that it was reported they were done for the year.

According to the "Some Trust in Chariots" book about Challenger, there was also a recycle on January 7 although exactly why they had to recycle to T-20 minutes and count back down to T-9 minutes when they could have just waited at T-9 minutes until the end of the window is not clear.
Possibly the same thing as one of the drivers from the previous day's recycle -- the IMUs needed to be realigned.  Forgot to add to earlier post; this has been linked before, but you can see some references to this in the Space Shuttle Missions Summary book:
http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf

The realign is noted in the Jan. 6 attempt after the recycle, but given a long weather hold on the 7th, they also might have held past the unplanned hold limit for the IMUs at that time (or knew they were going to hold that long) and based on the procedures at the time had to recycle to T-20.

Quote
After the crew-on-back limits were more strictly enforced, there were a couple of cases in the late 80s and early/mid 90s with long-ish holds that ran close to 90 minutes or a bit longer.  The last long one I can think of was with STS-64 in September, 1994.
Would these have just been long holds though rather than recycles?
Refer to the SSMS book link.  There were a few other situations like that back then (post RTF after 51L) and that was during a period of time (late 80s/early 90s) when the Shuttle program was upgrading hardware, so it's conceivable that the countdown clock held at T-9 but different procedures were executed.  (But that's why I was wondering about upgrades related to either the original IMUs or the HAINS units and whether that changed/extended the unplanned hold capability.)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/17/2012 01:07 am
After the crew-on-back limits were more strictly enforced, there were a couple of cases in the late 80s and early/mid 90s with long-ish holds that ran close to 90 minutes or a bit longer.  The last long one I can think of was with STS-64 in September, 1994.
The Space Shuttle Missions Summary Book notes another long weather hold I'd forgotten about -- the STS-73 launch attempt on 15 October 1995.  It did get a little better than these two shots, but not good enough when the crew-on-back time ran out.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/17/2012 01:26 am
My point was that whatever caused the cutoff inside the "go for auto sequence start" GLS milestone might preclude use of any hypothetical capability to recycle.  So in the case of the December, 1985, attempt -- or the STS-51 attempt in July, 1993 -- even if there had been an unlimited launch window, the failure that caused the cutoff was also going to require a lengthy R&R (multiple days).
So effectively even though second launch attempt after cutoff below T-31 seconds was allowed in S0007, it's very unlikely it would ever have been used due to the reasons you said above.  I can't find any reference to the rule mkirk talked about but if there was a rule then this would not have been in S0007?

Quote
Possibly the same thing as one of the drivers from the previous day's recycle -- the IMUs needed to be realigned.  Forgot to add to earlier post; this has been linked before, but you can see some references to this in the Space Shuttle Missions Summary book:
http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf
Interestingly one source I have said that the countdown on January 6 was recycled first to T-9 minutes and then back to T-20 minutes.  If the LOX drainback issue resulted in the recycle to T-9 then maybe it was IMU alignement issues that required a recycle back to T-20 minutes.  However I am not convinced about this as I believe GLS cutoff was called at T-31 seconds which would have required a recycle all the way to T-20 minutes.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 02/17/2012 03:33 am
My point was that whatever caused the cutoff inside the "go for auto sequence start" GLS milestone might preclude use of any hypothetical capability to recycle.  So in the case of the December, 1985, attempt -- or the STS-51 attempt in July, 1993 -- even if there had been an unlimited launch window, the failure that caused the cutoff was also going to require a lengthy R&R (multiple days).
So effectively even though second launch attempt after cutoff below T-31 seconds was allowed in S0007, it's very unlikely it would ever have been used due to the reasons you said above.  I can't find any reference to the rule mkirk talked about but if there was a rule then this would not have been in S0007?

Quote
Possibly the same thing as one of the drivers from the previous day's recycle -- the IMUs needed to be realigned.  Forgot to add to earlier post; this has been linked before, but you can see some references to this in the Space Shuttle Missions Summary book:
http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf
Interestingly one source I have said that the countdown on January 6 was recycled first to T-9 minutes and then back to T-20 minutes.  If the LOX drainback issue resulted in the recycle to T-9 then maybe it was IMU alignement issues that required a recycle back to T-20 minutes.  However I am not convinced about this as I believe GLS cutoff was called at T-31 seconds which would have required a recycle all the way to T-20 minutes.


Sorry if my answer back then confused you!  Time to back step from that a little bit….Honestly I don’t think a “cut-off” after T-31 in itself meant that a second attempt was out of the question.  I do know that was the assumption on my part – and most of the people I worked with – during the Space Station era where the short launch windows ruled the day.  I do remember beating the subject to death in the MCC back rooms with my co-workers during the STS-93 launch attempts (which wasn't a station flight) and that likely accounts for my “know it all attitude” in my previous answer.

Anyway, the other stuff I mentioned would certainly come into play after T-31 seconds and apart from the issue that stopped the countdown in the first place, a second launch attempt would be dependent on where the “cut-off” occurred.  Were the HPUs started? I think another HPU start was technically permissible, but if I recall correctly there was only enough fuel for 165 seconds of total run time, so you would have to ensure that the fuel quantity redline was satisfied on the second run thru.  Did the sound suppression and firex systems flow?  Did the ROFIs fire?  I’m almost positive that you had only one shot with the ROFIs, but if there is a GSE expert out there hopefully they will confirm or rebut that.

The LCC (Launch Commit Criteria) had 3 or 4 sections that discussed General rules, crew constraints, RSLS constraints, sequencing, safing, etc that may provide you with more info.  In earlier versions there was even a section titled Hold & Cut-off Guidelines, but it was ultimately deleted and absorbed by other sections.  I don’t remember what it said and since I am traveling I don’t have access to my shuttle documents right now.  Even if I was back at my office I’m not sure I could stand to look at my shuttle stuff now – too depressing given the recent retirement.

As stated by others in response to your question, all of those factors were pretty much irrelevant for Space Station launches since you simply could not recycle and get back into the launch posture in time – thus if a “cut-off” occurred you were done for the day and the only reasonable course of action was to safe the vehicle and then head out the south gate to “Shuttle’s” for some hot wings and a select cold beverage.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/18/2012 03:13 pm
So effectively even though second launch attempt after cutoff below T-31 seconds was allowed in S0007, it's very unlikely it would ever have been used due to the reasons you said above.  I can't find any reference to the rule mkirk talked about but if there was a rule then this would not have been in S0007?
No, sorry if I'm confusing things, too, but if you're referring to the second 61-C launch attempt (6 January 1986), that did not proceed through the "auto sequence start" milestone:
http://forum.nasaspaceflight.com/index.php?topic=10600.msg315235#msg315235

The link in that post (to an archived posting of the 61-C mission report) has a detailed explanation of what happened.

Interestingly one source I have said that the countdown on January 6 was recycled first to T-9 minutes and then back to T-20 minutes.
This may have been standard for re-configuring the vehicle at the time for a recycle inside the late GLS milestones.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 02/19/2012 04:34 am
No, sorry if I'm confusing things, too, but if you're referring to the second 61-C launch attempt (6 January 1986), that did not proceed through the "auto sequence start" milestone:
http://forum.nasaspaceflight.com/index.php?topic=10600.msg315235#msg315235

The link in that post (to an archived posting of the 61-C mission report) has a detailed explanation of what happened.
No, the confusion was over why S0007 contained procedures for another attempt on the same day if the countdown was below T-31 seconds when I thought that once you went below T-31 seconds that was it for the day but it has now been clarified that this did not automatically result in a scrub.  As you said above though, on the December launch attempt of STS-61-C this was never going to be an option due to the time needed to resolve the issue.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/19/2012 05:43 am
If a rendezvous was required, then the window was (much) shorter (from a little over an hour down to 5 minutes).  So there was no time to recycle to 20 minutes.

Depended on the inclination of the rendezvous target. For Mir and ISS, you're right, it was 5 minutes and there was no chance for recycle. For lower inclination targets like HST, the window was longer, around fifty minutes IIRC. Still iffy for a recycle, so your basic point stands.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/19/2012 05:58 am
Quote
Quote
Quote from: sivodave on 02/05/2012 07:53 PMHi all.

Question about the star trackers. I know that two different types were used, namely the solid state start tracker and the image dissector tube star tracker. 

I'd like to know the advantage of the one type respect the other. Which
one was better? could an orbiter have both types at the same time?

Thanks very much

Regards

Davide

Yes, the two types could be used interchangeably and mixed on the same flight. I suspect the older ones were simply becoming unsupportable due to their age.

Thanks DMeader. Just another question: in what sense the only ones became unsupportable? Unsupportable from a software point of view or maintenance? If they were unsupportable, why they flew with both type together?

Thanks very much

Regards

Davide

The software didn't "know" which type of star tracker was being flown.  There were a lot of pieces of equipment we had to know which type was being used, but not the star trackers.  For the other equipment, the selection was usually done with an I-Load (or TMBU update), so it wasn't that difficult as long as there wasn't a late change.

Usually aging equipment that needs to be replaced was due to the inability to find spare parts.  I suspect that the image dissector tube was not a very common part and is probably no longer made.

Quite true, though the program had a few spares and we were able to support IDT through the end of the program. Which was a good thing since the IDTs tracked bright rendezvous targets like ISS better than the solid state trackers. We actually reverted the -Z tracker on one orbiter (OV-104) back to IDT for this very reason. At the end of the program, all three orbiters had IDTs in the -Z slot (since that star tracker was prime during rendezvous ops) and solid state trackers in the -Y slot (for tracking dim stars while docked to ISS).
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/23/2012 03:07 pm

Quite true, though the program had a few spares and we were able to support IDT through the end of the program. Which was a good thing since the IDTs tracked bright rendezvous targets like ISS better than the solid state trackers. We actually reverted the -Z tracker on one orbiter (OV-104) back to IDT for this very reason. At the end of the program, all three orbiters had IDTs in the -Z slot (since that star tracker was prime during rendezvous ops) and solid state trackers in the -Y slot (for tracking dim stars while docked to ISS).

Jorge, thanks!  I did not know that.  I'm hoping it was because this was all transparent to us and not because my memory is faulty :-)

Was it the streaking line effect effect that caused the solid state trackers to be worse for bright objects?  I've seen enough CCD and CMOS sensors generate a line above and below a really bright object with a dark background.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 02/25/2012 10:46 pm
Hi all,

I'm reading on the CAIB Volume 1 at page 51, that after ET-93 the foam types changed from the NCFI 24-124, NCFI 24-57 and BX-250, but then nothing else is added.

Does anybody of you know which are then new types of foam used after ET-93?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 03/07/2012 07:55 pm
What are the dimensions of the middeck LxWxH?

Where did they put the removeable seats during the mission?  Were the 2 seats behind the PLT and CDR on the flight deck removed while in orbit as well?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/08/2012 02:12 pm
Quote from: spacecane
What are the dimensions of the middeck LxWxH?
Where did they put the removeable seats during the mission?  Were the 2 seats behind the PLT and CDR on the flight deck removed while in orbit as well? 

I don't remember the middeck dimensions, but I can tell you that the removable seats were stored in the cabin, in some of the middeck lockers while the pilots seats where left where they were for the all duration of the flight.

if you have a look [link=http://www.nasa.gov/centers/johnson/pdf/390651main_shuttle_crew_operations_manual.pdf] here [/link] you can find more info about it.

Davide
 
 
 
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/08/2012 02:13 pm
Hi all.

A question of orbital mechanics. When the Shuttle had to perform OMS burns for reaching a target (ISS, satellite, HST, etc…), was the burn calculated for accomplishing a Hohmann transfer (that’s to say an elliptic orbital transfer) or was instead a Lambert solution (that’s to say a transfer that required more energy then a Hohmann transfer?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Liryc on 03/09/2012 08:32 am
Question deleted and reported to the Launch Complex 39 Q&A (http://forum.nasaspaceflight.com/index.php?topic=14430.msg871058#msg871058) section
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/10/2012 05:48 pm
Were the Flight Readiness Firings done with inert SRB's or loaded SRB's?

And (this could possibly belong in the SRB Q&A thread), what is an inert SRB? Just the empty casings, or loaded with inert mass to simulate propellant?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/10/2012 05:54 pm
Were the Flight Readiness Firings done with inert SRB's or loaded SRB's?

And (this could possibly belong in the SRB Q&A thread), what is an inert SRB? Just the empty casings, or loaded with inert mass to simulate propellant?
The FRFs were done with a complete and ready flight-stack. Only things changed between the FRF and the launch were the SSMEs.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/10/2012 05:56 pm
loaded SRM's
Inert SRM's have the rubber fuel compound but no oxidizer (AP)
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 03/11/2012 05:57 pm
Did SLC-6 have the centaur Umbilical system when cancelled, or was it planned to be added after a few launches?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/11/2012 06:09 pm
Did SLC-6 have the centaur Umbilical system when cancelled, or was it planned to be added after a few launches?
No Centaur servicing equipment at SLC-6 when the launches were cancelled.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/11/2012 07:16 pm
Did SLC-6 have the centaur Umbilical system when cancelled, or was it planned to be added after a few launches?
No Centaur servicing equipment at SLC-6 when the launches were cancelled.

Or planned.  It was only studied.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 03/12/2012 08:15 pm
Did SLC-6 have the centaur Umbilical system when cancelled, or was it planned to be added after a few launches?

Don't forget the lift capability would have been limited for polar orbits and this was before the superlightweight tank.  So, a massive fueled Centaur would have taken away from what payload weight was available.  Also once already in a low Earth polar orbit, what would you have used Centaur for?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/12/2012 09:51 pm
Hi all.

A question about the Space Shuttle final approach during rendezvous. With reference to the attached drawing I don’t understand the difference between an approach along the +V bar and an inertial approach. Which are the differences and how it was possible to fly them?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/12/2012 09:55 pm
Hi all.

A question about the Space Shuttle final approach during rendezvous. With reference to the attached drawing I don’t understand the difference between an approach along the +V bar and an inertial approach. Which are the differences and how it was possible to fly them?

In a +Vbar approach the orbiter was maintained in a tail-to-Earth attitude after arrival on the +Vbar. In an inertial approach the orbiter was maintained in inertial attitude hold throughout the approach. Piloting techniques were similar; the CDR would maintain a prescribed range-rate profile and keep the target above the payload bay.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/12/2012 10:08 pm
Quote from: Jorge
In a +Vbar approach the orbiter was maintained in a tail-to-Earth attitude after arrival on the +Vbar. In an inertial approach the orbiter was maintained in inertial attitude hold throughout the approach. Piloting techniques were similar; the CDR would maintain a prescribed range-rate profile and keep the target above the payload bay.

Thanks for the answer. However I was wondering why the two curves in the diagram are different. My thinking is that with an intertial attitude flown along the +V Bar the orbiter would have then approached the target with not the right relative attitude. Was that the case?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/12/2012 10:12 pm
Quote from: Jorge
In a +Vbar approach the orbiter was maintained in a tail-to-Earth attitude after arrival on the +Vbar. In an inertial approach the orbiter was maintained in inertial attitude hold throughout the approach. Piloting techniques were similar; the CDR would maintain a prescribed range-rate profile and keep the target above the payload bay.

Thanks for the answer. However I was wondering why the two curves in the diagram are different. My thinking is that with an intertial attitude flown along the +V Bar the orbiter would have then approached the target with not the right relative attitude. Was that the case?

Correct.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/12/2012 10:16 pm
Did SLC-6 have the centaur Umbilical system when cancelled, or was it planned to be added after a few launches?

Don't forget the lift capability would have been limited for polar orbits and this was before the superlightweight tank.  So, a massive fueled Centaur would have taken away from what payload weight was available.  Also once already in a low Earth polar orbit, what would you have used Centaur for?

GSO missions.  I funded a DOD study.  With FWC SRB, 109 MPL and Centaur G prime 10klb to GSO.  But with a loss of 10 feet of payload length vs an east coast mission
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 03/13/2012 04:09 am
Why go to GSO from VAFB?  Do you possibly mean SSO?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/13/2012 04:16 am
Why go to GSO from VAFB?  Do you possibly mean SSO?

From context, I don't think so... payload from VAFB to SSO would have been a lot more than 10 klb.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/13/2012 07:21 am
Why go to GSO from VAFB?  Do you possibly mean SSO?

Alternate and backup launch site.

It took a 3 burn bi elliptic transfer orbit
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/13/2012 02:49 pm
Hi all.

Another question for the rendezvous expert guys.

After Ti burn, how were the MCs burns computed? If I’ve understood well the MCs burns were targeted by the crew since they had more accurate data available during the last part of the approach.

What I’d like to understand is how each MC burn was computed. Because using Lambert to compute the burn, they had to feed the computers with data regarding the point of arrival, along the trajectory. So, for example, which kind of data they provided for executing MC-1 burn to get to the point for MC-2?

Were always all MCs burns done or sometimes they could skip some burn?

Thanks very much

Davide

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 03/17/2012 12:54 pm
Hi all.

Another question for the rendezvous expert guys.

After Ti burn, how were the MCs burns computed? If I’ve understood well the MCs burns were targeted by the crew since they had more accurate data available during the last part of the approach.

What I’d like to understand is how each MC burn was computed. Because using Lambert to compute the burn, they had to feed the computers with data regarding the point of arrival, along the trajectory. So, for example, which kind of data they provided for executing MC-1 burn to get to the point for MC-2?

Were always all MCs burns done or sometimes they could skip some burn?

Thanks very much

Davide


Davide, after the TI burn and the first MC (MC4), the crew would be in "manual" mode.   For the manual part of the burns, the computations were performed on the ground and onboard in RPOP on the ThinkPads (for the later half of the Shuttle flights).  RPOP used rendezvous radar, handheld lidar and the TCS payload bay laser as inputs.  The rendezvous radar was of limited use as the target got bigger, which is why it could be transitioned back to TV/data mode during later prox ops.

Onboard, I believe a COAS fix on the target was also used to manually compute a solution - particularly in the "old days" (before RPOP).

Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/17/2012 10:10 pm
After Ti burn, how were the MCs burns computed? If I’ve understood well the MCs burns were targeted by the crew since they had more accurate data available during the last part of the approach.

Correct.

Quote
What I’d like to understand is how each MC burn was computed. Because using Lambert to compute the burn, they had to feed the computers with data regarding the point of arrival, along the trajectory. So, for example, which kind of data they provided for executing MC-1 burn to get to the point for MC-2?

Refer to the STS-135 rendezvous procedures on the NASA public site:

http://www.nasa.gov/centers/johnson/pdf/567076main_RNDZ_135_F.pdf

The MC targeting procedures are in blocks 17A, 17B, 18A, 18B, 19B, and 20A (pages 67-70 of the PDF). I've attached the MC1 targeting block (17A) as an example. The procedures were basically the same as for the previous onboard targeted burns (NCC and Ti). Navigation state vectors went to the targeting software automatically, so the crew only had to check that the correct orbiter state vector was selected prior to targeting. The crew performed one keyboard entry to recall the targeting data for the desired burn, checked the targeting data, performed another keyboard entry to compute the solution, then recorded the solution in the PAD in the book. MC1, 2, and 3 targeted the MC4 point. MC4 targeted the Rbar.

Quote
Were always all MCs burns done or sometimes they could skip some burn?

The RCS burn cue card (page 209 of the PDF) directed the crew to trim the VGOs to less than 0.2 fps. So if the final solution was less than 0.2, the crew would skip the burn unless MCC directed otherwise.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/20/2012 09:51 pm
Guys, thanks very much for your answers, they are really helpful. I’ve started to give a better look to the Rendezvous Flight Data File for STS-135 (just as an example since Jorge used the same).

Taking for example page 67, I see that at the beginning of the timeline, the crew has to target the burn for MC-1 (preliminary) then MC-1 (intermediate) and finally MC-1 (final). What do they mean? Why are the three different MC-1 burn targets? I also see that in the document there is the target condition for only one MC-1 and not for MC-1 preliminary, or intermediate or final.

Reasoning about it, my guess is that the solution for a given MC was computed three times so to refine it up to when the burn had to be executed. Probably because from when the MC burn preliminary was computed up to when the MC burn final was executed the trajectory could be somehow perturbed. Is my guess correct?

Always at the same page, at minute PET 00:17 is written to perform TARGET MC-1 (final) and then to perform RCS BURN (cue card). I don’t understand if this RCS burn had to be carried out by the crew (PLT is shown in the timeline) or if it was automatic. Or, based on what Jorge has written, the RCS burn had to perform only if the solution computed for the given MC had a Delta-V more than 0.2 ft/s?

Also I see from the same page that for computing the burn solution ORBIT TGT was used. Why was used this display and not MNVR display?
Also I don’t understand if the RPOP was used before MC-4 or after? If I am right RPOP did not communicate with GNC so my guess is that RPOP was used only after MC-4 or to better say for departure from the +R Bar for the final approach. Could you please confirm this?

Thanks very much for your help
Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/21/2012 02:53 am
Taking for example page 67, I see that at the beginning of the timeline, the crew has to target the burn for MC-1 (preliminary) then MC-1 (intermediate) and finally MC-1 (final). What do they mean? Why are the three different MC-1 burn targets? I also see that in the document there is the target condition for only one MC-1 and not for MC-1 preliminary, or intermediate or final.

Reasoning about it, my guess is that the solution for a given MC was computed three times so to refine it up to when the burn had to be executed. Probably because from when the MC burn preliminary was computed up to when the MC burn final was executed the trajectory could be somehow perturbed. Is my guess correct?

Yes. The software only kept the most recent solution so only the final solution mattered when it came to actually performing the burn. The other two solutions were computed for trend monitoring.

Quote
Always at the same page, at minute PET 00:17 is written to perform TARGET MC-1 (final) and then to perform RCS BURN (cue card). I don’t understand if this RCS burn had to be carried out by the crew (PLT is shown in the timeline) or if it was automatic. Or, based on what Jorge has written, the RCS burn had to perform only if the solution computed for the given MC had a Delta-V more than 0.2 ft/s?

It had to be performed by the crew.

Quote
Also I see from the same page that for computing the burn solution ORBIT TGT was used. Why was used this display and not MNVR display?

The crew keyboard entries for performing various actions were tied to the items on the displays. ORBIT TGT contained the display items for recalling the targeting data and computing the solution. ORBIT MNVR EXEC contained the display items for loading and executing the burn after the solution was computed.

Quote
Also I don’t understand if the RPOP was used before MC-4 or after? If I am right RPOP did not communicate with GNC so my guess is that RPOP was used only after MC-4 or to better say for departure from the +R Bar for the final approach. Could you please confirm this?

RPOP received data from GNC but could not talk to it. It was used purely for situational awareness by the crew. The procedures called for the crew to run RPOP on p. 57 of the PDF. So the RPOP display was available well before MC4 but the crews typically did not use it for much until after MC4.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/21/2012 02:53 pm
Does anyone know if there is a technical reason why the LO2 connections are on the starboard side and the LH2 connections are on the port? I’m talking about the ET feed lines, umbilical wells and T-0 panels.

I can’t find a reason why they would be that way, but I can find a reason why they shouldn’t. The LH2 and LO2 dewars at the pads are in the north east and north west corners of the pad respectively and they were there long before the shuttle was designed. That means that the LH2 lines run down side 4 of the MLP which is the starboard side of the shuttle and the LO2 lines run down side 2 which is to port. That in turn means that the lines have to cross over each other on side 1 to get to their respective TSMs. The LH2 lines go up and run under the blast shield and then turn into the tunnel while the LO2 lines run along the face of the MLP before turning up to enter their tunnel. If the connections on the shuttle were reversed the lines could be kept separate and provided with physical barriers to limit gas mixing if there were leaks.

If there isn’t a specific reason for this, is it possible that Marshall just missed it back in the early 70’s? That sound impossible to me, but you never know.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/21/2012 03:37 pm
Does anyone know if there is a technical reason why the LO2 connections are on the starboard side and the LH2 connections are on the port? I’m talking about the ET feed lines, umbilical wells and T-0 panels.

I can’t find a reason why they would be that way, but I can find a reason why they shouldn’t. The LH2 and LO2 dewars at the pads are in the north east and north west corners of the pad respectively and they were there long before the shuttle was designed. That means that the LH2 lines run down side 4 of the MLP which is the starboard side of the shuttle and the LO2 lines run down side 2 which is to port. That in turn means that the lines have to cross over each other on side 1 to get to their respective TSMs. The LH2 lines go up and run under the blast shield and then turn into the tunnel while the LO2 lines run along the face of the MLP before turning up to enter their tunnel. If the connections on the shuttle were reversed the lines could be kept separate and provided with physical barriers to limit gas mixing if there were leaks.

If there isn’t a specific reason for this, is it possible that Marshall just missed it back in the early 70’s? That sound impossible to me, but you never know.


I'll SWAG it...

The need for GH2 venting and the fact that the umbilical for that has to be on the FSS, which is to port?

I doubt they "forgot" about the locations of the LC-39 tanks. LC-39 was not necessarily going to be the STS launch site early on.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/21/2012 04:16 pm
I'll SWAG it...

The need for GH2 venting and the fact that the umbilical for that has to be on the FSS, which is to port?
Possible, but I kind of doubt it. The LH2 vent line in the interstage is "behind" the SRB beam while the LO2  J-leg is in front of it. Moving the J-leg to the port side shouldn't have affected the LH2 vent any.

Quote
I doubt they "forgot" about the locations of the LC-39 tanks. LC-39 was not necessarily going to be the STS launch site early on.

 I thought of that, but no. By the time they reached the phase B studies in the 1970 time frame (which is when the ET concept firmed up) they were already commited to LC-39 (based on cost, if nothing else). The decision of what side to run the line on probably didn't get made until the phase C/D work in 71 or 72 if not later.

 I'm not suggesting that they just "forgot" where the tanks were. Originaly, activities at the cape fell under Marshall's "Launch Opperations Directorate". That included design of the launch pads and equipment. There were some notorious problems with the project management of the swing arms for the SaturnV LUT. Whether or not that had anything to do with what happened subsequently is open to debate, but the fact is that KSC was formed as it's own center and assumed the responsability for launch equipment design and fabrication. By the time the Shuttle came along, the launch pad wasn't really Marshall's problem anymore and so this issue might not have come up on their radar.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/21/2012 05:58 pm
I'll SWAG it...

The need for GH2 venting and the fact that the umbilical for that has to be on the FSS, which is to port?
Possible, but I kind of doubt it. The LH2 vent line in the interstage is "behind" the SRB beam while the LO2  J-leg is in front of it. Moving the J-leg to the port side shouldn't have affected the LH2 vent any.

Quote
I doubt they "forgot" about the locations of the LC-39 tanks. LC-39 was not necessarily going to be the STS launch site early on.

 I thought of that, but no. By the time they reached the phase B studies in the 1970 time frame (which is when the ET concept firmed up) they were already commited to LC-39 (based on cost, if nothing else). The decision of what side to run the line on probably didn't get made until the phase C/D work in 71 or 72 if not later.

 I'm not suggesting that they just "forgot" where the tanks were. Originaly, activities at the cape fell under Marshall's "Launch Opperations Directorate". That included design of the launch pads and equipment. There were some notorious problems with the project management of the swing arms for the SaturnV LUT. Whether or not that had anything to do with what happened subsequently is open to debate, but the fact is that KSC was formed as it's own center and assumed the responsability for launch equipment design and fabrication. By the time the Shuttle came along, the launch pad wasn't really Marshall's problem anymore and so this issue might not have come up on their radar.

Maybe fire suppression, then? That's on the FSS, and it would be harder to extinguish an H2 fire on the starboard side of the stack.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/21/2012 07:10 pm
Maybe fire suppression, then? That's on the FSS, and it would be harder to extinguish an H2 fire on the starboard side of the stack.
Actually, the fire suppresion of a fire involving the vehicle is done by nozzles on the deck of the MLP and on top of the TSMs and is pretty symetrical. The FireX system on the FSS is mostly to cool and protect the FSS itself.

 I'm not trying to shoot down every idea you have. Keep em comming and we may find the answer.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/22/2012 11:42 am
Maybe fire suppression, then? That's on the FSS, and it would be harder to extinguish an H2 fire on the starboard side of the stack.
Actually, the fire suppresion of a fire involving the vehicle is done by nozzles on the deck of the MLP and on top of the TSMs and is pretty symetrical. The FireX system on the FSS is mostly to cool and protect the FSS itself.

 I'm not trying to shoot down every idea you have. Keep em comming and we may find the answer.

Probably has to with how they decided to plumb the MPS in the boattail, then. Unless some of the NASA folks here know, you're going to have to dig through some archives at MSFC and JSC. I'll bet those decisions date back to 1974 or '75.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/22/2012 11:56 am
I'll SWAG it...

The need for GH2 venting and the fact that the umbilical for that has to be on the FSS, which is to port?
Possible, but I kind of doubt it. The LH2 vent line in the interstage is "behind" the SRB beam while the LO2  J-leg is in front of it. Moving the J-leg to the port side shouldn't have affected the LH2 vent any.


I would say that is the best answer.  That means that all H2 lines are on the west side of the flame trench
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 03/22/2012 01:14 pm
I'll SWAG it...

The need for GH2 venting and the fact that the umbilical for that has to be on the FSS, which is to port?
Possible, but I kind of doubt it. The LH2 vent line in the interstage is "behind" the SRB beam while the LO2  J-leg is in front of it. Moving the J-leg to the port side shouldn't have affected the LH2 vent any.

I would say that is the best answer.  That means that all H2 lines are on the west side of the flame trench

Actually, the LH2 lines are mostly on the east side. The lines run from the storage dewar and flare off stack to the tower on the north east corner of the MLP. From there, the fill and drain line and the TSM vent line run down the east and south sides of the MLP itself to the valve skid on AP-3. The vent line from the GUP on the ET interstage runs thru the t-0 umbilicle to the FSS and then down to about 35 ft above the hard stand. It then runs to the north and then along the bridge across the north end of the flame trench to the tower at the north east corner of the MLP were it joins the other lines.

From the point of view of the launch pad and facilities, it wouuld make sense to have all the LH2 stuf to the east and LO2 to the west. That is why I'm assumming there is some driving reason on the vehicle itself why the ET and MPS lines are where they are.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 03/23/2012 09:23 am
Hi Jorge.

Thanks for you answers…they are very clear and I’m seeing the light now!

Just two last things regarding this subject:

Quote from: Jorge
Quote
Always at the same page, at minute PET 00:17 is written to perform TARGET MC-1 (final) and then to perform RCS BURN (cue card). I don’t understand if this RCS burn had to be carried out by the crew (PLT is shown in the timeline) or if it was automatic. Or, based on what Jorge has written, the RCS burn had to perform only if the solution computed for the given MC had a Delta-V more than 0.2 ft/s?
It had to be performed by the crew.

When you say that the burn had to be performed by the crew, does this mean that the pilot (or CDR) had to impart commands on the THC for performing the burn, stopping to provide input when the computed Delta-Vs were reached?

Quote from: Jorge
Quote
Also I see from the same page that for computing the burn solution ORBIT TGT was used. Why was used this display and not MNVR display?
The crew keyboard entries for performing various actions were tied to the items on the displays. ORBIT TGT contained the display items for recalling the targeting data and computing the solution. ORBIT MNVR EXEC contained the display items for loading and executing the burn after the solution was computed.

Again just a clarification. Did ORBIT TGT communicate the burn solution to ORBIT MNVR EXEC? Thinking about how the single displays worked and to the fact that there was a PAD for each burn, my guess is that the two displays did not communicate with each other, but that the astronauts had to write the burn solution into the PAD so to know what to insert into the MNVR EXEC display.

One last question. In [link=http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023479_2011024697.pdf] this [/link] document, at page 81 at the bottom of left column, is written the +R approaches became viable with the addition of proximity operations sensors and for this reason STS-66 was the first mission flying this approach. However STS-32 for retrieving LDEF flew a –R approach. So what was the problem in doing a +R bar approach? –R Bar and +R bar are no practically each other’s mirror copy?

Thanks very much

Davide


Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/29/2012 03:05 pm
Question re: STS-88.  According to the post-mission report, Endeavour conducted a Dual Engine OMS Assist maneuver (102 seconds in duration) at 00:02:14 MET, just after SRB speration.  Why was that maneuver performed?  Unity's mass?  Rendezvous considerations?  Something else?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/29/2012 03:21 pm
Question re: STS-88.  According to the post-mission report, Endeavour conducted a Dual Engine OMS Assist maneuver (102 seconds in duration) at 00:02:14 MET, just after SRB speration.  Why was that maneuver performed?  Unity's mass?  Rendezvous considerations?  Something else?  Thanks!

Performance enhancement. Wasn't just STS-88. Almost all shuttle missions to ISS performed OMS Assist.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/29/2012 03:26 pm
Hi Jorge.

Thanks for you answers…they are very clear and I’m seeing the light now!

Just two last things regarding this subject:

Quote from: Jorge
Quote
Always at the same page, at minute PET 00:17 is written to perform TARGET MC-1 (final) and then to perform RCS BURN (cue card). I don’t understand if this RCS burn had to be carried out by the crew (PLT is shown in the timeline) or if it was automatic. Or, based on what Jorge has written, the RCS burn had to perform only if the solution computed for the given MC had a Delta-V more than 0.2 ft/s?
It had to be performed by the crew.

When you say that the burn had to be performed by the crew, does this mean that the pilot (or CDR) had to impart commands on the THC for performing the burn, stopping to provide input when the computed Delta-Vs were reached?

Yes.

Quote
Quote from: Jorge
Quote
Also I see from the same page that for computing the burn solution ORBIT TGT was used. Why was used this display and not MNVR display?
The crew keyboard entries for performing various actions were tied to the items on the displays. ORBIT TGT contained the display items for recalling the targeting data and computing the solution. ORBIT MNVR EXEC contained the display items for loading and executing the burn after the solution was computed.

Again just a clarification. Did ORBIT TGT communicate the burn solution to ORBIT MNVR EXEC?

Yes.

Quote
One last question. In [link=http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023479_2011024697.pdf] this [/link] document, at page 81 at the bottom of left column, is written the +R approaches became viable with the addition of proximity operations sensors and for this reason STS-66 was the first mission flying this approach. However STS-32 for retrieving LDEF flew a –R approach. So what was the problem in doing a +R bar approach? –R Bar and +R bar are no practically each other’s mirror copy?

The +Rbar approach involved performing a retrograde burn at the initial +Rbar crossing in order to stay on the +Rbar and not continue to the +Vbar. This reduced orbital energy. Without accurate sensors the approach rate could not be maintained due to lack of energy.

The STS-32 LDEF -Rbar approach involved continuing to fly up to the +Vbar and around to the -Rbar so sufficient energy to reach the -Rbar was assured. The Rbar approach was only for the last 250 ft or so, so the crew could confirm and maintain approach rate visually if no sensors were available.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 03/29/2012 03:49 pm
Question re: STS-88.  According to the post-mission report, Endeavour conducted a Dual Engine OMS Assist maneuver (102 seconds in duration) at 00:02:14 MET, just after SRB speration.  Why was that maneuver performed?  Unity's mass?  Rendezvous considerations?  Something else?  Thanks!

Performance enhancement. Wasn't just STS-88. Almost all shuttle missions to ISS performed OMS Assist.

Thanks Jorge!
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/31/2012 01:27 pm
Just checking so I have gotten it right: The KU ANTENNA DIRECT STOW switch on R13L, it rotates the DA to the stowed position regardless of the gimbal positions?

If the DIRECT STOW has to be used and the normal way of moving the gimbals to the stowed positions have failed, a EVA is required to manually position the gimbals before a DIRECT STOW is attempted?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 03/31/2012 04:01 pm
Question re: STS-88.  According to the post-mission report, Endeavour conducted a Dual Engine OMS Assist maneuver (102 seconds in duration) at 00:02:14 MET, just after SRB speration.  Why was that maneuver performed?  Unity's mass?  Rendezvous considerations?  Something else?  Thanks!

As Jorge said, added as part of performance enhancements and included as part of OI-26 FSW.   Very similar to what we would have done to dump OMS prop in the event of a single-engine-out abort.  Since the OMS were hypergolic, the difference between a dump and a burn is symantics.

In my simple way of looking at it, the OMS assist burn was closer to perigee (on the ground) and so was more efficient than an OMS-1 burn.  Also you didn't want to carry the prop weight any further than you needed to.  The other constraint is that the OMS could not be burned below a certain altitude.

I believe we always left the burn enabled, but if we didn't want it, the uplinked time could be set to 0.  The OMS assist burn time would be adjusted on launch day.
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 04/02/2012 01:20 am
What was the official name for the suit worn by Shuttle crews between the phaseout of the ejection suit after STS-4 and the introduction of the LES for STS-26? I'm trying to find out about its capabilities and reasons it was used, but a quick search isn't bringing up much about it.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/02/2012 01:27 am
flight suit.  Just like Air Force pilots
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 04/02/2012 01:27 am
flight suit

Damn.  Beat me to it.
Title: Re: Shuttle Q&A Part 5
Post by: Namechange User on 04/02/2012 01:30 am
Since the OMS were hypergolic, the difference between a dump and a burn is symantics.


No, not really.  One is just dumping propellant to shed mass, the other is is shedding mass in the form of increased performance via the burn.

When it became clear that increased performance was required, there was a trade to make.  Just not load extra prop, or load it and burn it once the stack got to sufficient altitude for the engines. 

The net result was increased performance because mass was still being "shed" but in the form of thrust. 
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 04/02/2012 01:59 pm
Question re: STS-88.  According to the post-mission report, Endeavour conducted a Dual Engine OMS Assist maneuver (102 seconds in duration) at 00:02:14 MET, just after SRB speration.  Why was that maneuver performed?  Unity's mass?  Rendezvous considerations?  Something else?  Thanks!

Reminds me of Mike Mullane's book. He was the astronaut working with flight dynamics during the Challenger stand-down when the idea of pre-MECO OMS burns was hatched. Apparently John Young hated the idea.

Hence the comment in this video of 135's launch.

http://www.youtube.com/watch?v=2b0tXtuG9lM&list=UUud6hJ_R1CiKLpXS7_qXFfw&index=5&feature=plcp

On another note, did we ever figure out why they put the gas cap on the left side? I'm guessing because it was made in America. Our cars are all like that. It's those European imports that always have me pulling up to the pump twice at the service station! :)
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 04/03/2012 09:16 pm
Does anyone have any information re: the 20-g floor modification that the orbiters went through?  Based on what I have seen so far, it sounds like a re-enforcement of the flight deck around the seating areas.  Is that the case, or is it something else?
Title: Re: Shuttle Q&A Part 5
Post by: Mark Dave on 04/05/2012 01:43 pm
How are the AFRSI and Nomex FRSI blankets replaced? I saw video of how the tiles are replaced, just chisel out the old tiles by hand and clean up the metal surface  for the new tile. How are the blankets replaced?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 04/09/2012 12:12 pm
Hi all.

two questions again about rendezvous profile.

1. Why MC2 burn was targeted for being carried out based at a specific elevation angle? Was because in this way the star trakkers/COAS/radar had the best field of view of the target, or some other reason?

2. Which is the difference between an NH maneuver in which the height of the orbit is changed and NC maneuver in which the phase of the orbit is changed? are not the same thing? If you do a NC maneuver for changing the closure rate with the target, are you not changing also the shape (and therefore the height) of the orbit?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/09/2012 01:48 pm
How are the AFRSI and Nomex FRSI blankets replaced? I saw video of how the tiles are replaced, just chisel out the old tiles by hand and clean up the metal surface  for the new tile. How are the blankets replaced?

Same way, they are also attached with RTV.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 04/16/2012 04:25 pm
Hi all.

One question about DOLILU. I’ve learned from [link=http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110003654_2011001858.pdf] this [/link] document, that as part of the DOLILU analyses, there was the determination of the Structural Load Indicator (SLI) Constraints for 40 critical points on the structure.

Always as part of DOLILU, there was  also the determination for each Mach number of different Q-plane constraints. One of these plane, was the Orbiter Q-plane, which the file, said was used to determine the orbital structural load redlines.

My question is: which is the difference between the SLI constraints and the Orbiter Q-plane?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 04/16/2012 05:49 pm
Hi all.

two questions again about rendezvous profile.

1. Why MC2 burn was targeted for being carried out based at a specific elevation angle? Was because in this way the star trakkers/COAS/radar had the best field of view of the target, or some other reason?

Targeting MC2 on an elevation angle constraint results in zero inertial line-of-sight rates during manual takeover, making it easier for the crew to discern motion of the target against a fixed star background. Buzz Aldrin explained this effect in his doctoral dissertation.

http://dspace.mit.edu/handle/1721.1/12652

Quote
2. Which is the difference between an NH maneuver in which the height of the orbit is changed and NC maneuver in which the phase of the orbit is changed? are not the same thing? If you do a NC maneuver for changing the closure rate with the target, are you not changing also the shape (and therefore the height) of the orbit?

The difference is the constraint being targeted. NH targets delta-H at a future time and NC targets a given downrange distance at a future time. There is no difference, obviously, in how each type of burn is actually performed, and targeting one constraint obviously affects the other.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 04/18/2012 01:00 pm
I have a question regarding rain on the orbiter.  I have read recently that the tiles and thermal blankets absorbed water in the rain and that in the cases where this happened after landing there was sometimes a need to dry them out during processing.  I have also read that the absorbed water added a lot of weight and was a constraint for SCA transport.

Here is my question.  I attended the launch of STS-128 including the original scrub.  At one point during the night of the first attempt there was such hard rain over the pad that the entire stack seemed to disappear like a David Copperfield trick.  At this point there was no RSS protecting the Orbiter.  Why didn't this rain cause any issue?  I would have thought that at the very least it would have added launch weight which would have affected ascent performance.  I would also think that there would be issues with the water freezing once it got into space.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/18/2012 01:13 pm
I have a question regarding rain on the orbiter.  I have read recently that the tiles and thermal blankets absorbed water in the rain and that in the cases where this happened after landing there was sometimes a need to dry them out during processing.  I have also read that the absorbed water added a lot of weight and was a constraint for SCA transport.

Here is my question.  I attended the launch of STS-128 including the original scrub.  At one point during the night of the first attempt there was such hard rain over the pad that the entire stack seemed to disappear like a David Copperfield trick.  At this point there was no RSS protecting the Orbiter.  Why didn't this rain cause any issue?  I would have thought that at the very least it would have added launch weight which would have affected ascent performance.  I would also think that there would be issues with the water freezing once it got into space.

The tiles and blankets are waterproofed (with Scotchgard, I believe).  The problem is that it is burned off after entry and has to be reapplied during processing.  So that is why it is a post landing issue and not a prelaunch issue.
Title: Re: Shuttle Q&A Part 5
Post by: ChrisC on 04/23/2012 03:21 am
Question for you all ...

The Shuttle Carrier Aircraft 747 has two vertical stabilizer surfaces added to the ends of the horizontal stabilizer to improve "directional stability".

Do those two additional surfaces articulate, i.e. move along with the main rudder?  Or are they static, and the central rudder is the sole provider of yaw control authority?

Here's the best pic I've found of the tail:
http://www.collectspace.com/news/news-041212c.html
(scroll to bottom)

EDIT:  thanks Jim
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/23/2012 10:53 am
Question for you all ...

The Shuttle Carrier Aircraft 747 has two vertical stabilizer surfaces added to the ends of the horizontal stabilizer to improve "directional stability".

Do those two additional surfaces articulate, i.e. move along with the main rudder?  Or are they static, and the central rudder is the sole provider of yaw control authority?



Static
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 04/23/2012 08:45 pm
What temperature are the gasses fed into the ET as pressurant?

Thanks, Martin
Title: Re: Shuttle Q&A Part 5
Post by: Art LeBrun on 04/23/2012 08:58 pm
Question for you all ...

The Shuttle Carrier Aircraft 747 has two vertical stabilizer surfaces added to the ends of the horizontal stabilizer to improve "directional stability".

Do those two additional surfaces articulate, i.e. move along with the main rudder?  Or are they static, and the central rudder is the sole provider of yaw control authority?



Static
Since the shuttle blanks much of the effect of the vertical stabilizer could we assume the rudder is also somewhat blanked and hence engine power is used to aid in turns (yaw)?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/24/2012 01:47 am

Since the shuttle blanks much of the effect of the vertical stabilizer could we assume the rudder is also somewhat blanked and hence engine power is used to aid in turns (yaw)?

I believe there is still enough control authority in the rudder. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/24/2012 01:49 am
What temperature are the gasses fed into the ET as pressurant?

Thanks, Martin

Prelaunch

Helium for the LH2 tank and I think nitrogen for the LOX tank
During flight, the SSME provide heated gases.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 04/24/2012 01:12 pm
Since the shuttle blanks much of the effect of the vertical stabilizer could we assume the rudder is also somewhat blanked and hence engine power is used to aid in turns (yaw)?
Not really. Remember, in a normal, coordinated turn, the rudder is not used very much if at all. It is used in skid / slip conditions like when making an approach to landing in a crosswind, but the SCA / Orbiter configuration has pretty stringent limits on crosswind velocity. It would also be used in an engine out situation. I don't believe they ever did any testing of that, but that would be one reson why those flights are practically flown as test flights.
Title: Re: Shuttle Q&A Part 5
Post by: Prober on 04/24/2012 03:01 pm
Would the Space shuttle have benefited from the use of a fairing during assent?

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/24/2012 03:16 pm
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?
Title: Re: Shuttle Q&A Part 5
Post by: Prober on 04/24/2012 03:28 pm
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/24/2012 03:37 pm
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.


What is its weight, attach methods, and how does it come off, nominally and in aborts?

Its weight would reduce payload by the same amount.
Its drag would reduce payload also.
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 04/24/2012 05:05 pm
What temperature are the gasses fed into the ET as pressurant?

Prelaunch

Helium for the LH2 tank and I think nitrogen for the LOX tank
During flight, the SSME provide heated gases.

Thanks.

What temp are the gases from the SSMEs at the point they're injected?

Cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: Prober on 04/24/2012 07:19 pm
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.


What is its weight, attach methods, and how does it come off, nominally and in aborts?

Its weight would reduce payload by the same amount.
Its drag would reduce payload also.

drag should be reduced (if designed right).  We have gotten better since the shuttle was designed.

weight would be an issue

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/24/2012 07:25 pm

drag should be reduced (if designed right).  We have gotten better since the shuttle was designed.

No, it will be more than the existing shuttle.  It will have a larger profile and some of the shuttle is still exposed.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 04/24/2012 07:40 pm

Since the shuttle blanks much of the effect of the vertical stabilizer could we assume the rudder is also somewhat blanked and hence engine power is used to aid in turns (yaw)?

I believe there is still enough control authority in the rudder. 

Probably way more than enough. Stomping on rudder pedals has the effect of separating the vertical stabilizer from the fuselage in normal aircraft. :)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 04/25/2012 02:48 am
From the SLWT system definition handbook, vol. I (section-page):

 - The LO2 and LH2 tanks are pressurized with dry GN2 at 6 psig (+/-1) after fabrication at MAF and during shipment to KSC (3-2). 

 - After the stack is assembled on the MLP, both tanks are purged with GHe prior to and during prop loading (3-4, 9-6).

 - Pre-launch, both tanks are pressurized with GHe, the LO2 tank at T-155 sec, and the LH2 tank at T-106 sec (3-5).  Pressurization is autogenous after T-6 sec (9-7).

 - Heated GN2 is used to purge the Intertank and nose cap (9-3, 9-7), and GHe is injected into the LO2 feedline aft elbow to suppress/prevent geysering (9-6).

From the LWT system definition handbook, vol. III (1988):

 - GO2 ullage gas temperature is 600 deg F max at the diffuser inlet, and an average of 390 deg F at the ET/Orbiter interface.

 - GH2 ullage gas temperature is 100 deg F max at the diffuser inlet, and an average of -10 deg F at the ET/Orbiter interface.



What temperature are the gasses fed into the ET as pressurant?

Prelaunch

Helium for the LH2 tank and I think nitrogen for the LOX tank
During flight, the SSME provide heated gases.

Thanks.

What temp are the gases from the SSMEs at the point they're injected?

Cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 04/25/2012 12:41 pm
Someone the other day was asking me if there were ever any issues with wind levels during roll-out of Shuttle to the pad. What were the wind limits like for rollout and then for remaining on the pad? I know they usually rolled back to the VAb in the face of hurricane threats, but can someone lay out the actual critieria involved?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 04/26/2012 06:23 pm
In this article;

http://www.nasaspaceflight.com/2011/07/atlantis-down-processing-mer-review-notes-flawless-return/

 “performed flawless, bar typical GPC (General Purpose Computer) errors during rollout.”


What are these errors, causes and where can I find out more about this?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: MP99 on 04/26/2012 06:39 pm
Fequalsma,

great - thanks.

cheers, Martin
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 04/30/2012 08:37 pm
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/03/2012 12:18 am
Is each bay of the orbiter payload bay of equal length or does they vary in length?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/03/2012 01:48 am
Is each bay of the orbiter payload bay of equal length or does they vary in length?

From the Space Shuttle Systems Summary, 1980.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/03/2012 03:05 am
Is each bay of the orbiter payload bay of equal length or does they vary in length?

From the Space Shuttle Systems Summary, 1980.
Thanks. That is the kind of schematic I was looking for. It answers the question nicely with the fuselage station numbers.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 05/07/2012 02:12 am
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide

ASCENT TRAJ was the display used by PASS for both first and second stage. ASCENT TRAJ 1 and 2 were the respective BFS displays for first and second stage. Starting with the OI-32 software version (STS-120), PASS used similar displays to the BFS and were also called ASCENT TRAJ 1 and 2.

The old ASCENT TRAJ display was designed mainly to assist RTLS aborts and wasn't very useful for nominal ascents.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/09/2012 01:51 am
Does anyone have diagrams of the forward RCS module?  I'd like to know where the struts supporting the prop tanks are connected, and which one buckled during STS-1. 

Thanks,
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/09/2012 02:04 am
Anyone know the clearance between PLB Camera B and the SRMS End Effector? Based on photos I would estimate it's no more than 3". This is with the SRMS stowed and the camera in 0/0.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/13/2012 01:43 pm
In this article;

http://www.nasaspaceflight.com/2011/07/atlantis-down-processing-mer-review-notes-flawless-return/

 “performed flawless, bar typical GPC (General Purpose Computer) errors during rollout.”


What are these errors, causes and where can I find out more about this?

Thanks

It wasn't an error in some ways but an expected condition.  At this point in the flight, the orbiter was stopped near the end of the runway.  Entry guidance was still running in OPS 3.  As you can imagine entry guidance was designed for a forward moving vehicle not one that should be stopped.

If the crew jumped up and down (excited crew) or the wind caused the vehicle to bounce up and down on the landing gear while stopped (vertical motion but no horizontal motion), entry guidance would generate a message saying we went through a math issue (tan 90 or divide by zero, I forget).  The GPC software's math routines handled the issue and there was never a real problem. 

We could have easily have changed this to not have messages occur (we wouldn't have changed the math), but why tinker with code that was working fine for a part of "flight" that really wasn't flight?  As soon as we went to OPS 9, the messages stopped since OPS 9 was designed for being stopped near the end of the runway.

So, not an oversight and not an error in reality.  It also gave the on-console folks a chance to guess how many "error messages" would be received, which depended upon winds, crew exhuberance and time in OPS 3 while stopped.

As far as I know, unless you find the user note (which says to ignore the messages), there is no other documentation available.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/13/2012 01:51 pm
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide

ASCENT TRAJ was the display used by PASS for both first and second stage. ASCENT TRAJ 1 and 2 were the respective BFS displays for first and second stage. Starting with the OI-32 software version (STS-120), PASS used similar displays to the BFS and were also called ASCENT TRAJ 1 and 2.

The old ASCENT TRAJ display was designed mainly to assist RTLS aborts and wasn't very useful for nominal ascents.

The newer PASS Ascent Traj displays were collectively known as 6X Traj (or XXXXXX TRAJ) since the XXXXXX could be changed from ASCENT to an abort name.  RTLS TRAJ was significantly different than ASCENT TRAJ.  The newer displays were an attempt to implement some of what had been planned with CAU display work.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 05/13/2012 02:16 pm
Thanks, alk. Being a computer guy, the software and GPCs had always interested me and I always like reading your posts.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/14/2012 12:52 am
Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/14/2012 01:25 am
305 or 308.4 per the diagram above.  it says the longerons are at 414...


Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/14/2012 02:45 am
Thanks, alk. Being a computer guy, the software and GPCs had always interested me and I always like reading your posts.

Your welcome and I'm glad you find the appends interesting.  Sorry I don't get too much time anymore to answer these (now) historical questions.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/14/2012 03:30 am
305 or 308.4 per the diagram above.  it says the longerons are at 414...


Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
I don't think Zo414.0 is for the longerons but rather payload bay door hinge line. Based on my research the PLBD door hinge lines are at Yo±95 with the longerons at Yo±90. And the shape of the longerons from bottom to top roughly corresponds to a 5" square.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/15/2012 11:37 pm
Anyone know if the encircled brackets in the attached photo is equally spaced along the length of the PLB longerons or if it varies? Also, any ideas what the metal cylinder in the photo is for? I'm thinking it's a drive rod of sorts for the MPMs.
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 05/21/2012 10:09 pm
Was the solar array that slipped its tensioning cables during STS-97 the same one that jammed during 116 and tore during 120?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/24/2012 09:10 am
Hi All.

Question of the day is: was there any difference between the APDS used for docking to the MIR and the one used for docking to the ISS?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/24/2012 07:18 pm
Thank you alk3997 for your reply re: GPS errors during roll out.

Title: Re: Shuttle Q&A Part 5
Post by: Spaceguy5 on 06/08/2012 08:40 pm
Why are the blankets in the aft of Endeavour's payload bay different from the rest of the orbiters?

For example, this blanket (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/49x33%20Blanket/iss022e062859.jpg) (VO70-362609-058): If you look at one up close (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/49x33%20Blanket/Front.jpg), it has a velcro flap (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/49x33%20Blanket/Front_D.jpg), a set of flaps with snap buttons (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/49x33%20Blanket/Front_C.jpg), and a snap-shut hole in the middle (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/49x33%20Blanket/Front_B.jpg). The blanket on the opposite side also has similar features.

Similarly, this blanket (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/54x23%20Blanket/iss022e062859.jpg) (VO70-362610-042) as well as it's twin... if you look up close (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/54x23%20Blanket/Front.jpg), they both also have a velcro flap (http://i9.photobucket.com/albums/a66/Spaceguy05/Collection/Blankets/54x23%20Blanket/Cover.jpg).
Title: Re: Shuttle Q&A Part 5
Post by: Archer on 06/11/2012 06:59 pm
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/11/2012 07:02 pm
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.
Title: Re: Shuttle Q&A Part 5
Post by: Archer on 06/11/2012 07:46 pm
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.
Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: Archer on 06/11/2012 10:08 pm
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.
What takes more time: inspection or repairs?
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/13/2012 06:51 pm
Hi all.

one question about deorbit burn.

Which is the reason for which during the deorbit the Orbiter was placed with the belly up? As long as you have tail-first is shouldn't be important if the belly is up or down, right?

My guess is that in this was, at completion of the burn it would have been faster maneuvering to the entry attitude of 40 degrees of angle of attack and that maybe in this way the pilots had a better situation awarness.

What do you think?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 06/13/2012 07:22 pm
Hi all.

one question about deorbit burn.

Which is the reason for which during the deorbit the Orbiter was placed with the belly up? As long as you have tail-first is shouldn't be important if the belly is up or down, right?

My guess is that in this was, at completion of the burn it would have been faster maneuvering to the entry attitude of 40 degrees of angle of attack and that maybe in this way the pilots had a better situation awarness.

What do you think?

Thanks very much

Davide

If the deorbit burn is roughly halfway around the planet from entry interface, then the "belly-up" burn will have the Orbiter in (or near) the proper reentry attitude.

At burn = Orbiter "top" towards Earth
At halfway point = Orbiter "nose" towards Earth
At EI = Orbiter "belly" towards Earth

Remember the only reason the Orbiter orbits the Earth with its "top" pointed toward Earth is because it has been imparted with a pitch motion with period equal to the orbital period. Without that it would be a cycle of "nose"/"top"/"tail"/"belly" (or the reverse).

I hope that wasn't too basic of an answer due to me misunderstanding the question.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/13/2012 10:09 pm
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 06/15/2012 02:10 pm
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide

Perhaps the maneuver was done such that the attitude was for a completely +x burn at TIG? I'm not sure, this will have to be answered by Jorge or someone else with the expertise.

My assumption (which is probably incorrect) is that things are done to minimize propellant consumption.
Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 06/17/2012 01:30 pm
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide

Perhaps the maneuver was done such that the attitude was for a completely +x burn at TIG? I'm not sure, this will have to be answered by Jorge or someone else with the expertise.

My assumption (which is probably incorrect) is that things are done to minimize propellant consumption.
That's correct; a constant inertial attitude means that the shuttle is always rotating in an LVLH frame. The inertial burn attitude will result in the correct LVLH attitude at TIG.

I think an inertial burn is actually more efficient than an LVLH burn, because you're always thrusting in the same direction. If you think about an LVLH burn, the direction is changing, so the thrust at the end of the burn partially cancels out the thrust at the start of the burn.

For deorbit burns, it's possible to deliberately waste propellant by burning out-of-plane. This reduces the shuttle's landing weight.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/20/2012 08:32 am
Thanks SiameseCat. I think now I've understood how it worked the deorbit burn.

Davide
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 06/20/2012 08:34 am
Hi all.

a question regarding the HAC. Why at the beginning the HAC was a cylinder and and not a cone? and also why for the OFT missions the HAC (which was a cylinder) was flown following a straight-in approach and not an overhead approach?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 06/22/2012 09:24 pm
Hi all.

a question regarding the HAC. Why at the beginning the HAC was a cylinder and and not a cone? and also why for the OFT missions the HAC (which was a cylinder) was flown following a straight-in approach and not an overhead approach?

Thanks very much

Davide
Probably to make it easier for the crew if they lost stearing commands on the HSI needles and had to manually navigate the approach using the TACANs. A cylindrical HAC is functionaly similar to a DME arc approach.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 07/07/2012 02:10 am
(Apologies in advance if this has been asked and answered previously.)

What were the planned and actual maximum values of dynamic pressure during any Shuttle launch? What was the design limit? How does that compare to the planned, max, and design limit for Apollo?

EDITs: The graph at http://www.aerospaceweb.org/question/aerodynamics/q0025.shtml seems to show Shuttle max Q values of approx. 700 lb/ft2.

"Apollo by the numbers" gives max-q values also in lb/ft2 of
Apollo 7 665.60
Apollo 8 776.938
Apollo 9 630.73
Apollo 10 694.232
Apollo 11 735.17
Apollo 12 682.95
Apollo 13 651.63
Apollo 14 655.80
Apollo 15 768.58
Apollo 16 726.81
Apollo 17 701.75
Title: Re: Shuttle Q&A Part 5
Post by: Kyra's kosmos on 07/13/2012 06:38 pm
Could anyone please positively identify the purpose of the unusual lockers MF710 and MF71M on the STS-27, 30, 32, 34, and 36 missions ?

Ive attached a collage from the mission videos.

Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/14/2012 09:14 am
Hi all.

A question regarding TPS on Columbia. Why throughtout the program up to the last mission the LRSI tiles on the nose and upper wing surface where not replaced by the AFRSI as in the other Orbiters?

And also why were the black tiles kept in place on the glove area of the wings?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/14/2012 12:28 pm
Hi all.

A question regarding TPS on Columbia. Why throughtout the program up to the last mission the LRSI tiles on the nose and upper wing surface where not replaced by the AFRSI as in the other Orbiters?

And also why were the black tiles kept in place on the glove area of the wings?

Thanks very much

Davide

No need to.  Was just cheaper to leave as is.
Title: Re: Shuttle Q&A Part 5
Post by: Ronsmytheiii on 07/14/2012 03:24 pm
And also why were the black tiles kept in place on the glove area of the wings?

From pg 169 of this thread:

The black chine areas on Columbia were to minimize on-orbit thermal stresses on the underlying structure; later vehicles incorporated structural changes that made the extra thermal absorption unnecessary.
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 07/14/2012 08:42 pm
Can anyone tell me what the technical reason(s) were for the Shuttle External Tank to have a limit of 13 cryo/pressure cycles?

I guess it has to do with crack behavior in the Al and Al-Li materials used for the primary tank skins, but I can't find any reference (even in the SLWT handbook) to which specific element on the tank was responsible for the limitation. Can anyone here shed some light? Jim?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 07/15/2012 12:30 pm
al-li fracture mechanics
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 07/16/2012 03:39 am
I speculate the External Tank cycle limit, and maybe other limits, were fundamentally due to the disposal without recovery of the ET for each flight. Without the ability to examine the tanks after recovery it was never possible to say, "Oh, we have plenty of margin here" or, "Ooh, we've just been getting lucky there!"

Take for example the STS-133 stringer issue. In a sense we got lucky the foam cracked, leading to the investigation which showed the trouble with the underlying stringers. But did anyone ever estimate how many prior tanks were launched with cracked stringers which were never noticed because there were no cracks in the covering foam?

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110023677_2011024985.pdf
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 07/16/2012 12:03 pm
So that suggests that somewhere in their archives NASA has some detailed test data that shows Al-2219 and Al-Li 2195 in a given thickness develops a certain amount of crack behavior when subjected to n cycles of pressure/cryo exposure.

Assuming you have access to that sort of data, what is the typical solution if you need to increase the number of safe cycles? Is it mostly a question of thickening the material up and just taking the weight penalty?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: vulture4 on 07/16/2012 12:28 pm
So that suggests that somewhere in their archives NASA has some detailed test data that shows Al-2219 and Al-Li 2195 in a given thickness develops a certain amount of crack behavior when subjected to n cycles of pressure/cryo exposure.

Assuming you have access to that sort of data, what is the typical solution if you need to increase the number of safe cycles? Is it mostly a question of thickening the material up and just taking the weight penalty?

-MG.
Aluminum alloys always tend to have a fatigue limit based on the number of cycles they are exposed to a given level of cyclic stress. If a crack develops stress is concentrated at its tip and the crack propagates. Increasing thickness in high-stress areas and/or checking carefully for cracks are the only general countermeasures I am aware of, though careful avoidance of corrosion and crack-initiating stress concentrations can help.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 07/19/2012 11:38 pm
Fracture Control Methodology for the Space Shuttle Aluminum-Lithium External Tank

Wells, Douglas N., NASA Marshall Space Flight Center, USA; McGill, Preston B., NASA Marshall Space Flight Center, USA; Elfer, Norman C., Lockheed Martin Michoud Assembly Facility, USA; Faile, Gwyn C., NASA Marshall Space Flight Center, USA

ASTM 33rd National Symposium on Fatigue and Fracture Mechanics, 26 Jun. 2001, Moran, WY, USA; Sponsored by American Society for Testing and Materials, USA

The Space Shuttle External Tank (ET) serves as the structural centerpiece of the Space Shuttle system, connecting the Solid Rocket Boosters and the Orbiter while carrying 730 000 kg of propellants for the main engines. Due to the size and criticality of the structure, the ET presents a tremendous challenge for implementing a complete fracture control program. Typical approaches to pressure vessel fracture control are inadequate for the structure due to a combination of low attainable proof factor, extremely short cyclic mission life and nonlinear material behavior. Fracture control for the ET is empirically based and established via mission-specific testing, proof test, nondestructive evaluation, and process control. A recent redesign of the tank incorporating aluminum-lithium alloys has presented unique challenges to the established ET fracture control methodology. This paper describes the fracture control approach for the ET and the adaptation of methodologies for the aluminum-lithium redesign. The described approach can be applied to any fracture critical structure with short mission life and operational stresses which approach the capability of the material.
Title: Re: Shuttle Q&A Part 5
Post by: STS-85 on 07/24/2012 07:33 pm
Correct me if I'm wrong.. but was STS-41G the only flight to make a LEFT overhead turn around the HAC to runway 33 at KSC? And STS-79 the only flight to make a RIGHT overhead turn to runway 15?
Or were the others that had the unusual approach?

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 07/26/2012 05:29 pm
I'm not enough of a rocket scientist to crunch the numbers, so I'll ask.

How much of a payload increase to ISS orbit would an STS with 3 SSME's at 109% bring?

Then, add 5-seg SRB's to the 109% SSMEs, and how much does it increase (assuming the stack can take those loads)?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 07/27/2012 03:55 am
I'm not enough of a rocket scientist to crunch the numbers, so I'll ask.

How much of a payload increase to ISS orbit would an STS with 3 SSME's at 109% bring?

Then, add 5-seg SRB's to the 109% SSMEs, and how much does it increase (assuming the stack can take those loads)?

I seem to remember that 3 engine 109% with a superlightweight tank would have been beyond the attach point's capabilities.  You might be able to extrapolate if someone remembers the STS-61F/G increase for Centaur at 109%.  Of course the Centaur flights would have used a lightweight tank, so that answer really isn't accurate and they didn't fly to 51.6 degrees or carry that particular amount of OMS prop or insert to as high of an apogee...

5-seg SRBs would have been a new outer-moldline for the stack.  It would have had to been analyzed to determine how much dynamic pressure would have been allowed and therefore it isn't really possible to say how much of a payload increase.  It isn't just making the structure lighter that is needed to increase payload weight.  You really have to do the engineering to determine it.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/12/2012 08:13 pm
I have read somewhere that during Approach&Landing the speedbrake closed setting is fixed at 15%. Is this correct and why 15% and not fully closed (0%)?.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/12/2012 08:20 pm
Hey Dave S

The space shuttle approach landing and rollout flight procedures handbook  has a great run down of the spread brake logic.  Do you have access to that?  Also I think I covered it as well in an earlier q&a.  If those don't help let me know and I will try and cover it again.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/12/2012 08:40 pm
Hey Dave S

The space shuttle approach landing and rollout flight procedures handbook  has a great run down of the spread brake logic.  Do you have access to that?  Also I think I covered it as well in an earlier q&a.  If those don't help let me know and I will try and cover it again.

Mark Kirkman
Thanks for the tip on the handbook, it covers it nicely there.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 08/12/2012 11:06 pm
Do we have this handbook posted anywhere?   If so, perhaps a link??

Thanks!!
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/19/2012 03:42 pm
Hi all.

I'm looking for documents explains the start and shutdown sequences of the SSMEs. I've got all the handbooks, workbooks available on L2 and I've also searched on NTRS but I haven't found anythig that explains in details what happen instant by instant during SSME start and shutdown. They all explains very well how they worked during flight but not at the begining or end.

Thanks very much for your help.

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 08/19/2012 04:45 pm
Hi all.

I'm looking for documents explains the start and shutdown sequences of the SSMEs. I've got all the handbooks, workbooks available on L2 and I've also searched on NTRS but I haven't found anythig that explains in details what happen instant by instant during SSME start and shutdown. They all explains very well how they worked during flight but not at the begining or end.

Thanks very much for your help.

Davide

This is rather good...

http://www.enginehistory.org/SSME/SSME3.pdf (http://www.enginehistory.org/SSME/SSME3.pdf)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/19/2012 05:48 pm
Thanks very much...that's exactly what I wanted! ;D
Title: Re: Shuttle Q&A Part 5
Post by: jnc on 08/19/2012 06:41 pm
This is rather good... (http://www.enginehistory.org/SSME/SSME3.pdf)

Wow. Very cool site. Thanks for the pointer.

Noel
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/20/2012 08:22 pm
Hi all.

Questions on the SSMEs. Which was the order in which the engines were ignited? And why that sequence was chosen?
Which was the reason for igniting the engine in a staggered pattern (120 millisec if I'm right)?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: jnc on 08/20/2012 08:55 pm
Which was the reason for igniting the engine in a staggered pattern (120 millisec if I'm right)?

This part I seem to recall. There's this thing the Shuttle stack does that's called 'twang', which is when the liquids light off, since they are offcenter, the whole stack sways back and forth (quite a bit - I think it's like 2m at the nose). So I would guess that the offset ignition is to minimize the shock loading to the stack's structure from liquid ignition - if they all lit simultaneously, it would be even greater.

Noel
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/20/2012 10:29 pm
Which was the order in which the engines were ignited?
3-2-1 (right-left-center).
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/20/2012 10:37 pm
Quote from: jnc
This part I seem to recall. There's this thing the Shuttle stack does that's called 'twang', which is when the liquids light off, since they are offcenter, the whole stack sways back and forth (quite a bit - I think it's like 2m at the nose). So I would guess that the offset ignition is to minimize the shock loading to the stack's structure from liquid ignition - if they all lit simultaneously, it would be even greater

Thanks jnc...it makes sense.

Quote from: psloss
3-2-1 (right-left-center)

Thanks psloss...do you know why this sequence was chosen? I mean, why not the opposite for example?

Thanks again

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/21/2012 03:44 pm
Thanks psloss...do you know why this sequence was chosen? I mean, why not the opposite for example?

Thanks again

Davide

I've wondered this myself (not so much the sequence but rather the staggered start). Plausible reasons include:

1) Fluid dynamics in the 17" feed lines. What happens to turbopump inlet pressures if all 3 start at the same time? Would that cause too much of a drop?

2) Nozzles resonate at startup, so best to not have all 3 resonating in phase with one another.

I suspect "twang" of the stack, or loads on the thrust structure have little to do with it. The twang period is measured in seconds (~6 seconds), as is thrust buildup to 100% RPL (~3 seconds). The staggered start is measured in milliseconds (~120 ms). Turbopump overspeeds and overtemps are the only thermodynamic effects I can think of that have time constants of similar magnitude.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/21/2012 03:52 pm

I suspect "twang" of the stack, or loads on the thrust structure have little to do with it.

Yes, it does also have to do with the structure.
Title: Re: Shuttle Q&A Part 5
Post by: jnc on 08/21/2012 08:41 pm
1) Fluid dynamics in the 17" feed lines. What happens to turbopump inlet pressures if all 3 start at the same time? Would that cause too much of a drop?
2) Nozzles resonate at startup, so best to not have all 3 resonating in phase with one another.

I suspect "twang" of the stack, or loads on the thrust structure have little to do with it. The twang period is measured in seconds (~6 seconds), as is thrust buildup to 100% RPL (~3 seconds). The staggered start is measured in milliseconds (~120 ms).

Sorry, my post wasn't as clear as it could/should have been. I wasn't meaning to imply that the stagger had to do with the twang directly, I was more mentioning the twang to give a sense of the magnitude of the effects on the structure of the engines' thrust.

To the two excellent points you mention, let me add a third suggestion (well, actually, it's another way of looking at your first), which is the inertia of the propellant in the lines. Once things are up and running, the entire line is filled with fuel/oxidizer moving at constant (basically) speed. But of course it starts with all that fluid at rest. So starting the engines with slight delays allows a longer transition from 'no flow' to 'full flow'. (Of course, these inertial effects are what cause the potential temporary pressure drop you mentioned.)

Noel
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/21/2012 09:00 pm
Sorry, my post wasn't as clear as it could/should have been. I wasn't meaning to imply that the stagger had to do with the twang directly, I was more mentioning the twang to give a sense of the magnitude of the effects on the structure of the engines' thrust.

I would think that the greatest stress on the thrust structure occurs after liftoff, when the engines are running at 104% and the stack is approaching max Q (Orbiter getting "pushed" by 3 SSME's and "squashed" by oncoming air). But, heck, I am just an electrical engineer guessing at mechanical engineering problems. I'm lucky to know how to spell thermodynamics.  :D

There's a pretty well known fellow around here who got his start at NASA working Shuttle propulsion at JSC. I'll bet you he knows the answer (or answers, as the case usually is with complex engineering problems).  ;)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/22/2012 10:06 pm
hi guys.

thanks for your answers...they're all very interesting.

Quote from: jnc
To the two excellent points you mention, let me add a third suggestion (well, actually, it's another way of looking at your first), which is the inertia of the propellant in the lines. Once things are up and running, the entire line is filled with fuel/oxidizer moving at constant (basically) speed. But of course it starts with all that fluid at rest. So starting the engines with slight delays allows a longer transition from 'no flow' to 'full flow'. (Of course, these inertial effects are what cause the potential temporary pressure drop you mentioned.)

Regarding this point, however, I have kind of my doubts. Reason being that starting with loading of the ET around 6 hours before lift off, also SSMEs thermal conditionig started and this consisted in having propellants going around the engines' components. In particular both propellants flowing up to the high-pressure turbopumps. So the propellants were never still.

I've been thinking that the reason for the staggered ignition sequence was due to the possible water hammer that could occur in the hydrogen feedline coming from the ET.

What I mean it's the following: during thermal conditioning the hydrogen flowed up to the high-pressure turbopump but didn't pass inside the coolant channels of the nozzle and combustion chamber. At ignition when the main fuel valve in each engine is open, the hydrogen passing in the coolant channels of the combustion chamber and nozzle flashed to gaseous due to the high difference between the hydrogen temperature (cryogenic) and combustion chamber/nozzle (room temperature). This instantanous formation of gaseous hydrogen caused oscillations in the fuel line, which also cause a lot trouble in developping a safe ignition sequence.

My guess is that these oscillations propagated upstreams, creating kind of water hammer effect. If the three engines where ignited all together at the same time, then these oscillations could sum up together creating disraptions in the flow of fuel delivered from the ET.

For the starting sequence, I've to say that it made sense to have the center engine to be the last one to be ignited since in this way there would have been less time for the twang. Well just few hundreads of milliseconds but I suppose that with the tremendous forces in place, few milliseconds less of twang were welcomed by the structure.

What do you think? Do my reasons make sense?

Thanks very much

Davide

Title: Re: Shuttle Q&A Part 5
Post by: SiameseCat on 08/23/2012 03:23 am
I have a question about manual throttling during ascent. The crew can take over SSME throttling by pressing the takeover switch on the throttle and moving the throttle to within 4% of the commanded value. It seems to me that this would cause the commanded throttle value to change slightly - for example, if the GPCs were commanding 104% thrust, takeover would occur when the throttle was moved to the 100% position, and the SSMEs would be set to 100% thrust. Is this acceptable, or am I missing something here?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/23/2012 03:29 am
I have a question about manual throttling during ascent. The crew can take over SSME throttling by pressing the takeover switch on the throttle and moving the throttle to within 4% of the commanded value. It seems to me that this would cause the commanded throttle value to change slightly - for example, if the GPCs were commanding 104% thrust, takeover would occur when the throttle was moved to the 100% position, and the SSMEs would be set to 100% thrust. Is this acceptable, or am I missing something here?

They are going to change the setting anyways so it shouldn't matter
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/27/2012 07:17 am
Hi all.

A question about the ET. Why the propellant loading started with a slow filling followed after 5% of propellant loaded by a fast loading?

My guess is that when the tanks started to be filled, they were still "hot", at least at room temperature, and therefore upon contact the propellant started to boil. So to avoid a large mass of propellant boiling (possibly quite violently), the filling started at slow rate first so that the tank had time for chilling down and so allowing a faster loading without having everything boiling as cooking pot.

Am I correct?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/27/2012 01:26 pm
Hi all.

A question about the ET. Why the propellant loading started with a slow filling followed after 5% of propellant loaded by a fast loading?

My guess is that when the tanks started to be filled, they were still "hot", at least at room temperature, and therefore upon contact the propellant started to boil. So to avoid a large mass of propellant boiling (possibly quite violently), the filling started at slow rate first so that the tank had time for chilling down and so allowing a faster loading without having everything boiling as cooking pot.

Am I correct?

Thanks very much

Davide


Standard process used by most cryogenic vehicles.  It is not just the boil off but also conditioning the vehicle to take the thermal shock
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/29/2012 02:19 am
I know that this won't happen but my question is CAN it happen...

Could the retired orbiters ever be made spaceworthy again or were they basically turned into 1:1 scale models of themselves? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/29/2012 02:45 am
No,

The pad systems are gone,
The LCC systems are gone,
The industrial capability (suppliers, documentation, personnel, etc) are gone
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 08/29/2012 04:59 pm
Hi All.

Quick one: I know that Endeavour was the first Orbiter to have the GPS system on board. Had also all the other Orbiters (Columbia included) received the GPS systems?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/31/2012 04:22 pm
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/01/2012 05:39 pm
Hi All.

Quick one: I know that Endeavour was the first Orbiter to have the GPS system on board. Had also all the other Orbiters (Columbia included) received the GPS systems?

Thanks very much

Davide

Davide, that's a more difficult question than you might think.

The way the GPS (MAGR) was put onboard was that the orbiters first had a GPS unit put in a locker and a PGSC recorded the data from the GPS for post-flight analysis.  This started with just on-orbit and proceeded to ascent/entry data collection (which meant we had to park the PGSC's spinning hard drive and use a solid state drive long before those became popular).  This level of testing was done in the mid-1990s.

The next step was to allow the BFS to see the GPS data and then have that shipped to the ground as part of the BFS telemetry.  This was followed by incorporating the GPS data into PASS on-orbit only.  It was then we hit our first real issue in 1998.  That showed the various software (PASS and GPS) needed some work and so it was a few years before the MAGR-3S was ready to be used in PASS again.

The original intent was that all three (really at that time, four) vehicles would get three-string GPS and the TACANs would be removed.  However, PASS and BFS software allowed for no GPS, 1 GPS/3 TACANs and 3 GPS/no TACAN configurations (the configuration had to be programmed into that flight's software).  So, once the MAGR-3S was being used the initial vehicles received one GPS and OV-105 during her final KSC OMDP received MEDS and a 3 string GPS configuration.  Had long OMDPs been available for the other vehicles, they would have also received a 3-string GPS configuration.

So to say that OV-105 was the first to get GPS is incorrect.  It is correct, however, to say that OV-105 was the first to get three string GPS and the first to fly entry using GPS  units instead of TACANs.

Besides my memory, I'll list this as a reference in case you need more details:
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=4570031&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel5%2F4557992%2F4569960%2F04570031.pdf%3Farnumber%3D4570031

Andy
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/05/2012 06:07 am
Why did the pilot take over flying part of the Heading Alignment Cone?  Is it just to give the pilot experience flying the shuttle?
Title: Re: Shuttle Q&A Part 5
Post by: mogso on 09/09/2012 08:23 pm
Hi all
Who knows where to take the drawings are the commander seat drive
Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: Chandonn on 09/09/2012 10:52 pm
Hi all
Who knows where to take the drawings are the commander seat drive
Thank you!


Um.... WHAT?
Title: Re: Shuttle Q&A Part 5
Post by: mogso on 09/10/2012 10:13 pm
Hi all
Who knows where to take the drawings are the commander seat drive
Thank you!


Um.... WHAT?

"The commander and pilot can move their seats along the orbiter's Z (vertical) and X (longitudinal) axes so they can reach and see controls better during the ascent and entry phases of flight. Seat movement for each axis is provided by a single ac motor. The total travel distance for the Z and X axes is 10 and 5 inches, respectively..." As to look at this motor? Drawing, etc.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/12/2012 08:19 am
A NASA document states that STS 108 violated the minimum landing requirements. 

What requirements were violated?

http://spaceflight.nasa.gov/outreach/SigInc_Poster_2012.jpg
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/12/2012 05:17 pm
Thanks, Jorge. 

Looking at the HUD in the STS 108 landing video, it appears the ceiling was 6000 feet or lower. 
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/15/2012 01:47 am
What parts/systems of the Orbiter were actually reusable as opposed to rebuildable?  To start the list obviously the primary structure and TPS (even though it required a lot of inspection) would be considered reusable.

I qualify reusable as systems that only required inspection, minor repair and refueling (if applicable) vs. systems that had to be disassembled and have major work done between flights.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/15/2012 02:03 am
What parts/systems of the Orbiter were actually reusable as opposed to rebuildable?  To start the list obviously the primary structure and TPS (even though it required a lot of inspection) would be considered reusable.

I qualify reusable as systems that only required inspection, minor repair and refueling (if applicable) vs. systems that had to be disassembled and have major work done between flights.

The whole orbiter, except for engines
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/15/2012 03:03 pm
The whole orbiter, except for engines

Tires. MLG's once, nose twice, right?
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/17/2012 10:00 am
What parts/systems of the Orbiter were actually reusable as opposed to rebuildable?  To start the list obviously the primary structure and TPS (even though it required a lot of inspection) would be considered reusable.

I qualify reusable as systems that only required inspection, minor repair and refueling (if applicable) vs. systems that had to be disassembled and have major work done between flights.

The whole orbiter, except for engines

If that's the case, what was it that made the turn around processing take so much longer than the ordiginal plan?  Was it just the TPS inspection/repair process?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/17/2012 11:31 am

If that's the case, what was it that made the turn around processing take so much longer than the ordiginal plan?  Was it just the TPS inspection/repair process?

You had most of it: "inspection, minor repair and refueling" and include testing and payload bay reconfiguring.  As part of "refueling" the OMS and RCS pods were removed.  As for the middeck, all the lockers and crew accommodations were removed after each flight.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/17/2012 05:39 pm
If that's the case, what was it that made the turn around processing take so much longer than the ordiginal plan?  Was it just the TPS inspection/repair process?

Engines came out after each flight, too. IIRC, Block-III SSME's were supposed to be able to stay installed between flights. Not sure how many flights, though.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/21/2012 06:11 pm
Is there any archived video of SSME development, specifically some of the early-on test stand failures?
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/24/2012 10:28 am
How much LH2 and LO2 were stored on board for fuel cells/water generation and where were the tanks?

Also, how were they insulated to keep the liquids from evaporating when the Orbiter was in the sun?

Last, did the shuttle dump wastewater/urine like Apollo or store it like an airliner?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/24/2012 11:41 am
How much LH2 and LO2 were stored on board for fuel cells/water generation and where were the tanks?

Also, how were they insulated to keep the liquids from evaporating when the Orbiter was in the sun?

Last, did the shuttle dump wastewater/urine like Apollo or store it like an airliner?

"Cryogenic hydrogen and oxygen are stored in a supercritical condition in double-walled, thermally insulated spherical tanks with a vacuum annulus between the inner pressure vessel and outer shell of the tank. Each tank has heaters to add energy to the reactants during depletion to control pressure. Each tank is capable of measuring quantity remaining.

The tanks are grouped in sets consisting of one hydrogen and one oxygen tank. The number of tank sets installed depends on the specific mission requirement. Up to five tank sets can be installed. The five tank sets are all installed in the midfuselage under the payload bay liner.

The oxygen tanks are identical and consist of inner pressure vessels of Inconel 718 and outer shells of aluminum 2219. The inner vessel is 33.43 inches in diameter and the outer shell is 36.8 inches in diameter. Each tank has a volume of 11.2 cubic feet and stores 781 pounds of oxygen. .........

The hydrogen tanks also are identical. Both the inner pressure vessel and the outer shell are constructed of aluminum 2219. The inner vessel's diameter is 41.51 inches and the outer shell's is 45.5 inches. The volume of each tank is 21.39 cubic feet, and each stores 92 pounds of hydrogen."

 In this location, they were shielded from the sun.

Yes, water dumps were performed.
Title: Re: Shuttle Q&A Part 5
Post by: zt on 09/24/2012 01:24 pm
I didn't know the shuttle had more than a meter of space between its bottom and the bottom of the payload bay. Are there publicly available diagrams?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/24/2012 07:41 pm
I didn't know the shuttle had more than a meter of space between its bottom and the bottom of the payload bay. Are there publicly available diagrams?

Look for a book called "The Space Shuttle Operator's Manual". It's probably out of print, but someone will have a copy. I've had mine since I was about an 8-year old kid. It's so dated it even has the STS-1 terminal count, which had me confused for years as to when the main engines actually start! :D

But I do recall lots of diagrams (exploded and otherwise), dimensions, weights, etc. It's a very decent reference, even if it is 1980's memorabilia.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/24/2012 07:42 pm
Title: Re: Shuttle Q&A Part 5
Post by: Quindar Beep on 09/25/2012 04:45 pm
OK...I have a question about the Shuttle's cross-range capability, particularly the decision to re-design it from one with not much (i.e., Max Faget's "DC-3") to what we actually ended up with.

I know this was done so that the Shuttle could return to Vandenberg after a single polar orbit. But this confuses me as, as I understand it, Vandenberg was going to need a lot of building to handle the Shuttle. So if you're basically building a Shuttle launch facility anyway, I can see -- bearing in mind that I am not a rocket scientist or orbital mechanic -- two other solutions that would have satisfied the "single orbit" criterion without having to add cross-range distance to the orbiter.

So my question is "Why would either of these two solutions not be selected instead?", suspecting that the answer is going to be "cost" or "Quindar, you silly person, that wouldn't work!"

Solution 1: Launch from someplace 1500 miles to the east of Vandenberg (by my calculation, somewhere on a line running north/south from about Oklahoma City), then land at Vandenberg one orbit later. Obvious downside: you're building and manning two facilities instead of one, so cost. But as much extra cost as building the redesigned orbiters as compared to Faget's design? You're also launching over land, but then so is Vandenberg, no?

Solution 2: Build a new launch/landing site much further north, say at Barrow, Alaska. I mean, the necessary cross-range is dictated by the length of the circle running around the Earth at the latitude of where you want to land, right? And the circle at the latitude of Barrow (71°N) is a lot smaller than the one at the equator -- unless I've messed up the calculation, the Earth would rotate only 500 miles or so underneath a polar orbit launched from Barrow. This is within striking distance of the original Shuttle design's cross-range capability. Cons: Cost of building a second facility, and building it up near Santa Claus where the logistical difficulties would be huge. But I note that the Russians are happy to launch from Plesetsk at 62°N

So what am I missing? That neither option was selected says to me that much smarter people than I ruled them out, or realized instantly that they were stupid (see "Quindar, you silly person!", above) but I don't know why and can't find any discussion of the issue -- the Shuttle histories I've read just say that it needed the cross-range capability to get back to Vandenberg, end of discussion.

Edit: OK, the text filters here are amusing -- I wasn't calling myself a "silly person" in the original draft of this  ::)
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/25/2012 04:52 pm
1. Vandenberg launches go to the south, over ocean.  No land is flown over. 

Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/25/2012 06:11 pm
Barrow, AK wouldn't have been a good place especially if SRBs were involved.  Regardless, trying to land there and avoid snowfall wouldn't have been fun either.

From wikipedia:
"Temperatures remain below freezing from early October through late May. The high temperature is above freezing on an average of only 120 days per year, and there are temperatures at or below 0 °F (−18 °C) on an average of 160 days per year.[10] Freezing temperatures, and snowfall, can occur during any month of the year"

I often wonder if the Shuttle would have actually have been economical if not for the two DoD requirements that were never used (cross range for single orbit and payload bay length).
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/25/2012 06:51 pm

I often wonder if the Shuttle would have actually have been economical if not for the two DoD requirements that were never used (cross range for single orbit and payload bay length).

The length requirement wasn't just DOD and it was used on NASA missions among others
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/25/2012 07:01 pm
I often wonder if the Shuttle would have actually have been economical if not for the two DoD requirements that were never used (cross range for single orbit and payload bay length).

There's a better thread for that.

http://forum.nasaspaceflight.com/index.php?topic=28474.0

Let's keep this one Q&A about the STS we actually built and used for 30 years.
Title: Re: Shuttle Q&A Part 5
Post by: Quindar Beep on 09/25/2012 08:46 pm
Both requirements were used frequently. Crossrange was never used "for single orbit" but it was used for nominal entry to increase deorbit opportunities, and for TAL site availability.

That was a case of using what they already had, though, wasn't it? The initial requirement was all Air Force, so far as I understand it, and then once they had it anyway, NASA looked at other things they could so with the capability. Please correct me if I'm wrong.

I suppose my question could be rephrased more succinctly as "What's so great about Vandenberg" that NASA felt they needed to build the Shuttle as they did rather than get them to shift to some other launchpad for military-related missions to polar orbit.

To be precise, what made them decide this way in 1972 or so? Any knowledge gained after that time is unfair 20/20 hindsight  ;)

Addressing another reply: As for Barrow, I thought about the weather too and most certainly you could be right. Like I said, though, the Russians launch from Plesetsk, ain't exactly Ft. Lauderdale either. Granting they don't launched manned missions and don't try to land anything there either, but still....
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/25/2012 09:01 pm
Both requirements were used frequently. Crossrange was never used "for single orbit" but it was used for nominal entry to increase deorbit opportunities, and for TAL site availability.

That was a case of using what they already had, though, wasn't it? The initial requirement was all Air Force, so far as I understand it, and then once they had it anyway, NASA looked at other things they could so with the capability. Please correct me if I'm wrong.


No, NASA agreed it had similar requirement.

From the Space Shuttle Decision:
"In addition, a 15-by-60 foot bay would serve the needs of both agencies by providing room for the space tug and its payloads. Many spacecraft would fly to high orbit, including geosynchronous orbit, and the payload bay had to address such expectations as that future communications satellites would also grow larger. Thus, when Dale Myers asked Grant Hansen to weigh the merits of a reduction to 12 x 40 feet, Hansen replied:

    The length of the payload bay is the more critical dimension affecting DOD mission needs. If the payload bay length is reduced to 40 feet, then 71 of the 149 payloads forecasted for the 1981 to 1990 time period in Option C and 129 of the 232 payloads forecasted in Option B of the mission model will require launch vehicles of the Titan III family....
     
    The 15 foot diameter by 60 foot length payload bay size previously stated as the DOD requirement is based upon payloads presently in the inventory, on the potential use of a reusable upper stage to accomplish our high energy missions, and on a capability to provide limited payload growth. This requirement is still considered valid.
     
    In summary, should you elect to develop the shuttle with a 12 ft x 40 ft payload compartment, it will preclude our full use of the potential capability and operational flexibility offered by the shuttle.... Also, if a portion of the present expendable launch vehicle stable must be retained to satisfy some mission requirements, then the potential economic attractiveness and the utility of the shuttle to the DoD is severely diminished."
Title: Re: Shuttle Q&A Part 5
Post by: Quindar Beep on 09/25/2012 09:04 pm
Both requirements were used frequently. Crossrange was never used "for single orbit" but it was used for nominal entry to increase deorbit opportunities, and for TAL site availability.

That was a case of using what they already had, though, wasn't it? The initial requirement was all Air Force, so far as I understand it, and then once they had it anyway, NASA looked at other things they could so with the capability. Please correct me if I'm wrong.


No, NASA agreed it had similar requirement.


Whoops, we're talking at cross purposes. I meant just the cross-range capability of 1500 miles that the Air Force requested. So far as I know, NASA only wanted 400 and only went along because the White House made it clear they weren't go to get approval for the Shuttle unless they met the USAF's needs too.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/25/2012 09:04 pm

I suppose my question could be rephrased more succinctly as "What's so great about Vandenberg" that NASA felt they needed to build the Shuttle as they did rather than get them to shift to some other launchpad for military-related missions to polar orbit.

To be precise, what made them decide this way in 1972 or so? Any knowledge gained after that time is unfair 20/20 hindsight  ;)


No, it is the other way around.
The final shuttle configuration chosen drove the need to use VAFB for the same reasons that existing launch vehicles used VAFB, no overflight of land during launch.

Back when the shuttle was going to be TSTO RLV, they were looking for other launch sites than KSC.
Title: Re: Shuttle Q&A Part 5
Post by: Oberon_Command on 09/25/2012 09:07 pm

I suppose my question could be rephrased more succinctly as "What's so great about Vandenberg" that NASA felt they needed to build the Shuttle as they did rather than get them to shift to some other launchpad for military-related missions to polar orbit.

To be precise, what made them decide this way in 1972 or so? Any knowledge gained after that time is unfair 20/20 hindsight  ;)


The final shuttle configuration chosen drove the need to use VAFB for the same reasons that existing launch vehicles used VAFB, no overflight of land during launch.

Were there any (alternative) shuttle configurations under consideration prior to the final selection which would not have required the use of VAFB for polar orbit flights?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/25/2012 09:09 pm
Both requirements were used frequently. Crossrange was never used "for single orbit" but it was used for nominal entry to increase deorbit opportunities, and for TAL site availability.

That was a case of using what they already had, though, wasn't it? The initial requirement was all Air Force, so far as I understand it, and then once they had it anyway, NASA looked at other things they could so with the capability. Please correct me if I'm wrong.


No, NASA agreed it had similar requirement.


Whoops, we're talking at cross purposes. I meant just the cross-range capability of 1500 miles that the Air Force requested. So far as I know, NASA only wanted 400 and only went along because the White House made it clear they weren't go to get approval for the Shuttle unless they met the USAF's needs too.

NASA realized that they would need it too if they were going to launch from VAFB for aborts
Title: Re: Shuttle Q&A Part 5
Post by: Quindar Beep on 09/25/2012 10:06 pm
Even if that was the case, it wouldn't make your claim (that they "were never used") any less wrong.

Uhhhh...I know that's a common claim, but if you look back you'll see I didn't say that. What I said was that NASA did not originally intend to use it, and that just went with it after it was baked in for other reasons. Really, go look ;)

Quote from: Jorge
I'll let the original shuttle program manager (Robert Thompson) do the correcting. Here's his CAIB testimony:

http://caib.nasa.gov/events/public_hearings/20030423/transcript_am.html

Ah! Now that was the sort of thing I was looking for. So they must have changed their ideas between Max Faget's initial design (and the North American Phase A proposal that tried to hit that design on the nose) and 1973. Thanks.

You wouldn't happen to have anything else along those lines, would you?

Quote from: Jorge
It was an existing USAF-controlled facility that allowed polar launches without land overflight and was within CONUS for easier logistics. It had the extra benefit (though I don't think this drove the original decision) that the groundtrack for the single-orbit mission never overflew USSR ground stations.

Yeah, I was thinking about that in the context of the Barrow thing...it's not over land for the first bit over the Arctic Ocean, but then it was across the USSR for a long way after that. If aborting to Banjul would have been embarrassing, imagine having to abort to within spitting distance of Baikonur!

(Though if you launched south from Valdez or thereabouts you'd get most of the benefit of being far north, have pretty good logistics by sea, and have nothing but Pacific under you until you were over Antarctica.)
Title: Re: Shuttle Q&A Part 5
Post by: Quindar Beep on 09/25/2012 10:28 pm
Yikes. You were actually thinking of launching *north* from Barrow!? Never mind abort safety; the *nominal* launch would be headed straight toward the USSR. I can think of a couple more obvious issues with that than abort safety.

So you don't think that putting a big neon sign on the underbelly that read "NOT AN ICBM HONEST" in Russian would work, then?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/26/2012 12:47 am

I suppose my question could be rephrased more succinctly as "What's so great about Vandenberg" that NASA felt they needed to build the Shuttle as they did rather than get them to shift to some other launchpad for military-related missions to polar orbit.

To be precise, what made them decide this way in 1972 or so? Any knowledge gained after that time is unfair 20/20 hindsight  ;)


The final shuttle configuration chosen drove the need to use VAFB for the same reasons that existing launch vehicles used VAFB, no overflight of land during launch.

Were there any (alternative) shuttle configurations under consideration prior to the final selection which would not have required the use of VAFB for polar orbit flights?

Any of the TSTO RLV vehicles.  They didn't require KSC either.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 09/27/2012 12:52 pm
I'm not sure what thread this question should be in.  It isn't exclusive to shuttle but applies to shuttle.  How do the T-0 umbilical quick releases work? 

I have always been fascinated by the fact that a connection can be tight enough to prevent LH2 leaks but release quickly and reliably enough to be pulled away at liftoff.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/27/2012 02:17 pm
I'm not sure what thread this question should be in.  It isn't exclusive to shuttle but applies to shuttle.  How do the T-0 umbilical quick releases work? 

I have always been fascinated by the fact that a connection can be tight enough to prevent LH2 leaks but release quickly and reliably enough to be pulled away at liftoff.

Explosive bolts to the side of the Orbiter, plus cables in high tension attached to the "plates" of the umbilicals, I believe. At T-0 the bolts blow, the cables pull the umbilical plate into to tail service mast, and a very heavy clamshell door falls closed to shield from booster exhaust.

There's a DVD called "Ascent" that has some footage from inside the TSM's.

Also here - https://www.youtube.com/watch?v=urxrOI6-RlE
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2012 02:24 pm
Explosive bolts to the side of the Orbiter, plus cables in high tension attached to the "plates" of the umbilicals, I believe. At T-0 the bolts blow, the cables pull the umbilical plate into to tail service mast, and a very heavy clamshell door falls closed to shield from booster exhaust.

Bolts are not always used.  LH2 upperstages don't have bolted on carrier plates.  The umbilicals use a clamping mechanism that undone by a tension wire that is pulled by either vehicle movement or swing arm retraction.
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 09/28/2012 05:32 am

If that's the case, what was it that made the turn around processing take so much longer than the ordiginal plan?  Was it just the TPS inspection/repair process?

You had most of it: "inspection, minor repair and refueling" and include testing and payload bay reconfiguring.  As part of "refueling" the OMS and RCS pods were removed.  As for the middeck, all the lockers and crew accommodations were removed after each flight.

The pods and modules were not removed for a standard flow.  They were only removed for OMDP requirements and if there was a significant issue that required an LRU to be replaced.

The pods/modules carried whatever residual prop was in them until they were filled again at the pad. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/28/2012 11:24 am
They were only removed for OMDP requirements and if there was a significant issue that required an LRU to be replaced.


OMRSD requirements
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 09/28/2012 11:57 am
They were only removed for OMDP requirements and if there was a significant issue that required an LRU to be replaced.


OMRSD requirements

Right, the OMDP requirements in the OMRSD.  Otherwise, if an LRU had to be replaced.  Otherwise they remained on the vehicle, which was the far majority of the time.
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 09/28/2012 07:07 pm
Was the ET that was shipped to Port Hueneme in California via the Panama Canal in 1985 ever returned to KSC? If not, what became of it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/28/2012 08:55 pm
Was the ET that was shipped to Port Hueneme in California via the Panama Canal in 1985 ever returned to KSC? If not, what became of it?

It was shipped to VAFB and not Port Hueneme.  It was returned to MSFC I believe.
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 09/29/2012 04:36 am
I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/29/2012 12:23 pm
I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?

Yes, it is inaccurate.  That concept changed died in the mid 70's.  There is a boat dock created for the standard ET barge at VAFB and Delta IV now uses it.

http://goo.gl/maps/MnQv7
Title: Re: Shuttle Q&A Part 5
Post by: craigcocca on 09/29/2012 08:58 pm
I've read in a number of books that the plan was to ship and store the ETs at port Hueneme, and then move them by hovercraft to VAFB. Is that inaccurate?

Yes, it is inaccurate.  That concept changed died in the mid 70's.  There is a boat dock created for the standard ET barge at VAFB and Delta IV now uses it.

http://goo.gl/maps/MnQv7

Thanks, never knew that dock existed at VAFB!

For future posterity, here are the four tanks that were shipped to Vandenberg in 1985-86, along with their final disposition:

ET-23: Launched with STS-27 (DoD)
ET-27: Launched with STS-34 (Galileo)
ET-33: Launched with STS-36 (DoD)
ET-34: Launched with STS-31 (HST)

Looks like the Air Force got some use out of two of the four tanks in the end.

-Craig
Title: Re: Shuttle Q&A Part 5
Post by: NavySpaceFan on 10/02/2012 04:10 pm
I'm looking for anything related to Endeavour's OMM, specifically milestone dates, work performed, flow manger at the time, etc.  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: rbfnet on 10/10/2012 01:59 pm
Question about abort boundaries:  During ascent, there will be a transition through the following flour states:
(1) If a single engine is lost, the shuttle cannot make a safe/stable orbit period. 
(2) If a single engine is lost, the shuttle can make a safe/stable orbit if an ATO is called.
(3) If a single engine is lost, and no ATO is called, the shuttle will not make its desired orbit, but it will (at the time shutdown occurs as a result of ECO sensors going dry) make a safe/table orbit.
(4) If a single engine is lost, and no ATO is called, the shuttle will, on two engines, make it to a normal guidance-initiated shutdown in it's desired orbit.

(Obviously I haven't listed all the abort boundaries above ... just enough to frame my question.)

Is the transition from "ATO" to "Press to MECO" (for single engine failure) at the transition from (2) to (3) above, or from (3) to (4) above?

Or, put another way, during the period of time where flying on two engines without an ATO call will lead to a safe/stable orbit, but not the desired orbit, is the practice to call ATO on single engine loss, or to press to MECO on single engine loss (knowing that it will likely be an ECO-initiated shutdown prior to desired orbit).

Secondary question:  When an ATO occurs, does the shuttle always fly to propellant exhaustion (ECO-initiated shutdown)?  Or does abort guidance initiate a shutdown when some acceptable orbit has been attained?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/11/2012 01:37 pm
Question about abort boundaries:  During ascent, there will be a transition through the following flour states:
(1) If a single engine is lost, the shuttle cannot make a safe/stable orbit period. 
(2) If a single engine is lost, the shuttle can make a safe/stable orbit if an ATO is called.
(3) If a single engine is lost, and no ATO is called, the shuttle will not make its desired orbit, but it will (at the time shutdown occurs as a result of ECO sensors going dry) make a safe/table orbit.
(4) If a single engine is lost, and no ATO is called, the shuttle will, on two engines, make it to a normal guidance-initiated shutdown in it's desired orbit.

(Obviously I haven't listed all the abort boundaries above ... just enough to frame my question.)

Is the transition from "ATO" to "Press to MECO" (for single engine failure) at the transition from (2) to (3) above, or from (3) to (4) above?

Or, put another way, during the period of time where flying on two engines without an ATO call will lead to a safe/stable orbit, but not the desired orbit, is the practice to call ATO on single engine loss, or to press to MECO on single engine loss (knowing that it will likely be an ECO-initiated shutdown prior to desired orbit).

Secondary question:  When an ATO occurs, does the shuttle always fly to propellant exhaustion (ECO-initiated shutdown)?  Or does abort guidance initiate a shutdown when some acceptable orbit has been attained?


You're kind-of all over the place with your description of "abort boundaries".  Abort boundaries were simply velocity versus abort capability.  In other words, at this feet / sec, the orbiter could had this capability to reach a landing site or orbit, assuming we were on the standard ascent flight profile.

For intact abort modes, which were RTLS, TAL and ATO, based on payload weights and engine capabilities (and other things) there were a set of velocity cutoffs that said at this point you have both RTLS and TAL capability or you no longer have RTLS capability (negative return).  Intact aborts covered all single engine out cases, while contingency aborts included two-engine outs, three-engine outs as well as stuck throttles and other unusual cases.  The abort boundary velocities were computed months before flight and then updated on the day of flight.

For ATO, there was a velocity that allowed us to recompute (in real-time), the orbit targets and get to the best orbit we could (such as on STS-51F).  This orbit was less than the target orbit but was a stable orbit where the situation could be assessed.  Once we hit the single-engine-out MECO velocity, then we could make the normal MECO targets (and therefore the desired orbit) even if one engine was out.  ECO sensor dry MECOs are a completely separate subject than intact or contingency aborts since that happens so close to your normal MECO targets that an OMS burn could have made-up any deficiencies (but with the loss of OMS prop).

Contingency aborts had quite a number of permutations as different boundaries were available for two-engine out and three-engine out cases.  The intent was to always have a runway available for each of these cases but there were situations (called black-zones) where a runway was not available.  For these east coast abort landing contingency aborts, during later flights an onboard display was available that gave the crew a rough idea of which runways were reachable (both in the US and in Europe).  Unfortunately we never really had time to fully integrate the use of the display but fortunately it was never really needed.

Finally, I did not include AOA above because the RTLS/TAL/ATO intact aborts covered the entire velocity range to orbit.  So, AOA became only necessary for multiple failure scenarios (SSME out plus OMS problem, for instance). 

Also note that all of my answers are in the past tense since the program is well over now.  That means I'm also relying on my memory, so any details should be double-checked.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 10/13/2012 02:24 am
Let me preface this by saying that I am nothing near a rocket scientist so this could be a really dumb question.

Could the External Tank have been made 25% or so smaller (and a decent percentage lighter) if the SSMEs didn't ignite until staging?  Even with the 25% lighter liquid fuel/oxidizer load could the SRBs alone have lifted the stack off the pad and got it high/fast enough at staging for the SSMEs to take the orbiter the rest of the way into orbit?

I have always wondered if the use of the SSMEs prior to liftoff was a performance issue or if the system was designed that way solely to have the ability to evaluate SSME function prior to liftoff.  I would imagine that without a launch escape system there would be a pretty big risk if the engines didn't start at staging.
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 10/13/2012 04:39 pm
Press to MECO is not based on making the nominal MECO targets.  I is based on keeping the tank off a land mass.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 10/13/2012 05:15 pm
Let me preface this by saying that I am nothing near a rocket scientist so this could be a really dumb question.

Could the External Tank have been made 25% or so smaller (and a decent percentage lighter) if the SSMEs didn't ignite until staging?  Even with the 25% lighter liquid fuel/oxidizer load could the SRBs alone have lifted the stack off the pad and got it high/fast enough at staging for the SSMEs to take the orbiter the rest of the way into orbit?

I have always wondered if the use of the SSMEs prior to liftoff was a performance issue or if the system was designed that way solely to have the ability to evaluate SSME function prior to liftoff.  I would imagine that without a launch escape system there would be a pretty big risk if the engines didn't start at staging.

You may want to read the Ares-I/CxP details with regard to an air-startable SSME. There was some hefty ground equipment (on the pad), among other things, that get the SSMEs up and running. The original Ares 1 design had a 4 segment SRB and a single SSME (air-start) upper stage. The air-start was not impossible but it was not going to be easy OR cost effective.

Also keep in mind that in an overly simplified perspective, the total thrust of all three SSMEs effectively makes the whole stack about 1.1 million pounds "lighter", so the SRB's have less to lift.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 10/22/2012 02:11 pm
What are the holes seen in the TPS of the hatch in this photo?

http://www-pao.ksc.nasa.gov/kscpao/images/medium/2012-5774-m.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/22/2012 02:41 pm
What are the holes seen in the TPS of the hatch in this photo?

http://www-pao.ksc.nasa.gov/kscpao/images/medium/2012-5774-m.jpg

Those tiles are the last to be installed after the hatch is closed.  How the "holes" aid in the installation will have to be provided by someone else.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 10/27/2012 09:51 pm
What are the holes seen in the TPS of the hatch in this photo?

http://www-pao.ksc.nasa.gov/kscpao/images/medium/2012-5774-m.jpg

The tiles are bonded to thin metal plates, which are screwed to the rest of the hatch structure. The plates cover the access's to the hatch locking mechanism and other things (like the inspection port they stick a borescope thru to check and make sure the latches have all engaged). The plates have to be installed after the hatch is closed, so the tiles have holes thru them to allow the fastenesr to be inserted. The bright white stuff is a filler compound that is stuffed over the fastener heads to protect them.

Here is a photo showing one of the fasteners being installed.

http://mediaarchive.ksc.nasa.gov/imageviewer.cfm?mediaid=62893&mr=l&w=0&h=0&fn=2012-5773&sn=KSC-2012-5773
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/27/2012 10:22 pm
like the inspection port they stick a borescope thru to check and make sure the latches have all engaged
Not quite. They don't use a borescope for this task but a multimeter to measure the electrical resistance. The resistance should be less than 2.0Ω to indicate an successful latching.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 10/28/2012 03:36 am
Actually, they do both a visual and electrical test. I did misspeaks when I said borescope. They actually just use a small mirror on a stick and a flashlight to see if a mark painted on the latch linkage is visable.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 10/31/2012 02:49 am
Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll).  For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/31/2012 12:28 pm
Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll).  For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).


By adjusting the thrust vector of the SRB's and SSME's, the vehicle can fly at different attitudes with respect to the flight path.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/12/2012 05:56 pm
Spacecane -

CBS News' Space Place has STS trajectory info available at:

http://www.cbsnews.com/network/news/space/home/flightdata/downloads.html

Download either of these files:

STS-135 SpaceCalcMac (Macintosh formatting; Zip archive)
STS-135 SpaceCalcPC (PC formatting; Zip archive)

And look under the Trajectory tab of the SpaceCalc_XXX.xls workbook for the data.

F=ma

Does anybody have (or can draw even if crude) a diagram of the angle of the stack vs. direction of travel during ascent (after roll).  For some reason I can't picture how the orbiter was at a negative AoA vs. the slip stream when it seams like the forward direction would be somewhat on the ET side (based upon the drift at liftoff).
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/12/2012 09:33 pm
Anyone know if the pre-launch aerosurface check (T-3:55) and gimbal check (T-3:25) is commanded by the GLS or is it the RSLS that commands those?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 11/30/2012 01:07 am
Quote
There was some hefty ground equipment (on the pad), among other things, that get the SSMEs up and running.

What is this in reference to?  The SSMEs started using head pressure from the ET and their own internal igniters.  There was no special GSE related to SSME start except for the sparklers.  There was, of course, GSE to fill and pressurize the ET, but none related to starting the SSMEs. 

I have seen this misinformation posted several times and honestly wonder where it came from.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/30/2012 01:41 am
Quote
There was some hefty ground equipment (on the pad), among other things, that get the SSMEs up and running.

What is this in reference to?  The SSMEs started using head pressure from the ET and their own internal igniters.  There was no special GSE related to SSME start except for the sparklers.  There was, of course, GSE to fill and pressurize the ET, but none related to starting the SSMEs. 


There are the purges and the gas for them
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 12/11/2012 09:25 pm
Hi all.
A quick question on the SRB. As part of the modification introduced post-Challenger there was the creation of a so called J-seal in lieu of the zinc chromate putty placed between the two motor segments insulation at the field joint.

The reason for adding such seal, was to avoid imperfection (ie: air pockets) in the injection of such potty which could create an easy way for the exhaust to find their way to the joint. However, based on the attached schematics, it seems to me that this configuration  had a weak point in the form of a little corner in the slot cut in the insulation. In fact, the small radius corner would constitute stress concentration point for the high pressure-high temperature exhaust for pushing through the insulation and carving the slot further up to the joint.

Does all of this make sense? Where am I wrong in my thinking?

Thanks very much
Davide
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 12/11/2012 10:47 pm
The purpose of the J-seal was to add another level of protection for the field joint against the hot gas.  During assembly, the free leg of the J-seal was glued to the opposite face of the adjoining SRM segment.  When the SRB ignited, the hot gas pressurized the open end of the J-seal and forced it to open wider and seal better.  The hot gas was trapped in the dead end, and could not reach the field joint and O-rings.
F=ma

Hi all.
A quick question on the SRB. As part of the modification introduced post-Challenger there was the creation of a so called J-seal in lieu of the zinc chromate putty placed between the two motor segments insulation at the field joint.

The reason for adding such seal, was to avoid imperfection (ie: air pockets) in the injection of such potty which could create an easy way for the exhaust to find their way to the joint. However, based on the attached schematics, it seems to me that this configuration  had a weak point in the form of a little corner in the slot cut in the insulation. In fact, the small radius corner would constitute stress concentration point for the high pressure-high temperature exhaust for pushing through the insulation and carving the slot further up to the joint.

Does all of this make sense? Where am I wrong in my thinking?

Thanks very much
Davide

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/12/2012 01:18 am
Anyone know if the pre-launch aerosurface check (T-3:55) and gimbal check (T-3:25) is commanded by the GLS or is it the RSLS that commands those?

Dave, that was commanded by the GLS.  We had to simulate the GLS when testing the RSLS.  The GLS left the engines in their start-up position when completed with the checks.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/12/2012 01:24 am
Anyone know if the pre-launch aerosurface check (T-3:55) and gimbal check (T-3:25) is commanded by the GLS or is it the RSLS that commands those?

Dave, that was commanded by the GLS.  We had to simulate the GLS when testing the RSLS.  The GLS left the engines in their start-up position when completed with the checks.
Thanks. Just to be certain: The GLS did all the commanding from T-9 minutes to RSLS Autosequence Start at T-31 seconds?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/12/2012 04:36 am
No.  RSLS was running from T-9 minutes on down.  Things like the orbiter vent doors were commanded by RSLS (I believe we changed the timing after the STS-30 hold at T-50-some seconds) which was at one time before T-31 seconds.  The Go for Autosequence was simply a flag that said to proceed past T-31 seconds.

So not so cut and dry as saying all commanding was done by GLS.  Most (almost all) is probably correct.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 12/13/2012 09:13 pm
Hi all.

I was reading some posts posted few posts ago, in particular this reply concerning the tiles sourrounding the hatch:

Quote from: JayP
The tiles are bonded to thin metal plates, which are screwed to the rest of the hatch structure. The plates cover the access's to the hatch locking mechanism and other things (like the inspection port they stick a borescope thru to check and make sure the latches have all engaged). The plates have to be installed after the hatch is closed, so the tiles have holes thru them to allow the fastenesr to be inserted. The bright white stuff is a filler compound that is stuffed over the fastener heads to protect them.

Does this really mean that those tiles were manually screwed on the Orbiter just few hours before launch? it seems to me that there is quite a good number of such tiles had to be installed at the "last minute".

Did they also have to unscrew everything once the Orbiter was back home to allow the astronaut to exit? Regarding this question, I would say no since in case of emergency the astronauts could open the hatch by themself from the inside, right?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 12/19/2012 12:45 pm
Hi all.

I was reading some posts posted few posts ago, in particular this reply concerning the tiles sourrounding the hatch:

Quote from: JayP
The tiles are bonded to thin metal plates, which are screwed to the rest of the hatch structure. The plates cover the access's to the hatch locking mechanism and other things (like the inspection port they stick a borescope thru to check and make sure the latches have all engaged). The plates have to be installed after the hatch is closed, so the tiles have holes thru them to allow the fastenesr to be inserted. The bright white stuff is a filler compound that is stuffed over the fastener heads to protect them.

Does this really mean that those tiles were manually screwed on the Orbiter just few hours before launch? it seems to me that there is quite a good number of such tiles had to be installed at the "last minute".

Did they also have to unscrew everything once the Orbiter was back home to allow the astronaut to exit? Regarding this question, I would say no since in case of emergency the astronauts could open the hatch by themself from the inside, right?

Thanks

Davide
Yes installing those panels was the very last vehicle close outs done before launch. After that, they closed out the white room and evacuated the pad. Those were the only TPS closeouts done in the final countdown. everything else was done before fueling.

Also yes, those panels were the first things removed by the ground crew after they got the mobile white room in place on the runway. The crew could open the hatch from the inside but that was never done since that would involve basically "droping" the hatch dowanward to the 90 degree open position which would strain the hinges considerably. Removing the panels alowed the ground crew to atach the external handle and support the hatch as it lowered (as well as give them access to the latch drive mechanism).
Title: Re: Shuttle Q&A Part 5
Post by: cautionjump on 12/22/2012 11:00 pm
Hello everyone!
I just joined L2 Premium and love all the high res photos! I have this cable that is documented as being a data cable flown on 134 for the STORRM experiment.
I looked at all the photos on NASAs site of the mission and was unable to find the cable although there were similar ones. What makes this one unique is it has orange stripes on the label. Does anyone know why they labels are striped when no others in the cabin are? Is it a back up cable? Where would it be located?

Heres a photo and the labels.

"STORRM RS-422 DATA Cable"
Model number 528-21526-1
Serial 1005

Ends are labeled
"Vision Navigation Sensor"
"PDO"
"Spare 1"
"Docking Camera"

Is this the best section to ask this or should I move it else where? Thanks!
Eric
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/23/2012 12:01 am
Post a photo or pdf of your documentation.
Title: Re: Shuttle Q&A Part 5
Post by: cautionjump on 12/23/2012 11:01 pm
Ill try and find the paper work on it, its interesting because I was able to find an identical cable plugged into a flight laptop, but that cable had yellow tags on it and didnt have the orange stripes, so im thinking maybe it was a back up cable that was flown on the mission...
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/23/2012 11:02 pm
It could be a training cable
Title: Re: Shuttle Q&A Part 5
Post by: cautionjump on 12/24/2012 01:43 am
Yeah it does say on the paperwork it was removed from stock and "ok for for STS 134". It was a surplus government auction which also notes it from STS 134...
Title: Re: Shuttle Q&A Part 5
Post by: Chris Bergin on 12/24/2012 12:24 pm
Hey CJ, firstly, I'll need to merge this thread into the Shuttle Q&A *see the rules on threads in this section at the top thread of the section*, but that'll be later.

Seen as you're on L2. Check out these MOD and SSP FRR presentations covering STORRM on L2:

http://forum.nasaspaceflight.com/index.php?topic=20337.0
http://forum.nasaspaceflight.com/index.php?topic=20813.0
http://forum.nasaspaceflight.com/index.php?topic=24418.0
http://forum.nasaspaceflight.com/index.php?topic=24424.0

And these images and videos for STORRM on L2:
http://forum.nasaspaceflight.com/index.php?topic=25134.0
http://forum.nasaspaceflight.com/index.php?topic=24242.0
http://forum.nasaspaceflight.com/index.php?topic=24572.0

That's about 1,000mb of STORRM content on L2 that will keep you busy :)
Title: Re: Shuttle Q&A Part 5
Post by: cautionjump on 12/24/2012 04:41 pm
Thank you for the links, the information was very helpful! It seems to verify what I thought, that the cable connects the PGCS to the orbiter, and it appears only one PGCS computer was connected to the STORRM system.
So I guess if I could find out why the labels have the orange stripping it would explain why that cable was made and flown on Endeavour, but not hooked up to a PGCS laptop. My best guess is that it was a back up at this point, unless anyone know for sure of ca point me in the direction of some documentation that I can look through for an answer on the cabling used on flights...
Thanks again for everyone's help!
Eric
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/24/2012 06:37 pm
My best guess is that it was a back up at this point, unless anyone know for sure of ca point me in the direction of some documentation that I can look through for an answer on the cabling used on flights...
Thanks again for everyone's help!
Eric

You would  need the installation procedure to determine which serial number of the cable flew.  You would need an FOIA request.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 12/26/2012 01:05 am
First it is a PGSC - Payload and General Support Computer.  That was for a DTO, so it was not a standard PGSC cable.  It was created for that specific DTO.  You would probably need to talk with the DTO principle investigator for the answer on specific uses of this cable.  The round cannon-type plug looks like one that would connect to a control panel.   The DB-9 plugs (or DB-15) were the RS-422 data cables.

Other than that I'd need to see the drawing to tell more.  The yellow stripes could also indicate a ground version or a training version or a certification version.  You would have to reference the cable serial number to the flight manifest to determine if the cable was flown.
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 12/27/2012 11:30 pm
Is there any information available detailing how much LOX and LH2 was lost to boil-off during the Shuttle Program, either per year or per launch?

I know each launch required about 735,000kg at lift-off, but I'm curious how much more was needed to support each launch and also how much was needed just to keep the cryo-tanks conditioned correctly between flights?

Does anyone know?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 12/28/2012 12:50 am
Is there any information available detailing how much LOX and LH2 was lost to boil-off during the Shuttle Program, either per year or per launch?

I know each launch required about 735,000kg at lift-off, but I'm curious how much more was needed to support each launch and also how much was needed just to keep the cryo-tanks conditioned correctly between flights?

Does anyone know?

Some info on LH2 use recently posted by NASA/KSC which may be of partial help on a per-launch basis:

"The supply of LH2 at KSC LC39B currently is provided by over the road tankers from Louisiana. Past Space Shuttle launches have required that an existing 850,000 gallon storage tank located at LC39B be filled by this method prior to the start of LH2 tanking operations. Replenish losses were 12.6%, evaporation losses were 12.2%, normal launch loss was 12.9%, and launch scrub with 24 hour turnaround was 7.8%."

Did not mention between-launch consumption.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 12/28/2012 12:57 am
If I remember correctly we would lose 50-75k gallons each scrub on the average. The wildcard usually being how long between tanking and when the decision was made to detank. As far as normal boiloff, less than 1k a week at pad a, 3-5k a week at B due to the perlite problem. And we usually tried to not go under 250k at all times in the tanks.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 12/28/2012 02:03 am
wow!!!!
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 12/28/2012 03:09 am
Thanks for the responses guys, that's exactly what I was curious about!

3-5k a week at B due to the perlite problem.

That reminds me, when I did the Tour de KSC back in October, it looked like both tanks were undergoing work. Has the perlite problem been solved during this down-time?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 12/28/2012 02:02 pm
They topped off the perlite back in 2010, 2011 timeframe. Right now they are doing some painting/corrosion control on B. I don't think A has anything going on on it these days....
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 12/28/2012 10:24 pm
3-5k a week at B due to the perlite problem.

What was the perlite problem?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 12/30/2012 12:43 am
The tank at B had a large void in the annular space which is filled with perlite and under vacuum. There was probably air trapped when they filled it back in the 60's. Then 50 yrs of launches caused it to settle since the void was on the side toward the pad. You can probably see in some pictures a large dark area on the tank from mold growth since it stayed wet from condensation. The boiloff would average around 3k a week unless it was full for launch, then it would jump to 5k or more due to more liquid in contact with the warm area.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 12/30/2012 01:02 pm
3-5k a week at B due to the perlite problem.

What was the perlite problem?

To add to padrat's reply - there was a paper published in June 2011 that gives a detailed description of the problem, diagnosis and repair.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110014372_2011014935.pdf

Copy also attached.
Title: Re: Shuttle Q&A Part 5
Post by: simmy on 01/01/2013 01:57 pm
at http://news.nationalgeographic.com/news/2012/04/120416-nasa-space-shuttle-discovery-smithsonian-360-tour-panorama-science/ there is something called "Russian Panel". Anyone know what its purpose was?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 01/01/2013 02:06 pm
at http://news.nationalgeographic.com/news/2012/04/120416-nasa-space-shuttle-discovery-smithsonian-360-tour-panorama-science/ there is something called "Russian Panel". Anyone know what its purpose was?

Thanks!

That is the control panel for the docking system (hint: read the decals: 'hooks', 'latches', 'ring').. . The Docking System was provided by the Russians and made in Russia, I think. The decals and text on the panel are in English, though.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 01/02/2013 06:40 am
How did the ejection seats worked on the sts-1-4? Where there blow away hatches on top? Are there any drawings / diagrams?
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/03/2013 05:00 pm
How did the ejection seats worked on the sts-1-4? Where there blow away hatches on top? Are there any drawings / diagrams?

Yes, If you look at an image of Enterprise or Columbia from before STS-9 you can see the out line of them in the tile pattern.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/03/2013 05:06 pm
at http://news.nationalgeographic.com/news/2012/04/120416-nasa-space-shuttle-discovery-smithsonian-360-tour-panorama-science/ there is something called "Russian Panel". Anyone know what its purpose was?

Thanks!

That is the control panel for the docking system (hint: read the decals: 'hooks', 'latches', 'ring').. . The Docking System was provided by the Russians and made in Russia, I think. The decals and text on the panel are in English, though.

And when the orbiters were preped for museum display, a large warning placard was attached to that panel pertaining to the cadmium plated parts inside of it. The US specs for equipment in the orbiters cabin precluded using cadmium, but the russian design didn't.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/05/2013 01:04 am
CDR and PLT would have sure one heckuva headache if there weren't some kind of separable section...

Seconded on the drawings and diagrams request.  Interesting that the blow-away section interfaces with both the crew compartment and the upper forward fuselage.

How did the ejection seats worked on the sts-1-4? Where there blow away hatches on top? Are there any drawings / diagrams?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 01/05/2013 02:14 pm
CDR and PLT would have sure one heckuva headache if there weren't some kind of separable section...
Heh, sounds like one of John Young's old Gemini quotes.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/07/2013 03:15 am
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?
Giving this a bump as I never received an answer on this. This is between the vertical of the OBSS only.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 01/10/2013 12:05 am
If the ET umbilical doors could not be closed and latched after ET separation by the nominal procedure, what other procedures and options were available? Was there some sort of "emergency procedure" to close and latch them manually by astronauts on EVA? (Similar to payload bay doors, which could be closed and latched manually for deorbit by astronauts on EVA.)
It seems very difficult, if not impossible, because the ET umbilical doors are on the orbiter's belly. Obviously there are no handrails there and the RMS could not reach there either. So, how would an EVA crew get there?
I imagine there must have been some back-up procedure in case of failure of the nominal procedure.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/10/2013 12:55 am
There was an EVA procedure.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 01/10/2013 01:22 am
Thanks a lot Jorge and Jim!
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/10/2013 02:17 pm
How did the TPS cover the forward attach point after ET sep?  In the photos I have seen there isn't an apparent door.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/10/2013 04:39 pm
It doesn't; there is no "trap door" like the aft attachments.
F=ma

How did the TPS cover the forward attach point after ET sep?  In the photos I have seen there isn't an apparent door.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/10/2013 04:55 pm
How did the TPS cover the forward attach point after ET sep?  In the photos I have seen there isn't an apparent door.

There is an "arrowhead" shaped piece of TPS that has a hole in it for the bolt that separates the forward ET bipod. The whole bipod remains attached to the ET, and the bolt is captured in the Orbiter. The hole is a bit below the mold line of the TPS so thermal issues are mitigated on re-entry.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/10/2013 08:54 pm
Arrowhead is RCC, per this:

http://www.columbiassacrifice.com/techdocs/RCC_Design.pdf

How did the TPS cover the forward attach point after ET sep?  In the photos I have seen there isn't an apparent door.

There is an "arrowhead" shaped piece of TPS that has a hole in it for the bolt that separates the forward ET bipod. The whole bipod remains attached to the ET, and the bolt is captured in the Orbiter. The hole is a bit below the mold line of the TPS so thermal issues are mitigated on re-entry.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/11/2013 01:24 am
How did the TPS cover the forward attach point after ET sep?  In the photos I have seen there isn't an apparent door.

There is an "arrowhead" shaped piece of TPS that has a hole in it for the bolt that separates the forward ET bipod. The whole bipod remains attached to the ET, and the bolt is captured in the Orbiter. The hole is a bit below the mold line of the TPS so thermal issues are mitigated on re-entry.

The "Arrow Head" simply surrounds the fitting itself. The fitting is a metallic spherical bearing with a hole thru it for the connection bolt. The bolt has pressure charges at each end and is specifically designed to break exactly flush with the outer face of the spherical bearing. (Personally, I think this is one of the most impressive engineering feats on the whole shuttle) the bearing is sprung loaded to rotate flush with the outer surface after separation. Both the faces of the outer race and spherical ball as well as the broken face of the bolt remain exposed to the slipstream and heating effects of re-entry, but the mounting of the entire system is a very heavy metal structure that acts as a heat sink so there is no thermal damage to the parts.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/11/2013 12:25 pm
Does anybody have a link to a good closeup picture of the "arrowhead" either with ET attached or without?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/11/2013 02:02 pm
Does anybody have a link to a good closeup picture of the "arrowhead" either with ET attached or without?

I have one of Discovery with the bipod mount still attached after the ferry flight to DC. You can see it well because it is painted red. I'll post when I get home tonight.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/12/2013 12:14 pm
As promised.

Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/13/2013 12:09 am
Does anybody have a link to a good closeup picture of the "arrowhead" either with ET attached or without?

Here's one from STS-133
http://www.nasa.gov/images/content/521274main_iss026e029923_hires.jpg
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/13/2013 01:39 am
That STS-133 picture is great but now I'm confused.  I pictured the ET bipod having a ball at the end and this ball going into the hole in the arrowhead and then an explosive bolt holding the ball in.  I figured upon ET separation the bolt would blow and the ball would come out of the hole leaving a hole in the orbiter belly.

In that picture, it appears as if the silver colored metal is almost flush with the bronze/gold colored ring. 

So what exactly is (was)  the attachment/separation method of the forward ET addach point.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/13/2013 03:53 am
That STS-133 picture is great but now I'm confused.  I pictured the ET bipod having a ball at the end and this ball going into the hole in the arrowhead and then an explosive bolt holding the ball in.  I figured upon ET separation the bolt would blow and the ball would come out of the hole leaving a hole in the orbiter belly.

In that picture, it appears as if the silver colored metal is almost flush with the bronze/gold colored ring. 

So what exactly is (was)  the attachment/separation method of the forward ET addach point.

 Here is a drawing of the attachment point including a section thru the middle of it. The ball is shown rotated to the maximum extent away from its nuetral position and the bolt is not shown.

 The "bolt" is a specially manufactured component of course. What would normaly be the "head" of the bolt is actually a wider cylinderical section with threads on the out side that screws into the upper part of the ball. You can see the threads in the drawing below. The other end of the bolt sticks thru the ET bi-pod head and is secured with a nut from the bottom.

 As it was explained to me, The bolt has a pressure charge intalled at each end. When the charges detonate, they create two pressure waves that travel towards each other down the length of the bolt. When the waves meet, they reinforce each other and the tension forces peak causing the bolt to snap flush with the bottom face of the ball. The upper half stays in the ball in the orbiter and the bottom half is retained in the ET bipod fitting.

 The clever thing about this system is that it doesn't produce any debris that need to be contained (unlike the sytem used for the aft fittings and the SRB hold downs) and that it leaves a flush metal surface with no voids or exposed edges that could dissrupt the plasma flow on reentry and create a localized hot spot.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 01/13/2013 07:54 pm
JayP, the explanation you were given on the how the frangible bolt works appears to be from another application rather than the one used on the orbiter forward attachment.

I've attached a cross-sectional drawing of the head-end of the bolt showing the pyrotechnic mechanism that shears the bolt and results in the clean flush outer surface shown in the STS-133 RPM photograph.

The left-hand side of the drawing shows the mechanism before separation, and the right-hand side after separation.

The head of the bolt (colored yellow) is a hollow cylinder whose internal diameter very similar to the outer diameter of bolt's shank where it passes through the spherical bearing (green) to the outside world.  Within the bolt is a free piston (light blue) made of Inconel 718, as are the bolt and bearing parts.

Two pyrotechic pressure cartridges (for redunancy) rapidly force the piston downwards causing the bolt to shear along a cylindrical inner surface.  The piston and spherical bearing act as a punch and die set shearing the bolt, rather like a paper punch does acting on a stack of paper.  The difference is that the end of the piston is dead flat rather than having an acute shaped cutting edge like the paper punch has.

After the piston shears the bolt, an attenuator skirt on the upper part is slammed and flanges outwards into a 45 degree circular groove - this absorbs excess energy from the piston in a controlled fashion ensuring the end of the piston ends up flush with the flat outer faces of the spherical bearing (ball and mount).

The aerothermal requirement was that there be no more than a ±0.017 inch (±0.43mm) step between the piston and the bearing surfaces, and a gap no greater than 0.035 inch (0.89mm) around the piston.

The pyrotechnic bolt used on the Approach and Landing Test (ALT) flights also used a piston arrangement, but the bolt was fractured in tension around a hollow part of the head.  It was found that the exposed fracture surface of the bolt (which surrounded the piston) created a 0.1 inch wide x 0.2 inch deep groove (2.5 x 5.1mm) failing to meet the requirements of re-entry from orbit.  This led to the redesign for orbital flights.

Robert Pearlman took a photo of the metallic parts of Enterprise's arrowhead assembly, complete with bolt - its about half-way down this web page:
http://www.collectspace.com/news/news-031510b.html (http://www.collectspace.com/news/news-031510b.html)

(click images to enlarge)
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/13/2013 10:09 pm
Thank you for the clarification. I thought it was a pretty impressive piece of engineering, getting the pressure waves to coincide at exactly the right point. Oh well, this does seem a lot more reliable.

I noticed that the flange around the head of the piston, in addition to attenuating the motion, also serves to lock the piston in the extended position and keep it from sliding back up inside the body durring the flight.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/13/2013 10:37 pm
Note also that the "fwd" orientation in the drawing JayP posted from:
http://www.columbiassacrifice.com/techdocs/RCC_Design.pdf

is opposite from the RPM photo at:
http://www.nasa.gov/images/content/521274main_iss026e029923_hires.jpg

AnalogMan - what is the source for your excellent drawing?
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 01/14/2013 02:08 pm
AnalogMan - what is the source for your excellent drawing?

I found the original monochrome drawing in:
http://hdl.handle.net/2060/19780024234
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/14/2013 02:41 pm
AnalogMan,

Thanks for posting that.  It makes sense now.  I have 3 other questions related to this:

1) What locked the piston in the down position so that it stayed flush with the ball?

2) Related to #1, what locked the ball in the "flat" position?

3) What was the process of mating this attach point?  Was it something like half of the bearing plate and the piston assembly in attached to the orbiter while the other half of the bearing plate, the bolt and the ball attached to the ET and then the two halves joined with fasteners?

This was an amazing piece of engineering, I guess that's why I'm so interested into such a small part fo the system.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/14/2013 03:24 pm


3) What was the process of mating this attach point?  Was it something like half of the bearing plate and the piston assembly in attached to the orbiter while the other half of the bearing plate, the bolt and the ball attached to the ET and then the two halves joined with fasteners?


The yoke is attached to the orbiter before it rolls over to the VAB.  Each leg of the bipod is then attached to the yoke during Orbiter ET mate.
Title: Re: Shuttle Q&A Part 5
Post by: sdsds on 01/14/2013 08:19 pm
I've attached a cross-sectional drawing of the head-end of the bolt

Thanks for the great diagram! Are the "dual pressure cartridges" to make the mechanism single fault tolerant? Also, it's clever how the shear section is only 0.79 cm yet the loads nonetheless get carried around it.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/14/2013 08:25 pm
1) What locked the piston in the down position so that it stayed flush with the ball?

2) Related to #1, what locked the ball in the "flat" position?


I'd be willing to bet it's a pretty decent interference fit once that piston travels downward.

Edit: Analog Man already had the answer.

"After the piston shears the bolt, an attenuator skirt on the upper part is slammed and flanges outwards into a 45 degree circular groove - this absorbs excess energy from the piston in a controlled fashion ensuring the end of the piston ends up flush with the flat outer faces of the spherical bearing (ball and mount)."

The deformed metal into that groove will prevent upward travel of the piston.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 01/14/2013 11:59 pm
AnalogMan,

Thanks for posting that.  It makes sense now.  I have 3 other questions related to this:

1) What locked the piston in the down position so that it stayed flush with the ball?

2) Related to #1, what locked the ball in the "flat" position?

3) What was the process of mating this attach point?  Was it something like half of the bearing plate and the piston assembly in attached to the orbiter while the other half of the bearing plate, the bolt and the ball attached to the ET and then the two halves joined with fasteners?

This was an amazing piece of engineering, I guess that's why I'm so interested into such a small part fo the system.

1) If you look at the earlier diagram I posted you will see something labelled "piston attenuator skirt" on the underside of the upper part of the piston.  This is a thin cylindrical shell that runs all the way around the piston.  When the piston slams down shearing the bolt, this skirt is deformed and forced into a channel between the 45 degree chamfer on the outer top edge of the bolt (yellow) and a corresponding chamfer on the housing (pink).  This helps slow down the piston and also, as JayP pointed out, locks it into its final position so it can't move.

2) There are two powerful spring loaded plungers on the forward side of the body that act against the upper surface of the bearing plate and which pivot the whole assembly from the tilted orientation to one where the flat on the ball/piston is aligned with the bearing plate surface.  A post on the opposite side acts as a locating stop for the assembly.  See the attached drawing.

3) The bolt mechanism (bolt shank/piston/body/cartridges) is fitted into the spherical bearing from behind, and the the whole arrowhead assembly is bolted back into the orbiter.

Then, as Jim has mentioned, the yoke (top part of the ET support structure, and actual flight hardware) is clamped to the orbiter using the bolt with a nut on the end.  This all happens in the Orbiter Processing Facility (OPF).  The yoke is used to support the orbiter on the transporter during rollover to the VAB.

Once in the VAB the yoke is unbolted from the transporter support structure ready for the vertical lift and bolting to the ET struts.

I've attached part of a photo taken by Larry Sullivan (NSF photographer) that shows the flight yoke in use during the rollover (orange structure is part of transporter), and a drawing of the ET forward struts/yoke for comparison (courtesy of fequalsma via L2).

(click images to enlarge)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/18/2013 02:11 am
AnalogMan, I think that you omitted a really interesting part of the figure (III-21) from the SLWT SDH.  The enclosed portion of that figure shows the side view of the Forward Bipod.  It shows that the center of the forward orbiter fitting is 5.5 inches forward of vertical for the loaded ET.  I estimate that the unloaded ET's orbiter fitting is 1.0 inches aft of vertical, for a total nominal range of motion of 6.5 inches.  So why does this motion occur? 

The answer is thermal contraction of the loaded ET.  The unloaded ET is nominally at room temperature (70F), and the loaded ET LH2 tank is at -423F, for a total temperature difference of -493F.  The length of the LH2 tank barrel is (2058 - 1130), or 928 inches, and the coefficient of thermal expansion (CTE) for aluminum is 13.1e-6 in/inF.  The equation for thermal contraction is CTE x length x temp. diff., or 6.0 inches.  So the LH2 tank shrinks ~6 inches after it's loaded - wow.

Another interesting tidbit is how the Orbiter is aligned relative to the ET.  The center of the forward orbiter fitting is 220.34 inches above the ET center line, and the centers of the aft orbiter fittings are 204.06 inches above the ET center line.  So the front is 16.28 inches above the back and, when divided by the 928 inch horizontal separation, trigonometry shows that the Orbiter attachment plane sits 1.0 degree nose-high w.r.t. the ET center line. 

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 01/18/2013 01:32 pm
Another interesting tidbit is how the Orbiter is aligned relative to the ET.  The center of the forward orbiter fitting is 220.34 inches above the ET center line, and the centers of the aft orbiter fittings are 204.06 inches above the ET center line.  So the front is 16.28 inches above the back and, when divided by the 928 inch horizontal separation, trigonometry shows that the Orbiter attachment plane sits 1.0 degree nose-high w.r.t. the ET center line. 

True, but the forward attachment is at the outer mold line while the aft attachments are recessed in the umbilical wells so the angle in regards to the belly of the orbiter (which is slightly convex anyways) would be greater than 1 deg. Does anyone know the actual angle of attack of the wings in relation to the ET CL?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 01/19/2013 12:31 am
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?

If you are looking out the aft windows the grapple pin on the forward grapple fixture is rotated 10.5 degrees clockwise from vertical.

I can't post the reference I have for this, but if you go to the JSC FOIA page, get the 135 PDRS checklist, go to the OBSS BERTH procedure, and add up the joint angles at grapple, you should get the same answer (remember that shoulder yaw is -90 so all the pitch joints are in the orbiter y-z plane, and that the port MPM rollout angle is 19.5).
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/19/2013 02:27 am
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?

If you are looking out the aft windows the grapple pin on the forward grapple fixture is rotated 10.5 degrees clockwise from vertical.
That is with the starboard MPMs that hold the OBSS in the deployed configuration?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/20/2013 12:10 pm
Right, that's why I specifically said "Orbiter attachment plane", and not just "Orbiter".  As you point out, the local angle w.r.t. the Orbiter belly will be highly variable (increasing up to 90 deg. at the nose). 

The airfoils used for the wing are NACA 0010 (mod) at the root, and NACA 0012-064 (mod) at the tip.  The wing angle of incidence (which is fixed w.r.t. the Orbiter coordinate system, and is not equal to angle of attack) is 0.50 degrees per these references:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19850008602_1985008602.pdf, page numbers 303 and 305

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19820065779_1982065779.pdf, page number 56

F=ma


True, but the forward attachment is at the outer mold line while the aft attachments are recessed in the umbilical wells so the angle in regards to the belly of the orbiter (which is slightly convex anyways) would be greater than 1 deg. Does anyone know the actual angle of attack of the wings in relation to the ET CL?

Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 01/21/2013 10:19 pm
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?

If you are looking out the aft windows the grapple pin on the forward grapple fixture is rotated 10.5 degrees clockwise from vertical.
That is with the starboard MPMs that hold the OBSS in the deployed configuration?

Correct.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/22/2013 07:27 am
Anyone know the angle between vertical and the c/l of the OBSS grapple fixtures?

If you are looking out the aft windows the grapple pin on the forward grapple fixture is rotated 10.5 degrees clockwise from vertical.
That is with the starboard MPMs that hold the OBSS in the deployed configuration?

Correct.
Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/22/2013 07:30 am
Another question: Anyone know if the aft orbiter attachments are bolted when the orbiter is mated to the OTS or if they're unbolted and the orbiter just rests on the attachments when it is mated to the OTS?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/22/2013 01:12 pm
Another question: Anyone know if the aft orbiter attachments are bolted when the orbiter is mated to the OTS or if they're unbolted and the orbiter just rests on the attachments when it is mated to the OTS?

I'm going to hazard a guess and say bolted. Remember the thing has wings! Wind gusts have been known to relocate aircraft.  ;)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/22/2013 01:18 pm
Another question: Anyone know if the aft orbiter attachments are bolted when the orbiter is mated to the OTS or if they're unbolted and the orbiter just rests on the attachments when it is mated to the OTS?

I'm going to hazard a guess and say bolted. Remember the thing has wings! Wind gusts have been known to relocate aircraft.  ;)
Yes but we're not talking tornado/hurricane winds here. They never moved an orbiter with even TS speeds observed. Even sitting on its landing gear in 30kt winds won't move it much.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/24/2013 10:55 am
Why was the OTS needed?  Couldn't a lot of development and operational money have been saved by just towing the orbiters on their landing gear?  When they went from the OPF to the VAB they could lift them with the cranes and then retract the gear.  Had this method been designed from the get go you would think that provisions could have been designed in to allow the gear closeout procedure to be done in the VAB like that.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/24/2013 11:05 am
Why was the OTS needed?  Couldn't a lot of development and operational money have been saved by just towing the orbiters on their landing gear?  When they went from the OPF to the VAB they could lift them with the cranes and then retract the gear.  Had this method been designed from the get go you would think that provisions could have been designed in to allow the gear closeout procedure to be done in the VAB like that.

It was needed for VAFB for the 20 mile trip between OMCF and SLC-6.  Before Challenger, the orbiters were towed.  Once the OTS was available, it was shipped to KSC.  Using the OTS at KSC, they found they could save time and money and have a safer ops by closing out the gear in the OPF, where there was better access and the orbiter is suspended by GSE.  The op in the VAB required personnel to be under a suspended load.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/24/2013 11:08 am
Why was the OTS needed?  Couldn't a lot of development and operational money have been saved by just towing the orbiters on their landing gear?  When they went from the OPF to the VAB they could lift them with the cranes and then retract the gear.  Had this method been designed from the get go you would think that provisions could have been designed in to allow the gear closeout procedure to be done in the VAB like that.

It was needed to transport the Orbiters from the final assembly building at Palmdale to Edwards Air Force Base for ferry flights to KSC. Also would have been needed for operations at VAFB, I believe.

Initially Orbiters were towed on their landing gear at KSC from OPF to VAB. Then the "tow-around" tires were exchanged with flight tires in the VAB. Once the transporter was no longer needed (Palmdale got VAFB's MDD), KSC got it. I believe KSC has Vandenberg's transporter, and the Palmdale one stayed in Cali, only recently to be used in OV-105's parade.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/24/2013 11:12 am
Why was the OTS needed?  Couldn't a lot of development and operational money have been saved by just towing the orbiters on their landing gear?  When they went from the OPF to the VAB they could lift them with the cranes and then retract the gear.  Had this method been designed from the get go you would think that provisions could have been designed in to allow the gear closeout procedure to be done in the VAB like that.
This is how it was done until 1989.

The OTS was originally designed to be used at Vandenberg AFB to transport the orbiter the 21 miles (33.6 km) from the OMCF on North Base to the pad located on South Base. The terrain at Vandenberg is very hilly so in order to save on the orbiter's critical landing gear and tires, a self powered transporter was designed. The manufacturer of the OTS was Commetto of Turin, Italy.

After the Air Force decided to withdraw from active participation in the shuttle program, SLC-6 was mothballed and some of the shuttle equipment was brought to KSC including the OTS and the workstands needed to convert the OMRF at KSC into the third OPF, OPF-3.

The OTS allows TPS and hydraulic operations to be completed in the OPF prior to rollover. The OPF is much more suited for this as it has all of the equipment and is climate controlled.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/24/2013 11:14 am

It was needed to transport the Orbiters from the final assembly building at Palmdale to Edwards Air Force Base for ferry flights to KSC. Also would have been needed for operations at VAFB, I believe.

Initially Orbiters were towed on their landing gear at KSC from OPF to VAB. Then the "tow-around" tires were exchanged with flight tires in the VAB. Once the transporter was no longer needed (Palmdale got VAFB's MDD), KSC got it. I believe KSC has Vandenberg's transporter, and the Palmdale one stayed in Cali, only recently to be used in OV-105's parade.

There was only one OTS and it was at VAFB and not Palmdale.  It was a transport frame used at Palmdale and the OV-105 parade. 
Also, the device moved from VAFB to Palmdale was the Orbiter Lifting Frame vs an MDD.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 01/24/2013 04:09 pm
Echoing Jim's post:
http://forum.nasaspaceflight.com/index.php?topic=25399.msg944005#msg944005

1. OLF at Vandenberg, November, 1983. (Picture ref (http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=58554) -- which has an incorrect date.)
2. Overland transporter carrying Columbia at Dryden, July, 1985.
3. OTS carrying Enterprise at Vandenberg, March, 1985. (Picture ref (http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=57974))
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/25/2013 02:45 am
What was the difference between the OLF and the MDD?  Was it just the work platforms?  Was there anything that could be done with the MDD that couldn't with the OLF?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/25/2013 03:10 am
What was the difference between the OLF and the MDD?  Was it just the work platforms?  Was there anything that could be done with the MDD that couldn't with the OLF?

The MDD was designed to proved access for servicing an orbiter at DFRC.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 01/25/2013 01:51 pm
What is the story behind this photo showing Enterprise and Columbia together?

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=17437.0;attach=492192;image
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 01/25/2013 03:41 pm
What is the story behind this photo showing Enterprise and Columbia together?

http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=17437.0;attach=492192;image
Couple of pictures (I believe NASA pictures) that were taken on one of the occasions when they were briefly together at Dryden.  Another pic here:
http://forum.nasaspaceflight.com/index.php?topic=28788.msg892691#msg892691

Enterprise spent a lot of time there in between facility checkouts and public tours and Columbia was being transported from Palmdale back to Florida.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/25/2013 11:01 pm
I saw this photo over in the STS-135 walkdown thread.  To my uncalibrated eye, it looks like the center of the ball fitting is pretty close to the Orbiter OML.  But I don't have any drawings to back that up.
F=ma


True, but the forward attachment is at the outer mold line while the aft attachments are recessed in the umbilical wells so the angle in regards to the belly of the orbiter (which is slightly convex anyways) would be greater than 1 deg. Does anyone know the actual angle of attack of the wings in relation to the ET CL?

Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 01/31/2013 02:04 am
I found this figure (III-22) in vol. 2 of the SLWT SDH, where the Orbiter OML is shown as a red line.  From vol. 1 of the SLWT SDH, the aft ET-Orbiter attachment fitting radius is 5.275 inches.  Using this dimension, the scaled distance from the Orbiter OML to the center of EO-2 hemisphere is about 4 inches, and is not on the OML as I thought. 

Also, the center of the EO-1 forward ET-Orbiter attachment monoball is about 1 inch inside the Orbiter OML.  This dimension is scaled off the figure that AnalogMan posted.  However, the sep plane is ~on the OML, as others have noted.

F=ma

I saw this photo over in the STS-135 walkdown thread.  To my uncalibrated eye, it looks like the center of the ball fitting is pretty close to the Orbiter OML.  But I don't have any drawings to back that up.
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 01/31/2013 02:32 pm
Are there any diagrams showing the shape of the nozzles of the OMS engines?  A side on view? I saw one photo where you can somewhat see the lines of the panels used to build the nozzle.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/05/2013 04:29 pm
DPS question: Is the scratchpad cleared when the crew completes an entry (like ITEM 19 EXEC) or does it remain afterwards?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/05/2013 06:53 pm
DPS question: Is the scratchpad cleared when the crew completes an entry (like ITEM 19 EXEC) or does it remain afterwards?

It remained on the scratchpad until the crew either pressed CLEAR or started a new key sequence.

True for Item Entries.  If I remember right, OPS...PRO sequences would be cleared upon execution. How's my memory (it seems like it was much longer ago than it was)?

Also the ITEM entry and OPS/SPEC inputs were not sent to the GPC until a terminator key (EXEC or PRO) was pressed.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 02/06/2013 02:39 pm
What is a "Snoopy Maneuver"?

I read this on page 30 of the STS-96 Press Kit: There is a flight profile drawing of Terminal Phase and TORRA. #7 says: ARRIVE -RBAR NEAR 350 FT AND BEGIN SNOOPY MANEUVER IF NECESSARY

So, what exactly does "Snoopy Maneuver" mean?

And another question: Obviously, this flight profile drawing seems to be from the STS-96 RNDZ Checklist. Is this RNDZ Checklist available for download somewhere? Or any other RNDZ or other Checklists from pre-STS-113 ISS or Mir missions?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 02/06/2013 02:49 pm
...
So, what exactly does "Snoopy Maneuver" mean?

SNOOPY - Shuttle Nose Out-Of-Plane Yaw
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 02/06/2013 03:11 pm
...
So, what exactly does "Snoopy Maneuver" mean?

SNOOPY - Shuttle Nose Out-Of-Plane Yaw

Wow, that was fast! Thanks a lot!

What is the purpose of this maneuver? Alignment of the Orbiter's X-axis with the PMA?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 02/06/2013 07:05 pm
Did any of the retired orbiters have any of their frame / structure inspected / tested to see how well their life expectancy measured up to predictions? I assume that each flight put loads on the structure such that it would fatigue- much like how commercial aircraft are limited to a certain amount of "cycles"?

Thank you.


Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/06/2013 08:13 pm
Anyone have any data on the clearance between the SRMS End Effector and PLB Camera "B"? This is with the SRMS cradled and stowed and the camera in 0 pan and 0 tilt.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 02/06/2013 11:44 pm
...
So, what exactly does "Snoopy Maneuver" mean?

SNOOPY - Shuttle Nose Out-Of-Plane Yaw

Wow, that was fast! Thanks a lot!

What is the purpose of this maneuver? Alignment of the Orbiter's X-axis with the PMA?

On certain launch dates where the beta angle at docking was predicted to be large, the Russians wanted to point the FGB solar arrays out-of-plane for better power generation during approach. This required a 90 degree shuttle yaw to keep the docking mechanism clocked properly. The yaw would have been performed at 170 ft.

This maneuver was actually designed for the STS-71 shuttle-Mir mission and would have been required if the mission had launched in early June 1995. The launch slipped to late June and this allowed the normal approach to be used.

Thank you, Jorge!
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/07/2013 12:20 am
Orbiter airframe design life = 100 flights x 4 for fatigue factor of safety => 400 flights.  Discovery flew 39 times, the most of any Orbiter, so thats ~ 40 percent of the design life, and ~ 10 percent of the "total" airframe life.  Don't know of any post-retirement inspections, although I'm sure that they were during the OMDPs.
F=ma


Quote from: iskyfly link=topic=17437.msg1009586#msg1009586
date=1360181127
Did any of the retired orbiters have any of their frame / structure inspected / tested to see how well their life expectancy measured up to predictions? I assume that each flight put loads on the structure such that it would fatigue- much like how commercial aircraft are limited to a certain amount of "cycles"?

Thank you.



Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 02/11/2013 08:19 pm
I have 2 questions.
First, I just saw a documentary on the shuttle and it was talking about the tiles. It stated the shuttle atlantis had the fewest tiles of the fleet. I figured it would have been endeavour as she was the most recent. Why didn't she?

Second relates to launch. I head it is possible for the crew to fly a manual ascent. How is this achieved?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/11/2013 10:18 pm

Second relates to launch. I head it is possible for the crew to fly a manual ascent. How is this achieved?

Via the hand controller and throttle, using guidance generated cues on the ADI.  Basically, only useful in few instances, since it is not a backup to a guidance or control system failures since those are still required during "manual" control.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 02/12/2013 02:00 am

Via the hand controller and throttle, using guidance generated cues on the ADI.  Basically, only useful in few instances, since it is not a backup to a guidance or control system failures since those are still required during "manual" control.

Ken Reightler is of the opinion that this was impossible in first stage ascent. I'm inclined to agree. Trying to manually vector SRB's is going to do nothing but flip the vehicle over.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/12/2013 03:37 am

Via the hand controller and throttle, using guidance generated cues on the ADI.  Basically, only useful in few instances, since it is not a backup to a guidance or control system failures since those are still required during "manual" control.

Ken Reightler is of the opinion that this was impossible in first stage ascent. I'm inclined to agree. Trying to manually vector SRB's is going to do nothing but flip the vehicle over.

That was assumed in my answer
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/12/2013 01:01 pm
FYI to the original poster of the question, we're running out of original questions -- there's some additional interesting discussion on one of those previous occasions that this came up.  Start here:
http://forum.nasaspaceflight.com/index.php?topic=10600.msg220889#msg220889

Or go back a few posts and start there:
http://forum.nasaspaceflight.com/index.php?topic=10600.msg220858#msg220858
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 02/12/2013 08:08 pm

Via the hand controller and throttle, using guidance generated cues on the ADI.  Basically, only useful in few instances, since it is not a backup to a guidance or control system failures since those are still required during "manual" control.

Ken Reightler is of the opinion that this was impossible in first stage ascent. I'm inclined to agree. Trying to manually vector SRB's is going to do nothing but flip the vehicle over.

The Flight Rules forbade manual ascent prior to 1:30 anyway.

What were the results if this was ever tried in the SAIL/SMS?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/13/2013 01:46 pm
I flew a few "manual" first stage ascents in the SMS.  I was all over the sky.  Because of the thrust level in the SRBs any small movement of the stick resulted in a large movement of the vehicle.  I'm sure I would have broken off the wings and the attach points without any problem, if the SMS had modeled that.

I suppose we could have changed the gain in the RHC during first stage but why would anyone do that when the time could have been spent making more useful software changes?  Basically there was no reason for anyone to be flying first stage manually.  GN&C was more than capable of handling open loop control during first stage.  At this velocity, go to this attitude isn't that difficult.

Jorge, do you remember the split-s abort mode tests?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/13/2013 03:13 pm
Jorge, do you remember the split-s abort mode tests?
Wow, blast from the past...didn't this come up during the first RTF period?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 02/13/2013 04:02 pm
Jorge, do you remember the split-s abort mode tests?
Wow, blast from the past...didn't this come up during the first RTF period?


Good memory - yes it did.  I believe only one crew member was able to successfully fly the split-s (and leave the wings on in post abort analysis).  Kind of part abort and part air show.

For those curious it was a proposed contingency abort mode in first stage with three engines out.  I believe with the vehicle flying an inverted loop in pitch.  That was a long time ago.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/13/2013 04:33 pm
Jorge, do you remember the split-s abort mode tests?
Wow, blast from the past...didn't this come up during the first RTF period?


Good memory - yes it did.  I believe only one crew member was able to successfully fly the split-s (and leave the wings on in post abort analysis).  Kind of part abort and part air show.

For those curious it was a proposed contingency abort mode in first stage with three engines out.  I believe with the vehicle flying an inverted loop in pitch.  That was a long time ago.
Still sounds interesting, thanks.

There was a paragraph on it in AvWeek back then and never saw another word on it.  If I recall correctly, another one of those from that era was doing the post-liftoff roll to heads up instead of heads down.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 02/13/2013 07:11 pm
Did President Reagan really have jelly beans placed in the crew compartment storage as a surprise for the astronauts?
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 02/13/2013 10:20 pm
Hi guys,

is there anyone who know for which medium were these ruby colored pipes there on MLP-2 on STS-6?  :-\

(http://img543.imageshack.us/img543/2874/sts63pfeile.jpg)
Source: http://www.retrospaceimages.com (STS-6)

Here again slightly larger:

(http://img838.imageshack.us/img838/769/sts6111.jpg)

I suspect that the upper pipe might be a gas line, am but not sure?

This pipe was consistently ruby colored on the STS-6 and run from the right to left corner of Side 1 also under the Blast Shields.

Later, and until the last missions this pipe had only these ruby colored markings.

(http://img89.imageshack.us/img89/4325/ap41.jpg)
Source: www.capcomespace.net

(http://img441.imageshack.us/img441/3064/farbemlp2.jpg)
Source: T. McClellan (ARC Forums)

I want to mix this color for my MLP-2 build.

(http://s362974870.onlinehome.us/forums/air/public/style_emoticons/default/hi2.gif)
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 02/15/2013 01:32 pm
Are there any diagrams or photos of the AFRSI on Discovery during the time of STS-26R?

The diagram seen in Jenkin's book shows the AFRSI covering the entire orbiter from nose to aft fuselage. Is this accurate?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/17/2013 11:58 am
Found another report with additional details of the EO-1 interface on NTRS:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19810005630_1981005630.pdf

Pyrotechnic shock at the orbiter/external tank forward attachment
by W. F. Rogers, D. S. Grissom and L. R. Rhodes of JSC.

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/17/2013 12:17 pm
Are there any diagrams or photos of the AFRSI on Discovery during the time of STS-26R?

The diagram seen in Jenkin's book shows the AFRSI covering the entire orbiter from nose to aft fuselage. Is this accurate?
You mean the upper surface of the "entire" orbiter, right?  Which diagram?  The one I see in Chapter X of the 3rd Edition doesn't look like that to me.  (From a texture standpoint, the FRSI on a lot of the payload bay door area and parts of the wing upper surface stand out in pictures/person.)
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 02/17/2013 07:54 pm
The side view diagrams.

I mean as in this photo you clearly see the AFRSI cover the entire side of the vehicle, even the aft fuselage. Could someone find a larger photo of this and more photos of Discovery at Rockwell Int from the 80s before her first flight?

http://www.wintertime.com/OH/disc-hangar.jpg
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 02/18/2013 11:20 pm
They're FIREX lines. Fire protection/sprinklers.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 02/19/2013 06:00 am
Thanks padrat for your reply, that means a water pipe. What was connected to this line?

I ask therefore, because this line was not connected with the emergency shower and the eye wash, which were fed via a separate pipe (green arrow), right?

(http://img51.imageshack.us/img51/5110/sts63pfeilerg.jpg)
Source: http://www.retrospaceimages.com (STS-6)

To STS-6 but this ruby colored pipe didn't run around the corner to Side 4, but only later, do you know?  :-\

When used the emergency shower/eye wash? Has there been ever accidents to your time?  :o

(http://s362974870.onlinehome.us/forums/air/public/style_emoticons/default/hi2.gif)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/19/2013 11:42 pm
Could someone find a larger photo of this and more photos of Discovery at Rockwell Int from the 80s before her first flight?
There are some on L2.

There are also a few from the overland transport, at Dryden (getting spotted in the MDD), and during the first ferry hop to Vandenberg in early November, 1983 -- in the set referred to here:
http://forum.nasaspaceflight.com/index.php?topic=13952.msg1014581#msg1014581

(Not necessarily highlighting the mid-fuselage side walls, but they might be worth looking at.)
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 02/20/2013 12:54 am
Anyone have any data on the clearance between the SRMS End Effector and PLB Camera "B"? This is with the SRMS cradled and stowed and the camera in 0 pan and 0 tilt.

Somewhere very close to 5 inches. 

You can derive this distance from information in the Shuttle Crew Operations Manual (posted on the JSC FOIA page).  For example, this document shows the CCTV B pivot point is at X+1294 and says that the camera is sixteen inches long, so it would extend to roughly X+1286.  Elsewhere in the document you can figure out that the RMS EE pokes a little past X+1280. 
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 02/20/2013 12:35 pm
Could someone find a larger photo of this and more photos of Discovery at Rockwell Int from the 80s before her first flight?
There are some on L2.

There are also a few from the overland transport, at Dryden (getting spotted in the MDD), and during the first ferry hop to Vandenberg in early November, 1983 -- in the set referred to here:
http://forum.nasaspaceflight.com/index.php?topic=13952.msg1014581#msg1014581

(Not necessarily highlighting the mid-fuselage side walls, but they might be worth looking at.)


I looked and the replies there show the link doesn't work for looking at the photos.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/22/2013 11:20 pm
Anyone have any data on the clearance between the SRMS End Effector and PLB Camera "B"? This is with the SRMS cradled and stowed and the camera in 0 pan and 0 tilt.

Somewhere very close to 5 inches. 

You can derive this distance from information in the Shuttle Crew Operations Manual (posted on the JSC FOIA page).  For example, this document shows the CCTV B pivot point is at X+1294 and says that the camera is sixteen inches long, so it would extend to roughly X+1286.  Elsewhere in the document you can figure out that the RMS EE pokes a little past X+1280. 
Thanks. For some reason I had missed that in the SCOM. Now on to something else.

Looking through some T&R photos of the orbiters I noticed this, has the PLB "liner" always been flown in Bays 1 and 2? Or did it start when the external airlock started flying on STS-71?
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 02/26/2013 12:31 am
I was down at KSC today, and we took the launch pad tour.  I was curious as we got over to LC-39B to see the lightning protection system up close.

I noticed there's a "spider's web" of wires up top, with a diamond-shaped hole big enough for what looked like the Ares rocket.  For STS-125, LON-400 was on the pad out there...  Were those wires up top there for that mission as well?  They just didn't seem to make a hole big enough for the stack, so I was curious how that would work.  Can provide pics if necessary, but I don't have editing tools with me so it'd be a pretty big file..

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 02/26/2013 11:14 am
What was the "orientation" of the Shuttle in orbit relative to the earth's surface?  Was it always top facing earth or was it top facing sun or did it vary by mission?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/26/2013 11:25 am
What was the "orientation" of the Shuttle in orbit relative to the earth's surface?  Was it always top facing earth or was it top facing sun or did it vary by mission?

It varied by mission, but payload bay to earth was the most prevalent.
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 02/26/2013 05:03 pm
What was the "orientation" of the Shuttle in orbit relative to the earth's surface?  Was it always top facing earth or was it top facing sun or did it vary by mission?

It varied by mission, but payload bay to earth was the most prevalent.
Wouldn't the Earth's heat affect the radiators efficiency?
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 02/26/2013 09:32 pm
I was down at KSC today, and we took the launch pad tour.  I was curious as we got over to LC-39B to see the lightning protection system up close.

I noticed there's a "spider's web" of wires up top, with a diamond-shaped hole big enough for what looked like the Ares rocket.  For STS-125, LON-400 was on the pad out there...  Were those wires up top there for that mission as well?  They just didn't seem to make a hole big enough for the stack, so I was curious how that would work.  Can provide pics if necessary, but I don't have editing tools with me so it'd be a pretty big file..

Thanks!

If memory serves, I believe the towers were still under construction during STS 125. Ares 1-X only had a wire between two towers. The web wasnt finished until later....  Ill try to remember to check my pics at home...
Title: Re: Shuttle Q&A Part 5
Post by: padrat on 02/27/2013 01:45 am
I stand corrected. the FIRST time the shuttles rolled out for STS 125/400 the towers were still being built. The SECOND time the towers were built but only had the one wire between them. And of course Ares 1-X still only had the one...

(P.S. forgive my choice in pics. Thought it would raise a few eyebrows... ;)
Title: Re: Shuttle Q&A Part 5
Post by: Ford Mustang on 02/27/2013 10:38 pm
Thank you!  Was just curious as the tour guide did say that it was there for the future generation rockets, but also said it was put up while the towers were being constructed as well - so just had my curiosity for LON-400.  Thanks again!

PS - Nice picture.  Bittersweet seeing 39B like it is now.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/27/2013 11:15 pm
Pot-stirrer!


(P.S. forgive my choice in pics. Thought it would raise a few eyebrows... ;)
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 03/04/2013 07:24 pm
I just thought of something: how come certain space-dedicated websites or space historians misinterpret the STS-1 FRF on February 20, 1981 with the actual liftoff on April 12, 1981? I can tell that some of the photos belong to the FRF because of two reasons:

1: No clouds during the FRF, but clouds during the launch.
2: The smoke from the heated Sound Suppression System stands higher than Columbia in the FRF photos because the shuttle just stays on the pad and the engines fire for 20-22 seconds.

Do you think that is a reasonable stating?
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 03/04/2013 07:29 pm
Another thing, go to this website link that is posted below and look for the pictures that have the caption, "STS-1 Columbia's Ignition", or another caption that has a similar title, and study them. Next, compare the photos with the FRF video footage.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/04/2013 07:46 pm
I just thought of something: how come certain space-dedicated websites or space historians misinterpret the STS-1 FRF on February 20, 1981 with the actual liftoff on April 12, 1981? I can tell that some of the photos belong to the FRF because of two reasons:

1: No clouds during the FRF, but clouds during the launch.
2: The smoke from the heated Sound Suppression System stands higher than Columbia in the FRF photos because the shuttle just stays on the pad and the engines fire for 20-22 seconds.

Do you think that is a reasonable stating?

No, the greatest distinguisher is the cargo net on the intertank.
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 03/04/2013 07:50 pm
That's a good difference, but also, the weather and the exhaust smoke are two other differences. Another difference is the brightness in the FRF pictures. The FRF took place at 8:46 AM EST while the launch took place at 7:00 AM EST. Now, I know you guys are already aware of the times, but I'm just making notices on the pictures.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/04/2013 07:53 pm
Another difference is the brightness in the FRF pictures.

Can't depend on that due to photo processing and archiving issues.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/04/2013 07:54 pm
That's a good difference, but also, the weather and the exhaust smoke are two other differences.

Not for non experts and people without an eye for detail.  the smoke and weather can be overlooked, the cargo net wasn't going to fly.

This is really a non issue.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/04/2013 08:18 pm
I just thought of something: how come certain space-dedicated websites or space historians misinterpret the STS-1 FRF on February 20, 1981 with the actual liftoff on April 12, 1981?
Because it doesn't mean as much to them as it does to us?  There's a good deal of casually published information online across lots of subjects and this is one of them.

Another difference is the brightness in the FRF pictures.

Can't depend on that due to photo processing and archiving issues.
Right, better to look for differences in the test configuration from a launch configuration -- couple others besides the cargo net are the heat shield on the MLP and the OMS engine nozzle bags.  Both being details that would probably go unnoticed by a general audience.
Title: Re: Shuttle Q&A Part 5
Post by: SamfordOfSpace on 03/11/2013 04:42 pm
Regarding the shuttle hull material.

Is the green hull material painted aluminum or something else?  Are the struts titanium or aluminum?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/11/2013 05:56 pm
Regarding the shuttle hull material.

Is the green hull material painted aluminum or something else?  Are the struts titanium or aluminum?

Green is aluminum. 
Title: Re: Shuttle Q&A Part 5
Post by: Lurker Steve on 03/12/2013 08:08 pm
This description of the "original" Shuttle design with the flyback booster was posted on the SpaceX board.

http://www.wired.com/wiredscience/2013/02/where-to-launch-and-land-the-space-shuttle-1972/

How far did they get with the "original" design, before switching to the SRBs and external fuel tank ? I assume they switched due to schedule/funding, or was their some technical reason ?

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/12/2013 08:18 pm
This description of the "original" Shuttle design with the flyback booster was posted on the SpaceX board.

http://www.wired.com/wiredscience/2013/02/where-to-launch-and-land-the-space-shuttle-1972/

How far did they get with the "original" design, before switching to the SRBs and external fuel tank ? I assume they switched due to schedule/funding, or was their some technical reason ?


It never got into design.  It was only concepts before settling on the final configuration.  And it was money that dictated the end result.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 03/12/2013 09:50 pm
The green coating is the Super Koropon primer (2-part epoxy) over the (mostly) aluminium primary structures.  The struts in the mid-fuselage (under the payload bay) were originally all boron/aluminium composites.  Many were replaced with aluminium as they were damaged in service.  The struts in the wing ribs and spars are also aluminum.
F=ma

Regarding the shuttle hull material.

Is the green hull material painted aluminum or something else?  Are the struts titanium or aluminum?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/15/2013 02:06 pm
Does anyone know the throat and base diameter as well as the length of the OME nozzles?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 03/16/2013 02:29 pm
Found a conference paper on NTRS on "Space Shuttle Orbit Maneuvering Engine" by Robert Polifka from NASA MSC.  It's NASA TM-X-70221 from the 1972 JANNAF Propulsion Meeting.  It reports a 50" x 75" envelope for the OME, and an expansion ratio of 72.
F=ma

Does anyone know the throat and base diameter as well as the length of the OME nozzles?
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 03/18/2013 03:56 pm
Why does the Shuttle have wings? 

This question was raised at the Columbia + 10 conference last week at GWU.  The response was graded as "incomplete"......so I thought this might be a good thread to have the COMPLETE discussion.....

ready....GO!
Title: Re: Shuttle Q&A Part 5
Post by: Danny Dot on 03/18/2013 04:50 pm
Why does the Shuttle have wings? 

This question was raised at the Columbia + 10 conference last week at GWU.  The response was graded as "incomplete"......so I thought this might be a good thread to have the COMPLETE discussion.....

ready....GO!

Better lift over drag equals bigger cross range.

Danny Deger
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 03/18/2013 05:53 pm
Why does the Shuttle have wings? 

This question was raised at the Columbia + 10 conference last week at GWU.  The response was graded as "incomplete"......so I thought this might be a good thread to have the COMPLETE discussion.....

ready....GO!

Better lift over drag equals bigger cross range.

Danny Deger

QED
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 03/18/2013 07:31 pm
Was failure and breakup of the ET after discarding induced in some way? Wether through some destructive mechanism, or some sort of intergrated failure points? Or was it purely aerodynamic forces on falling that broke it apart?

Another question along the same lines, is it known how large the fragments that reached the ocean were?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/19/2013 03:15 pm
Was failure and breakup of the ET after discarding induced in some way? Wether through some destructive mechanism, or some sort of intergrated failure points? Or was it purely aerodynamic forces on falling that broke it apart?

Another question along the same lines, is it known how large the fragments that reached the ocean were?

http://www.flickr.com/photos/nasamarshall/3953790458/

You can see there is quite a bit of tumbling (brighter glow when the ET turns broadside to the wind). Wasn't the GOX vent valve left open after sep to promote tumbling?
Title: Re: Shuttle Q&A Part 5
Post by: john7p on 03/25/2013 09:18 am
Hello,

I got a question.
When on launch day the crew exited the elevator at the launch pad, one of them, often the CDR, got to a phone. This phone was next to the catwalk to the whiteroom. Who got called and why?


Greetz John
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/25/2013 12:54 pm
Wasn't the GOX vent valve left open after sep to promote tumbling?
No; early tanks had a separate tumble valve, but it was eventually deleted.  There's a good deal of film/video shot by the flight crews of the LH2 vent valve relieving, post sep.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/06/2013 11:29 pm
What was the average altitude/velocity when the first stage roll program was initiated at?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 04/07/2013 01:17 am
Lots of data available at:

http://www.cbsnews.com/network/news/space/home/flightdata/downloads.html

According to the STS-135 ascent timeline, the roll program takes place between T+11 and T+18 seconds.

F=ma


What was the average altitude/velocity when the first stage roll program was initiated at?
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 04/10/2013 06:49 pm
What was the average altitude/velocity when the first stage roll program was initiated at?

According the Ascent/Aborts Flight Procedures Handbook, roll program was standardized at Vrel 118.45 fps starting with OI-23.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/22/2013 01:03 am
Does anyone know the distance between the aft compartment and the outboard elevons and the gap between the outboard elevons and inboard elevons?
Title: Re: Shuttle Q&A Part 5
Post by: spacescribe on 04/26/2013 05:41 pm
And the entry director, is he based in Houston or KSC?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/26/2013 05:49 pm
And the entry director, is he based in Houston or KSC?
All post-launch activities were controlled from the regular shuttle FCR in the MCC. The FRs were used to support post-landing activities starting at hand-off from MCC to KSC once ground cooling and purge were activated.

The Entry Flight Director is in MCC.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 04/29/2013 03:51 pm
What will become of the Orbiter Transporter that was used to transport the orbiters from the OPF to the VAB now that it's use of moving Atlantis is over?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/29/2013 04:12 pm
What will become of the Orbiter Transporter that was used to transport the orbiters from the OPF to the VAB now that it's use of moving Atlantis is over?

Sold to another user, given to a museum or sold for scrap.  In that order.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 04/29/2013 05:46 pm
What will become of the Orbiter Transporter that was used to transport the orbiters from the OPF to the VAB now that it's use of moving Atlantis is over?

Sold to another user, given to a museum or sold for scrap.  In that order.

Durring the move from the VAB to the KSCVC last year, there were Beyel Brothers logos on the OTS in several locations, but I don't know if that was because they had purchased it or just because they were opperating it at the time.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/29/2013 06:04 pm

Durring the move from the VAB to the KSCVC last year, there were Beyel Brothers logos on the OTS in several locations, but I don't know if that was because they had purchased it or just because they were opperating it at the time.

It is sitting in a excess equipment yard right now
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/03/2013 07:49 pm
Does the upper section of the aft compartment base heatshield have a different angle than the lower section where the left/right SSMEs go? Or is it uniform? The lower engines are installed at a different pitch (10° vs 16° for the center) than the center engine.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/17/2013 10:48 pm
I have come across quite a conundrum when it comes to the length of orbiter.

Going by the station numbers of the three major sections of the orbiter (forward, mid and aft including the vertical stabilizer) I get 119.5 ft for the length when all my sources states that the length of the orbiter measured from nose the vertical stabilizer is 122.2 ft. So that leaves 2.7 ft unaccounted for. Where could those be?

Here's the stations I used in the calculations:

Forward fuselage: XO236-XO582
Midbody: XO582-XO1307
Aft including the vertical stabilizer: XO1307-XO1693
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 06/07/2013 08:44 pm
Two questions:

Were the OMS/RCS pods used interchangeably through the orbiter fleet or did the same pods normally go up with the same orbiter?

When did the removal of the LRSI tiles take place?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/07/2013 08:55 pm
Two questions:

Were the OMS/RCS pods used interchangeably through the orbiter fleet or did the same pods normally go up with the same orbiter?

When did the removal of the LRSI tiles take place?

They were interchanged.   
LSRI tiles where?  OMS pods OV-099.  whole vehicle, OV-103
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 06/07/2013 10:29 pm

They were interchanged.   
LSRI tiles where?  OMS pods OV-099.  whole vehicle, OV-103

So Columbia went through her whole career with the LRSI tiles?

I don't know where I got the impression that the orbiters came from Rockwell with the tiles and were refitted with blankets later on.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/07/2013 10:48 pm
So Columbia went through her whole career with the LRSI tiles?

I don't know where I got the impression that the orbiters came from Rockwell with the tiles and were refitted with blankets later on.
OV-102 (only OV-102) did have a significant number replaced with blankets on the mid-fuselage sidewalls during the long stand-down after the 51-L accident.  As Jim noted, beginning with OV-103 new vehicles were delivered from Palmdale with extensive use of blankets.  IIRC, there's a contemporary video...let me see if I can find it on YouTube.  (Edit: sorry, couldn't find it on YT...I think it was played on NASA TV back around the 25th anniversary of STS-1.)
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 06/08/2013 12:36 am
Good to know I'm not completely crazy then  ;D

Thanks to both of you.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 06/09/2013 06:00 pm
What are the dimensions of the middeck (LxWxH)?
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 06/12/2013 08:15 pm
For sts-71, the first docking to Mir, what were the reasons to dock with Spacelab instead of SPACEHAB?   

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/12/2013 09:15 pm
For sts-71, the first docking to Mir, what were the reasons to dock with Spacelab instead of SPACEHAB?   

Spacehab wasn't under contract for such missions yet.  Spacehab submitted an unsolicited proposal for logstics missions, January 1994.   A letter contract was issued in November 1994, which was definitized in July 95.  STS-71 flew in June 95.  Spacehab logistics system (modules, bags, straps,racks, etc) development did not start until 95.   
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 06/12/2013 11:43 pm
Thank you, Jim.  That is exactly what I was looking for. 
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 06/14/2013 12:21 am
As a tangental follow-up to my earlier question:

How many OMS and FRCS pods did the fleet have?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/14/2013 12:27 am
As a tangental follow-up to my earlier question:

How many OMS and FRCS pods did the fleet have?
10 OMS Pods (2/vehiclex5) and 5 FRCS modules (1/vehiclex5).
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/14/2013 02:57 am
As a tangental follow-up to my earlier question:

How many OMS and FRCS pods did the fleet have?
10 OMS Pods (2/vehiclex5) and 5 FRCS modules (1/vehiclex5).

One set per vehicle
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/14/2013 05:16 am
As a tangental follow-up to my earlier question:

How many OMS and FRCS pods did the fleet have?
10 OMS Pods (2/vehiclex5) and 5 FRCS modules (1/vehiclex5).

One set per vehicle
True but they could be mixed (OMS pods that is, it's my understanding that FRCS modules were vehicle specific and could not be swapped between vehicles).
Title: Re: Shuttle Q&A Part 5
Post by: john7p on 06/24/2013 04:46 pm
Hello,

An question asked a few pages ago ;D
On launch day one of the crew picks up the phone next to the orbiter access arm.
See at time-stamp 6.26
http://www.youtube.com/watch?v=-NTjM6EtZZc


Are they phoning home  ??? ;D ;D
Who gets called and why?


Thanks John

(fixed error in url)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/24/2013 04:57 pm
Hello,

An question asked a few pages ago ;D
On launch day one of the crew picks up the phone next to the orbiter access arm.


Are they phoning home  ??? ;D ;D
Who gets called and why?


The LCC or crew office,because they can
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/26/2013 08:14 am
Is the LH2 disconnect plate on the ET thinner than the LOX disconnect plate? The reason why I ask is because of the attached photo. I just now noticed the difference in the thickness of the two disconnect plates.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 06/26/2013 09:36 am
In the photo, it looks almost, but I believe that the perspective is deceptive and the plates have the same thickness. (http://s362974870.onlinehome.us/forums/air/public/style_emoticons/default/coolio.gif)

(http://s362974870.onlinehome.us/forums/air/public/style_emoticons/default/hi2.gif)
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 07/12/2013 06:06 pm
Could a polar launch from VAFB have used a direct ascent, or did it require OMS-1 to keep the tank in the Pacific?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/12/2013 07:22 pm
Has +X RCS maneuvers always been used post-MECO or was that a later addition?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/15/2013 01:23 am
Has +X RCS maneuvers always been used post-MECO or was that a later addition?

Yes it was done from the begining.  Initiated 2 seconds after transitioning to MM104 by pushing the Translational Hand Controller in for 11 seconds. 

I know for a fact it was done at least as early as STS-3.  I can double check on STS-1 & 2.

Mark
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 07/15/2013 03:52 am
Were the PAPI landing aids installed for all of the lakebed landings at Edwards?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/31/2013 04:57 pm
Anyone know the targeted date for STS-62A at the time of the loss of the STS-51L mission?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/31/2013 06:05 pm
Anyone know the targeted date for STS-62A at the time of the loss of the STS-51L mission?
A slip to NET mid-July was announced in late November.  Given the ongoing schedule slips for the other orbiters in January before the accident and the upcoming planetary windows in May, it may have been further back unofficially by the end of month.  (I don't think addressing the hydrogen entrapment pad issue had been factored into publicly announced dates.)
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 08/02/2013 03:21 am
In the MCC replays, at liftoff somebody says "liftoff confirmed".

What is being used to determine "liftoff"?

Also;

What requirements must be met for MET to start counting up?


Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/02/2013 12:04 pm
In the MCC replays, at liftoff somebody says "liftoff confirmed".

What is being used to determine "liftoff"?

Also;

What requirements must be met for MET to start counting up?


Thank you.


Lift off is required for MET to start counting up.

The shuttle rising X inches is what determines lift of
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 08/05/2013 02:03 am
How was Enterprise connected to the SCA's aft connectors for the ALT series of tests, since the ET umbilical doors had to be closed? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/05/2013 02:16 am
How was Enterprise connected to the SCA's aft connectors for the ALT series of tests, since the ET umbilical doors had to be closed? 

There were no doors
Title: Re: Shuttle Q&A Part 5
Post by: Overflow on 08/06/2013 03:30 pm
Sorry if this has been asked before.. But after the loss of STS-107, was there ever the slightest talk about replacing Columbia with another shuttle? Or even replacing the entire fleet with new shuttles?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/06/2013 03:37 pm
Sorry if this has been asked before.. But after the loss of STS-107, was there ever the slightest talk about replacing Columbia with another shuttle? Or even replacing the entire fleet with new shuttles?

Not new shuttles, but new systems such as OSP, commercial crew, etc.
Title: Re: Shuttle Q&A Part 5
Post by: Overflow on 08/06/2013 03:38 pm
Sorry if this has been asked before.. But after the loss of STS-107, was there ever the slightest talk about replacing Columbia with another shuttle? Or even replacing the entire fleet with new shuttles?

Not new shuttles, but new systems such as OSP, commercial crew, etc.

Thank you for the info, Jim!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/06/2013 03:40 pm
But after the loss of STS-107, was there ever the slightest talk about replacing Columbia with another shuttle?
Perhaps a little, but there was more serious talk and consideration to ending the program at that point.

Or even replacing the entire fleet with new shuttles?
No.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/09/2013 06:33 pm
Anyone know the depth of the two ET umbilical wells on the orbiter?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/12/2013 02:32 am
Another question: When retracted and the doors closed, does the NLG tires rest on the inside of the doors or is are they above them?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/12/2013 03:43 am
Another question: When retracted and the doors closed, does the NLG tires rest on the inside of the doors or is are they above them?

Dave, it would have to be above.  The gear/tires when retracted was hooked in.  If they were against the door any vibration would cause the gear to be intermittently impact the door.  That would not be good since that was a barrier against reentry heating.

Also the tires would change shape when there was no atmospheric pressure against them on-orbit.  An inflatable tire is not static when the external pressure goes from 15 psia to 0 psia and then back again.

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-gear.html
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 08/12/2013 11:32 am
Another question: When retracted and the doors closed, does the NLG tires rest on the inside of the doors or is are they above them?

Above, as noted by alk3997.  See the attached diagram.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/13/2013 02:17 pm
Thanks to both you. That settles it nicely. Anyone know the measurements between the different elements pointed out by the arrows in the attached photo?
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 08/14/2013 11:35 am
Are there any contingency plans if the ET doesn't separate?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2013 12:03 pm
Are there any contingency plans if the ET doesn't separate?

No survivable scenarios existed
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 08/14/2013 01:11 pm
Are there any contingency plans if the ET doesn't separate?

No survivable scenarios existed

Which brought to mind a question I've wondered about for a while. Lots of SF stories describe various vehicles and structures built from expended Shuttle external tanks. Was it even possible for the Shuttle to take the tank all the way into orbit?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2013 01:38 pm

Which brought to mind a question I've wondered about for a while. Lots of SF stories describe various vehicles and structures built from expended Shuttle external tanks. Was it even possible for the Shuttle to take the tank all the way into orbit?

Yes, at the expense of payload.  The shuttle was suborbital at the time of ET sep for the specific reason of ET disposal.  There is no reason it couldn't take it to orbit. 
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 08/14/2013 02:32 pm
The shuttle was suborbital at the time of ET sep for the specific reason of ET disposal.

I understand that...so would this have been a longer main engine burn (was there enough prop for that) or OMS?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2013 02:54 pm
The shuttle was suborbital at the time of ET sep for the specific reason of ET disposal.

I understand that...so would this have been a longer main engine burn (was there enough prop for that) or OMS?

reduced payload
Title: Re: Shuttle Q&A Part 5
Post by: Overflow on 08/14/2013 05:48 pm
On the front of the Shuttles, there are always white streaks near the nose. What is that?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2013 05:49 pm
On the front of the Shuttles, there are always white streaks near the nose. What is that?

Waterproofing and RTV cooking off
Title: Re: Shuttle Q&A Part 5
Post by: Overflow on 08/14/2013 07:10 pm
Now here's a personal one for you, Jim. How do you know so much about the Shuttle off the top of your head?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2013 07:40 pm
Now here's a personal one for you, Jim. How do you know so much about the Shuttle off the top of your head?

Got my first NASA shuttle document in 1976.
Got the Shuttle News Reference in 1980
Was in the USAF Shuttle program office 83-88
Worked USAF Shuttle Payload ops at Cape from 88-92
Worked Spacehab ground ops from 92-00
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/14/2013 08:27 pm
Now here's a personal one for you, Jim. How do you know so much about the Shuttle off the top of your head?
http://forum.nasaspaceflight.com/index.php?topic=24176.0

(That is one place to start, but there are others.)
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/15/2013 01:10 pm
The shuttle was suborbital at the time of ET sep for the specific reason of ET disposal.

I understand that...so would this have been a longer main engine burn (was there enough prop for that) or OMS?

Now you are getting more into flight design.  Assuming we're talking about a superlightweight tank, that was about 57,500 lbs dry mass.  That was close to the limit for a due east (28.45 inclination) low orbit payload mass, after all of the performance enhancements.  But, I'm not sure that matters (see below).  We just didn't fly many due east missions after all of the performance enhancements.

So, it probably would have required a reduced cabin stowage and no OMS assist burn (since the payload bay was empty and save the prop for OMS-2) and probably other things I'm not thinking about off the top of my head.

What may have been a problem was that the payload bay was empty during launch.  That would have violated a number of rules for minimum payload amounts.  cg was one and I believe we would have broken some max dynamic pressure rules.  Could those have been solved by tweaking the flight profile?  I don't know - you would have to have designed some ascent profiles to see.

At the same time, the MECO targets should have been easy to hit but the OMS-2 targets would have been the difficult ones.  How much penalty would there have been during an OMS-2 burn with having an extra 57,500 pounds attached in a below the cg position? 

So, based on payload weight limits you probably could have taken the tank to orbit.  But, how the flight would have been designed would have been an interesting challenge.  There was only so much prop in the ET, so a greater SSME burn time during nominal (you still have to protect for RTLS) would not have been an option and also would not have helped OMS-2 but other flight design items would have been tweaked if it were do-able and only then would you know the answer to your question.

BTW, a few of our simulators allowed you to land with the ET attached since it was just a mass model (not a physical model).  Kind of amusing the first time you tried it. 

Andy   
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 08/15/2013 10:44 pm
Thanks very much....that's all very interesting and touches on things I was wondering about.

I was also thinking about the CG issues this would entail. Could the Shuttle even maneuver properly in orbit with the ET attached?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 08/16/2013 02:03 am
Maneuvering would not have been a problem (I don't think).  We maneuvered the Station stack without any problems (with some DAP changes).  Station has far more mass.

OMS burn loss would have been interesting.  Also how much payload would have had to be added just to move the cg and fix the other constraints.  Combine the ET + added payload + orbiter for the mass at OMS-2.  Don't know the answer there.
Title: Re: Shuttle Q&A Part 5
Post by: Overflow on 08/24/2013 11:37 pm
Now here's a personal one for you, Jim. How do you know so much about the Shuttle off the top of your head?
http://forum.nasaspaceflight.com/index.php?topic=24176.0

(That is one place to start, but there are others.)


This is so cool!! Thank you SO much for posting this! (And thank you Jim for taking them of course)
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 08/25/2013 01:42 am
This is sort of an historical question. I understand that the concept while developing the STS was to be the definitive LEO transport. But I think that LEO stations was an integral part of the program. Since space stations require a Crew Evacuation Vehicle, was Shuttle specified from the beginnings to 30 days in space or was that the fall out of the limited development budget? Once they set that limit, did they assumed that the rate of launch was such that they could have always at least one shuttle or was the CEV a necessary development from the beginnings?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/25/2013 07:06 pm
Anyone know the depth of the two ET umbilical wells on the orbiter?

See the diagram in my Reply #2828 on: 01/31/2013 03:04 AM on page 189.

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: mogso on 08/31/2013 12:26 pm
QUESTION: somebody has drawings of a seat of the commander of the Shuttle. (The front, behind, below views, etc.) Thanks
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 09/04/2013 12:11 am
When it comes to shuttle launching, you can see the shuttle do the roll-to-heads-up maneuver thru the ET cam. For night launches such as STS-116, STS-123, STS-126, STS-128, and STS-130, which direction do the shuttles roll? I believe it's the GUIDANCE officer's choice.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/04/2013 12:48 am
When it comes to shuttle launching, you can see the shuttle do the roll-to-heads-up maneuver thru the ET cam. For night launches such as STS-116, STS-123, STS-126, STS-128, and STS-130, which direction do the shuttles roll? I believe it's the GUIDANCE officer's choice.
No, that was the onboard (automated) guidance.  That was discussed here in (sort of) real-time on several ascents (STS-132 comes to mind, since the CDR called down that he 'got it').  I'm sure the pros can elaborate, but I'll see if I can find a couple of old posts.

STS-132 -- start here, and continue in chronological order:
http://forum.nasaspaceflight.com/index.php?topic=21594.msg589222#msg589222

STS-122:
http://forum.nasaspaceflight.com/index.php?topic=11773.msg239557#msg239557

There's also a great ascent/aborts procedures handbook on L2 that goes into some technical detail.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/04/2013 02:01 am
When it comes to shuttle launching, you can see the shuttle do the roll-to-heads-up maneuver thru the ET cam. For night launches such as STS-116, STS-123, STS-126, STS-128, and STS-130, which direction do the shuttles roll? I believe it's the GUIDANCE officer's choice.
No, that was the onboard (automated) guidance.  That was discussed here in (sort of) real-time on several ascents (STS-132 comes to mind, since the CDR called down that he 'got it').  I'm sure the pros can elaborate, but I'll see if I can find a couple of old posts.

STS-132 -- start here, and continue in chronological order:
http://forum.nasaspaceflight.com/index.php?topic=21594.msg589222#msg589222

STS-122:
http://forum.nasaspaceflight.com/index.php?topic=11773.msg239557#msg239557

There's also a great ascent/aborts procedures handbook on L2 that goes into some technical detail.


Yep, it's all up to on board guidance (i.e. the General Purpose Computers). 

All I'd like to add is that guidance is trying to achieve a roll angle of 0 degrees (heads up, wings level) and will roll the shortest distance to get there from the 180 degree (heads down, wings level) attitude the shuttle is in prior to the start of the maneuver.  Even theough the attitude errors are quite small, the starting attitude prior to RTHU (roll to heads up) is never exactly 180.000, so whichever wing tip happens to be closest to the targeted 0 degree objective, that is the direction the stack will roll.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/04/2013 04:10 am
Does anyone know the diameters of the OME heatshields? I taalking about the truncated cones that covers the actual engine assy of the OMEs, where they attach to the actual OMS pods.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/11/2013 07:10 pm

In a non malfunction scenario, do the ssme's always gimball together or are there times when one needs to be gimballed "out of sync" with the others?

If there is an engine malfunction requiring it to be shutdown, does it still gimball when the other engines gimball?

Thans!
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/11/2013 07:13 pm
As a programmer I am fascinated and amazed by flight computers.

In regards to the GPC's, has there ever been a fault during a mission that was attributed to a software bug?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/11/2013 07:43 pm

In a non malfunction scenario, do the ssme's always gimball together or are there times when one needs to be gimballed "out of sync" with the others?


For roll control, there will be differential gimbaling.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/11/2013 07:53 pm
Some time ago I posted a youtube video of sts-123 launch from inside the cockpit. There was a C&W alarm that sounded. The video is gone :( Anybody know where I can find it? Thanks!

http://forum.nasaspaceflight.com/index.php?action=profile;u=14524;area=showposts;start=30

"bias in the PC booster" 1:47

what does that mean?

whats with the counting right after liftoff?

also, is that a C&W alarm going off at 3:09 ?

also, compared to the handful of cabin vids ive seen this crew seems more vocal about their emotions ("i love you guys"), and more excited in their tone of voice (engine ig and liftoff) than others.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/11/2013 08:03 pm
Some time ago I posted a youtube video of sts-123 launch from inside the cockpit. There was a C&W alarm that sounded. The video is gone :( Anybody know where I can find it? Thanks!
Web search: "sts-123 launch cockpit"

(Not the same clip, but from the same source, NASA TV.)
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/12/2013 02:08 am
Some time ago I posted a youtube video of sts-123 launch from inside the cockpit. There was a C&W alarm that sounded. The video is gone :( Anybody know where I can find it? Thanks!

http://forum.nasaspaceflight.com/index.php?action=profile;u=14524;area=showposts;start=30

"bias in the PC booster" 1:47

what does that mean?

whats with the counting right after liftoff?

also, is that a C&W alarm going off at 3:09 ?

also, compared to the handful of cabin vids ive seen this crew seems more vocal about their emotions ("i love you guys"), and more excited in their tone of voice (engine ig and liftoff) than others.

Box is referring to a "bias in the PC ducer" (which stands for chamber pressure transducer).  Throttle/Power settings for the Space Shuttle Main Engines (SSMEs) and Orbital Maneuvering System (OMS) Engines are displayed to the crew in percent of chamber pressure.  For example the nominal full power setting during ascent for the SSMEs is 104.5% of the rated thrust level.  I don't recall the details from this flight, so I am not sure which engine indication had a bias or why it had a bias.  Both the SSME and OMS PC indications are on the same display page - which is where he seems to be pointing as he reminds the MS2 Mike Foreman (who was the flight engineer and would also be scanning these instruments) of the biased indicator.

As for the counting; I am just guessing it is Dom's technique for maintaining situational awareness - I think he is counting up from about the T+4 second point where the crew confirmed the engines had actually throttled up to 104.5% (from the 100% used for engine start) to the point where he is expecting to see guidance initiate the roll program.

The caution and warning alarm was a series of fault messages related to the Left RCS (reaction control system).  These were cauased by a failure of a dedicated signal conditioner (DSC) card.

Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/13/2013 08:28 pm
As a programmer I am fascinated and amazed by flight computers.

In regards to the GPC's, has there ever been a fault during a mission that was attributed to a software bug?

Thanks!

There have been a few.  The last one I remember was on STS-126.  Here is a writeup:
http://nsc.nasa.gov/SFCS/SystemFailureCaseStudyFile/Download/11
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/14/2013 04:48 pm
Thank you Jim, psloss, mkirk and S-I for your replies.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/14/2013 04:54 pm
I am looking for a "primer" on open loop vs closed loop guidance.

Why doesn't the shuttle use closed loop from launch all the way up?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/14/2013 05:19 pm
I am looking for a "primer" on open loop vs closed loop guidance.

Why doesn't the shuttle use closed loop from launch all the way up?

Thanks!

Because it has to ride out winds aloft.   It worries about q alpha vs proper path to orbit
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/14/2013 06:35 pm
I am looking for a "primer" on open loop vs closed loop guidance.

Why doesn't the shuttle use closed loop from launch all the way up?

Thanks!

Because it has to ride out winds aloft.   It worries about q alpha vs proper path to orbit

If I understand the part about the winds- if closed loop, correcting for winds might overstress the stack?

q alpha?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/14/2013 08:41 pm
I am looking for a "primer" on open loop vs closed loop guidance.

Why doesn't the shuttle use closed loop from launch all the way up?

Thanks!

Because it has to ride out winds aloft.   It worries about q alpha vs proper path to orbit

If I understand the part about the winds- if closed loop, correcting for winds might overstress the stack?

q alpha?
Here is a really good paper explaining the shuttle day of launch trajectory design process; peruse it and you will learn all about q and alpha and much more.  The author knows whereof he speaks, he was involved in the process for many shuttle missions.  Read through it and come back if you still have questions.
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110003654_2011001858.pdf
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/14/2013 08:54 pm
That PDF won't load for me.  Anyone else?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 09/14/2013 09:04 pm
That PDF won't load for me.  Anyone else?

Worked for me.  I've attached a copy - see if that's any better.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 09/14/2013 09:08 pm
Worked great, thank you AnalogMan!
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/15/2013 02:44 pm
I am looking for a "primer" on open loop vs closed loop guidance.

Why doesn't the shuttle use closed loop from launch all the way up?

Thanks!

Because it has to ride out winds aloft.   It worries about q alpha vs proper path to orbit

If I understand the part about the winds- if closed loop, correcting for winds might overstress the stack?

q alpha?

As you'll see from the paper, there was correction done based on the winds aloft (high altitude winds).  But, those were based on balloon data taken multiple times, with the last balloon being about 3 hours before launch.  The results were integrated to make sure that the trends were good, as well as the last balloon data.

The problem you have with closed loop guidance in first stage is how to determine winds in real time and then feeding that back into guidance in time.  If you work out a method for measuring the winds aloft in real time while going supersonic, let me know.  It's something I've pondered for years.  Using a ground system was probably not workable due to the possibility of dropouts for the radio uplink.

We always considered it bad form to reach orbit without the wings attached (:-)) and that is what you are trying to prevent by managing dynamic pressure on the various surfaces.  So we stayed open loop until second stage.  The penalty wasn't that great since you can think of the whole purpose of first stage is just to accelerate enough for second stage flight and get out of the heavier atmosphere.

And, feel free to use past tense with Shuttle.  It's taken a while but the program really is over even if there is no replacement vehicle yet.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/15/2013 02:57 pm
As a programmer I am fascinated and amazed by flight computers.

In regards to the GPC's, has there ever been a fault during a mission that was attributed to a software bug?

Thanks!


There were a few - it averaged one found every 6 years in-flight (roughly).  None of them prevented the mission from being accomplished.  None were classified as a safety of flight issue other than the bug escaped our very thorough process of detection on the ground.  Remember we did not classify requirements issues as flight software issues since the requirements were often provided by groups outside of flight software.

Try this paper for more (you can click on the pdf link at the top of the page):
http://ntrs.nasa.gov/search.jsp?R=20110014946

and these charts...
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100029536_2010030196.pdf


Andy
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/15/2013 04:15 pm

1.  The problem you have with closed loop guidance in first stage is how to determine winds in real time and then feeding that back into guidance in time.  If you work out a method for measuring the winds aloft in real time while going supersonic, let me know.  It's something I've pondered for years.  Using a ground system was probably not workable due to the possibility of dropouts for the radio uplink.

2.  We always considered it bad form to reach orbit without the wings attached (:-)) and that is what you are trying to prevent by managing dynamic pressure on the various surfaces.  So we stayed open loop until second stage.  The penalty wasn't that great since you can think of the whole purpose of first stage is just to accelerate enough for second stage flight and get out of the heavier atmosphere.


1.  ELV's have the issues.

2.  ELV wanted their fairings intact until they determine to jettison them.  Same process for ELV's
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 09/15/2013 09:28 pm
Wasn't GPS precise enough?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/16/2013 01:14 am

Am I incorrect in recalling that Challenger encountered high winds / shear and because of that and of the venting / igniting of the fuel leak the computers commanded corrective actions? If so, how is that possible in open loop?

Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/16/2013 01:26 am

Am I incorrect in recalling that Challenger encountered high winds / shear and because of that and of the venting / igniting of the fuel leak the computers commanded corrective actions? If so, how is that possible in open loop?



Still have to maneuver to maintain q alpha. 
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 09/16/2013 05:27 am
Simply (with Shuttle) a table of yaw and pitch commands that were commanded based on velocity (reach this velocity then command this pitch and yaw or theta and psi, more correctly).  The table could be uplinked with DOLILU before launch.  To go much deeper would require more math than I'm 1) comfortable with in an open forum and 2) can probably remember.

It's not an easy problem and GPS doesn't help because we knew exactly where we were, just not what the winds were when flying through them.

Jim, if I understood what you wrote then does that mean EELV has not found a better solution than table driven?
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 09/16/2013 01:37 pm
What happens with pressure transducers at supersonic speeds? That's not the information you need or you simply can't react fast enough?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/16/2013 02:54 pm
What happens with pressure transducers at supersonic speeds? That's not the information you need or you simply can't react fast enough?

Pressure transducers aren't used for ascent. 
Launch vehicle ascent through the atmosphere is like a boat in a storm; the boat is more concern with fighting the waves vs the actual course.  And it isn't really fighting the waves, it is going with them.  Once the boat breaks through the storm (vehicle leaves the atmosphere) then close loop guidance can be initiated.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/16/2013 09:52 pm

Am I incorrect in recalling that Challenger encountered high winds / shear and because of that and of the venting / igniting of the fuel leak the computers commanded corrective actions? If so, how is that possible in open loop?

It's the commanded values of pitch and yaw that are open loop.  The vehicle still has to maneuver in pitch and yaw to achieve the commanded state. 

51-L was before DOLILU but even with DOLILU, changes in the wind after the last balloon would change the structural loads to be different from the predicted loading.  There was margin built into the system based on wind history statistics to cover for this, on top of other margin.
Title: Re: Shuttle Q&A Part 5
Post by: Planegazer on 09/18/2013 08:44 pm
Hello!

I was wondering if anyone could recommend some books that would contain information about the equipment that supported the Space Shuttle program, such as the Shuttle Carrier Aircraft, the Shuttle Training Aircraft, the Rotating Service structure, the Crawler, etc.  Most of the resources I have consulted so far concentrate on the main components of the shuttle stack, with very detailed descriptions on the orbiters and boosters.  I’d like to learn more about other “stuff”.

Any suggestions would be appreciated. Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 09/19/2013 12:08 am
There is the WorldSpaceflight News site that has stuff like this. LC-39: A history from Apollo to the shuttle is a big binder of diagrams and data on the LC-39 complex. I own a copy of this and reference it a lot for my model project.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 09/19/2013 08:20 am
Would you be so kind sharing a link to this source for all of us? (http://s362974870.onlinehome.us/forums/air/public/style_emoticons/default/coolio.gif)

(http://scaleworld.forenworld.net/images/smilies/hallo.gif)
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 09/19/2013 02:03 pm
Well their website is gone,but Amazon has their books and such.

http://www.amazon.com/1961-21st-Century-Complex-Facilities/dp/1893472388
Title: Re: Shuttle Q&A Part 5
Post by: Warren Platts on 09/23/2013 10:05 pm
Does anyone know what the temperature of the water was prior to a water dump?? Do they heat it up to sterilize it?

I know the pressure in the storage tank was ~31 psi, and that the exit velocity was 50 ft/sec (15.24 m/s). This seemingly indicates that the (Ostwald) solubility coefficient for dissolved air was only ~0.02, which for that pressure indicates a temperature pretty close to boiling!
Title: Re: Shuttle Q&A Part 5
Post by: Warren Platts on 09/25/2013 09:15 pm
OK, I did a little more research. It turns out the ISS wastewater is heated up to 120 C. If the wastewater were heated up to 200 F by the time it was ejected, the solubility coefficient would be 0.0135, yielding a theoretical exit velocity of 9.25 m/s, which compares well with the observed 9.45 m/s.

Meanwhile, the Shuttle wastewater tank was pressurized by N2, but there is no mention of heating, so presumably it's kept at about room temperature. Thus, the Ostwald solubility coefficient would be about 0.017, yielding a theoretical exit velocity of 15.25 m/s which also agrees very well with the observed velocity.

The formula used is

1/2 v2 =  λ * P0 /  ρ0 * (ln(P0/Pout) - 1 + Pout/P0)

http://www-personal.umich.edu/~youxue/publications/Zhang2000JVGR.pdf
Title: Re: Shuttle Q&A Part 5
Post by: mjp25 on 09/27/2013 01:52 am
I know that with the relatively spacious quarters of the Space Shuttle compared to Soyuz it wasn't necessary, but was the shuttle capable of a fast rendezvous like Soyuz and Progress now use? As I understand it, the reason it has only been used recently was due to the ability of the booster to loft Soyuz into a precise orbit and ISS's ability to precisely control its orbit. So was the shuttle capable of this precision?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 09/27/2013 10:47 am
"Why does it take so long to get to ISS?"
http://forum.nasaspaceflight.com/index.php?topic=4273.msg66595#msg66595
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/27/2013 11:08 pm

Meanwhile, the Shuttle wastewater tank was pressurized by N2, but there is no mention of heating, so presumably it's kept at about room temperature. Thus, the Ostwald solubility coefficient would be about 0.017, yielding a theoretical exit velocity of 15.25 m/s which also agrees very well with the observed velocity.

http://www-personal.umich.edu/~youxue/publications/Zhang2000JVGR.pdf

The shuttle water tanks were in the lower equipment bay, in the pressurized crew module.  To a first approximation, they were the same temperature as the middeck, so room temperature is a good bet.  No heaters on the tanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/28/2013 11:29 am

The shuttle water tanks were in the lower equipment bay, in the pressurized crew module.  To a first approximation, they were the same temperature as the middeck, so room temperature is a good bet.  No heaters on the tanks.

There were heaters in the nozzles.
Title: Re: Shuttle Q&A Part 5
Post by: Warren Platts on 09/29/2013 11:54 am
Do you know if they were at 120 C like the ISS nozzles?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/02/2013 11:27 am
Does anyone know the spacing between the Ku band DEA and the lower-most starboard PLBD bulkhead latch roller? Also, does anyone have the dimensions of the actual DEA and the white deployment structure the entire Ku band DA sits on?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/03/2013 12:02 am
Do you know if they were at 120 C like the ISS nozzles?

IIRC, there weren't thermostats on the nozzle heaters, they reached a steady state temp based on the water flow rate.  After flow was terminated the temperature was allowed to rise and bake out the nozzles for a while, then power was removed from the heaters.

The lines between the tanks, nozzles, FES, etc, had thermostatically controlled heaters on them.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/03/2013 08:21 pm
Q on the payload bay doors: How thick are the ribs/longerons/intercostals of the PLBD framework? I have looked just about everywhere but have come up with nothing on the subject.
Title: Re: Shuttle Q&A Part 5
Post by: Poseidonious on 10/04/2013 09:47 am
Sorry in advance for my bad English. I would like to ask if there is a specific point through which space shuttles in orbit choose for their re entry in the atmosphere.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/04/2013 11:25 am
Sorry in advance for my bad English. I would like to ask if there is a specific point through which space shuttles in orbit choose for their re entry in the atmosphere.

Do you mean the same point in space (a location)  on every mission?  Or the same parameters (orbital height etc)? 

The shuttle has deorbited from many different orbits (different altitudes, inclinations, etc) to three different landing sites (Kennedy Space Center, Edwards AFB, and White Sands) with different payload weights, so the where the shuttle starts to re enter varies.   However, no matter what the orbital height is at deorbit burn, the shuttle will coast awhile until it reaches 400,000 feet, which is the entry interface (the start of re entry)
Title: Re: Shuttle Q&A Part 5
Post by: Poseidonious on 10/06/2013 03:29 am
Is there a way to calculate from which location above Earth will be initiated a re entry procedure in order for a shuttle to land in South Mexico? And while the re entry is in progress above which parts of our planet will the shuttle fly?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/06/2013 02:17 pm
Is there a way to calculate from which location above Earth will be initiated a re entry procedure in order for a shuttle to land in South Mexico? And while the re entry is in progress above which parts of our planet will the shuttle fly?

1.  It would be between the locations for the initiations for Florida and California landings ;-)

2.  It would be similar to the orbital path but with some maneuvering.

This is outside the capability of a layman to figure out.  One might be able to use some simulator games such as Orbiter and Space Shuttle Simulator to get an idea.

Title: Re: Shuttle Q&A Part 5
Post by: Poseidonious on 10/06/2013 06:01 pm
I read somewhere that to get to Canaveral a shuttle in orbit must abandon orbit and fall in the atmosphere when it is above the Indian Ocean.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/06/2013 07:23 pm
I read somewhere that to get to Canaveral a shuttle in orbit must abandon orbit and fall in the atmosphere when it is above the Indian Ocean.
It depends on the actual orbit. For example, the de-orbit burn for STS-107 occurred over Australia. The goal is always the same: put the Entry Interface position approximately 4400 nautical miles from the landing site which in this case was KSC. If I remember correctly, the entry angle targeted was 1.5°. EI always occurred over the Pacific, never the Indian Ocean.
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 10/07/2013 06:09 am
I have been trying to search for information on a proposal made by an aerospace company in the late 80's or early 90's for a lunar architecture that was flown to orbit on the shuttles and then launched to the moon.  I first read of it in Aviation Week and actually wrote the company and received a wonderful book detailing their plans.  I can not even remember the company (possibly Lockheed?) and I have searched everywhere for the book.  Any ideas on whose program it was and if there is any info around on it?

Edit: Never mind, found it...I was thinking of Early Lunar Access from General Dynamics.
Title: Re: Shuttle Q&A Part 5
Post by: Poseidonious on 10/07/2013 07:13 pm
I read somewhere that to get to Canaveral a shuttle in orbit must abandon orbit and fall in the atmosphere when it is above the Indian Ocean.
It depends on the actual orbit. For example, the de-orbit burn for STS-107 occurred over Australia. The goal is always the same: put the Entry Interface position approximately 4400 nautical miles from the landing site which in this case was KSC. If I remember correctly, the entry angle targeted was 1.5°. EI always occurred over the Pacific, never the Indian Ocean.
I calculated that if a shuttle wants to land on Yacatan it has to proceed to de-orbit burn over Mauretania in Africa. If it is correct how much time will it take to reach Mexico?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/07/2013 08:03 pm
I read somewhere that to get to Canaveral a shuttle in orbit must abandon orbit and fall in the atmosphere when it is above the Indian Ocean.
It depends on the actual orbit. For example, the de-orbit burn for STS-107 occurred over Australia. The goal is always the same: put the Entry Interface position approximately 4400 nautical miles from the landing site which in this case was KSC. If I remember correctly, the entry angle targeted was 1.5°. EI always occurred over the Pacific, never the Indian Ocean.
I calculated that if a shuttle wants to land on Yacatan it has to proceed to de-orbit burn over Mauretania in Africa. If it is correct how much time will it take to reach Mexico?
Time from de-orbit burn to wheelstop is approximately 1 hour. It's slightly longer if it was a HST service mission due to the higher orbital altitude.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 10/13/2013 03:40 pm
I know that the Spacelab (LM 1) module is on dispaly at the Udvar Hazy Centre in Virginia alongside Space Shuttle Discovery.
Where is  the Spacelab LM 2 module stored?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/13/2013 08:53 pm
I know that the Spacelab (LM 1) module is on dispaly at the Udvar Hazy Centre in Virginia alongside Space Shuttle Discovery.
Where is  the Spacelab LM 2 module stored?
Thank you.


It is in Germany
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/13/2013 09:24 pm
Specifically, at the Bremen airport.

http://en.wikipedia.org/wiki/Bremen_Airport
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 10/14/2013 06:34 am
Where there any shuttle missions which came close or might have led to a bailout situation after reentry using ' the pole '?
Title: Re: Shuttle Q&A Part 5
Post by: woods170 on 10/14/2013 09:45 am
None.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 10/16/2013 10:12 am
Can anyone inform me what the average costs where to make an orbiter and strb's reusable again after flight.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/16/2013 11:50 am
Can anyone inform me what the average costs where to make an orbiter and strb's reusable again after flight.

there are only the flight costs, and you can get that from the yearly shuttle budget and divide it by the number of flights
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 10/25/2013 08:50 am
What is the average altitude of the shuttle after reentry that it starts to 'fly'
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/25/2013 11:18 am
What is the average altitude of the shuttle after reentry that it starts to 'fly'

define "fly".  Meaning using aero surfaces?  There isn't a set altitude.  The RCS and aerosurfaces were blended for control, with yaw thrusters firing at speeds as low as Mach 2 (it could be seen from the landing site cameras)
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 10/25/2013 05:03 pm
What is the average altitude of the shuttle after reentry that it starts to 'fly'

I believe the elevons and body flap began to have control authority at 10 psf dynamic pressure. The rudder couldn't do anything until the alpha angle came down below 40 degrees, as it was completely in the wake of the fuselage.

If you have L2, watch some of the reentry videos and note where the CDR makes comments like "starting to fly like an airplane".
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 10/25/2013 05:58 pm
What is the average altitude of the shuttle after reentry that it starts to 'fly'

As the other replies to your question have indicated, there really isn't a simple answer.  From a piloting perspective, I'd say the orbiter for the most starts flying like a plane at around Mach 2.5 and 82,000 feet.  By that point the angle of attack (alpha) has ramped down to a more "pointy nose forward" attitude and the GNC (guidance, navigation, and control) scheme acts more airplane like. The RCS (reaction control system) jets aren't completely phased out until Mach 1 which generally occurs at an altitude of 50,000 feet. From there on, the orbiter uses just the aero-surfaces for flight control.

The simplest technical overview I can think of that describes this transition is located here in the SCOM (Shuttle Crew Operations Manual) beginning at around page 5.4-5.

http://www.nasa.gov/centers/johnson/pdf/390651main_shuttle_crew_operations_manual.pdf

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/25/2013 07:34 pm
Question on the Payload Bay Doors: Is the lengths of areas Xf and Xa in the attached photo the same in the Z plane? Also, what is the thickness of the ribs (blue rectangle) as well as the radiator panels?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/26/2013 02:52 am
What is the average altitude of the shuttle after reentry that it starts to 'fly'

"Entry Interface" (EI) was defined as 400K feet.
Title: Re: Shuttle Q&A Part 5
Post by: JWag on 10/28/2013 08:50 pm
Question on the Payload Bay Doors: Is the lengths of areas Xf and Xa in the attached photo the same in the Z plane?

No. The forward end of the doors have a different contour due to the cockpit window "bulge". If you look at the bright highlight on the doors of Enterprise at U-H (http://upload.wikimedia.org/wikipedia/commons/6/6d/Space_shuttle_enterprise.jpg), you can see that the Xf is smaller than Xa.

Back when I was a kid and drew 10 pictures of shuttle orbiters every day, this was a detail I struggled to get right.  ;D
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 11/19/2013 01:39 am
What are the approximate floor dimensions of the mid-deck?
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 11/20/2013 04:24 am
What are the approximate floor dimensions of the mid-deck?

In "space club" in 5th grade a long time ago the teacher that ran it told us 10' x 10' and made a box with masking tape to illustrate.  I've never seen an official answer.
Title: Re: Shuttle Q&A Part 5
Post by: manboy on 11/20/2013 10:39 pm
Has anyone here seen this image before?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/21/2013 12:02 am
Used to be de rigueur, back in the non-PC days, to have a pretty lady in the hardware photos.  No mas...
Title: Re: Shuttle Q&A Part 5
Post by: demoman on 12/05/2013 02:32 am
I'm filming a documentary on the demolition of the Orbiter Processing facilities at KSC and I'm looking for someone that worked at an OPF and is willing to talk about the processes involved in preparing a shuttle for it's mission inside the OPF.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/08/2013 02:36 am
I'm looking for the distance in the orbiter X axis between the FWD Orb/ET attachment (EO-1) and the two aft Orb/ET attachments(EO2/EO3).
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/12/2013 07:00 am
What was the reason for the first 3 ALT flights to have the tail cone in place?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/12/2013 10:39 am
What was the reason for the first 3 ALT flights to have the tail cone in place?

To come off the SCA and land with a better L/D (reduce risk)
Title: Re: Shuttle Q&A Part 5
Post by: Darren_Hensley on 12/12/2013 04:50 pm
Has anyone here seen this image before?

I saw this and many others like it in a document that described "the history of the Docking System". This one is a prototype for the CBM, about the time that VonBraun was working on the design for SS freedom. I belive it's a Boeing design that was eventually replaced by the current CBM. This design was androgenous, the current CBM is not.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/12/2013 05:46 pm
This one is a prototype for the CBM, about the time that VonBraun was working on the design for SS freedom.

He died long before there was an SSF and he was booted upstairs to NASA HQ in DC way before then.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/12/2013 06:50 pm
What was the reason for the first 3 ALT flights to have the tail cone in place?

IIRC, cone off vs cone on roughly halved the gliding distance. Big difference!
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/12/2013 08:09 pm
But why the 3 test with cone while the real orbiter obviously never lands with it
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/12/2013 10:09 pm
But why the 3 test with cone while the real orbiter obviously never lands with it

Incremental testing.  It was deemed too risky to start the testing off the SCA without the tailcone.   

Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/13/2013 06:56 am
But why the 3 test with cone while the real orbiter obviously never lands with it

Incremental testing.  It was deemed too risky to start the testing off the SCA without the tailcone.   



Got it..
Final question. What does SCA stand for?
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 12/13/2013 07:15 am
Shuttle Carrier Aircraft.

That's the official name of the two modified 747s that ferried the orbiters around.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 12/13/2013 07:18 am
There were really only two SCAs? (http://www.raumfahrer.net/forum/smf/Smileys/yabb/undecided.gif)

(http://scaleworld.forenworld.net/images/smilies/hallo.gif)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 12/13/2013 11:35 am
There were really only two SCAs?
Yes, and the second purchase only came out of recovery from the 51-L accident.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 12/13/2013 06:36 pm
But why the 3 test with cone while the real orbiter obviously never lands with it

Risk to both OV-101 and SCA (905).

905 also needed a crew escape system during ALT. Remnants remain to this day, I believe. Basically it was a way to blow out some (former) first-class cabin windows and bail out far enough in front of the wings and engines to survive.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 12/18/2013 12:48 am
During the first ALT test "sideway lurch" was mentioned by one of the crew. It was stated in a way that the "sideway lurch" was to be expected.

What where they referring to?


Oh, and was ALT ever considered as a method / means to train the crew for the landing phase?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 12/18/2013 12:50 am
What is omicron?

I think I have heard it being read up to the crew from MCC possibly as part of the numbers called up for a burn.


Thanks

Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 12/18/2013 12:56 am
What is omicron?

I think I have heard it being read up to the crew from MCC possibly as part of the numbers called up for a burn.


Thanks



Omicron is the angle of rotation about the orbiter body vector

Mark
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/18/2013 12:58 am
What is omicron?

I think I have heard it being read up to the crew from MCC possibly as part of the numbers called up for a burn.


Thanks



An angle
Title: Re: Shuttle Q&A Part 5
Post by: Shuttle Endeavour on 01/03/2014 03:29 am
Hello
I have seen the Space Shuttle Tile key created by NASA and I was wondering if there was another similar key or information about the whereabouts of various components in the fuselage and payload bay. If anybody has one, it would be greatly appreciated if you could post it.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 01/03/2014 11:54 am
Hello
I have seen the Space Shuttle Tile key created by NASA and I was wondering if there was another similar key or information about the whereabouts of various components in the fuselage and payload bay. If anybody has one, it would be greatly appreciated if you could post it.

NASA used to have a collection of drawings showing locations of various systems/components on their website at www.spaceflight.nasa.gov/shuttle/reference/sodb/ (http://www.spaceflight.nasa.gov/shuttle/reference/sodb/)  Sadly this seems to have disappeared quite some time ago.  The good news is that an archived version of the page and all the pdf files still exists on the "Wayback Machine" (web.archive.org).

NASA page can be found here:
http://web.archive.org/web/20041030190632/www.spaceflight.nasa.gov/shuttle/reference/sodb/ (http://web.archive.org/web/20041030190632/www.spaceflight.nasa.gov/shuttle/reference/sodb/)

There's more than fifty drawings - should keep you busy for a while!
Title: Re: Shuttle Q&A Part 5
Post by: Shuttle Endeavour on 01/03/2014 02:32 pm
Thanks! Those are some pretty cool diagrams. But are there any where it is labeled with V070 numbers for part reference?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/03/2014 02:36 pm
no, those drawings are not available
Title: Re: Shuttle Q&A Part 5
Post by: Shuttle Endeavour on 01/03/2014 02:37 pm
Is there a list or if I subscribe to L2 can I get that information?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/03/2014 05:16 pm
Is there a list or if I subscribe to L2 can I get that information?

no, the drawings are not available at that level on the web.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 01/03/2014 06:11 pm
According to this post (http://forum.nasaspaceflight.com/index.php?topic=17437.msg1084552#msg1084552), the Shuttle was not supposed to launch with an empty payload bay.  However, the STS-400 Hubble rescue flight was designed to launch with an empty payload bay (and indeed, the 39B modifications wouldn't have allowed a payload anyway).

Can someone explain the discrepancy?  Was the trajectory modified as the linked post speculates?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/03/2014 06:28 pm
According to this post (http://forum.nasaspaceflight.com/index.php?topic=17437.msg1084552#msg1084552), the Shuttle was not supposed to launch with an empty payload bay.  However, the STS-400 Hubble rescue flight was designed to launch with an empty payload bay (and indeed, the 39B modifications wouldn't have allowed a payload anyway).

Can someone explain the discrepancy?  Was the trajectory modified as the linked post speculates?

They would add ballast.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 01/03/2014 07:17 pm
How much ballast?  And where would they put it?  They can't put it in the payload bay, since 39B was no-go for payload operations during the STS-125 launch campaign.  (Or am I wrong about that last bit?)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 01/03/2014 07:56 pm
How much ballast?  And where would they put it?  They can't put it in the payload bay, since 39B was no-go for payload operations during the STS-125 launch campaign.  (Or am I wrong about that last bit?)
Among other things there are ballast boxes in the aft compartment.  There's a good amount of STS-400 documentation on L2...did you look at that?  (At least one of the versions there notes that the flight design allowed for those to be empty.)
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/03/2014 07:59 pm
How much ballast?  And where would they put it?  They can't put it in the payload bay, since 39B was no-go for payload operations during the STS-125 launch campaign.  (Or am I wrong about that last bit?)

They can put it in while the vehicle was in the OPF.
Title: Re: Shuttle Q&A Part 5
Post by: Sesquipedalian on 01/03/2014 09:04 pm
Among other things there are ballast boxes in the aft compartment.  There's a good amount of STS-400 documentation on L2...did you look at that?  (At least one of the versions there notes that the flight design allowed for those to be empty.)

The problem is that there is so much documentation that I wouldn't know where to look. :)  You can't search attachments like you can search the forum.

EDIT: The Mission Overview presentation doesn't mention ballast, but it does show the docking system in the PLB.  I wonder if that would be enough.

EDIT2: Well, the FOIO presentation here (http://forum.nasaspaceflight.com/index.php?topic=14438.0) says that no ballast was carried.

They can put it in while the vehicle was in the OPF.

Except when STS-400 stood down, Endeavour went straight to 39A, it didn't go back to the OPF.

Although with one more intuitive jump, this might work.  Could they have put the ballast in the PLB in the OPF, then gone to 39B for STS-400, then gone to 39A and unloaded the ballast using 39A's payload facility?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/13/2014 03:03 pm
When the US Air Force entered its requirement for a certain cross range capability, apparently they did so in order to be able to snatch and run with Soviet satellites. then land in the USA all in one single orbit. In reality was this even possible.

I have "heard" that the Russians feared the STS's capabilities, specifically the fact that STS could overfly Soviet territory, take pictures and more importantly release high yield thermonuclear devices.  Are these statement true and is this why the Soviets developed Buran, to also have this nuclear delivery capability? The public cover could be "Oh we are just launching to release a weather satellite, Psych we are dropping Tsar Bomba from orbit" sort of scenario.

I would think that the early Shuttle launches were followed very closely by the Soviets.  Any evidence to support that the Soviet military raised their defense conditions when STS would be overflying Soviet territory.

Thankyou in advance.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/13/2014 03:11 pm
When the US Air Force entered its requirement for a certain cross range capability, apparently they did so in order to be able to snatch and run with Soviet satellites. then land in the USA all in one single orbit. In reality was this even possible.


No, and it is covered earlier in these threads.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/13/2014 03:12 pm

I would think that the early Shuttle launches were followed very closely by the Soviets.  Any evidence to support that the Soviet military raised their defense conditions when STS would be overflying Soviet territory.


No, but all launches were watched by the USSR.
Title: Re: Shuttle Q&A Part 5
Post by: shuttlemodeler on 01/16/2014 06:46 pm
Does anyone know when the OWP doors went up on the FSS?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/16/2014 07:13 pm
Does anyone know when the OWP doors went up on the FSS?
Pad B had the +Y OWP Curtain Wall from the onset it went into service for the shuttle program in 1985 for the STS-51L flow. It was however missing the -Y OWP Curtain Wall on the RSS. This was added later in 1986 in time for the practice sessions with Atlantis in October 1986.

Pad A had the entire OWP system in place when it went back into service for the STS-32 flow in 1989.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/20/2014 01:29 pm
How were the strongbacks attached to/detached from the payload bay doors?  My question is two-fold.  First, I'd like to know what they attached to and how those attach points were uncovered/covered.

The second part is on the pad, what was used to handle them in the RSS?

Finally, why doesn't Atlantis need the strongbacks in the exhibit?
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 01/20/2014 01:42 pm
At the exhibit, the doors are held by several cables.  I think at least 6 or 7 per door.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/20/2014 02:20 pm
How were the strongbacks attached to/detached from the payload bay doors?  My question is two-fold.  First, I'd like to know what they attached to and how those attach points were uncovered/covered.

The second part is on the pad, what was used to handle them in the RSS?

They were bolted and some TPS was just removed to exposed the attach points.  The TPS would be replaced after the strongbacks were removed.  The strongbacks were used at the pad.
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/20/2014 06:19 pm
At the exhibit, the doors are held by several cables.  I think at least 6 or 7 per door.

Looks like 6 per door to me:

http://forum.nasaspaceflight.com/index.php?topic=32414.msg1129139#msg1129139
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 01/20/2014 06:55 pm
A few TPS related questions:

In an article I was reading about the TPS and the issues they had early on, it mentioned that there was some ablative TPS installed between elevons.  Why was this needed and can it be seen in any pictures?

How was the surface kept "flat" when they changed some of the tiles to the blankets?  Did they make the blankets the exact same thickness that the tiles were or did they add spacers?

What were the enterprise tiles made out of and why didn't they have the same issues getting them to stick as the Columbia tiles?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 01/20/2014 07:02 pm
Re: Atlantis museum display and open payload bay doors:
http://forum.nasaspaceflight.com/index.php?topic=32169.0
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/20/2014 07:18 pm
What were the enterprise tiles made out of and why didn't they have the same issues getting them to stick as the Columbia tiles?

OV-101 is covered in fiberglass (nose, wing leading edge) and foam rubber. It's just painted black in some spots.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/20/2014 08:26 pm

1.  In an article I was reading about the TPS and the issues they had early on, it mentioned that there was some ablative TPS installed between elevons.  Why was this needed and can it be seen in any pictures?

2. How was the surface kept "flat" when they changed some of the tiles to the blankets?  Did they make the blankets the exact same thickness that the tiles were or did they add spacers?

3.  What were the enterprise tiles made out of and why didn't they have the same issues getting them to stick as the Columbia tiles?

1.  It's there and it is needed because of localized heating.   It is a small area

2.  Same thickness

3.  Not real tiles.
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 01/20/2014 09:16 pm
At the exhibit, the doors are held by several cables.  I think at least 6 or 7 per door.

Looks like 6 per door to me:

http://forum.nasaspaceflight.com/index.php?topic=32414.msg1129139#msg1129139

Yep. 6. With my pictures, I couldn't tell if there were 2 on the front like there are 2 on the rear.
Title: Re: Shuttle Q&A Part 5
Post by: Mike_B on 02/10/2014 05:25 pm
I'm working on a 3D model of the shuttle external tank, and in my research, I discovered the "beanie cap" for gaseous oxygen venting, and a "ground umbilical carrier plate" that vents gaseous hydrogen. But where do you pour the liquid oxygen and liquid hydrogen into the tank?
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 02/10/2014 05:34 pm
Through the tail service masts, of course ;)
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 02/10/2014 05:36 pm
Then, through here....
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/10/2014 05:49 pm
It flowed through the orbiter's Main Propulsion System and then into the ET.  The cryos entered the orbiter through the T-0 umbilicals located on the aft of the ship as noted above.  Left hand side is where LH2 entered, right hand side was LOx
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2014 06:06 pm
You can see the lines extending from the TSM's here
http://www.nasa.gov/images/content/118194main_1297-m.jpg

And here is a top down view

http://www.nasaspaceflight.com/2010/09/sts-133-discovery-tracking-monday-rollout-t-0-bolt-progress/
Title: Re: Shuttle Q&A Part 5
Post by: Mike_B on 02/10/2014 06:09 pm
Oh that's interesting! I never knew that the liquids flowed through the engines and then all the way up the pipes on the sides to reach the tanks. Thanks, that really explains it. I guess that has to change for the SLS, since there's no orbiter anymore.

Thanks again,
-Mike
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/10/2014 06:20 pm
I guess that has to change for the SLS, since there's no orbiter anymore.

Thanks again,
-Mike

No same concept, slightly different execution style.  There will still, and has to be, a main propulsion system.  There will be service masts from the pad that interface the MPS through similar umbilicals and fill mehtods (for at least the core stage).  Any upper stage would be a same basic method, just higher up.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2014 06:36 pm
Oh that's interesting! I never knew that the liquids flowed through the engines and then all the way up the pipes on the sides to reach the tanks. Thanks, that really explains it. I guess that has to change for the SLS, since there's no orbiter anymore.

That is the standard practice for most if not all launch vehicles.  For the first stage, they have masts/umbilicals that interface with the booster propulsion system at the base of the vehicle.  Saturn V had 3 TSM's, Delta IV uses 2, Atlas uses 1, Falcon 9 incorporates them into the holddown system.  There is no need to go any higher on vehicle.  The feed lines from the tanks go into the propellant feed system/manifolds at the base of the vehicle , so just plumb into it for the umbilicals.   (the tanks fill from the bottom up, not from a inlet on top.  There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves.  Hence the term like fill and drain valves)


The hydrogen didn't have to go up.  The tank is right there.

Title: Re: Shuttle Q&A Part 5
Post by: Mike_B on 02/10/2014 07:02 pm
Quote
(the tanks fill from the bottom up, not from a inlet on top.  There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves.  Hence the term like fill and drain valves)
That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.

Thanks again,
-Mike
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/10/2014 07:08 pm
Quote
(the tanks fill from the bottom up, not from a inlet on top.  There is no faucet like a bath tub, just the drain and the propellant comes in through the same orifice that it leaves.  Hence the term like fill and drain valves)
That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.

Thanks again,
-Mike

Yes, it's called head pressure.  Plus the tank vents are open still so the tank is not pressurized. 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2014 07:19 pm

That makes sense. Since you fill from the bottom, would you have to overcome the pressure generated by the column of fuel/oxidizer? I'm sure that's a basic physics question, but this is an interesting education today.


Pressure is only determined by the column height of the fluid and not the area.  So filling from the bottom takes less energy than filling from the top.  Filling from the top, the column height would be more than filling from the bottom and hence the pressure would be more.

http://faculty.wwu.edu/~vawter/physicsnet/topics/Pressure/HydroStatic.html
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 02/10/2014 07:44 pm
When I get home, I'll try to post a picture of the interface between the ET and the orbiter (got a great shot of Endeavour's while visiting CSC), but I have a question:
Is the fill/drain line from the MPS in to the ET different than the orifice/17" line that carried the prop from ET to MPS during actual engine firing?
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/10/2014 07:49 pm
Is the fill/drain line from the MPS in to the ET different than the orifice/17" line that carried the prop from ET to MPS during actual engine firing?

The fill/drain line was an 8" line that was the interface from the T-0 disconnects into the orbiter MPS and then eventually into the 17" feedlines where they interfaced to the tank. 
Title: Re: Shuttle Q&A Part 5
Post by: muomega0 on 02/10/2014 08:24 pm
To be complete, how is excess propellant dumped on orbit, though the nozzle and/or the fill and drain valves before the He purge?
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/10/2014 08:44 pm
To be complete, how is excess propellant dumped on orbit, though the nozzle and/or the fill and drain valves before the He purge?

To vent and safe the MPS system after ET jettison:

LOX was through the engine bells.

LH2 was through the fill and drain valve and out the T-0 interface. 
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 02/11/2014 12:53 am
Okay, here are port and starboard sides of the interfaces between Orbiter and ET.  You can see why I asked about if the fill/drain was done via the big 17", or the smaller ifc/pipe.  I imagine the smaller ones are for pressurizing the LOX and LH2 tanks via the MPS during flight.
I should add the "staining/streaking" aft of the port side (LH2) interface was more pronounced on the TPS than on the starboard side.
Title: Re: Shuttle Q&A Part 5
Post by: Go4TLI on 02/11/2014 01:36 pm
I imagine the smaller ones are for pressurizing the LOX and LH2 tanks via the MPS during flight.
I should add the "staining/streaking" aft of the port side (LH2) interface was more pronounced on the TPS than on the starboard side.

On the LH2 umbilical there was the 17" feedline, a 4" recirculation line and a 2" GH2 line that was used to provide ullage and pressurize the hydrogen tank.

On the LOX umbilical there was the 17" feedline and the 2" GOX line that was used for the same purposes as the GH2 line but for the ox tank. 

There was also the electrical interfaces and the ET mount interfaces. 
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 02/11/2014 03:27 pm

Good stuff--thanks Go4TLI.
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 02/26/2014 04:03 pm
Reading about Shuttle tanking problems I noticed that the External Tanks could only be cryocycled a maximum of 13 times, with a fill-cycle counting as one and a pressure cycle counting as a second.

Does anyone here (Jim?) know which particular components of the tank were responsible for this limit? Was it the Al-Li tanking, the welds, the valves, vents, baffles, parts of the feedlines, flex-joints or what precise bits were the limiting factor?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/26/2014 04:58 pm
Foam was a big part of it.
Title: Re: Shuttle Q&A Part 5
Post by: JayP on 02/28/2014 04:32 pm
I'm working on a project dealing with the layout of mechanical systems and I'm using the shuttle airlock hatch 5 bar hinge design as an example. Does anyone know what the X and Y dimensions in the attached sketch would be or know of a document that would lay this out. Thee rest of it can be determined once we know where the hatch ends up when it is open relative to it's closed position.  it doesn't matter which of the 3 hatches we go by, the linkage design is functionally the same in all cases. Thanks,
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/02/2014 01:46 am
Does anyone know the weights for the Orbiter Docking System and the External Airlock with the truss assembly? I'm not talking about both added together but separately.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/04/2014 05:29 pm
I'm curious about the dimensions (X and Y) of the payload umbilical access panel on the orbiter midbody. It's the one with the red lines in the attached photo.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 05/13/2014 07:43 am
What was the first shuttle flight that had full orbital communicatons (so no LOS)?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/13/2014 09:44 am
What was the first shuttle flight that had full orbital communicatons (so no LOS)?

There was always ZOE and antenna blockage.  STS-26 and STS-29 delivered the 2nd and 3rd TDRS.  So somewhere in between LOS was reduced to 85%
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/13/2014 11:53 am
The Space Shuttle Missions Summary reference says STS-27 was the first flight with TDRS-East and West.  (Also first flight with "no comm blackout" during re-entry.)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/13/2014 04:25 pm
Hello all.

Quick question about the IUS and PAM-D upper stages. After having deployed the upper stage, the Shuttle had to orient itself, in such a way to use the belly as a shield from the upper stage rocket exhausts. Obviously by the time the upper stage fired the orbiter would have been at a certain distance, but what if some damage occurred to the belly? how could they know if it had been damage in the first place? with no OBSS or procedure for checking out the belly with the RMS (as capability demonstrate by STS-8), how could they have know if the belly had been compromise? I've to say this type of procedure for satellite deployment has always made me raise an eyebrow.

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/13/2014 04:36 pm
Quick question about the IUS and PAM-D upper stages. After having deployed the upper stage, the Shuttle had to orient itself, in such a way to use the belly as a shield from the upper stage rocket exhausts. Obviously by the time the upper stage fired the orbiter would have been at a certain distance, but what if some damage occurred to the belly?
There was a sequence of post-deploy separation burns with a pretty large one (relatively speaking) at the end, so by the time of upper stage ignition it was fairly great distance.

(The STS-44 mission report has the OMS sep burn as a two-engine burn with a delta-V of ~30 fps.)
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/13/2014 04:53 pm
Quote
There was a sequence of post-deploy separation burns with a pretty large one (relatively speaking) at the end, so by the time of upper stage ignition it was fairly great distance.

that's true, but why then taking anyway the precaution of using the belly as a shield? it was fairly distance, it wouldn't have mattered the shuttle attitude at the time of upper stage ignition.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/13/2014 05:06 pm
Quote
There was a sequence of post-deploy separation burns with a pretty large one (relatively speaking) at the end, so by the time of upper stage ignition it was fairly great distance.

that's true, but why then taking anyway the precaution of using the belly as a shield? it was fairly distance, it wouldn't have mattered the shuttle attitude at the time of upper stage ignition.
Press kits say to protect the orbiter windows:
http://science.ksc.nasa.gov/shuttle/missions/sts-44/sts-44-press-kit.txt

Quote
At approximately 45 minutes after ejection from the orbiter,
the pyrotechnic inhibits for the first solid rocket motor are
removed.  The belly of the orbiter has been oriented towards the
IUS/DSP combination to protect the orbiter windows from the IUS's
plume.  The IUS recomputes the first ignition time and maneuvers
necessary to attain the proper attitude for the first thrusting
period.
Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 05/19/2014 05:43 am
I know the Apollo astronauts trained and could theoriticly fly the Saturn V to orbit, but I also remember reading the Shuttle could not because of the complexity of the boost phase. Another gent is telling me this was only true under stage 1 boost (SRB powered) but after they were jettisoned the Shuttle could be manually flown to orbit.

Thought? TIA.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 05/19/2014 01:05 pm
I know the Apollo astronauts trained and could theoriticly fly the Saturn V to orbit, but I also remember reading the Shuttle could not because of the complexity of the boost phase. Another gent is telling me this was only true under stage 1 boost (SRB powered) but after they were jettisoned the Shuttle could be manually flown to orbit.

Thought? TIA.


They would follow the same guidance that the autopilot would be using.  The point is that if the guidance failed, there is no way the crew could fly to orbit.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 05/19/2014 01:51 pm
Manual control (CSS mode) was available during the entire ascent phase.  It was extremely difficult during first stage due to the control authority available from the SRB TVC. 
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/19/2014 02:08 pm
I know the Apollo astronauts trained and could theoriticly fly the Saturn V to orbit, but I also remember reading the Shuttle could not because of the complexity of the boost phase. Another gent is telling me this was only true under stage 1 boost (SRB powered) but after they were jettisoned the Shuttle could be manually flown to orbit.

Thought? TIA.


Could you fly the Shuttle stack manually into orbit?  Technically yes, but you probably would not have survived first stage.   Control Stick Steering was available and the CDR/PLT and the ground always made sure they didn't accidentally switch to CSS while the crew was getting into their seats.

But, having tried this in the SMS, first stage ended up with manual control flying all over the sky.  Because the large amount of SRB thrust and the way the SRB nozzles moved, a little stick input would produce a large amount of vehicle position change.  In the simulator, that worked.  In real life, the wings would have been torn off by atmospheric pressure. 

The other thing to remember, like Jim said, is that the only way to get into orbit would have been to follow guidance.  Well, if guidance is working why would you take the risk of flying the vehicle manually during powered flight?  So, while it's "cool" to think that someone could have flown to orbit manually, there wasn't really a reason since you would have had to fly manually.

By the way, before we automated some of the two-engine out and three-engine out modes, the crew was taught to fly the last parts of second stage manually.  They did this because certain attitude or positional targets had to be met at certain times and the software had not yet been designed for those very-off-nominal situations.

So, second stage manual capabilities were trained but not for reaching orbit.  Also I must remind you that even so-called manual inputs went through the flight computers since this was a fly-by-wire vehicle.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 05/19/2014 04:55 pm
I believe flight rules prohibited manual control for the first 90 seconds of powered ascent.

The reality is it was very unlikely you could control the vehicle at any point with the SRB's attached and not exceed load limits. Both fixed and motion simulators assumed the stack was a rigid body and required the sim operator to inform the crew that they got crushed like a beer can. ;)
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 05/19/2014 07:16 pm
How would the sim operator have known that?

I have some knowledge of the SMS models, BTW.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 05/19/2014 07:29 pm
How would the sim operator have known that?

I have some knowledge of the SMS models, BTW.

Maybe not the operator in real-time, but post-process the data and figure out if load limits were exceeded. In other words, you couldn't "snap the wings off" in the simulator. Somebody had to go do some math after the fact and tell you whether you survived or not.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/19/2014 09:31 pm
My 2 cents regarding a couple points not yet covered in the discussion so far of CSS (control stick steering or manual control) prior to 90 seconds into the ascent/launch.

I was always taught – and this is what I always repeated to students (usually VIP guests since the CB types understood this already) – the real concern with CSS during this timeframe was “load relief”.

Remember 1st stage guidance was “open loop”.  All the shuttle stack is trying to do during this timeframe is maintain a canned attitude versus velocity profile.  However, there were combinations of inputs to guidance from the Orbiter and SRB rate gyro assemblies (RGAs), and orbiter accelerometer assemblies (AAs) that allowed the vehicle to manage loads on the stack and wings.  The exact combination of inputs was body axis dependent.  For example we used the roll rates from the orbiter RGAs instead of the SRB RGAs because of their relative distances from the center of gravity (CG).

In perhaps an oversimplified explanation, the shuttle managed “load relief” by;
- steering the stack into the wind

- adjusting the SSME (space shuttle main engine) throttle level (during the bucket) based on “hot” or “cold” burning SRBs (This was done based on a “snapshot” of vehicle performance at about T+20 seconds.  If you got to the expected velocity cue for the 20 second point early, then you had hot boosters, if you got to that velocity point a little later than 20 seconds, then you had cold boosters)

- wing loading was managed by deflecting - usually differentially - the orbiter elevens (and there was certainly no way to do that with the control stick in the cockpit)

From the perspective of the cockpit you did not have the necessary cues and feedback to make these kinds of adjustments.  Just keeping the ADI (attitude indicator) needles centered would not do the trick.  As an example, a perfectly nominal ascent could occur with deflected needles.  This is because the ADI needles are displaying attitude error, but guidance during the load relief phase would preferentially manage loads over attitude.  So it was perfectly normal on some days to see the orbiter steer away from the planned/canned 1st stage attitude in an effort to manage vehicle loads.  On launch day we briefed the crew on the expected atmospheric conditions and winds aloft so that they would not be surprised by these attitude excursions.

Training to fly manual 1st stage ascents was pretty straight forward.  We only trained the crews to take CSS after 90 seconds (which was past the load relief region).   After 90 seconds the technique was to fly the pitch attitude (theta) supplied to them on the ADI CUE card (remember this was a good approximation since 1st stage guidance was open loop and was based on a canned profile of attitude verses velocity).  The crew would also yaw to keep the HSI (horizontal situation indicator) bearing pointer under the lubber line and then roll out the resulting bank caused by the yaw maneuver – this Beta (or sideslip) management technique was done in an effort to keep from violating thermal constraints.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 05/20/2014 11:40 am
How was SRB ignition synchronized?  I'm interested in the design of the control system that guaranteed the ignition signals would arrive simultaneously to each SRB.  Did it require that the communication wiring from the orbiter to the SRBs be exactly the same length to each one?

What was the maximum acceptable difference in ignition time between the two SRBs? 
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/20/2014 12:37 pm
How was SRB ignition synchronized?  I'm interested in the design of the control system that guaranteed the ignition signals would arrive simultaneously to each SRB.  Did it require that the communication wiring from the orbiter to the SRBs be exactly the same length to each one?

What was the maximum acceptable difference in ignition time between the two SRBs? 

You want to look up a "Master Events Controller" (MEC), not to be confused with a Main Engine Controller (MEC).  The Master Events Controller was the interface between the flight computers and the pyrotechnics on the vehicle.  The General Purpose Computers (GPCs) would send an arm / fire sequence to the MEC for the particular pyrotechnic that was the blow.  There were redundant channels to each pyro and, yes, the wiring was the same length.

I don't remember the specs for the differences in ignition times but it was small.  A bigger key was that the thrust had to build-up at the same rate.  But, that's outside of your question.

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts-av.html#sts-dps-mec
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 05/20/2014 02:42 pm
How was SRB ignition synchronized?  I'm interested in the design of the control system that guaranteed the ignition signals would arrive simultaneously to each SRB.  Did it require that the communication wiring from the orbiter to the SRBs be exactly the same length to each one?

What was the maximum acceptable difference in ignition time between the two SRBs?

The only electrical connection between the Orbiter and the rest of the stack is through the ET umbilicals. The SRBs had cables to the ET. Tom Jones recalls in his book STS-98 being rolled back to inspect/replace those cables because there had been a failure on a previous mission (STS-97?) where the primary pyrotechnics on the hold-down nuts did not fire, but the redundant set did.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/20/2014 03:28 pm
How was SRB ignition synchronized?  I'm interested in the design of the control system that guaranteed the ignition signals would arrive simultaneously to each SRB.  Did it require that the communication wiring from the orbiter to the SRBs be exactly the same length to each one?

What was the maximum acceptable difference in ignition time between the two SRBs?

The only electrical connection between the Orbiter and the rest of the stack is through the ET umbilicals. The SRBs had cables to the ET. Tom Jones recalls in his book STS-98 being rolled back to inspect/replace those cables because there had been a failure on a previous mission (STS-97?) where the primary pyrotechnics on the hold-down nuts did not fire, but the redundant set did.
The problem that caused the STS-98 rollback was that on STS-97/4A one of two explosive cartridges called NASA Standard Initiators (NSIs) on the left SRB ETAR that connects the SRB with the ET failed to fire. The second one did fire and SRB sep was successful. The problem was traced to a wiring fault that prevented the separation signal from reaching the NSI.

They did check the wiring on each SRB prior to rollout of STS-98/5A but later while in the VAB following a successful Orbiter/ET Mate, the NSI wiring on the left SRB failed a electrical resistance test, it was traced to a bad connector.

Later on the eve prior to the start of the launch countdown (January 15 2001), when four other SRB cables in inventory were discovered to be defective, SSP managers decided to rollback the STS-98/5A stack to the VAB and X-ray and test the SRB wiring. Due to the fact that the wiring runs along the length of the boosters in so called "systems tunnels" the wiring could only be inspected and tested in the VAB.

The problem with the holddown post bolts occurred on a later Atlantis flight, STS-112/9A in October 2002.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 05/20/2014 10:02 pm
The previous posts about CSS during ascent made thing if instead performing CSS during entry and TAEM would have been more realistic and survivable?

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 05/21/2014 12:46 am
The previous posts about CSS during ascent made thing if instead performing CSS during entry and TAEM would have been more realistic and survivable?

Davide

You could certainly fly reentry by hand, from deorbit burn to landing. Crews routinely trained for it.

Engle did most if not all of it on STS-2.
Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 05/21/2014 02:58 am

You could certainly fly reentry by hand, from deorbit burn to landing. Crews routinely trained for it.

Engle did most if not all of it on STS-2.

Another reason I'd love to hear General Engle do a talk, or write a book about his career.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/22/2014 02:21 am
The previous posts about CSS during ascent made thing if instead performing CSS during entry and TAEM would have been more realistic and survivable?

Davide

Davide, sure - entry CSS from EI to landing was an available mode and, as pointed out, was used on STS-2.  However, except for some intermediate OFT test objectives, the guidance needles were followed.  So, it was the crew following what the GPCs indicated but it showed that CSS would work.

The way the vehicle was flown meant that auto was followed to just under Mach 1 (usually Mach 0.95) and before the HAC was entered.  This was to allow the GPCs to fly the higher speed parts of entry and then let the crew "get the feel" of the vehicle after going subsonic.  A lot of that was the result of the STS-3 landing where the crew took back over at 300 feet altitude.  Post landing the crew said that they didn't have a good feel for how the vehicle behaved subsonic, so they didn't think 300 feet was an appropriate time to take over.

So, no real good reason to do CSS from EI to HAC, but it was available.  Autoland was tried to 300 feet during the early flights.  It wasn't used further, well, because the crew liked to land the vehicle.  The official reason was that the MLS signal could disappear just over the runway threshold.  STS-53 was scheduled for an autoland DTO but that was cancelled 1-2 months before the flight.

So, CSS entry would have been fine.  Ascent CSS - probably a really bad day if you needed that.  Also remember that if BFS had been engaged during entry, BFS had no auto mode.  You were CSS all the way in.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/22/2014 03:47 pm
What is the whining sound that I frequently hear on cockpit re-entry video's? To describe it- it sounds like beginning of a Cessna 152 stall warning.

It starts here at 15 seconds and can also be heard at 59 seconds and 1:15.

Also, what is DTI? (or is it PTI 19:41) that triggers the master warning at 20:08.

Finally, note at 1:23 how the crew calls Columbia "it" and "boy".

https://www.youtube.com/watch?v=98SbI5Wv1Ck


Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/22/2014 04:22 pm
Yes the correct term is PTI (programmed test input).  These were usually flight control inputs (typically done automatically) that were intended to further refine the various aerodynamic coefficients used in modeling the orbiter's flight characteristics.  The PTI could be something as simple as a timed control stick deflection at a specific mach number/airspeed and or altitude.

The physics majors can probably provide a more elaborate explanation regarding the noise....but.....You're right, in this video it does sound similar to the Cessna stall warning.  In this case it is actually noise/interference over the intercom system caused by the plasma flow outside the orbiter during entry.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/22/2014 04:59 pm
Thank you Mark.

At 29:37 the commander advises the crew, "at 8,000 - 9,000 feet you are going to feel a roll and yaw, don't worry".  The maneuver occurs at 30:16. Was that a PTI and what were they testing?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/22/2014 05:30 pm
Yes it looks like a stick and a rudder deflection.  These were likely a part of a series of inputs that made up a specific DTO (detailed test objective).  I would have to see the flight plan notes, entry checklist/cue card to decipher what the exact maneuver(s) were and what the specific objectives were.  Generally, as I said before, these were to help derive and validate the exact aerodynamic coefficients used in modeling flight characteristics for the simulators.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/22/2014 05:49 pm

https://www.youtube.com/watch?v=k0UOu-1aIWo

At 17:40 What is a (phonetically pronounced) puckamu swap?


Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/22/2014 06:08 pm

At 17:40 What is a (phonetically pronounced) puckamu swap?



It's PCMMU or Pulse Code Modulation Master Unit.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/22/2014 06:21 pm
Thank you Mark and Dave.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/22/2014 09:36 pm

At 17:40 What is a (phonetically pronounced) puckamu swap?



It's PCMMU or Pulse Code Modulation Master Unit.

Purchase Davide's book (and it's a good book) and you can find out more.  But, basically they were swapping between units that encoded the telemetry so that it was formatted in a way the ground could decode (commutated and decommutated).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/22/2014 09:41 pm
Yes it looks like a stick and a rudder deflection.  These were likely a part of a series of inputs that made up a specific DTO (detailed test objective).  I would have to see the flight plan notes, entry checklist/cue card to decipher what the exact maneuver(s) were and what the specific objectives were.  Generally, as I said before, these were to help derive and validate the exact aerodynamic coefficients used in modeling flight characteristics for the simulators.

Mark Kirkman

Mark, probably this one (luckily the STS-65 press kit text is online):

          DTO 251: Entry Aerodynamic Control Surfaces Test

The DTOs were designed to push the envelope, although usually only by a little bit.  I always like the PTIs because we (in the old MCDS cockpit) could see flashing with double-overbright characters.  A rare combination that is one of those space-geek type things to remember.

Andy

Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/22/2014 10:35 pm

https://www.youtube.com/watch?v=k0UOu-1aIWo

At 17:40 What is a (phonetically pronounced) puckamu swap?
Another one of those PCMMU swap cases in one of the runs of a STS-129 ascent sim I was lucky enough to report on for the site:
http://www.nasaspaceflight.com/2009/11/sts-129-practising-launch-flight-controllers-put-to-the-test/

(Nice to see that Matt Travis posted that NASA TV video from one of the STS-135 media days...I think it was missing at one time from YT.)
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/22/2014 11:20 pm
Yes it looks like a stick and a rudder deflection.  These were likely a part of a series of inputs that made up a specific DTO (detailed test objective).  I would have to see the flight plan notes, entry checklist/cue card to decipher what the exact maneuver(s) were and what the specific objectives were.  Generally, as I said before, these were to help derive and validate the exact aerodynamic coefficients used in modeling flight characteristics for the simulators.

Mark Kirkman

Mark, probably this one (luckily the STS-65 press kit text is online):

          DTO 251: Entry Aerodynamic Control Surfaces Test

The DTOs were designed to push the envelope, although usually only by a little bit.  I always like the PTIs because we (in the old MCDS cockpit) could see flashing with double-overbright characters.  A rare combination that is one of those space-geek type things to remember.

Andy



Actually the one performed on final appears to be part of DTO 254 "Subsonic Aerodynamics Verification".  I wouldn't mind seeing the entry maneuvers cue cards from those flights or something else that breaks down the parameters of the test inputs (timing, magnitude, duration, etc).

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/23/2014 12:27 am
Phillip, thank you! I have not read that article before.

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/23/2014 04:01 am
Yes it looks like a stick and a rudder deflection.  These were likely a part of a series of inputs that made up a specific DTO (detailed test objective).  I would have to see the flight plan notes, entry checklist/cue card to decipher what the exact maneuver(s) were and what the specific objectives were.  Generally, as I said before, these were to help derive and validate the exact aerodynamic coefficients used in modeling flight characteristics for the simulators.

Mark Kirkman

Mark, probably this one (luckily the STS-65 press kit text is online):

          DTO 251: Entry Aerodynamic Control Surfaces Test

The DTOs were designed to push the envelope, although usually only by a little bit.  I always like the PTIs because we (in the old MCDS cockpit) could see flashing with double-overbright characters.  A rare combination that is one of those space-geek type things to remember.

Andy



Actually the one performed on final appears to be part of DTO 254 "Subsonic Aerodynamics Verification".  I wouldn't mind seeing the entry maneuvers cue cards from those flights or something else that breaks down the parameters of the test inputs (timing, magnitude, duration, etc).

Mark Kirkman

I didn't see that one in the press kit.  Doesn't mean it wasn't there - press kits were not FRDs.  I seem to remember that most of the item entry PTIs were in the supersonic range.  Makes sense since that is where you would be in auto.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/23/2014 02:29 pm
What is a "long form bus tie" and how does it differ from a regular bus tie?

Thank you
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/23/2014 04:10 pm
What is a "long form bus tie" and how does it differ from a regular bus tie?

Thank you


Wow, it’s probably been 15 years since I’ve answered this relatively common training question.  If I recall correctly…and in very over simplified terms;

If we lost equipment powered by one of the orbiter’s main electrical power buses (maybe because of a failed fuel cell for example), that bus and its related equipment could still remain powered by performing a "bus tie". Tying main buses is achieved by connecting the buses to the orbiter’s tie bus circuit. Power was then transferred between the buses across the common “tie bus”.  When performing a bus tie, the "bad bus" (the one with a fuel cell problem in this case) was tied to a good bus.  Standard tying convention was Main A to Main B, Main B to Main C and Main C to Main A with the bad bus being the first in the naming convention, and the good bus being the second. 

So, if fuel cell 2 had a problem, MN B, which is normally powered by fuel cell 2, is the "bad bus”, MN B would be tied to MN C by taking the MN B Bus Tie switch located on the Pilot's right console to ON followed by the MN C Bus Tie switch to ON.

Although you could tie buses with two simple switch throws, there was a cue card procedure (located on the PLT’s right console) that had about a dozen steps.  Generally during first stage, and when related voltages were at an acceptable level (about 20 volts), you would just do the short form (time critical) action of throwing those couple of switches.  However, the rest of the time you would follow the 12 steps or so of the “long form” procedure which entailed protecting related equipment on the buses from unacceptable voltage transients during the tie process.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/23/2014 05:00 pm
Thanks Mark!

Last one for now;

"4 minutes to spreading" "clear it" "can't be cleared".

?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/23/2014 10:15 pm
Thanks Mark!

Last one for now;

"4 minutes to spreading" "clear it" "can't be cleared".

?

Spreading is short for "Spread Spectrum" which is a mode of communications with the TDRS.  I'll need to listen to the conversation to understand the context for "clear it" and "can't be cleared".
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/24/2014 12:43 am
During the sim run posted here;
http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400 (http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400)

at 56 seconds;

I familiar with the engine performance calls (single engine ops 3, two engine TAL, etc etc). But I have never heard of (because it was never needed) it expressed in thirds, ie - "One and two thirds negative return."

What does "One and two thirds" mean?

Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/24/2014 01:42 am
re spreading;

mentioned here at 10:03.

http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400 (http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400)

Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/24/2014 12:20 pm
During the sim run posted here;
http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400 (http://forum.nasaspaceflight.com/index.php?topic=17437.msg1202400#msg1202400)

at 56 seconds;

I familiar with the engine performance calls (single engine ops 3, two engine TAL, etc etc). But I have never heard of (because it was never needed) it expressed in thirds, ie - "One and two thirds negative return."

What does "One and two thirds" mean?



"1 & 2/3" are abort boundary calls for "stuck" scenarios.  These are based on having a shuttle main engine "stuck" at a reduced power setting - for example this could happen when an engine fails to throttle all the way back up after being throttled down during 1st stage ascent.

In this video (which unfortunately doesn't cover the first part of the sim run) it appears they experienced a left engine hydraulic lockup during the timeframe of the throttle bucket, so this would mean the engine valves are effectively locked in their current position and the engine can not be throttled.  This lockup also played into why the engine is being intentionally shut down early at a velocity of 23K (23,000 feet per second).

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/24/2014 12:28 pm
Thanks Mark!

Last one for now;

"4 minutes to spreading" "clear it" "can't be cleared".

?

Spreading is short for "Spread Spectrum" which is a mode of communications with the TDRS.  I'll need to listen to the conversation to understand the context for "clear it" and "can't be cleared".


This is just a swag since my comm system knowledge was always a little week (and shame on me for that since it really is an absolutely critical system for a space flight system);

I think INCO is saying he can not manage the comm system for spreading because they are stuck with the SPCs (stored program commands) they had pre liftoff.  SPCs allow for antenna and comm system management during ascent.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/24/2014 04:38 pm
Oh thank you so much Mark, Andy and Dave, and Phillip.
Juicy stuff!

Title: Re: Shuttle Q&A Part 5
Post by: psloss on 05/25/2014 01:04 pm
Oh thank you so much Mark, Andy and Dave, and Phillip.
Juicy stuff!
If you are a L2 member, the audio from first part of that ascent sim run is covered in there.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 05/26/2014 05:21 am
Thanks Mark!

Last one for now;

"4 minutes to spreading" "clear it" "can't be cleared".

?

Spreading is short for "Spread Spectrum" which is a mode of communications with the TDRS.  I'll need to listen to the conversation to understand the context for "clear it" and "can't be cleared".


This is just a swag since my comm system knowledge was always a little week (and shame on me for that since it really is an absolutely critical system for a space flight system);

I think INCO is saying he can not manage the comm system for spreading because they are stuck with the SPCs (stored program commands) they had pre liftoff.  SPCs allow for antenna and comm system management during ascent.

Mark Kirkman

Filling in a bit more, BFS was in control of the antenna pointing during ascent / entry, including selecting which s-band antenna to use.  PASS didn't control the antennas until OPS 2 when the Systems Management computer was brought up.
Title: Re: Shuttle Q&A Part 5
Post by: mgfitter on 05/28/2014 09:18 pm
Whatever happened to the "Tin Whiskers" problem from back in 2006?

Clearly they were able to fly the remainder of the flights without problems, but I never heard what the solution was?

-MG.
Title: Re: Shuttle Q&A Part 5
Post by: jeff122670 on 05/28/2014 11:01 pm
Wayne Hale mentions the "Beester Balls" in a talk once at GWU...  Aside from me mis-spelling it, what was that again?
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 05/28/2014 11:07 pm
Whatever happened to the "Tin Whiskers" problem from back in 2006?

Clearly they were able to fly the remainder of the flights without problems, but I never heard what the solution was?

-MG.

Probably in the end, stop using solder with a high tin content, along with various coatings,  plating with different metals, etc.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/29/2014 02:33 am
Wayne Hale mentions the "Beester Balls" in a talk once at GWU...  Aside from me mis-spelling it, what was that again?



Ha....you said "balls"    ;)

As in Ball-Strut Tie Rod Assembly (BSTRA)


Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/29/2014 04:03 am

What does the following call from FDO to FD mean?

"we took a thrust update of plus 6"

Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/30/2014 07:32 pm
I promise I searched for hours before asking this.

I know there is the "The all-eventful STS-93 launch" and I have searched the Shuttle Q & A's and read a few posts (seem to remember one saying- oh now I know why the forums went crazy). Could somebody please point me to the threads that discuss the investigation and results of the short?

It was stated that this was a transient on AC1 and that AC1 looked ok in the later stages of launch. Why didn't the engine controllers that were knocked offline come back on after the "transient" ?

Thanks!
-Giles
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 05/30/2014 07:53 pm
I'm 100% certain if this but the only way to recover a lost DCU is to power cycle the MEC itself. That would mean shutting down the engine.

They never lost the entire MECs for the center and right engines, only the DCUs which are components of the MECs.
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 05/31/2014 06:48 pm
(Let's see if I know as much as I think  :P)

When the voltage got outside of the limits of the controller channel, it did a "self disqualification", and from then on it does nothing, regardless of what happens to the voltage. When you're in flight that's it, you can't do nothing else, and you become fully dependent on the other channel.
On the ground, you have more options (I could be wrong in some of this):
> if the controller went completely dead (no power) during the "transient", I think it goes into PROM standby when the power comes back on, and then the LCC would have to send several commands the controller, so it gets to the appropriate phase and mode.
> if it did not power off completely, the LCC can send a channel reset ou a controller reset command (not sure which) to "re-qualify" that controller channel.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/02/2014 02:52 pm
Is the audio on this a real RTLS / ditching sim? If so, does anyone know when this sim was conducted?

https://www.youtube.com/watch?v=t6fSUaZlsWw

What does "2 engine out blue" and "push buttons" mean?
also;
"He needs to get the nose down.... he's at alpha 7"


Thank you!
Giles
Title: Re: Shuttle Q&A Part 5
Post by: GLS on 06/02/2014 03:45 pm
"2EO Blue" is a contingency abort mode. The procedure, and the other 4 or 5, are explained in the ascent checklist (or similar), all available somewhere in the NASA/JSC website.

The push button reference is so the crew push the main engine shutdown push button, on the engine that just died, so the GPCs can close the prevalves and guidance knows that then engine is dead. This is only needed when there's a data path failure, and the GPCs don't have any info about the engine, but the crew and MCC "can tell" if the engine is on or off.

The nose down reference is for the CDR, to decrease the angle of attack (alpha) down to about 40º ou 50º (it was at 70º), so that control is not lost during the pullout.

BTW: judging by the audio the crew still hadn't done the PPA, so the video is wrong in that aspect, and the vehicle was pointing away from KSC the whole time.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/02/2014 04:48 pm
Is the audio on this a real RTLS / ditching sim? If so, does anyone know when this sim was conducted?

The video is not from the Shuttle Mission Simulator.  Although the audio sounds authentic to me, I can't say that I recognize any of the crew or flight controller voices.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/02/2014 05:13 pm
Is the audio on this a real RTLS / ditching sim? If so, does anyone know when this sim was conducted?
The audio has been re-encoded / re-uploaded to YT multiple times; another thread with some help identifying voices from Wayne Hale:
http://forum.nasaspaceflight.com/index.php?topic=23001.msg648174#msg648174

Given the audio is less than eight minutes long, it is heavily edited and thus we're losing important events and context to the sim run -- and I guess we can't necessarily say for sure if this audio is from a single run or multiple runs.  It would have been fascinating to hear the raw, unedited audio.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/02/2014 05:39 pm

What does the following call from FDO to FD mean?

"we took a thrust update of plus 6"

Thank you.


The Flight Dynamics group had a tool in the Mission Control Center called the ARD (abort region determinator) which was used to calculate the shuttle's abort mode boundaries in real time.   Actual ascent performance in this particular case was different than the predicted/modeled performance because of a small hydrogen leak in the #3 (right) shuttle main engine nozzle.  FDO was advising Flight that the ARD model was given a real time update of 6 feet per second to its thrust value.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/02/2014 06:02 pm
The audio has been re-encoded / re-uploaded to YT multiple times; another thread with some help identifying voices from Wayne Hale:
http://forum.nasaspaceflight.com/index.php?topic=23001.msg648174#msg648174


Thanks for the link; that explains why I didn't recognize the voices, it's from before my tour in the Nexus of Evil.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/04/2014 03:24 pm
Thank you  DaveS, GLS, S-I, Phillip and Mark.

I sure do miss the program.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/05/2014 07:29 pm
I'm not sure why this was published on June 2nd but it is an interesting look back at STS-51L and 107. Some relatively "new" launch footage from the public.

http://retroreport.org/major-malfunction-lessons-from-challenger/

Looks like recent interviews with;

Allan J. McDonald - director of Morton-Thiokol at the time. "I did the smartest thing I ever did in my lifetime, I refused to sign (the launch rationale)."

Larry Mulloy - NASA project manager for the SRB's at the time. He was told, "I wouldn't want to be the guy that had to appear at a board of inquiry if this things blows." Mulloy replied, "I understand that Al, and you won't have to. That will be me."

Then it goes on to STS 107;

Rodney Rocha - STS 107 "The decision to ask for more data was unanimous. The next day, I get an email saying the answer is no. I called up the chief engineer, why don't you back this up? The chief engineer replied, "I don't want to be a chicken little about this."

During a teleconference before entry an engineer said;
"We could lose an entire tile. It could be a significant area of tile damage."

Linda Ham said, "he was just reiterating that he doesn't believe that there isn't any burn through so no safety of flight issue.... alright any questions on that?"

Three requests were made of Ham for imaging. All were denied.

NASA's only communication to the crew about this, "there is absolutely no concern for entry."
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 06/05/2014 07:59 pm
The above abort training scenario brought a question to mind. In the event that crew would have to bail out was there any sort of "autopilot" (for lack of a better term) that could keep the craft steady so that the person at the stick actually had time to get from the flight deck to the mid deck and out the hatch without the shuttle starting to tumble from aerodynamic forces and lack of positive input.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/05/2014 08:22 pm
The above abort training scenario brought a question to mind. In the event that crew would have to bail out was there any sort of "autopilot" (for lack of a better term) that could keep the craft steady so that the person at the stick actually had time to get from the flight deck to the mid deck and out the hatch without the shuttle starting to tumble from aerodynamic forces and lack of positive input.


Basically there was an "attitude hold" function that could be armed only when the orbiter was subsonic and it's software was operating in either MM 305 (major mode software for approach and land) or MM 603 (RTLS/Contingency Abort glided flight software). Ideally the crew would stabilize the orbiter in a wings level - stable glide with an airspeed of around 185 to 195 KEAS.  Then they would arm the so called bailout function of the DAP (digital auto pilot) by rotating the abort knob to ATO (Abort to Orbit) and pressing the abort push button.  The word "BAILOUT" would appear and start flashing on the Vertical Situation Display indicating the mode had been armed.  The crew would then ensure the control stick steering (CSS) functions were in AUTO for roll/yaw and pitch.  "BAILOUT" would remain on steady (and overbright) when the mode was engaged.  The commander and pilot would then depower the flight controller switches (i.e. power for the control sticks) to make sure the bailout auto pilot wouldn't accidentally become disengaged by an inadvertent bump of the stick(s) as they climbed out of their seats.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 06/06/2014 01:22 am
I saw a preflight photo of the STS-4 crew (Mattingly and Hartsfield) standing in front of Columbia at LC-39A. There are several other astronauts in the photo including James van Hoften, Steve Hawley, Dick Richards, Mike Smith, Kathy Sullivan and Don Williams.
Were the additional astronauts considered "support personnel" for STS-4?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/06/2014 02:30 am
I don't have direct knowledge to answer your question, but if you wiki their names you will see what their roles were.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/06/2014 05:16 pm

...  The word "BAILOUT" would appear and start flashing on the Vertical Situation Display indicating the mode had been armed...


Example attached.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/09/2014 05:02 pm
Were there any anomalies with the MEDS upgrades during a mission?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/11/2014 02:58 am
Were there any anomalies with the MEDS upgrades during a mission?

The quality was comparable to that of PASS and BFS.  So about one in-flight error every 5 years at the end of the program.  None of the errors ever threatened the mission objectives.  There was one that was noticeable on-orbit, if I remember correctly.  It was towards the beginning of the MEDS flights.

The quality was maintained even though we were adding new capabilities.  The new capabilities were being added even at the end of the program.  We had started moving more and more display generation capability from the GPCs to the MEDS processors to free up more GPC memory.  We were also starting to use the MEDS system capabilities rather than being limited to drawing pictures of the original electromechanical displays.

You can find more PASS information at: http://ntrs.nasa.gov/search.jsp?R=20110014946.  There is some information about MEDS in the paper but I don't remember any MEDS quality numbers being published.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/13/2014 05:25 pm
Thank you Andy.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/14/2014 12:08 am
Does anyone know the width of the aft SRB IEA box and the thickness of the holddown post shoes?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/16/2014 05:18 pm
We all know about the SSME's #2#3 have a "Start" position, then once up and burning before liftoff, and then move into their "Launch" configuration.

1)I was wondering if the SSME's have a certain position for MECO(Main Engine Cut Off)?
2) If there is a certain MECO gimbal position, is it similar/same to the "Start" position?

TIA
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/17/2014 01:05 pm
We all know about the SSME's #2#3 have a "Start" position, then once up and burning before liftoff, and then move into their "Launch" configuration.

1)I was wondering if the SSME's have a certain position for MECO(Main Engine Cut Off)?
2) If there is a certain MECO gimbal position, is it similar/same to the "Start" position?

TIA

At fine countdown (just before MECO), the engines would have likely been in a position where the thrust would go through the center of gravity/mass.  After MECO, the APUs would be shutdown so that the engines could not be moved.  The positions tended to drift slighty during the on-orbit phase.  Then, many days (or weeks) later, when OPS 8 checkout was done, a single APU would be powered on which would allow the engines to be moved.

Just before entry when the APUs were powered-up again, the engines could be moved again.  This was done to put them into a position where they received protection from entry heating.  Once the drag chute was installed (STS-49 first flight), then after entry heating they would be moved again for drag chute clearance.  Then following landing they could be put in "rain drain" or other positions depending upon weather and whether a ferry flight was necessary.

Remember the engines could only be moved when the APUs were on (or at KSC).  So, the answers to your questions were really no and no, although as you can imagine at nominal MECO, the positions they ended up in flight-after-flight were very similar.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/17/2014 03:25 pm
The APU's would be running at MECO.  The SSME's have a start up position so teh engine bells dont hit each other during startup, just before liftoff they are moved into "flight" position, where engines 2 and 3 come very close to each other.

I was wondering that during the MECO process as the engines are being shutdown, if the  SSME's were moved into a specific position to avoid damage?  or do the engine bells not oscillate during shutdown as they do during startup?
SSME bells bending as they are started and throttled up. Engine#1 really starts bending as the blueish flame and mach cones emerge at 0:17 seconds.   At the very end of that video you can see engines 2 and 3 approach one another though it is cut off.
https://www.youtube.com/watch?v=hDCCBgppG4s

Shown better here, but is so slow its hard to notice, if you toggle between the 2 times its quite apparent. You are looking for engine 2 and 3 to approach each other while moving from their "start" to "flight" positions.
From 4:38-4:53
https://www.youtube.com/watch?v=wlz5u1OBe_c

On this older video from STS-1 FRR from 1:07-1:20, then just before MECO of the FRR at 2:36 just before Engine#1 begins its shutdown, Engines 2 and 3 begin to gimbal apart from each other.
Looks like MECO is just as "eventful" for the bells as startup is.
https://www.youtube.com/watch?v=2zVLsPSyo30

From these observations, I'm going to assume that there is a shutdown position for SSME #2 and #3 when in space, just as there is a startup position for those engines on the pad.

I did see a video that showed a very strange position after the orbiter had landed but before APU shutdown, I didnt realzie that the SSME's could gimble so much. It looked like the bell was loose and flopping over.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/17/2014 06:38 pm
In the STS-93 mission control video where the booster and its backroom loop can be heard, what are the controllers looking for on their data screens for them to make the call "ignition" ?


Thanks


Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/17/2014 06:42 pm
We all know about the SSME's #2#3 have a "Start" position, then once up and burning before liftoff, and then move into their "Launch" configuration.

1)I was wondering if the SSME's have a certain position for MECO(Main Engine Cut Off)?
2) If there is a certain MECO gimbal position, is it similar/same to the "Start" position?

TIA

This is the information I have about SSME gimballing at MECO:

Once MECO was confirmed the external tank separation sequence began.  Various valves were opened/closed and ET umbilical plates retracted - as part of this, the SSMEs were gimballed to the "MPS dump sequence" position.

If all was well, then ET separation pyrotechnics were fired and the tank and orbiter separated.  At this point there would be ~5400 lbs of cryogenic propellant trapped in the MPS (SSMEs and their feedlines).  Two minutes after MECO both propellants were dumped (LO2 under helium pressure through the SSME nozzles, and LH2 through the fill/drain and topping valves without the aid of pressurants). The propellant dump took two minutes.  Dumping the LO2 throught the SSMEs produced a small amount of propulsion - typically 9-11 fps of delta V.

Once the MPS dump was complete, the SSMEs were gimballed to their entry stow position, with the engine nozzles moved inward (toward one another) to reduce aerodynamic heating. 

15 minutes after the MPS dump was complete, traces of remaining LO2 and LH2 were removed by venting the manifolds to space for two minutes, followed by some valve closures.

Although the there appear to be two different positions for the SSMEs in the post-MECO sequence, in practice the "MPS dump" position was set the same as the "entry stow" position (they had the possibility of being programmed differently had that ever been required).

I could not find anything about SSME gimaballing prior to MECO.  About six seconds before MECO engines were throttled back to the minimum 67% in preparation for shutdown.

Hope this helps.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 06/17/2014 07:53 pm
AFAIK, MECO is the end of MM103 and guidance is closed-loop. I don't see how there can be any predefined gimbal angles immediately prior to MECO. It would be whatever guidance is commanding to keep the vehicle's state and acceleration vectors where they need to be. Granted, this late in the ascent those values would probably be quite similar from flight-to-flight.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/17/2014 08:29 pm
AFAIK, MECO is the end of MM103 and guidance is closed-loop. I don't see how there can be any predefined gimbal angles immediately prior to MECO. It would be whatever guidance is commanding to keep the vehicle's state and acceleration vectors where they need to be. Granted, this late in the ascent those values would probably be quite similar from flight-to-flight.
I do see your point here.  Maybe the the possibility of engine bell damage isnt as great in the vacuum of space as it is at approx. sea level while sitting at the pad.  The only time that the on vehicle SSME's have a commanded MECO at such low altitudes within the atmosphere is during Flight Readiness Firing and RSLS aborts.

If the engine bells were  as "active" during on orbit MECO's as they were during on-pad MECO's during FRR's as seen in the 3rd video I posted, the risk of bell collision "appears" to be increased.

During on orbit MECO the SSME's are under 3'g throttleing.  Not sure how 3 g throttleing to MECO while on orbit would compare to 100% to MECO while on the pad as picture during STS-1 FRR video above.

thanks alk3997,  Analogman and Wolfpack for your inputs.  I didnt realize that the engines were throttled back to their minimum throttle 6 seconds before MECO.

Any other input is welcome.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/17/2014 08:41 pm
We all know about the SSME's #2#3 have a "Start" position, then once up and burning before liftoff, and then move into their "Launch" configuration.

1)I was wondering if the SSME's have a certain position for MECO(Main Engine Cut Off)?
2) If there is a certain MECO gimbal position, is it similar/same to the "Start" position?

TIA

As far as I know there is no analogous “MECO shutdown position” similar to the “start position” you mentioned in your question. 

Guidance does enter a trim (positioning) bias late in powered flight because steering is so dynamic going into MECO, but I am not aware of any specific MECO position requirement for managing the shutdown loads.

While it is true that keeping the engine bells from colliding is an important consideration, the “start position” (as it was explained to me) is really about loads management of the entire stack (i.e. twang) during the thrust buildup.  The other day I just happened to have a discussion over lunch about thrust buildup with some of the folks involved in evaluating/quantifying the “Twang” pre and post STS-1.  As it turns out, the timing of those events did not go quite as expected or planned for STS-1.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/17/2014 08:53 pm
In the STS-93 mission control video where the booster and its backroom loop can be heard, what are the controllers looking for on their data screens for them to make the call "ignition" ?


Thanks
As in the call being made here at 1:01 of this video.

https://www.youtube.com/watch?v=f2c_hEY19n4
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/17/2014 09:22 pm
In the STS-93 mission control video where the booster and its backroom loop can be heard, what are the controllers looking for on their data screens for them to make the call "ignition" ?


Thanks




It’s really a combination of cues.  Among them are the MCC (main combustion chamber) pressures, discharge pressures and temperature for all the turbopumps, valve positions, engine status word (aka feedback from the main engine controllers mounted on the engines), etc.

I've attached screen grabs of a couple of the primary engine related displays in the Mission Control Center to give you an idea of what the data looks like coming into the room.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/18/2014 04:27 am
I read through the responses and would like to add a few more points,

1) There was always a chance that an engine or even all three could shutdown during ascent at any point.  Therefore relying on moving the engines at MECO to avoid transient movement of the bells or of the bell shape to avoid impacting another bell would be a problem during an unexpected shutdown.  The natural position of the bells for performance was such that the bells would not flex into each other at shutdown.

2) We only had a few seconds of margin for reaching nominal orbit, so anything that would cause a loss of performance (such as moving the bells away from cg thrusting) would probably not have been good for getting payload into orbit.  Of course since anything impacting the bells (see STS-95) could cause a hydrogen leak, a performance impact would have been preferable to the leak.  But, it wasn't necessary.

3) Pre-launch gimbaling was done by KSC using ground LPS commands.  The end of the T-4 minute ground sequence would then leave the engines in their desired start-up position.  The launch position was then commanded by the GPCs after ignition.

All SSME movement post-landing was planned movements initiated by the crew using their onboard displays (SPEC 104 maybe? - you would think I could remember that after all those landings in the MER waiting for that sequence to complete).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/18/2014 12:10 pm
All great input M Kirk and alk3997.

I dont know where I gained the working assumption that engine bell collison was a "primary" reason for a "start" engine position that transitions into a "flight" position after ignition.  Controlling application of forces during the "twang" movement didnt even factor.  This control of forces no doubt explains the engine startup sequence and shutdown sequence that was used during FRR's. Engine 3 (Edit-#1) being furthest away from the CG of the stack would induce a greater moment of inertia than engines 1(Edit-#3) and 2 each on their own, all else equal. Light up 2 and 3 in a position vectored from the vertical thrust centerline, then light up #1, then gimbal 2 and 3 towards each other, then reverse the process upon termination of a successful FRR(Edit-Flight Readiness FIRING-not Review).  Having 2 and 3 splayed outwards slightly during "ignition" would add a measure of lateral stability.  Such a dynamic event, even though the bottom portion of the SRB's remain completeley static on their mounts.

Also makes great sense that in the event of an engine cut during entry, that the engine would be shutdown rapidly regardless of its "flight" gimbal position.

Here is the anomaly showing the drag chute door contacting engine #1 bell during main engine startup. (note:the Mission Elapsed Time was Zero, trouble before the mission officially started)
SSVEO IFA List Date:02/27/2003
STS - 95, OV - 103, Discovery ( 25 ) Time:03:56:PM
Tracking No Time Classification Documentation Subsystem
MER - 1
MMACS-01
MET: 000:00:00:00
GMT: 302:19:19
Problem FIAR
SPR
IPR 96V-0001
IFA STS-95-V-01
UA
PR
STR,MECH
Manager: Mike Porter
562-922-3887
Engineer: Jeff Goodmark
281-483-0347
Title: Loss of Drag Chute Door (ORB)
Summary: During Main Engine ignition at approximately T-5 seconds, ground-based photography showed the drag chute door detach from the Orbiter and impact the rim
of SSME bell #1 during its downward descent. In-flight evaluation of the condition led to a decision to not deploy the chute for landing. Initial postlanding inspection
showed that the drag chute remained in place undisturbed throughout the flight. Follow-on inspection to determine the condition of the chute and other components in the
drag chute compartment is in work, as is an investigation and failure analysis to determine the cause of the door failure.


All discoveries of the mind lead to further exploration, hence a further question.
Aside from the changes to the thrust buildup portion made before and the actual STS-1 mission, were there any changes made to the FRR(Edit Flight Readiness FIRING) procedures as they occured during the STS program?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/18/2014 01:42 pm
Actually we lit the engines in 3, 2, 1 sequence.  I did some of the STS-26 and STS-49 FRF flight software testing and I used the countdown as a way to remember the sequence (it still has stuck).  BTW, they were 120 mSec apart in start time.

Engine #1 was in the top position much like bowling pins are numbered.

FRF = Flight Readiness Firing - Testing the MPS/SSMEs
FRR = Flight Readiness Review - a meeting to make sure the vehicle was ready for flight

The shutdown positions were not modified for the FRF.  We simply shutdown in 1,2,3 order as if lift-off hadn't occurred (which it hadn't).
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/18/2014 03:00 pm
Thank you Mark re: ignition.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/18/2014 04:01 pm
Actually we lit the engines in 3, 2, 1 sequence.  I did some of the STS-26 and STS-49 FRF flight software testing and I used the countdown as a way to remember the sequence (it still has stuck).  BTW, they were 120 mSec apart in start time.

Engine #1 was in the top position much like bowling pins are numbered.

FRF = Flight Readiness Firing - Testing the MPS/SSMEs
FRR = Flight Readiness Review - a meeting to make sure the vehicle was ready for flight

The shutdown positions were not modified for the FRF.  We simply shutdown in 1,2,3 order as if lift-off hadn't occurred (which it hadn't).
Apologies on the FRF/FRR and SSME 1,2 3 positions confusion, inconsistent numbering at best(edit-on my part). Thanks for the corrections. 
Shuttle when viewed from the rear, wheels on the ground #1 on top, #2 bottom left, #3 bottom right, OK great.

I like your mneumonic device, the actual coundown to remember engine ignition sequence, that will help.

1)So whenever the SSME's were shutdown in a nominal fashion as a triplet, the sequence will always be engines #1, #2 and #3 no matter if its a FRF on the pad or MECO sequence on orbit?
1 b) In other words, anytime the SSME's are nominally started and shutdown as a triplet, SSME in position #1 will always have the shortest burn time of the three?

2)Comparing the STS-26 RTF FRF's for Discovery, and the STS-26 FRF for Endeavours maiden flight, from your perspective, were there any differences or improvements between the two?

Thanks again, and as always anyone with any sort of input, please feel free to contribute.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/18/2014 04:23 pm
1)So whenever the SSME's were shutdown in a nominal fashion as a triplet, the sequence will always be engines #1, #2 and #3 no matter if its a FRF on the pad or MECO sequence on orbit?
1 b) In other words, anytime the SSME's are nominally started and shutdown as a triplet, SSME in position #1 will always have the shortest burn time of the three?
Same thing as the assumption before with engine gimballing -- shutdown for an abort on the pad isn't the same thing as shutdown at the end of powered flight.  As noted before, there's a different set of conditions and criteria.  The engines were shutdown together in flight -- with the exception of STS-125, there's video of all the MECOs beginning with STS-114 from the ET camera.

The pad abort shutdown sequence changed at some point in the 80s, probably during the first RTF; originally it was 1, then 2-3 essentially at the same time.  After that, it was 1, then 2, then 3.

2)Comparing the STS-26 RTF FRF's for Discovery, and the STS-26 FRF for Endeavours maiden flight, from your perspective, were there any differences or improvements between the two?
STS-26 was a mission/flight designation -- there was no "STS-26 FRF" for Endeavour.  As alk3997 noted, Endeavour's first flight was STS-49; the FRF was conducted during that launch campaign.

There's a lot of reference material online -- for example, Mark (mkirk) has written several posts in this thread and the previous four Q&A threads.  He also wrote a nice main engine overview here:
http://www.interspacenews.com/FeatureArticle/tabid/130/Default.aspx?id=2130
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/18/2014 04:48 pm
Here's a couple of historical references from Usenet -- "flash" launch reports from Marshall (MSFC); these can be used to find others.

STS-70:
https://groups.google.com/d/topic/sci.space.shuttle/zkPiL1yiykI

For contrast to the typical uneventful powered flight, the flash report for the STS-68 pad abort:
https://groups.google.com/d/topic/sci.space.shuttle/KkRj24BWrYo
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/18/2014 05:36 pm
At a nominal MECO the shutdown enable/shutdown command pairs went to all 3 engines simo.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 06/18/2014 06:20 pm
At a nominal MECO the shutdown enable/shutdown command pairs went to all 3 engines simo.

Would make for some interesting torque moments at MECO if they didn't! :)
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 06/18/2014 07:23 pm
Does anyone know the width of the aft SRB IEA box and the thickness of the holddown post shoes?

Page 369 for the box.

http://environmental.ksc.nasa.gov/projects/documents/HAER-sts.pdf

Credit to Jim for the find.

http://forum.nasaspaceflight.com/index.php?topic=34986.0
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/18/2014 11:52 pm
As mentioned previously, all inflight planned MECOs shutdown simultaneously.  Trying to hit a specific MECO target while shutting down at different times would have been more difficult but do-able but really wasn't necessary.  Again, performance being important you would have given up performance with a staggered shutdown as well.

STS-26 FRF was done for return to flight validation while STS-49 FRF was done for the first flight of OV-105.  The only difference I remember is that prior to STS-26, the FRFs involved special flight software patches of the code.  With STS-26 we changed the data (I-Loads) instead that went into the flight software.  It was subtle from the outside but was important from a testing standpoint since we didn't modify code.

I seem to remember the total time of engine firing was slightly different but I have no data to support that memory.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/22/2014 01:30 am
1)So whenever the SSME's were shutdown in a nominal fashion as a triplet, the sequence will always be engines #1, #2 and #3 no matter if its a FRF on the pad or MECO sequence on orbit?
1 b) In other words, anytime the SSME's are nominally started and shutdown as a triplet, SSME in position #1 will always have the shortest burn time of the three?
Same thing as the assumption before with engine gimballing -- shutdown for an abort on the pad isn't the same thing as shutdown at the end of powered flight.  As noted before, there's a different set of conditions and criteria.  The engines were shutdown together in flight -- with the exception of STS-125, there's video of all the MECOs beginning with STS-114 from the ET camera.

The pad abort shutdown sequence changed at some point in the 80s, probably during the first RTF; originally it was 1, then 2-3 essentially at the same time.  After that, it was 1, then 2, then 3.

2)Comparing the STS-26 RTF FRF's for Discovery, and the STS-26 FRF for Endeavours maiden flight, from your perspective, were there any differences or improvements between the two?
STS-26 was a mission/flight designation -- there was no "STS-26 FRF" for Endeavour.  As alk3997 noted, Endeavour's first flight was STS-49; the FRF was conducted during that launch campaign.

There's a lot of reference material online -- for example, Mark (mkirk) has written several posts in this thread and the previous four Q&A threads.  He also wrote a nice main engine overview here:
http://www.interspacenews.com/FeatureArticle/tabid/130/Default.aspx?id=2130
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.

Your 2nd point, should have read STS 26 FRR and STS 49 FRR, in the manner which alk3997 had listed. Of course there was no STS-26  "ENDEAVOUR FRF", tough to do without such an orbiter in existence. My apologies.

Thanks for the discussion everyone, a nominal on orbit MECO is commanded simutaneously.  Excellent!
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/22/2014 01:34 am
At a nominal MECO the shutdown enable/shutdown command pairs went to all 3 engines simo.

Would make for some interesting torque moments at MECO if they didn't! :)
Different than a single engine out during powered flight?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/22/2014 01:41 am
At a nominal MECO the shutdown enable/shutdown command pairs went to all 3 engines simo.

Would make for some interesting torque moments at MECO if they didn't! :)
Different than a single engine out during powered flight?

Yes, because you would still have two SSMEs operating during powered flight.  With a staggered shutdown you would have had (at some point) only one engine left controlling.  There were special modes for control with a single SSME.

At nominal MECO, it would have still be controllable but again, not necessary.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/22/2014 03:47 am
Excellent, thank you very much!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/22/2014 11:24 am
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.
A pad (RSLS) abort had much more in common with a FRF than an in-flight MECO.  (Not that it's definitive, but a PAO once referred to the FRF shutdown as an 'induced RSLS abort.')

I don't remember all the discussions about pad aborts or FRFs here, either -- I search for them; that phrase -- "RSLS abort" -- would find you most of the discussions here over the years.  Either the search function for the site or something like Google to search the site:
https://www.google.com/search?q=%22RSLS+abort%22+site%3Aforum.nasaspaceflight.com

Do the same for "FRF" and you would find that I asked about the pad shutdown sequence here eight years ago, probably not for last time:
http://forum.nasaspaceflight.com/index.php?topic=2377.msg34391#msg34391

Finding phrases in threads (or words) is also much easier if you use the Print button -- then use any modern browser's Find functionality.  Over the years, Chris merged scores of splinter threads into the Shuttle Q&A series, so that's the place to start.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/22/2014 12:44 pm
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.
A pad (RSLS) abort had much more in common with a FRF than an in-flight MECO.  (Not that it's definitive, but a PAO once referred to the FRF shutdown as an 'induced RSLS abort.')

I don't remember all the discussions about pad aborts or FRFs here, either -- I search for them; that phrase -- "RSLS abort" -- would find you most of the discussions here over the years.  Either the search function for the site or something like Google to search the site:
https://www.google.com/search?q=%22RSLS+abort%22+site%3Aforum.nasaspaceflight.com

Do the same for "FRF" and you would find that I asked about the pad shutdown sequence here eight years ago, probably not for last time:
http://forum.nasaspaceflight.com/index.php?topic=2377.msg34391#msg34391

Finding phrases in threads (or words) is also much easier if you use the Print button -- then use any modern browser's Find functionality.  Over the years, Chris merged scores of splinter threads into the Shuttle Q&A series, so that's the place to start.
I hope my "pad abort not being discussed here" wasnt percieved as flippant, I wanted to ensure I wasnt missing something in my reading.  Thank you for the clarification and the new info.  I have never had good luck with the sites search engine. Your methods will help.
Right after I posted last night I noticed some of your discussion of pad aborts in the Pre RTF forums.

 I know that redundant questions irritates the vast majority of the membership.  STS is done and over, I hope that all discussion about the program is NOT relegated to having to search a database, esp. with the wealth of people who have been "hands on " with the program.  Once these people are gone, they are gone.  I feel priviledged to "pick their brains"  and "rub shoulders" with giants.  Without NSF, that would be impossible, and a reason why I support the site.  The co-mingling of space professional and enthusiast, can be frustating for the professional and daunting for the enthusiast.  I appreciate everyones patience, and lets enjoy this interaction while we can.  The time we have for 1st hand accounts and interaction is finite.  Thank you all.

A quote from JIM discussing flight and start SSME positions.
"They are spaced apart to allow for motion during  the start transient.  They might bang together if they were in the flight position."
http://forum.nasaspaceflight.com/index.php?topic=2030.525



Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/22/2014 08:39 pm
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.
A pad (RSLS) abort had much more in common with a FRF than an in-flight MECO.  (Not that it's definitive, but a PAO once referred to the FRF shutdown as an 'induced RSLS abort.')

...


Remember an RSLS abort would occur because the Redundant Set Launch Sequencer (RSLS) software, which was part of OPS 1, determined that a main engine was either "not ready", the SRBs were not ready, the thrust was not at least 90% in an SSME or the Ground Launch Sequencer (GLS) had called an abort (there were probably a few other conditions I'm not remembering).  In the later FRFs, the duration of the pad abort was equal to the time to check to see if the SRBs were ready and since they would not be, an abort was called which then shutdown the main engines ending the FRF engine test.

Hog, the one difference between a Pad Abort (RSLS Abort) and an FRF would be that you don't choose which engine shutdown first in the event of a pad abort.  So, therefore the shutdown sequence was different depending upon which engine shutdown first causing the pad abort.  If 2 went down, then 3 was shutdown next.  It 3 went down, then 2 would be shutdown next.

There was also no BFS during an FRF.  It couldn't have been engaged and wasn't needed since no flight was going to take place.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/22/2014 09:57 pm
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.
A pad (RSLS) abort had much more in common with a FRF than an in-flight MECO.  (Not that it's definitive, but a PAO once referred to the FRF shutdown as an 'induced RSLS abort.')

...


Remember an RSLS abort would occur because the Redundant Set Launch Sequencer (RSLS) software, which was part of OPS 1, determined that a main engine was either "not ready", the SRBs were not ready, the thrust was not at least 90% in an SSME or the Ground Launch Sequencer (GLS) had called an abort (there were probably a few other conditions I'm not remembering).  In the later FRFs, the duration of the pad abort was equal to the time to check to see if the SRBs were ready and since they would not be, an abort was called which then shutdown the main engines ending the FRF engine test.
I've attached the FRF commentary audio that I was thinking of here.  This is from PAO commentary by Jim Ball for the FRF done on OV-104 / Atlantis in 1985.  I left in some additional "stuff" on the front and back for a little context, but the part that I was thinking of starts about 130 seconds in.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/23/2014 03:35 am
What percentage of total ground braking did the speed brake account for? Were procedures in place for an inop speed brake upon touchdown?

Thanks
 
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/23/2014 04:07 am
An inoperative speedbrake probably meant the rudder wasn't working either.  That would have put more pressure on the wheel brakes in differential steering mode.  There was a lot of redundancy to prevent this from occurring. 

The bigger concern was that the wheel brakes would fail (see STS-51D landing).  The drag chute was put in place for that reason and the brakes were upgraded.  So, both of those would have also worked for a stuck speedbrake.

Remember that speedbrake was used to modulate energy up until 5,000 feet alt when they retracted.  So that would have caused other problems which is why so much redundancy was included in the system, much like all of the surfaces.

So, I'm not sure how you could have a problem that only affected speedbrake control post landing.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/23/2014 05:25 pm
Understood and thank you.

Still curious about how much braking the speed brake contributed to during rollout.

Dim memory cells seem to recall issues that went undiscovered for quite some time with the rudder actuators?



Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/23/2014 11:08 pm
I dont remember pad aborts being discussed, but that is another mode/method /config of shutdown.  Thanks for the info. And the links.  Almost done the previous threads, I have seen some MKirk entries.
A pad (RSLS) abort had much more in common with a FRF than an in-flight MECO.  (Not that it's definitive, but a PAO once referred to the FRF shutdown as an 'induced RSLS abort.')

...


Remember an RSLS abort would occur because the Redundant Set Launch Sequencer (RSLS) software, which was part of OPS 1, determined that a main engine was either "not ready", the SRBs were not ready, the thrust was not at least 90% in an SSME or the Ground Launch Sequencer (GLS) had called an abort (there were probably a few other conditions I'm not remembering).  In the later FRFs, the duration of the pad abort was equal to the time to check to see if the SRBs were ready and since they would not be, an abort was called which then shutdown the main engines ending the FRF engine test.

Hog, the one difference between a Pad Abort (RSLS Abort) and an FRF would be that you don't choose which engine shutdown first in the event of a pad abort.  So, therefore the shutdown sequence was different depending upon which engine shutdown first causing the pad abort.  If 2 went down, then 3 was shutdown next.  It 3 went down, then 2 would be shutdown next.

There was also no BFS during an FRF.  It couldn't have been engaged and wasn't needed since no flight was going to take place.
Thanks ALK3997 Just to illustrate some of the things that you have mentioned.
FRF Columbia before STS-1 Feb 28, 1981
https://www.youtube.com/watch?v=2Gi5qJcPOMw

FRF #1 Challenger before STS-6 Dec 18, 1982
https://www.youtube.com/watch?v=svYjxfCI8Ag
FRF #2 Challenger  before STS-6 Jan 25, 1983
https://www.youtube.com/watch?v=2u3lhrMDRUE

FRF Discovery pre-41-D June 2, 1984  Marked twang reported by PAO
https://www.youtube.com/watch?v=SpCqyLCc3HU

FRF Atlantis before STS-51-J Sept 25, 1985
https://www.youtube.com/watch?v=QZ9iDqCni3s
FRF Atlantis before RTF STS-26  Aug 10, 1988  Very frosty engine bells post shutdown
https://www.youtube.com/watch?v=opeEtE_OZNk

FRF Endeavour before STS-49 April 6, 1992  I wish they stayed on camera 170, an abort was called, and notioned that this normal for FRF's by PAO.
https://www.youtube.com/watch?v=1sxOrqJFPCo


The attached STS-68 RSLS abort shows in great detail the bells of engines 2 & 3 in their "start" positions, the gimbal towards each other in to the "flight" position, then splaying apart during shutdown.  Interesting, I'm having trouble with the shut down order though. The issue was with SSME #3 (ME2032)and required a rollback to the VAB where 3 engines were removed and 3 flight cert. engines (SN-2028, 2033 and 2026) were taken from from STS-66 Atlantis and installed onto Endeavour.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/24/2014 01:23 pm
"Interesting, I'm having trouble with the shut down order though."

That may be because you didn't attach an STS-68 RSLS abort video. The last video is the STS-49 FRF on OV-105.

I remember STS-68 RSLS abort well since I was standing to the right of the giant KSC countdown clock at the press site during the launch attempt.  That's when I found out that the giant countdown clock was not directly "wired" into the same countdown circuit as the launch control room.  The LCC countdown stopped, as it should.  The big countdown clock started counting up, which would have been a much bigger problem if that had been real.

As I said, it wasn't an issue since the big countdown clock didn't have the "real" countdown but it sure got my attention at the time.  My memories from the STS-68 RSLS abort...

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/24/2014 02:10 pm
"Interesting, I'm having trouble with the shut down order though."

That may be because you didn't attach an STS-68 RSLS abort video. The last video is the STS-49 FRF on OV-105.

I remember STS-68 RSLS abort well since I was standing to the right of the giant KSC countdown clock at the press site during the launch attempt.  That's when I found out that the giant countdown clock was not directly "wired" into the same countdown circuit as the launch control room.  The LCC countdown stopped, as it should.  The big countdown clock started counting up, which would have been a much bigger problem if that had been real.

As I said, it wasn't an issue since the big countdown clock didn't have the "real" countdown but it sure got my attention at the time.  My memories from the STS-68 RSLS abort...

Andy
For clarification, I posted 7 FRF's within the textbox itself, and attached a clip labelled STS-68 RSLS as an attachment.(below the textbox-says its been downloaded 3 times), its from a discussion here at NSF.
I just found the same video on youtube, and it appears to view a bit better that the attachment video.  Engines 2&3 gimbal in, then out again, then shutdown, then the water fire ex. comes on. This all occurs before the stack's twang comes back to the "launch" position at T-0.

https://www.youtube.com/watch?v=ekDTXQet_as

Thanks for the STS-68 RSLS memories Andy.

Paul
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/24/2014 02:26 pm
Sorry, I missed the link. 

I looked at it and that camera was looking through SSME 1 to see SSME 3.  So, it's hard to see whether it's 1 or 3 changing plume and color.  I can see SSME 2 shutting down before the final SSME (assuming it's 1) was shutdown.

I can tell you that there were no issues with flight software performance for the STS-68 pad abort.  So whatever the shutdown order was, that was what it was supposed to be.
Title: Re: Shuttle Q&A Part 5
Post by: aero on 06/24/2014 05:49 pm
I am attempting to verify my SSME engine model with known data. There is a lot of publicly available SSME data but there were also modifications to the SSME over time so it is hard to locate a completely consistent data set.

Looking at the SSME with the larger throat, throttle set at 109% I calculate (F=mdot*Isp*g) that mdot is about 517 kg/s. Researching the external tank I find that the fuel lines are sized to 491 kg/s rate of fuel flow. How is this discrepancy reconciled?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/24/2014 08:28 pm
With all of your discussion about FRF's, perhaps these pdfs of the STS-41D "Sue 14" countdown bar charts may be of historical interest.  They scanned a little better than I expected considering the pages are almost exactly 30 years old and are definitely starting to turn a little yellow.   ;)

I included both the countdown charts and the immediate post ops charts.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/25/2014 12:30 pm
I am attempting to verify my SSME engine model with known data. There is a lot of publicly available SSME data but there were also modifications to the SSME over time so it is hard to locate a completely consistent data set.

Looking at the SSME with the larger throat, throttle set at 109% I calculate (F=mdot*Isp*g) that mdot is about 517 kg/s. Researching the external tank I find that the fuel lines are sized to 491 kg/s rate of fuel flow. How is this discrepancy reconciled?
This discussed in a thread that I had read recently here at NSF, I have been unable to re-find the thread though.  I will let you know if I find it.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/26/2014 02:36 pm
I was thinking about this discussion with pad aborts.  STS-68 was the 65th Shuttle mission and was also the last pad abort in program history.  That's over half the program missions without another pad abort.   I don't think that was luck.

I believe that was the result of the SSME upgrade program that started just after that pad abort.  The Block I, Block IIA and Block II engines were designed to be more reliable (less parts) and have greater margins.  The upgraded engine controller also helped.  Looking back, the upgrades seemed to have had their desired effect.

It was also the result of the program management accepting that a pad abort was only a few seconds away from being an RTLS and no one wanted to try that abort mode out.  Program management accepted a heavier engine in exchange for greater safety.  The only other event SSME-wise that I can remember was the loss of redundancy on STS-93 due to the aging wiring problem, but that was outside of the SSMEs.

So, when we look back at these pad aborts, it's important to remember that they led to system improvements later on.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/26/2014 10:04 pm
I was thinking about this discussion with pad aborts.  STS-68 was the 65th Shuttle mission and was also the last pad abort in program history.  That's over half the program missions without another pad abort.   I don't think that was luck.

I believe that was the result of the SSME upgrade program that started just after that pad abort.  The Block I, Block IIA and Block II engines were designed to be more reliable (less parts) and have greater margins.  The upgraded engine controller also helped.  Looking back, the upgrades seemed to have had their desired effect.

It was also the result of the program management accepting that a pad abort was only a few seconds away from being an RTLS and no one wanted to try that abort mode out.  Program management accepted a heavier engine in exchange for greater safety.  The only other event SSME-wise that I can remember was the loss of redundancy on STS-93 due to the aging wiring problem, but that was outside of the SSMEs.

So, when we look back at these pad aborts, it's important to remember that they led to system improvements later on.
Good points, IIRC one of the STS-93 attempts resulted in an RSLS hold, due to high {H2} in the aft, called at T-0.07.  Once Columbia was off the ground, there was a Low LOX cut-off at the end of powered flight, coupled with the redundancy issues you mentioned.  The video of the control room loops was interesting to say the least, esp after powered flight.

Interesting that the Block 2(RS25-D) was rated for 109% for intact and 111% for contingency aborts. Not only safer, but rated for more output. while using a MCC pressure that is 270psi lower than Block 1( 104% vs. 104.5%).  Even at 111% rated power, the Block II RS-25-D's MCC pressure(3050psi@111%) is lower than the Block-1 SSME MCC pressure of 3140psi@104%.
http://www.jsc.nasa.gov/news/columbia/frr/sts-104/08_ssme.pdf

A little ditty on pad aborts.
http://www.spacesafetymagazine.com/shuttle-launch-pad-aborts/

I'd say the SSME or RS25-RS25-D program did/will do just fine. Hopefully we get to see the RS-25E.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/27/2014 04:25 am
I wouldn't put too much weight into the 109% - it was never going to be used.  There were some issues at that level.

The Low LOX cutoff was the result of openings in the SSME nozzles where repairs had been made.   So I guess that counts.  The RSLS hold (much different than an RSLS abort) was called by the LCC due to high H2 in the aft, as you said.  However, that could best be described as an MPS issue not an SSME issue.
Title: Re: Shuttle Q&A Part 5
Post by: Wayne Hale on 06/27/2014 05:53 pm
Unfortunately there is a lot of oversimplification going on in this thread which could lead to an inaccurate understanding of several complex subjects regarding the SSME and its upgrade.  The block upgrade (from Phase II+ to Block I to Block II) took almost a decade and cost over $2B.  The intention was to provide a more robust engine, not just because of some pad abort that occurred.  The newer block engine had lower ISP (by about 1.5 sec) which required an increase in thrust from 104% RPL to 104.5%RPL to make up for the performance loss.  Neither engine was certified for 109% operation but that was certainly the intent for the Block II engine.  Both nominal flight and all intact aborts used the 104.5% RPL thrust level.  During testing to certify the 109% for aborts, it was found that there were components in the main propulsion piping in the orbiter which likely could not withstand the higher vibration environment associated with that flow rate.  Cracking of the metallic components could have lead to liberation of metal pieces into the engine inlet which would not have been good at the pumps.  So efforts to certify 109% or 111% were terminated.  109% throttles were authorized only in 'do or die' contingency abort scenarious which were multiple failures deep.

Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/28/2014 05:54 am
Wayne, first thank you for your reply.  I certainly did not mean to imply the upgrades were due to the pad aborts.  What I meant instead was that we didn't have any more pad aborts once the SSME upgrades were in place.  More of a (slightly) delayed realization that upgrades may have improved engine enough that pad aborts were no longer as prevalent.

That the Block I upgrades started being phased in on STS-70 and the last pad abort was on STS-68 may be coincidence but I think the number of flights without another pad abort is statistically significant.

I apologize that my writing wasn't clear originally.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/29/2014 12:40 am
.

Thanks for the input Andy&Wayne, and corrections of applications of 109% and 111%.

Is it incorrect to refer to the SSME's and their various upgrades as:
RS-25-A
RS-25-B
RS-25-C
RS-25-D, either inside NASA or outside?

The SSME's original development and it's subsequent upgrades are examples of the great things that determined people can accomplish when the will (and money)  is there.  What a great service record.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/29/2014 11:13 am
Is it incorrect to refer to the SSME's and their various upgrades as:
RS-25-A
RS-25-B
RS-25-C
RS-25-D, either inside NASA or outside?

There does not seem to be agreement on this point.

See this post (containing a NASA slide) and a few subsequent posts:
http://forum.nasaspaceflight.com/index.php?topic=27979.msg859515#msg859515 (http://forum.nasaspaceflight.com/index.php?topic=27979.msg859515#msg859515)
Title: Re: Shuttle Q&A Part 5
Post by: aero on 06/29/2014 07:42 pm
So regarding my question of identifying a consistent set of engine parameters for the SSME in order to validate my engine model, it seems clear that using the engine at 109% thrust is not a good choice. It also seems clear that there is no specific designation for a particular engine model so how does one correctly ask the question?

Let me ask this. With all of the modifications to the SSME over its lifetime, did the nozzle diameter ever change or was it fixed for all time?

I know the engine throat diameter changed and that the nozzle expansion ratio changed and the combustion chamber pressure changed and of course the thrust and Isp changed. Did the fuel mix ratio change?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/29/2014 09:45 pm
So regarding my question of identifying a consistent set of engine parameters for the SSME in order to validate my engine model, it seems clear that using the engine at 109% thrust is not a good choice. It also seems clear that there is no specific designation for a particular engine model so how does one correctly ask the question?

Let me ask this. With all of the modifications to the SSME over its lifetime, did the nozzle diameter ever change or was it fixed for all time?

I know the engine throat diameter changed and that the nozzle expansion ratio changed and the combustion chamber pressure changed and of course the thrust and Isp changed. Did the fuel mix ratio change?
There should be clear engine parameters for each engine model: (if  these are correct)
FMOF=(engines 2005, 2006 and 2007-STS 1-5)
Phase 1
Phase II
Block 1
Block 1-A
Block II-A
Block II

from Analogmans above post.

Here is Part#1 of a 10 part series, seems detailed.
http://www.enginehistory.org/SSME/SSME1.pdf
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/29/2014 10:07 pm
So regarding my question of identifying a consistent set of engine parameters for the SSME in order to validate my engine model, it seems clear that using the engine at 109% thrust is not a good choice. It also seems clear that there is no specific designation for a particular engine model so how does one correctly ask the question?

Let me ask this. With all of the modifications to the SSME over its lifetime, did the nozzle diameter ever change or was it fixed for all time?

I know the engine throat diameter changed and that the nozzle expansion ratio changed and the combustion chamber pressure changed and of course the thrust and Isp changed. Did the fuel mix ratio change?
There should be clear engine parameters for each engine model: (if  these are correct)
FMOF=(engines 2005, 2006 and 2007-STS 1-5)
Phase 1
Phase II
Block 1
Block 1-A
Block II-A
Block II

from Analogmans above post.

Here is Part#1 of a 10 part series, seems detailed.
http://www.enginehistory.org/SSME/SSME1.pdf

The paper pre-dates the Block I upgrade by a few years.  So I don't think that holds much water from a designation standpoint.

I'm not an engine guy so we just referred to them as SSMEs and then phase II, Block I, IIA and II when discussing the type of SSME.
Title: Re: Shuttle Q&A Part 5
Post by: aero on 06/29/2014 10:46 pm
Quote
Here is Part#1 of a 10 part series, seems detailed.
http://www.enginehistory.org/SSME/SSME1.pdf

A very interesting read. I did find that external tank pressurization takes 0.7 lb/s H2 and 1.2 lbs/s O2. This may (?) reduce the chamber mass flow by 1.8 lb/s or 0.8165 kg/s. A small but real amount. ~0.16%
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/30/2014 03:37 am

I know the engine throat diameter changed and that the nozzle expansion ratio changed and the combustion chamber pressure changed and of course the thrust and Isp changed. Did the fuel mix ratio change?

Yes the controller (i.e. commanded) mixture ratio changed over time.  I know it changed from 6.0262 to 6.011 in the mid 80s because I had to change a simulation model to match the real world change.  I am not as sure of this next bit but I think it was changed during the second return to flight as well.  Maybe other times too.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 06/30/2014 03:57 am

A very interesting read. I did find that external tank pressurization takes 0.7 lb/s H2 and 1.2 lbs/s O2. This may (?) reduce the chamber mass flow by 1.8 lb/s or 0.8165 kg/s. A small but real amount. ~0.16%

Pressurization flows varied with power level and the O2 flow also varied with the position of the GO2 repress valves....and yes, these flows didn't go overboard, which is one of the reasons that the overboard mixture ratio was different than the controller mixture ratio.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/02/2014 06:57 pm
Hello all.

I was interesting to know if the dog-leg maneuver Atlantis underwent during ascent on STS-36 to reach 62 deg of inclination had any effect on the abort modes? Would it have been possible to perform a TAL, for example? What about a RTLS?

Also, how much payload performance Atlantis lost in doing the dog-leg?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 07/02/2014 09:02 pm
Hello all.

I was interesting to know if the dog-leg maneuver Atlantis underwent during ascent on STS-36 to reach 62 deg of inclination had any effect on the abort modes? Would it have been possible to perform a TAL, for example? What about a RTLS?

Also, how much payload performance Atlantis lost in doing the dog-leg?

Thanks very much

Davide

You can figure an RTLS due to a failure prior to SRB sep would be the same as any other flight at the maximum northern azimuth from KSC, since the dogleg is performed after staging. Beyond that, it would depend on the flight dynamics, which we don't know.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/02/2014 09:15 pm
The nominal performance loss per degree of inclination was around 625 lb per degree.  TAL was still viable because the vehicle was still going over Europe. 
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 07/02/2014 11:22 pm
How much payload mass to ISS was lost on Shuttle launches due to that inclination? My understanding was that the majority of those payloads were limited by CG constraints rather than overall mass. I don't know how many missions were actually up against mass limits, though.

Another question - for Shuttle ascent control/performance, the weight and mass distribution was required, but how precise was this figure? Presumably they didn't weigh every astronaut's breakfast the morning before - but maybe they did and I didn't recall reading about it.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/03/2014 01:22 am
How much payload mass to ISS was lost on Shuttle launches due to that inclination? My understanding was that the majority of those payloads were limited by CG constraints rather than overall mass. I don't know how many missions were actually up against mass limits, though.

Another question - for Shuttle ascent control/performance, the weight and mass distribution was required, but how precise was this figure? Presumably they didn't weigh every astronaut's breakfast the morning before - but maybe they did and I didn't recall reading about it.

No, it was mass limited and not CG constraints.  The payloads were set aft in the payload bay for CG considerations.

(51.6-285)x625 lb is ?  I thought my post above self explanatory.

450lb was allocated for each crew member which includes the person, food, clothing ,suit and personal items.  I don't remember if the seat is included.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/03/2014 07:51 am
What was the reason for STS-39 and STS-44 being unclassified DoD missions?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/03/2014 01:19 pm
What was the reason for STS-39 and STS-44 being unclassified DoD missions?


DSP (STS-44) was an unclassified program.  All DOD missions were classified so that NRO missions could be hidden among them.  Since there were suppose to be no more (or one more) DOD missions on the shuttle, there was no sense in spending the money on security to keep up the shell game. 

STS-39 was a science mission, it did not have any operational spacecraft and it was towards the end of the DOD missions.  There was no need to classify for its own sake.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 07/04/2014 09:34 pm
Hi all,
i am looking for the title of a presentation that must be somewhere in L2 but I have been unable to locate it. It is either refering to STS-125 or -400 and includes the attached chart comparing orbiter orientation to LOCV risk (aptly named: "Micrometeoroid/Orbital Debris (MMOD) Loss of Crew & Vehicle (LOVC) Risk vs. Space Shuttle Orientation"). I would greatly appreciate it if someone could point me in the right direction.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 07/04/2014 10:46 pm
Hi all,
i am looking for the title of a presentation that must be somewhere in L2 but I have been unable to locate it. It is either refering to STS-125 or -400 and includes the attached chart comparing orbiter orientation to LOCV risk (aptly named: "Micrometeoroid/Orbital Debris (MMOD) Loss of Crew & Vehicle (LOVC) Risk vs. Space Shuttle Orientation"). I would greatly appreciate it if someone could point me in the right direction.

This is from an MMT/OPO (Mission Management Team/Orbiter Project Office) presentation from flight day 6 of the STS-125 mission "Potential MMOD Damage on Panel 11R".

See page 16 of either of the presentations linked in the first two posts of this L2 thread:
http://forum.nasaspaceflight.com/index.php?topic=17081.0 (http://forum.nasaspaceflight.com/index.php?topic=17081.0)
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 07/05/2014 07:26 am

This is from an MMT/OPO (Mission Management Team/Orbiter Project Office) presentation from flight day 6 of the STS-125 mission "Potential MMOD Damage on Panel 11R".

See page 16 of either of the presentations linked in the first two posts of this L2 thread:
http://forum.nasaspaceflight.com/index.php?topic=17081.0 (http://forum.nasaspaceflight.com/index.php?topic=17081.0)

thanks a lot. looks like my searching skills need some serious training.
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 07/05/2014 09:07 pm
Watching video of some pre-Challenger launches I noticed the test director using the callsign "LTD" instead of "NTD". Was this designation used for all pre-Challenger launches? Or was it changed away from NTD in anticipation of SLC-6 launches where the test director wouldn't actually be a "NASA Test Director" and instead be an Air Force officer?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/05/2014 10:22 pm
Watching video of some pre-Challenger launches I noticed the test director using the callsign "LTD" instead of "NTD". Was this designation used for all pre-Challenger launches?
Not sure about when it began to be used, but 'L' as in Lockheed (Lockheed Space Operations Company):
http://spaceflight.nasa.gov/shuttle/reference/shutref/sts/background.html

Quote
Rockwell's Launch Operations, part of the Space Transportation Systems Division, was under contract to NASA's Kennedy Space Center for turnaround, processing, prelaunch testing, and launch and recovery operations from STS-1 through the STS-11 mission.

On Oct. 1, 1983, the Lockheed Space Operations Co. was awarded the Space Shuttle processing contract at KSC for turnaround processing, prelaunch testing, and launch and recovery operations.

(My emphasis.)  This was prior to the post Cold War wave of mergers when Lockheed merged with Martin Marietta.  There are some online references to "Lockheed Test Director" (within the context of Shuttle).

Also:
http://forum.nasaspaceflight.com/index.php?topic=5410.msg86281#msg86281
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/06/2014 03:07 am
Watching video of some pre-Challenger launches I noticed the test director using the callsign "LTD" instead of "NTD". Was this designation used for all pre-Challenger launches? Or was it changed away from NTD in anticipation of SLC-6 launches where the test director wouldn't actually be a "NASA Test Director" and instead be an Air Force officer?


They got rid of the position in a few years.  There was no reason to have an integration position that took status from OTC, TBC, STM, SRO, PTC, Safety, etc and then report to the NTD.

The USAF position was AFTD.  Which also existed on the east coast for shuttle payloads and USAF ELV launches.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 07/08/2014 08:21 pm
At some point during the post Columbia stand-down, there was a news item regarding an upside-down installed actuator in the rudder/speed brake of Discovery. Is there any documentation about this and/or the work to replace it available?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 07/08/2014 09:13 pm
At some point during the post Columbia stand-down, there was a news item regarding an upside-down installed actuator in the rudder/speed brake of Discovery. Is there any documentation about this and/or the work to replace it available?


It's discussed in "Space Shuttle Program Action 11" in the Implementation Plan, which can be found at this link:

http://www.nasa.gov/pdf/58541main_RTF_rev2.pdf
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 07/09/2014 06:23 pm
It's discussed in "Space Shuttle Program Action 11" in the Implementation Plan, which can be found at this link:

http://www.nasa.gov/pdf/58541main_RTF_rev2.pdf

thanks a bunch!
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/10/2014 10:10 am
Hello all.

Question about the Malarkey Milkshake performed during STS-39. I'm reading from the mission press information that the OMS firings for plum observations by the SPAS/IBSS were done with only one engine and that this was the first time that a single OMS engine firing was performed.

I'd like to know why they decided to do the firing with only one engine? Was only for fuel savings or for what else?

Thanks very much

Davide
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/10/2014 01:46 pm
Hello all.

Question about the Malarkey Milkshake performed during STS-39. I'm reading from the mission press information that the OMS firings for plum observations by the SPAS/IBSS were done with only one engine and that this was the first time that a single OMS engine firing was performed.

I'd like to know why they decided to do the firing with only one engine? Was only for fuel savings or for what else?

Thanks very much

Davide

Only a plume was needed and not thrust. 
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 07/18/2014 06:05 pm
When I was at the Atlantis exhibit a few months ago I noticed the "No Step" markings on the elevons.  This would imply that, like an airliner, walking on the other parts of the wing was OK.  Was it normal for technicians to walk on the orbiter wings for normal repairs and maintenance? 

Also, if I recall, Columbia and Challenger had tiles on part of the wing surface.  Were technicians allowed to walk on these?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/18/2014 06:53 pm
When I was at the Atlantis exhibit a few months ago I noticed the "No Step" markings on the elevons.  This would imply that, like an airliner, walking on the other parts of the wing was OK.  Was it normal for technicians to walk on the orbiter wings for normal repairs and maintenance? 

Also, if I recall, Columbia and Challenger had tiles on part of the wing surface.  Were technicians allowed to walk on these?

Yes and no tiles on top of wing.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 07/20/2014 09:19 pm
The elevon flipper doors have the No Step markings. 
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 07/23/2014 10:18 am
When the USAF was developing SLC-6 for Space Shuttle launches there were concerns that gaseous  hydrogen could fill up the main engine ducts provoking a detonation during lift off, possibly damaging the shuttle.

I don't understand this issue. Why a shuttle on SLC-6 would have this problem? Couldn't they use burnoff preigniters as on the launch pad at the KSC?

Thanks

Davide
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/23/2014 10:28 am
When the USAF was developing SLC-6 for Space Shuttle launches there were concerns that gaseous  hydrogen could fill up the main engine ducts provoking a detonation during lift off, possibly damaging the shuttle.

I don't understand this issue. Why a shuttle on SLC-6 would have this problem? Couldn't they use burnoff preigniters as on the launch pad at the KSC?

Thanks

Davide
They did. The H2 burn-off ignitors only combust GH2 that is expelled at engine ignition. However there is GH2 that is expelled during the countdown which at SLC-6 would have accumulated in the closed exhaust duct. KSC's LC-39 pads have an open flame trench which blows the GH2 away preventing dangerous build ups.
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 07/28/2014 09:10 pm
Where are the SRB casings now?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/28/2014 10:04 pm
Where are the SRB casings now?

Utah, at the ATK plant
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 07/29/2014 02:04 pm
What is this feed line next to the  LO2 gaseous  press line on the ET for STS-1?  http://images.ksc.nasa.gov/photos/1981/high/KSC-381C-2366.03.jpg

It's not on the tank for STS-7, which is the same SWET as that for STS-1. http://www.nasa.gov/images/content/2163main_sts7_et_hi.jpg
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/29/2014 02:11 pm
What is this feed line next to the  LO2 gaseous  press line on the ET for STS-1?  http://images.ksc.nasa.gov/photos/1981/high/KSC-381C-2366.03.jpg

It's not on the tank for STS-7, which is the same SWET as that for STS-1. http://www.nasa.gov/images/content/2163main_sts7_et_hi.jpg

anti-geyser line, which was removed for STS-4
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 07/29/2014 03:54 pm
What is this feed line next to the  LO2 gaseous  press line on the ET for STS-1?  http://images.ksc.nasa.gov/photos/1981/high/KSC-381C-2366.03.jpg

It's not on the tank for STS-7, which is the same SWET as that for STS-1. http://www.nasa.gov/images/content/2163main_sts7_et_hi.jpg

Wow, nice old pics, very interesting. (http://scaleworld.forenworld.net/images/smilies/zustimm.gif) I could use similar shots of Challenger's STS-6. (http://www.raumfahrer.net/forum/smf/Smileys/yabb/cool.gif)

(http://scaleworld.forenworld.net/images/smilies/hallo.gif)
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 07/29/2014 05:44 pm
I see. Is there a diagram of it to show how far down the tank it went and if it connected to the orbiter? I'm building STS-1 in 1/72 scale.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 07/29/2014 07:42 pm
Maybe this will help you further here.

This is the thread of Mike (egt95) in ARC Forums, who has built an impressive stack of Columbia STS-1 (http://www.arcforums.com/forums/air/index.php?showtopic=273498&st=0), however 1:144, but he did a really fantastic job. (http://www.raumfahrer.net/forum/smf/Smileys/yabb/cool.gif)

(http://i1363.photobucket.com/albums/r709/egt95/ColumbiaSTS-1217768x1024_zpse5e75a2d.jpg)

(http://scaleworld.forenworld.net/images/smilies/hallo.gif)
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 07/30/2014 10:21 pm
I've seen that thread. :)  Though in the photos I linked, it looks like the anti-geyser line is thicker than the two pressurization lines are.

I wish there was a diagram of this line and how it fit with the first 3 ETs.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 07/31/2014 10:58 pm
This link may be helpful...

http://www.axmpaperspacescalemodels.com/REFERENCE.html#.U9rKC5tuNpM
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/02/2014 04:51 pm
What is this feed line next to the  LO2 gaseous  press line on the ET for STS-1?  http://images.ksc.nasa.gov/photos/1981/high/KSC-381C-2366.03.jpg

It's not on the tank for STS-7, which is the same SWET as that for STS-1. http://www.nasa.gov/images/content/2163main_sts7_et_hi.jpg

anti-geyser line, which was removed for STS-4

Can you describe the functionality of the anti-geyser line?  Asked another way, what kind of geyser did they fear may have been created?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/02/2014 05:46 pm

Can you describe the functionality of the anti-geyser line?  Asked another way, what kind of geyser did they fear may have been created?

To allow for recirculation of the LO2 in feed line, so it does not geyser since it was a narrow tube.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 08/02/2014 09:39 pm
Are there any diagrams of this line on the ET and photos of the first 3 external tanks with this line?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/02/2014 11:17 pm

Can you describe the functionality of the anti-geyser line?  Asked another way, what kind of geyser did they fear may have been created?


I've attached a pdf of a systems brief about the geyser phenomenon that will probably over answer your question.

Can't seem to find any good diagrams of the original tanks, best bet is probably to google early images of the first missions and see if you can get a good image of the lines from those pics.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/03/2014 04:50 pm

Can you describe the functionality of the anti-geyser line?  Asked another way, what kind of geyser did they fear may have been created?


I've attached a pdf of a systems brief about the geyser phenomenon that will probably over answer your question.

Can't seem to find any good diagrams of the original tanks, best bet is probably to google early images of the first missions and see if you can get a good image of the lines from those pics.

Mark Kirkman

Thanks for that PDF.  Now I understand what the geyser phenomenon is all about.  It's always nice to learn about things that you don't think about if you aren't a rocket designer like the thermal effects on the LO2 feedline.
Title: Re: Shuttle Q&A Part 5
Post by: OV135 on 08/03/2014 05:31 pm
I can't open the pdf. Could someone get the diagrams and photos from it please?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/03/2014 10:00 pm
Does anyone know the average max Q experienced by the stack during ascent? I thinking the average of max Q calculated over all the 135 launches.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/04/2014 01:55 pm
Does anyone know the average max Q experienced by the stack during ascent? I thinking the average of max Q calculated over all the 135 launches.

It's around 700 lbs/sq ft. Are you looking for more precision than that?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/04/2014 02:54 pm

Does anyone know the average max Q experienced by the stack during ascent? I thinking the average of max Q calculated over all the 135 launches.

It's around 700 lbs/sq ft. Are you looking for more precision than that?
No, that's precise enough, thanks.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/04/2014 03:04 pm
The old public revision of the "Green Book" data (published in 1999 or 2000) has a pretty large Max-Q data set, though the Max-Q data only runs about 80 launches or so:
http://www.spaceflight.nasa.gov/shuttle/reference/green/ascorb.pdf

(Updates for some of these data sets were posted on L2, but not sure about this one...I'd be interested in the Max-Q numbers after the "Performance Enhancements" that were done for Freedom/ISS after ASRM was cancelled.)

Edit: my bad, didn't look hard enough at the oft-cited Missions Summary Book (http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf); the Max-Q data is in there (including what I would take to be (P)redicted vs. (A)ctual numbers).
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 08/04/2014 04:35 pm
What is this feed line next to the  LO2 gaseous  press line on the ET for STS-1?  http://images.ksc.nasa.gov/photos/1981/high/KSC-381C-2366.03.jpg

It's not on the tank for STS-7, which is the same SWET as that for STS-1. http://www.nasa.gov/images/content/2163main_sts7_et_hi.jpg

anti-geyser line, which was removed for STS-4

Can you describe the functionality of the anti-geyser line?  Asked another way, what kind of geyser did they fear may have been created?
Great question.
Ive always had a mental picture of a geyser scenario, but I've never understood how the anti-gyser system functions. 
It's also interesting to read about the effects of "water/fluid hammer". This can be very destructive.
The " hot slug" of LOX during tanking is also interesting, hard for the "layperson" to grasp as we are dealing with temps. of approx 89° Kelvin/-183°C/-297ºF.  Good on the teams for figuring that issue out. 
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/05/2014 04:45 pm
Does anyone know the dry mass of the Standard Casing SRMs used on STS-1, 2, 3, 4, 5, 8 and 9? The same for the Medium Weight Casing SRMs used on STS-41B, 41C, STS-51G and STS-51F.
Title: Re: Shuttle Q&A Part 5
Post by: Pipcard on 08/06/2014 06:04 am
How did the tail cone (for approach and landing tests) manage to fit on to the space shuttle when the body flap would get in the way of the cone's bottom wall?

image illustrating my perplexion (http://i.imgur.com/MpnNQwm.png)

The reason I'm asking this is because I'm making a 3D model of the cancelled Japanese space shuttle "HOPE-X", but I'm not sure on how to make the launch vehicle's payload adapter with that body flap in the way.
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 08/06/2014 06:17 am
How did the tail cone (for approach and landing tests) manage to fit on to the space shuttle when the body flap would get in the way of the cone's bottom wall?

image illustrating my perplexion (http://i.imgur.com/MpnNQwm.png)

The reason I'm asking this is because I'm making a 3D model of the cancelled Japanese space shuttle "HOPE-X", but I'm not sure on how to make the launch vehicle's payload adapter with that body flap in the way.

This image should help!
Title: Re: Shuttle Q&A Part 5
Post by: Pipcard on 08/06/2014 06:22 am
But how come there isn't an indent at the bottom of the tail cone in the image I posted?
Title: Re: Shuttle Q&A Part 5
Post by: AS-503 on 08/06/2014 06:25 am
Take a closer look. The red lines are not correct. They should extend from the cone to the top of the body flap (not the bottom as the red lines indicate).
You can see in the image I posted that there are extra fairings and pieces not shown in your photo.
For example, the sides of the body flap are covered by fairings not shown in your photo.

I have re-attached your image with corrections.
The green box shows the area where the flap recesses (note the shape of the cone that matches the flap's rear edge).
Also, the green lines are drawn to show actual interface instead of the red lines.
Title: Re: Shuttle Q&A Part 5
Post by: Helodriver on 08/06/2014 06:49 am
The body flap formed part of the bottom surface of the tailcone when fully installed. 

http://media-cache-ec0.pinimg.com/736x/1b/34/91/1b3491fb4b7c99f25a8716123cd07151.jpg (http://media-cache-ec0.pinimg.com/736x/1b/34/91/1b3491fb4b7c99f25a8716123cd07151.jpg)
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/06/2014 10:38 am
But how come there isn't an indent at the bottom of the tail cone in the image I posted?
There is, but the way the image is framed or zoomed makes it more difficult to see it or gain much perspective.  Is that the whole image (sure looks like it's from the MDD at Dryden)?

Link to a shot of buildup at KSC that shows it better (small thumbnail attached):
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=59472
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 08/07/2014 03:24 pm
I can't open the pdf. Could someone get the diagrams and photos from it please?

This is all that was in there diagram wise.  No photos, just this (which is after removal of the line) and a bunch of graphs.
Title: Re: Shuttle Q&A Part 5
Post by: Pipcard on 08/08/2014 08:07 am
But how come there isn't an indent at the bottom of the tail cone in the image I posted?
There is, but the way the image is framed or zoomed makes it more difficult to see it or gain much perspective.  Is that the whole image (sure looks like it's from the MDD at Dryden)?

Link to a shot of buildup at KSC that shows it better (small thumbnail attached):
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=59472
I cropped it from a Wikipedia picture (I think) found via a Google image search. Sorry for not paying attention to its full context.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/08/2014 03:29 pm
But how come there isn't an indent at the bottom of the tail cone in the image I posted?
There is, but the way the image is framed or zoomed makes it more difficult to see it or gain much perspective.  Is that the whole image (sure looks like it's from the MDD at Dryden)?

Link to a shot of buildup at KSC that shows it better (small thumbnail attached):
http://mediaarchive.ksc.nasa.gov/detail.cfm?mediaid=59472
I cropped it from a Wikipedia picture (I think) found via a Google image search. Sorry for not paying attention to its full context.
No problem.  If you're interested, we have a few videos shot just prior to the end of the program out at Dryden (now Armstrong) on L2 (and also some footage courtesy of NASA).
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 08/13/2014 03:02 am
If Challenger had not been lost, would it have been able to participate in ISS assembly and resupply?  Or would it's weight have prevented it from most ISS flights like Columbia?  I have read that Challenger could carry 2500 lbs more that Columbia, but still far less than the rest of the fleet. 

And why was Columbia originally planned to fly STS-118 to ISS?  A lighter payload?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/14/2014 08:27 pm
If Challenger had not been lost, would it have been able to participate in ISS assembly and resupply?  Or would it's weight have prevented it from most ISS flights like Columbia?  I have read that Challenger could carry 2500 lbs more that Columbia, but still far less than the rest of the fleet. 

Would certainly have been used to build/service a Space Station Freedom @ 28.5 deg inclination.

I think the events of 51-L and the decision to build ISS are too far removed from one another in time to answer without a LOT of speculation.
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 08/14/2014 08:38 pm
If Challenger had not been lost, would it have been able to participate in ISS assembly and resupply?  Or would it's weight have prevented it from most ISS flights like Columbia?  I have read that Challenger could carry 2500 lbs more that Columbia, but still far less than the rest of the fleet. 

Would certainly have been used to build/service a Space Station Freedom @ 28.5 deg inclination.

I think the events of 51-L and the decision to build ISS are too far removed from one another in time to answer without a LOT of speculation.

I think I was mainly wonder how or if Challenger could have been used in place of Atlantis or Discovery at ISS if another orbiter had been used for 51-L and one of those was lost instead.  Could a fleet of Challenger, Atlantis and Endeavour have serviced ISS as it is currently built?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2014 09:04 pm

I think I was mainly wonder how or if Challenger could have been used in place of Atlantis or Discovery at ISS if another orbiter had been used for 51-L and one of those was lost instead.  Could a fleet of Challenger, Atlantis and Endeavour have serviced ISS as it is currently built?

Yes, there would have been no impact to the ISS.  Challenger was going to carry the Centaur G'.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/14/2014 09:05 pm
I have read that Challenger could carry 2500 lbs more that Columbia, but still far less than the rest of the fleet. 

And why was Columbia originally planned to fly STS-118 to ISS?  A lighter payload?
It was more that that,  It was only 100's less that the other orbiters.   116 & 118 were light payloads.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/21/2014 06:38 pm
Does anyone know the dimensions of the SSOR and EVA antennas in the PLB?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 09/02/2014 11:03 pm
Hypothetical question, if a shuttle was carrying spacehab/lab and there was a leak in the cabin, could hab/lab be sealed off for the crew to use and remain inside as a safety shelter?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 09/02/2014 11:16 pm
<terse mode>

No.

</terse mode>

A lot of work was done during STS-80 to cover contingency EVAs with the airlock hatch jammed.  Much analysis was done on "side hatch EVA" but since the cabin avionics needed air cooling, IIRC it would have required a total and non recoverable powerdown to take the cabin to vacuum.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/03/2014 01:21 pm
The lab/hab is not independent of the crew cabin live support systems.  The basic Spacehab modules only had heat removal, all the remaining items: H2O removal, CO2 removal, O2 makeup, pressure control, etc were done by the crew cabin.  Spacehab RDM added H2O removal and maybe C02.  Spacelab had CO2 & H2O removal and pressure control.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 09/27/2014 08:35 pm
Something totally different and ancient shuttle history.
The attached Image is taken from the infamous 1979 Bond movie "Moonraker". It shows an Orbiter getting lifted around the VAB. It looks rather unfinished to me with no visible markings, no TPS and missing flipper doors on the wings.

Columbia arrived at KSC on Mar. 24 and Enterprise on Apr. 10, 1979. Given the fact that Columbia at that time was having TPS issues and Enterprise was mounted to an ET and SRBs in April to be rolled out to the pad on May 1, 1979, it could only have been Enterprise to stand in for a Moonraker in the film (which was released on June 26, 1979). Can somebody confirm that and/or maybe shed some light on why the flipper doors were removed prior to stacking?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2014 08:42 pm
Something totally different and ancient shuttle history.
The attached Image is taken from the infamous 1979 Bond movie "Moonraker". It shows an Orbiter getting lifted around the VAB. It looks rather unfinished to me with no visible markings, no TPS and missing flipper doors on the wings.

Because it was a model.  No real shuttles were used.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 09/27/2014 08:58 pm
Because it was a model.  No real shuttles were used.

Ic! Must have read too much into the Wikipedia remark that they actually shot some scenes inside the VAB. Thanks for straighting me out.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/27/2014 08:59 pm
They might have facility shots that were real
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/27/2014 09:07 pm
And that's not the VAB either. I'm pretty familiar with the layout of the VAB High Bays as well as the transfer aisle and that screengrab doesn't match any of them. Also the orbiter sling is wrong. It only has the two side beams and is missing the aft sling structure which would be used to rotate the orbiter to and from vertical.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 09/28/2014 08:35 pm
And that's not the VAB either. I'm pretty familiar with the layout of the VAB High Bays as well as the transfer aisle and that screengrab doesn't match any of them. Also the orbiter sling is wrong. It only has the two side beams and is missing the aft sling structure which would be used to rotate the orbiter to and from vertical.
Being rotated from from vertical would be a rarity wouldnt it?  Any instances where that occured operationally?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/28/2014 09:30 pm
Orbiter rotations occurred in the VAB transfer aisle. They still need the aft sling structure to rotate the orbiter to vertical.

Destacks occurred several times even post-Columbia.
Title: Re: Shuttle Q&A Part 5
Post by: shuttlelegs on 09/29/2014 12:28 am
I believe the model is a 1/4 scale of the shuttle used in ground vibration tests at Downey in building 288.
You can just see the SRBs on the left hand side of the picture. Enterprise is seen behind Bond in the next scene in the movie. It has Moonraker on a banner on its side . This must have been in the VAB.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/30/2014 08:35 pm
Does anyone know the weight of the various parachutes of the SRB Recovery System (Pilot, drogue and mains)?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 09/30/2014 10:20 pm
Does anyone know the weight of the various parachutes of the SRB Recovery System (Pilot, drogue and mains)?
2180lbs. or 990kg for the mains

From Wiki
Each of the 136 ft (41 m) diameter, 20-degree conical ribbon parachutes have a design load of approximately 195,000 lb (88,000 kg) and each weighs approximately 2,180 lb (990 kg). These parachutes are the largest that have ever been used — both in deployed size and load weight


But this is NASA data:

For Steel cased SRB's launched from KSC
Orignal 1981 Pilot Chute (11.5ft diam.)
design load 14,500lbs
pack weight was 41.5lbs

Original 1981 Drogue Chute (54ft dia.)
design load 270,000lbs
pack Weight was 1250 lbs

Original 1981 Main Pack Chute, (small diameter of 115ft)
design load 173,300lbs
Pack Weight Each(1 of 3) was 1708 lbs

1985 Main Chutes (large diameter 136ft)
design load 150,000lbs
pack weight was 2160lbs


Filament Wound Case (FWC) SRB's for use from SLC-6

1981 Pilot chute (10ftdia.)
Design Load 32,500 lb
Pack Weight 72 lb

1981 design Drogue Chute (52.5ft dia.)
Design Load 375,000 lbs
Pack Weight 1250lbs

Both the FWC pilot  and FWC drogue  parachutes were overtested and
ready for operatiomd use. The drogue overtest produced a maximum load
of 471,500 lb at a deployment dynamic pressure of 687 psf.

At the same time the 136 ft main parachute was being developed, NASA
was preparing to fly the Space Shuttle from Vandenberg Air Force Base
(VAFB) for polar orbit missions. Filament wound case (FWC) SRBs were
developed for the higher energy requirements of these missions. Although
the FWC boosters were lighter, they had a more aft center gravity location.
The net effect was to cause more nozzle-first reentry attitudes and higher
reentry dynamic pressures at parachute deployment altitudes. This more
severe environment required the development of new pilot and drogue
parachute designs.

Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 10/02/2014 10:45 am
I'd be surprised if nobody has asked this question before, but since this is now a 5 part thread with lots of posts, it's not easy to check.

What is the theoretical maximum altitude of the Shuttle? Obviously we have the Hubble's altitude of just over 600 km as an maximum that was actually reached during the STS program, but is there anywhere that details any possibilities higher than that?

Obviously the question marks are how much payload is in the bay to begin with, and how much dV the OMS has for circularisation and deorbit. So, let's go with an empty payload bay, a Hubble-ish weight in the payload bay, and something half way between. Any ideas?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/02/2014 11:00 am
I'd be surprised if nobody has asked this question before, but since this is now a 5 part thread with lots of posts, it's not easy to check.

What is the theoretical maximum altitude of the Shuttle? Obviously we have the Hubble's altitude of just over 600 km as an maximum that was actually reached during the STS program, but is there anywhere that details any possibilities higher than that?

Obviously the question marks are how much payload is in the bay to begin with, and how much dV the OMS has for circularisation and deorbit. So, let's go with an empty payload bay, a Hubble-ish weight in the payload bay, and something half way between. Any ideas?

100lb per nautical mile was the rule of thumb for trades.
Title: Re: Shuttle Q&A Part 5
Post by: elmarko on 10/02/2014 12:22 pm
100lb per nautical mile was the rule of thumb for trades.

Thanks Jim. Presumably that only works until the OMS tanks are full. Which would be reached first? A full OMS tank or an empty cargo bay?

Hubble weighed 24,000 ish lbs, and a quick Google reveals the maximum payload weight to be 60,000+ lbs
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/02/2014 01:45 pm

Thanks Jim. Presumably that only works until the OMS tanks are full. Which would be reached first? A full OMS tank or an empty cargo bay?

No, the rule of thumb took at that into account if I recall.
Title: Re: Shuttle Q&A Part 5
Post by: Kim Keller on 10/02/2014 01:54 pm
I'd be surprised if nobody has asked this question before, but since this is now a 5 part thread with lots of posts, it's not easy to check.

What is the theoretical maximum altitude of the Shuttle? Obviously we have the Hubble's altitude of just over 600 km as an maximum that was actually reached during the STS program, but is there anywhere that details any possibilities higher than that?

Obviously the question marks are how much payload is in the bay to begin with, and how much dV the OMS has for circularisation and deorbit. So, let's go with an empty payload bay, a Hubble-ish weight in the payload bay, and something half way between. Any ideas?

I dimly recall that the TPS could only tolerate a descent from 600 miles altitude, due to increased velocity at entry interface.
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/13/2014 12:36 pm
An OMS payload bay kit was planned which would have greatly increased the available delta-v.  When I was working on the SMS in the early 80s there were scars in the models related to this kit.  It never flew though.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/13/2014 08:55 pm
An OMS payload bay kit was planned which would have greatly increased the available delta-v.  When I was working on the SMS in the early 80s there were scars in the models related to this kit.  It never flew though.

Direct insertion eliminated the need for the kits.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/14/2014 09:42 pm
Does somebody happen to be familiar with the XO coordinates of the FWD/aft Orb/ET attachment points?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/14/2014 10:18 pm
Does somebody happen to be familiar with the XO coordinates of the FWD/aft Orb/ET attachment points?

From the SLWT bible drawings:

Forward attachment XO = 338.045
Aft attachments     XO = 1317    YO ±96.50

(these are orbiter referenced, i.e. not XT values)

http://forum.nasaspaceflight.com/index.php?topic=14350.msg317169#msg317169 (http://forum.nasaspaceflight.com/index.php?topic=14350.msg317169#msg317169)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/14/2014 10:44 pm
Does somebody happen to be familiar with the XO coordinates of the FWD/aft Orb/ET attachment points?

From the SLWT bible drawings:

Forward attachment XO = 338.045
Aft attachments     XO = 1317    YO ±96.50

(these are orbiter referenced, i.e. not XT values)

http://forum.nasaspaceflight.com/index.php?topic=14350.msg317169#msg317169 (http://forum.nasaspaceflight.com/index.php?topic=14350.msg317169#msg317169)
Thanks. Do you happen to know the length of the nosecap and the NLG doors?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/19/2014 01:34 am
Now I need to know the height/width of the mid and aft vent doors.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 10/21/2014 07:12 pm
I just noticed in video #3 on the Discovery press day L2 videos, that there is a few moments where the Ascent Abort selector is visible.(pause at 14:15 of the video)
L2 video:  http://forum.nasaspaceflight.com/downloads/l2/Discovery_Media_Event_Pt3.wmv


The Abort Mode selection order on the dial of Discovery as of 2011 with her glass cockpit is "RTLS/OFF/ATO/TAL".

A picture taken during STS-51F Challenger, where you can se that Abort To Orbit(ATO) is selected. On Challenger the Abort selector's sequence is "OFF/RTLS/TAL-AOA/ATO".

Were these changes made during the "glass cockpit" upgrading?

What was the rational for the order of the Abort Modes on the dials?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/21/2014 10:59 pm
I remember this change being made (late 90s?).  IIRC, the idea was that after the change you could abort RTLS by just pushing the button without having to move the switch.    It's been a long time but there may have been rationale about the possibility of moving the switch too far and selecting an undesirable abort mode during the RTLS window.  I'll see if I can dig anything up, seems like there was more to this story.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 10/22/2014 02:42 am
I just noticed in video #3 on the Discovery press day L2 videos, that there is a few moments where the Ascent Abort selector is visible.(pause at 14:15 of the video)
L2 video:  http://forum.nasaspaceflight.com/downloads/l2/Discovery_Media_Event_Pt3.wmv

The Abort Mode selection order on the dial of Discovery as of 2011 with her glass cockpit is "RTLS/OFF/ATO/TAL".

A picture taken during STS-51F Challenger, where you can se that Abort To Orbit(ATO) is selected. On Challenger the Abort selector's sequence is "OFF/RTLS/TAL-AOA/ATO".

Were these changes made during the "glass cockpit" upgrading?

What was the rational for the order of the Abort Modes on the dials?

The glass cockpit upgrade did not touch the abort switch since the glass cockpit upgrade was initially transparent to the GPC flight software.  The GPC flight software initially did not know if it had a MEDS (glass) cockpit or a MCDS (original) cockpit on the other side.

As you can imagine moving what each position meant on the abort selector would feedback into the flight software.  I'm trying to remember how the rotary was wired.   But, the reason for the change was to prevent inadvertently selecting an RTLS instead of a TAL and, I think, also to make bailout less likely to be accidentally pressed (pressing my memory there).
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 10/22/2014 03:04 am
That sounds more like it.  Left for RTLS, right for TAL, harder to make a mistake.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 10/22/2014 01:32 pm
Thank you gents.
 
The following pics are courtesy of NASA and show the Abort Selector of the 4 orbiters(I couldnt find a verified Columbia cockpit photo) You will need to zoom in to see the Abort Selector in tehse pics.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 10/31/2014 05:00 pm
The engines of STS-93 Columbia.  STS-93 was the last time that these SSME's were flown.
SSME#2019/Powerhead#2020 (19th flight) Engine Position#1 (Center)
SSME#2031/Powerhead#2028 (17th flight) Engine Position#2 (Left)
SSME#2012/Powerhead#2025 (12th flight) Engine Position#3 (Right)

Since all 3 SSME's flown on STS-93 were of Block II design, the SSME Advanced Health Management System(AHMS) was not part of STS-93.

AHMS "Phase In"
•1st Flight - 1 AHMS controller in monitor-only mode, 2 Block II controllers
• Accomplished on STS -116 on 12/9/2006

• 2nd Flight - 1 AHMS controller in redline-active mode, 1 AHMS controller in
monitor-only mode
• Accomplished on STS -117 on 6/8/2007

• 3rd Flight - 3 AHMS controllers in redline-active mode
• Accomplished on STS -118 on 8/8/2007

Pratt & Whitney Overview and Advanced Health Management Program (circa 2006)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080023322.pdf

From Wayne Hale's blog titled "STS-93 We dont need anymore of those" http://waynehale.wordpress.com/2014/10/26/sts-93-we-dont-need-any-more-of-those/

"about a minute after launch, the booster officer and his team recognized the fact that the right engine turbine temperatures and speeds were higher than normal. They correctly identified that this might be due to a nozzle leak, but there was another potential anomaly that also had the same signature. If the oxidizer pump started to lose ‘efficiency’ (blades rubbing, pump clogging, etc.) it would look the same. As the SSME controller commanded mixture ratio changes to keep up with the loss of efficiency on the pump, the turbines would reach their temp limit and the engine would have to throttle down to prevent a shutdown: this was called ‘thrust limiting’. Until the SSME went into thrust limiting, the Booster team could not tell the difference between an oxidizer turbine/pump efficiency loss and a nozzle leak. The instrumentation just wasn’t precise enough to know what was going on. Jon and his team correctly identified that the engine was running off nominally (‘off tags’) but could not quantify it. Later on, when the FDO asked him, the Booster officer had to report that none of the engines were ‘suspect’. All these terms were precisely defined in the flight rules and had specific actions for the flight controllers and crew to take to maximize safety. But this leak was too small for any of that."


My question, would having AHMS installed on STS=93 Columbia helped to make the Booster Officer/Team to diagnose the SSME issues even quicker and/or with more certainty?
Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 11/01/2014 12:35 am
I don't believe so.  I think AHMS mostly added vibration shutdown, not a factor in STS-93.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 11/06/2014 01:57 pm
One of the calls made to the crew during ascent was something called "droop". What does this mean?

Thanks


edit- Also mentioned here- http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940017386.pdf
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/06/2014 02:59 pm
One of the calls made to the crew during ascent was something called "droop". What does this mean?

Thanks


edit- Also mentioned here- http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940017386.pdf
If you have L2, there's a great reference for Shuttle ascents/aborts (flight procedures handbook, circa OI-30 / 2005):
http://forum.nasaspaceflight.com/index.php?topic=3466.0

It's detailed in Section 2.5.2; ascent boundary calls in 4.3.3.2.

This is also covered in the public workbooks for intact and contingency aborts posted on the flight data file landing page:
http://www.nasa.gov/centers/johnson/news/flightdatafiles/index.html

Specific files:
http://www.nasa.gov/centers/johnson/pdf/383447main_intact_ascent_aborts_workbook_21002.pdf
http://www.nasa.gov/centers/johnson/pdf/383441main_contingency_aborts_21007_31007.pdf
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 11/06/2014 10:32 pm
Thank you.

Let me rephrase;

What does "droop" mean in this context?

Title: Re: Shuttle Q&A Part 5
Post by: Specifically-Impulsive on 11/07/2014 12:08 am
THE DROOP BOUNDARY REPRESENTS THE EARLIEST TIME AFTER
WHICH A TWO-SSME-OUT TRAJECTORY WILL NOT FALL BELOW
265,000 FEET AND TAL GUIDANCE WILL CONVERGE TO THE
SELECTED/REDESIGNATED SITE’S MECO TARGETS PRIOR TO
THE DESIRED MECO TIME.

You can read all about it from the source:
http://www.jsc.nasa.gov/news/columbia/fr_generic.pdf, flight rule A4-56
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 11/12/2014 10:31 am
Was fitting the SRB segments for rail delivery at all a driving force on Shuttle's cargo bay size?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/12/2014 01:30 pm
Was fitting the SRB segments for rail delivery at all a driving force on Shuttle's cargo bay size?

Unrelated.  The payload bay size was decided before booster selection.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 11/13/2014 09:11 pm
Was fitting the SRB segments for rail delivery at all a driving force on Shuttle's cargo bay size?

Unrelated.  The payload bay size was decided before booster selection.
Thanks Jim.  +1
Title: Re: Shuttle Q&A Part 5
Post by: cautionjump on 11/26/2014 12:15 am
Sorry if this isnt the best place to put this question!

I found this laptop on ebay.

http://www.ebay.com/itm/NASA-space-shuttle-flight-laptop-computer-most-likely-flown-/281509383099?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=lkzJOH8z9fgnB3GAnKPx1TohgHg%253D&orig_cvip=true&rt=nc

Dont think there is any documentation, but Im curious if there would be a way to distinguish it from being flown or used on the ground for testing. The yellow and blue "USA INV" stickers look unusual as none of the laptops on board had then, and the earliest seems to date to 2001. Any idea what the stickers denote?

Thanks for any advice or knowledge!
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/07/2014 11:17 am
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 12/08/2014 02:07 pm
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
You could save as much or as little as you desired as you would be designing an entirely different system than STS.
Title: Re: Shuttle Q&A Part 5
Post by: extide on 12/11/2014 04:54 pm
What is the name of those really really big gimballed cameras they used to use to track shuttle launches? I can't remember what they're called and it's driving me nuts!
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/11/2014 05:10 pm
What is the name of those really really big gimballed cameras they used to use to track shuttle launches? I can't remember what they're called and it's driving me nuts!
DOAMS (Distant Object Attitude Measurement System): http://www2.l-3com.com/ios/products/r_doams.htm
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/11/2014 05:15 pm
ROTI, IGOR, IFLOTS, DOAMS, MOTS, ATOTS?

DOAMS was in Cocoa Beach and IGOR is at PAAFB.  DOAMS no longer exists.
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 12/11/2014 05:50 pm
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
You could save as much or as little as you desired as you would be designing an entirely different system than STS.

If you did this but still wanted the same crew cabin size, payload bay size and capabilities and had the engines attached to the orbiter like they were for STS, wouldn't it become enormous if you tried to design that inside of a capsule shape?  I would think that it might actually end up heavier than the orbiter.

I'm certainly no expert, but I don't think that a 60 foot long payload bay capable of returning cargo lends itself well to a capsule design.  I would guess to eliminate the wings, you'd probably have to go with a powered re-entry system like SpaceX plans for the reusable Falcon 2nd stage since it would be roughly shaped like a fuel tank to be structurally efficient.
Title: Re: Shuttle Q&A Part 5
Post by: extide on 12/11/2014 06:17 pm
Yeah, DOAMS was the one I was thinking of. Thanks! Some of those other ones are pretty cool too.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/11/2014 06:49 pm
Yeah, DOAMS was the one I was thinking of. Thanks! Some of those other ones are pretty cool too.

There were only two.  Cocoa Beach and Playalinda Beach
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/16/2014 09:26 am
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
You could save as much or as little as you desired as you would be designing an entirely different system than STS.

If you did this but still wanted the same crew cabin size, payload bay size and capabilities and had the engines attached to the orbiter like they were for STS, wouldn't it become enormous if you tried to design that inside of a capsule shape?  I would think that it might actually end up heavier than the orbiter.

I'm certainly no expert, but I don't think that a 60 foot long payload bay capable of returning cargo lends itself well to a capsule design.  I would guess to eliminate the wings, you'd probably have to go with a powered re-entry system like SpaceX plans for the reusable Falcon 2nd stage since it would be roughly shaped like a fuel tank to be structurally efficient.

Just makes me wondering if the Crewcabin was to reenter like a capsule and the rest was to burn up (cargo and engine part). Could this be actually cheaper and carry more to orbit then to carry those costly wings which are only used for landing. And therefore flights be cheaper as there would be much less maintanance?
Title: Re: Shuttle Q&A Part 5
Post by: spacecane on 12/16/2014 11:57 am
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
You could save as much or as little as you desired as you would be designing an entirely different system than STS.

If you did this but still wanted the same crew cabin size, payload bay size and capabilities and had the engines attached to the orbiter like they were for STS, wouldn't it become enormous if you tried to design that inside of a capsule shape?  I would think that it might actually end up heavier than the orbiter.

I'm certainly no expert, but I don't think that a 60 foot long payload bay capable of returning cargo lends itself well to a capsule design.  I would guess to eliminate the wings, you'd probably have to go with a powered re-entry system like SpaceX plans for the reusable Falcon 2nd stage since it would be roughly shaped like a fuel tank to be structurally efficient.

Just makes me wondering if the Crewcabin was to reenter like a capsule and the rest was to burn up (cargo and engine part). Could this be actually cheaper and carry more to orbit then to carry those costly wings which are only used for landing. And therefore flights be cheaper as there would be much less maintanance?

Then you may as well have just kept flying the Apollo program.  The whole point of STS was reusability and the ability to return satellites from space.  There is also weight associated with the reentry system of a capsule (parachutes and things).  The service module also needs to go into orbit even if it isn't returned intact.

The wings were the size that they were because of the size of the payload bay and the desired cross range due to the single polar orbit missions envisioned by the Department of Defense.

To really get an idea of the weight penalty of wings vs. a capsule, you'd have to have the weights of a winged and non-winged spacecraft designed for the same mission.  Something like Dreamchaser vs. CST-100 or Dragon 2.  All of those are pretty much designed to take a crew of 6 to the ISS and back and don't have integrated/reusable engines.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 12/16/2014 01:39 pm
How much weight could be saved on the orbiter (thus extra weight to be carried in to space) if it had a wingless design and re-entered like apollo
You could save as much or as little as you desired as you would be designing an entirely different system than STS.

If you did this but still wanted the same crew cabin size, payload bay size and capabilities and had the engines attached to the orbiter like they were for STS, wouldn't it become enormous if you tried to design that inside of a capsule shape?  I would think that it might actually end up heavier than the orbiter.

I'm certainly no expert, but I don't think that a 60 foot long payload bay capable of returning cargo lends itself well to a capsule design.  I would guess to eliminate the wings, you'd probably have to go with a powered re-entry system like SpaceX plans for the reusable Falcon 2nd stage since it would be roughly shaped like a fuel tank to be structurally efficient.

Just makes me wondering if the Crewcabin was to reenter like a capsule and the rest was to burn up (cargo and engine part). Could this be actually cheaper and carry more to orbit then to carry those costly wings which are only used for landing. And therefore flights be cheaper as there would be much less maintanance?



...Then you may as well have just kept flying the Apollo program...

What a moneysaver that would have been :-)
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 01/15/2015 09:21 pm
On STS-134's liftoff, I saw that the External Tank Camera was a bit too bright for small details to be noted in, for example, STS-133's ET Cam footage. What went wrong with the ET Cam before the STS-134 launch?
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 01/15/2015 10:05 pm
I recall that the camera settings had to be adjusted beforehand. STS-134 was scrubbed with APU heater issues, and finally launched around two weeks later, if I read the timestamps correctly. I don't know if they reset the camera settings for the new lighting conditions - access to intertank would have been required, I believe.
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 01/16/2015 01:38 pm
If possible, can someone acquire the ET Cam footage from STS-134 and make enhancements to reduce the brightness like the STS-133 example I talker about?
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 01/16/2015 03:02 pm
I played around a bit in VLC. The background (Earth, clouds) is a total white-out for the most part. Are you trying to match the brightness of the shuttle itself in STS-133? I couldn't get a good result for that either.
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 01/16/2015 03:13 pm
Yup. I needed to someday change the settings to make the STS-134 ET Cam footage look like all others in daytime.
Title: Re: Shuttle Q&A Part 5
Post by: sivodave on 01/17/2015 10:22 pm
Hello all.

Questions about the Power Extension Package. In particular: Why was PEP discarded? And when did the idea die out?

Thanks very much and have a good weekend.

Davide

Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/18/2015 01:10 am
SSME question.

If I look straight into an SSME all the way to the center, I see a gold colored section (part of the nozzle prior to the regenerative part?) and a silver colored section with a lot of holes in it behind that.  Is that the main combustion chamber and the injectors?  I know this is somehow ITAR protected so I'm not sure I can post a picture I took at Udvar Hazy even though this area was sometimes visible even in the RPM photos.
Title: Re: Shuttle Q&A Part 5
Post by: joncz on 01/18/2015 01:38 pm
Similar photo and description at https://blogs.nasa.gov/J2X/2014/01/24/inside-the-leo-doghouse-light-my-fire/
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/18/2015 01:59 pm
Similar photo and description at https://blogs.nasa.gov/J2X/2014/01/24/inside-the-leo-doghouse-light-my-fire/


Ah...excellent, thanks!  Must not be an ITAR problem then.  :)
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/19/2015 02:35 pm
I watching a Wayne Hale presentation at MIT and he was talking about when faulty data was uploaded into the computers locating the Orbiter somewhere in the Andromeda galaxy or similar, and the Shuttle began spinning at 3 second thus losing comms for 10 minutes. 

Mr Hale does state the mission number, but it is garbled.  Can anyone confirm which STS mission this was?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/20/2015 04:29 pm
It was STS-32.

On FD 9 during crew sleep, INCO uploaded some bad state vector into the Inertial Navigation System which resulted in loss of attitude control.  Had the RCS been "on the big jets" there may not have been enough RCS fuel left for safe re-entry.  Thankfully the RCS was configured for the "small jets".
The loss of attitude control resulted in a 10 minute loss.
Mr Hale explains the cascade of human errors involved in this incident.

STS-32 incident discussion starts at 1:35:00
http://videolectures.net/mit16885f05_hale_lec18/
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/27/2015 10:17 pm
I'm studying STS-93 and a question has come up that I can't answer.  From Wayne Hale's blog post:

Regarding the hydrogen leak from the nozzle, "Since the chamber pressure dropped slightly due to the loss of fuel for the fire in the main combustion chamber, the SSME controller commanded more oxygen be sent to the MCC. "

What I don't understand is why the chamber pressure dropped.  If the engine is running fuel-rich, all the oxygen is being consumed even if there's a slight loss of fuel flow.  So, the same chemical reaction should be happening, albeit with a slightly lower mass flow and a slightly lower mixture ratio.  So why did the main combustion chamber pressure drop?

What am I missing here?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 01/28/2015 02:20 pm
I'm studying STS-93 and a question has come up that I can't answer.  From Wayne Hale's blog post:

Regarding the hydrogen leak from the nozzle, "Since the chamber pressure dropped slightly due to the loss of fuel for the fire in the main combustion chamber, the SSME controller commanded more oxygen be sent to the MCC. "

What I don't understand is why the chamber pressure dropped.  If the engine is running fuel-rich, all the oxygen is being consumed even if there's a slight loss of fuel flow.  So, the same chemical reaction should be happening, albeit with a slightly lower mass flow and a slightly lower mixture ratio.  So why did the main combustion chamber pressure drop?

What am I missing here?

The fuel rich condition means excess hydrogen injected into the chamber doesn't react with the oxygen, but it certainly gets heated and expands against the chamber walls. Take that away means less chamber pressure, doesn't it?
Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/28/2015 02:24 pm
I'm studying STS-93 and a question has come up that I can't answer.  From Wayne Hale's blog post:

Regarding the hydrogen leak from the nozzle, "Since the chamber pressure dropped slightly due to the loss of fuel for the fire in the main combustion chamber, the SSME controller commanded more oxygen be sent to the MCC. "

What I don't understand is why the chamber pressure dropped.  If the engine is running fuel-rich, all the oxygen is being consumed even if there's a slight loss of fuel flow.  So, the same chemical reaction should be happening, albeit with a slightly lower mass flow and a slightly lower mixture ratio.  So why did the main combustion chamber pressure drop?

What am I missing here?

The fuel rich condition means excess hydrogen injected into the chamber doesn't react with the oxygen, but it certainly gets heated and expands against the chamber walls. Take that away means less chamber pressure, doesn't it?

I suppose, a little, but the difference would be quite small, I would think.

I'm now thinking that maybe the difference is less fuel to the turbines, making them run slower and thus pump less fuel and oxygen to the combustion chamber.  But I don't know if that's true either!
Title: Re: Shuttle Q&A Part 5
Post by: MikeEndeavor23 on 01/29/2015 05:34 am

    Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?

     Was it done after their long maintenance periods?  Also, why the transition from black to white?  Was it for looks or did it serve a specific function?

      MikeEndeavor23
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 02/02/2015 11:55 am

    Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?

     Was it done after their long maintenance periods?  Also, why the transition from black to white?  Was it for looks or did it serve a specific function?

      MikeEndeavor23
I shouldn't do this, but here is a Wiki article on STS's Thermal Protection System(TPS).
http://en.wikipedia.org/wiki/Space_Shuttle_thermal_protection_system
Consider the source, but it should answer most of your questions.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/10/2015 09:25 am
Does anyone know where the floor is in the External Airlock? I mean the floor of the crew accessible area of the airlock. Is it the bottom of the cylindrical section or the bottom on conical section?

Edit:
Also, outer diameters of the ODS vestibule and the Structural Ring?
Title: Re: Shuttle Q&A Part 5
Post by: yatpay on 02/10/2015 06:55 pm
While reading the book "Comm Check..." about STS-107, I read that there was a 1/10 inch gap behind the top of the leading edges of the wings to allow pressure equalization within the wings. I was just curious if anyone could tell me more about that or any other similar open spaces on the vehicle. How did they keep water or insects out? My first thought was maybe it was covered similar to the RCS ports but I couldn't recall seeing covers falling off during launch.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/10/2015 07:01 pm
While reading the book "Comm Check..." about STS-107, I read that there was a 1/10 inch gap behind the top of the leading edges of the wings to allow pressure equalization within the wings. I was just curious if anyone could tell me more about that or any other similar open spaces on the vehicle. How did they keep water or insects out? My first thought was maybe it was covered similar to the RCS ports but I couldn't recall seeing covers falling off during launch.

http://spaceflight.nasa.gov/shuttle/reference/shutref/purge/
Title: Re: Shuttle Q&A Part 5
Post by: yatpay on 02/10/2015 07:02 pm
While reading the book "Comm Check..." about STS-107, I read that there was a 1/10 inch gap behind the top of the leading edges of the wings to allow pressure equalization within the wings. I was just curious if anyone could tell me more about that or any other similar open spaces on the vehicle. How did they keep water or insects out? My first thought was maybe it was covered similar to the RCS ports but I couldn't recall seeing covers falling off during launch.

http://spaceflight.nasa.gov/shuttle/reference/shutref/purge/

Oh perfect! Thanks very much!
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 02/18/2015 02:50 pm
The Filament Wound Case (FWC) designed for STS/Vandenberg polar flights was roughly 25,000lbs lighter than the 1/2" steel cases for lower inclination KSC launches.

1)Approx. how much extra payload mass would 25,000lbs decrease in booster weight allow for? (not worrying about the effects of inclination in this question-IIRC Jim stating its about 625lb/º and approx. 100lbs/nautical mile for altitude)

2) What effects does weight savings on the ET have on net payload capability?

3) Is weight savings on the Orbiter on a 1 to 1 ratio (a pound saved from orbiter weight, is a pound of added payload)?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 02/18/2015 03:01 pm
The Filament Wound Case (FWC) designed for STS/Vandenberg polar flights was roughly 25,000lbs lighter than the 1/2" steel cases for lower inclination KSC launches.

1)Approx. how much extra payload mass would 25,000lbs decrease in booster weight allow for? (not worrying about the effects of inclination in this question-IIRC Jim stating its about 625lb/º and approx. 100lbs/nautical mile for altitude)

The decrease in FWC mass was expected at the time to increase Shuttle lift capability by 4,600 lb.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/18/2015 04:42 pm
ET savings were almost 1 for 1 and orbiter was one for one
Title: Re: Shuttle Q&A Part 5
Post by: yatpay on 02/25/2015 07:08 pm
Was there ever an EVA to the rear of the orbiter? No real reason for asking, just curious if it ever came up and why.
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 02/26/2015 02:27 pm
1)Approx. how much extra payload mass would 25,000lbs decrease in booster weight allow for?

There's typically an exchange ratio between booster-stage weight reduction and LEO payload gain of very roughly ten.  You could plug some numbers into John Schilling's Launch Vehicle Performance Calculator (http://www.silverbirdastronautics.com/LVperform.html) to get a more accurate estimate.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/26/2015 02:32 pm
Was there ever an EVA to the rear of the orbiter? No real reason to asking, just curious if it ever came up and why.

No
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 02/26/2015 07:23 pm

    Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?

     Was it done after their long maintenance periods?  Also, why the transition from black to white?  Was it for looks or did it serve a specific function?

      MikeEndeavor23

Are you asking about the black wing chines seen only on Columbia?

If so, do a search here for "Columbia wing chines".  It has been discussed a lot. This is the best answer I remember:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg860524#msg860524
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 02/26/2015 08:52 pm

    Anyone remember when NASA made the decision to change the back stripe on the edge of the Shuttle wings to white squares?

     Was it done after their long maintenance periods?  Also, why the transition from black to white?  Was it for looks or did it serve a specific function?

      MikeEndeavor23

Are you asking about the black wing chines seen only on Columbia?

If so, do a search here for "Columbia wing chines".  It has been discussed a lot. This is the best answer I remember:
http://forum.nasaspaceflight.com/index.php?topic=17437.msg860524#msg860524
The question was vague...another wild guess that might, possibly, maybe sorta fit "back stripe" and "white squares" is the change to the elevon flipper doors.  Screen of a STS-109 FRR slide attached (that being the first flight for Columbia after her last OMDP), which notes the material change and TPS change.  I believe this was one of the "orbiter diet" parts of the Performance Enhancement "program" for a 51.6-degree inclined ISS.


Reference for the first screenshot:
http://www.jsc.nasa.gov/news/columbia/frr/sts-109/11_vehiclebu.pdf

Added a slide from "Proceedings of Symposium Commemorating the Space Shuttle Program" held at Georgia Tech in June 2011:
http://www.ae.gatech.edu/sites/default/files/pdf_files/ProceedingsWEBred.pdf
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 02/26/2015 11:52 pm
That last slide explains several changes to the TPS I have noticed while researching for models.  I often wondered why the blankets had a smaller area on the wing on later flights.

And yes, your answer fits the question better. 
Title: Re: Shuttle Q&A Part 5
Post by: MikeEndeavor23 on 03/03/2015 04:12 am

  Hi everyone!

     Thanks for the answer to my "black stripe" vers "white tiles" question.  I guess it was indeed the change to the flipper doors. Although I really had no idea that they were called "flipper doors."

        This leads to the question of what "flipper doors" were for....

        ;)

        MikeEndeavor23
Title: Re: Shuttle Q&A Part 5
Post by: SWGlassPit on 03/03/2015 02:08 pm
Jim will probably chime in and correct me if I'm wrong, but I believe they served to cover the elevon hinges.
Title: Re: Shuttle Q&A Part 5
Post by: joema on 03/03/2015 08:00 pm
Was there ever an EVA to the rear of the orbiter? No real reason for asking, just curious if it ever came up and why.

There was never one in actuality but every flight was prepared for a contingency EVA procedure to manually close the umbilical propellant doors beneath the orbiter aft end. If these somehow failed to close or the talkback indicator indicated they weren't latched, this would be critical during reentry.

There was specific ground hardware called the ET Door Trainer so crews could practice the procedure. They may have carried a tool to assist with this possibility -- I don't remember.

Obviously this was considered a low probability event, but not so low it was not considered or practiced. Since there was no easy way to get there, I think the procedure involved some makeshift methods such as throwing a laundry bag with a rope over the elevons. I'm sure someone will correct me if wrong.

This issue came up during the Columbia Accident Investigation. During the mission some felt an EVA to the payload bay to look at the wing leading edge was too risky, yet each flight had trained crew prepared for the much higher risk EVA underneath the orbiter aft end.
Title: Re: Shuttle Q&A Part 5
Post by: brahmanknight on 03/05/2015 03:44 pm
When SSMEs were replaced on the launch pad, was there a complete enclosure to protect the process from the elements, or was it open?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/05/2015 07:10 pm
When SSMEs were replaced on the launch pad, was there a complete enclosure to protect the process from the elements, or was it open?
It was (more or less) open -- similar to the component replacement on one of the engines at the pad during the last launch campaign.

(For something more extraordinary, there was the time a rudder/speed brake PDU was replaced at the pad.)
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/05/2015 07:26 pm
When SSMEs were replaced on the launch pad, was there a complete enclosure to protect the process from the elements, or was it open?
(For something more extraordinary, there was the time a rudder/speed brake PDU was replaced at the pad.)
Yes, STS-101: http://spaceflightnow.com/shuttle/sts101/000412repairplan/index.html
Title: Re: Shuttle Q&A Part 5
Post by: the_other_Doug on 03/06/2015 12:44 am
Hmmm...  I always thought that the Shuttle engines were pulled off an orbiter after a mission (as were the OMS pods), and taken off to be refurbished.  Since the engines usually took longer to go through their refurbishment process than the orbiter itself, it was common to see a different set of three engines re-installed onto the orbiter (though the OMS pods usually stayed with the same vehicles).  The engines, as I understood it, ended up flying on all of the orbiters at one time or another, right?

That said, when did they ever replace engines while the Shuttle was on the pad?  Didn't they normally only do that in the OPF?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/06/2015 01:21 am
Hmmm...  I always thought that the Shuttle engines were pulled off an orbiter after a mission (as were the OMS pods), and taken off to be refurbished.
That was the norm.  Issues would come up occasionally when Shuttle vehicles were out at the pad or in the VAB.  (IIRC, the engines were temporarily removed from the STS-117 vehicle in the VAB while the tank was getting all those hail repairs...link (http://forum.nasaspaceflight.com/index.php?topic=6938.msg133290#msg133290).)

That said, when did they ever replace engines while the Shuttle was on the pad?
Less and less over the time the program was flying...an obvious one would be STS-6 due to all the issues discovered around the two FRFs (there are some pictures in a historical thread starting around here (http://forum.nasaspaceflight.com/index.php?topic=33194.msg1115447#msg1115447); not sure when the last occurrence was but as an example the engines for the STS-49 vehicle were replaced at the pad after Endeavour's FRF.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 03/11/2015 11:52 am
Some questions regarding the sims (specifically launch & entry).

Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/11/2015 12:40 pm
Some questions regarding the sims (specifically launch & entry).

Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?

SAIL would have had everything the same. Not sure about the motion based simulator.
Title: Re: Shuttle Q&A Part 5
Post by: Malderi on 03/11/2015 08:57 pm
Some questions regarding the sims (specifically launch & entry).

Did the sims have the same GPC's and BFS that the orbiters had or were their functions simulated?

SAIL would have had everything the same. Not sure about the motion based simulator.

Motion base had GPCs and BFS running flight software, and indeed some software problems were occasionally found in that way (a few that required certain types of astronaut action, primarily.) I don't know exact details of these, but I know a few were found during training sims.

Edit: I believe the GPCs in the motion base  were engineering units and not flight units, but the software was unmodified as I recall (full redundant set etc). I may be wrong about that though.

Not sure about the fixed base sim. SAIL definitely did (as avionics integration was the entire point of SAIL). There were more Shuttle "cockpits" at JSC than many recognized, I attempted to count once and arrived at around a dozen. FBS, MBS, SAIL, 4 SSTs, JAEL, FFT, 2 front cabins in Building 9 SVMF that I forget the name of (neither they nor FFT had any avionics)... probably forgetting a few.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 03/12/2015 02:14 pm
From a Shuttle flight software testing standpoint, the most used simulator hasn't been mentioned.  That was the SPF with teh Flight Equipment Interface Devices (FEIDs).  Each FEID had up to 3 flight-level GPCs.  I think there were 5 FEIDs.  This was the primary testing facility for development of flight software.  It was usually only after the flight software was released that the software would be tested in SAIL and before flights.

SAIL (OV-095), of course, had 5 GPCs with the exact same length of wiring as the flight orbiters.

SMS used SIDs which had 5 flight-like GPCs for each of the three bases.  They had to have 5 GPCs since many of the sim training sessions involved practicing GPC failure scenarios.

I believe KSC had real GPCs for payload testing in their facility (I'm trying to remember the name of the testing lab).

As time marched on, more simulations appeared but many of those didn't use actual flight software.
Title: Re: Shuttle Q&A Part 5
Post by: Hoonte on 03/17/2015 09:15 pm
Can anyone tell me where the ''big hole'' is for? Cables?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 03/17/2015 09:26 pm
Can anyone tell me where the ''big hole'' is for? Cables?
That's where the star trackers were.
Title: Re: Shuttle Q&A Part 5
Post by: roma847 on 03/18/2015 06:53 am
Hi Hoonte,

this is the opening for the so-called Star trackers (http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/avionics/gnc/startracker.html). The star tracker system is part of the orbiter's navigation system.

(http://www.infovisual.info/05/img_en/096%20Space%20shuttle.jpg) (http://www.infovisual.info/05/096_en.html)

(http://home.comcast.net/~djpearson/rndz/f4.jpg) (http://home.comcast.net/~djpearson/rndz/rndzpaper.html)

I hope this helps. (http://www.kartonist.de/images/Smile/n060.gif)

(http://scaleworld.forenworld.net/images/smilies/hallo.gif)
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/18/2015 10:19 am
Another drawing showing the left-hand side of the orbiter
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 04/23/2015 10:37 pm
Where may I find every single flight deck camera-during-liftoff video? I've seen the following missions that had this particular camera along with ICOM audio:

STS-8
STS-65
STS-78
STS-83
STS-87
STS-92
STS-110
STS-112
STS-113
STS-121
STS-118
STS-122
STS-123
STS-130
STS-133
STS-135

Any other missions but those I listed I have not yet seen.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/01/2015 06:25 pm
Does anyone have any info/history on ME-2050.  It was last flown on STS-120 Discovery along with ME-2048(which flew again on 4 more STS missions #'s 124, 119, 129, 133) and ME-2058 which also flew 4 more missions (124, 119, 129, 133)coupled with ME 2048.

Seeing that ME-2048 and ME-2058 flewout the remainder of the SSP as a pair, what happened to ME-2050 that caused it to be pulled from service back after its last mission of STS-120 in 2007?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/01/2015 08:21 pm
Does anyone have any info/history on ME-2050.  It was last flown on STS-120 Discovery along with ME-2048(which flew again on 4 more STS missions #'s 124, 119, 129, 133) and ME-2058 which also flew 4 more missions (124, 119, 129, 133)coupled with ME 2048.

Seeing that ME-2048 and ME-2058 flewout the remainder of the SSP as a pair, what happened to ME-2050 that caused it to be pulled from service back after its last mission of STS-120 in 2007?

There is an SSME Schedule on L2 dated August 31, 2007 that shows Engine Assignments from STS-118 thru' STS-127.

E2050 is allocated to STS-120 (and actually flew as we know) but is marked with an note saying "Last Planned Flight due to DAR Life Limits".  DAR stands for Deviation Approval Request - these cover special inspections and part life-limits that are imposed to preclude inflight problems.

Link to schedule [L2 access only] is:
http://forum.nasaspaceflight.com/index.php?topic=9767.0 (http://forum.nasaspaceflight.com/index.php?topic=9767.0)

Interestingly an earlier flight plan for HPOTPs dated March 12, 2007 [also on L2] shows E2050 was previously allocated to STS-119.
http://forum.nasaspaceflight.com/index.php?topic=7081.msg120394#msg120394 (http://forum.nasaspaceflight.com/index.php?topic=7081.msg120394#msg120394)
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 06/01/2015 08:27 pm
Now, is it on display somewhere?
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/01/2015 09:00 pm
Now, is it on display somewhere?

In storage awaiting use on SLS (have not seen a mission allocation for this particular engine yet).

[and your follow-up question is going to be a good one!]
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 06/01/2015 09:41 pm
Oh yeah! How is it gonna be OK for SLS but not for STS? I presume the STS program just dumped it for cost reasons, and with some extended work it will be 100% good to go on SLS.

.. and for which part the DAR was for.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/02/2015 02:24 am
Does anyone have any info/history on ME-2050.  It was last flown on STS-120 Discovery along with ME-2048(which flew again on 4 more STS missions #'s 124, 119, 129, 133) and ME-2058 which also flew 4 more missions (124, 119, 129, 133)coupled with ME 2048.

Seeing that ME-2048 and ME-2058 flewout the remainder of the SSP as a pair, what happened to ME-2050 that caused it to be pulled from service back after its last mission of STS-120 in 2007?

There is an SSME Schedule on L2 dated August 31, 2007 that shows Engine Assignments from STS-118 thru' STS-127.

E2050 is allocated to STS-120 (and actually flew as we know) but is marked with an note saying "Last Planned Flight due to DAR Life Limits".  DAR stands for Deviation Approval Request - these cover special inspections and part life-limits that are imposed to preclude inflight problems.

Link to schedule [L2 access only] is:
http://forum.nasaspaceflight.com/index.php?topic=9767.0 (http://forum.nasaspaceflight.com/index.php?topic=9767.0)

Interestingly an earlier flight plan for HPOTPs dated March 12, 2007 [also on L2] shows E2050 was previously allocated to STS-119.
http://forum.nasaspaceflight.com/index.php?topic=7081.msg120394#msg120394 (http://forum.nasaspaceflight.com/index.php?topic=7081.msg120394#msg120394)
  Thank you.  Great info.
It's interesting to see that ME2050 and ME 2048 both had the same note "last planned flight due to DAR life limits" but ME2048 flew on flew again on 4 more STS missions 124, 119, 129, 133. 

1) Was that DAR life limit for the SSME or for the HPOTP?  In the list the asterisk appears under the HPOTP column.

For STS-120 ME-2048 had 7 flights while ME-2050 had 6 flights at the time, while ME's 2044, 2045 and 2047 which were scheduled for STS-123 planned for launch 4 months after STS-120 had 10, 10 and 11 flights on each of them respectively.
2)How can an engine with twice the flights, not have a DAR life limit that an engine with half the number of flights has?
Title: Re: Shuttle Q&A Part 5
Post by: MikeEndeavor23 on 06/04/2015 07:08 am

  Okay,
 
     Here is a question.  What was with STS 76's External tank? 

https://www.youtube.com/watch?v=CE2slW52llM


It looks like they tried to paint the tank white like they did on STS 1 and STS 2 and then forgot to finish.

      Or was this the Woody Woodpecker tank where the area Woodpeckers punched holes in the insulation and the white stuff is touch up paint?

    MikeEndeavour23
Title: Re: Shuttle Q&A Part 5
Post by: Ronpur50 on 06/04/2015 01:03 pm
I remember that and I just assumed it was frost when I saw it on TV.  I don't remember it being mentioned at the time, but it may have been.  That was a few years ago!
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/04/2015 01:12 pm

  Okay,
 
     Here is a question.  What was with STS 76's External tank? 

It looks like they tried to paint the tank white like they did on STS 1 and STS 2 and then forgot to finish.

...

    MikeEndeavour23

No, that's silly.  People didn't start to paint an ET and then forget to finish it.  That would have been noticed.  Nor did they suddenly decide to add more weight to one tank in the middle of the program.

I was there that early (pre-dawn) morning and it was one of the most humid launches in the program history.  There was plenty of condensation in the air.  The condensation then became very light frost on the tank in one direction.

Liquid hydrogen is very cold.  Add moisture and you get a light coating of frost.  You'll see in the launch video that by lift-off much of it had evaporated but not all.

If we had the ice debris prevention rules in place for STS-76 that we had later in the program, I don't know if we would have launched.  But, the frost was not dense and would have been moving very slow if it fell off at liftoff, so it may still have been acceptable. 
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 06/04/2015 03:36 pm
Another memorable instance of frost was on at least one of the STS-36 launch attempts, but this predates interwebs, so maybe I'm imagining.
Title: Re: Shuttle Q&A Part 5
Post by: MikeEndeavor23 on 06/05/2015 04:19 am
 
   Ah okay!

     Thanks for that info!  I thought it looked wierd because I had never seen that on a launch prior or after.

     The more you know...

      ;)

   MikeEndeavour23
Title: Re: Shuttle Q&A Part 5
Post by: MikeEndeavor23 on 06/05/2015 04:30 am

    Okay, 

          Here is another one.  Why did they change the camera targets on SRBs  from the glymph design to the simple black strip for the left SRB?

           I think the glymphs were more "artistic."

           ;)

            MikeEndeavour23
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/05/2015 02:20 pm

    Okay, 

          Here is another one.  Why did they change the camera targets on SRBs  from the glymph design to the simple black strip for the left SRB?

           I think the glymphs were more "artistic."

           ;)

            MikeEndeavour23

What is "glymph"?

Anything more other than a stripe differentiating the two SRB's was no longer required.
Title: Re: Shuttle Q&A Part 5
Post by: NovaSilisko on 06/05/2015 04:08 pm
No, that's silly.  People didn't start to paint an ET and then forget to finish it.  That would have been noticed.  Nor did they suddenly decide to add more weight to one tank in the middle of the program.

Pretty sure he was making a joke...  :P
Title: Re: Shuttle Q&A Part 5
Post by: mako88sb on 07/06/2015 06:29 pm
I've done some searching but not having much luck. What I'm curious about is the maintenance breakdown of the Space Shuttle system. Just how many man hours of it were required between launches? How much percentage wise did it increase for each shuttle as they got older. Considering they were designed for at least a 100 missions each, they were relatively low on actual flight time hours with Discovery at 39 missions and Endeavor at only 25 missions. Sorry if it's been addressed before.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/06/2015 08:34 pm
I've done some searching but not having much luck. What I'm curious about is the maintenance breakdown of the Space Shuttle system. Just how many man hours of it were required between launches? How much percentage wise did it increase for each shuttle as they got older. Considering they were designed for at least a 100 missions each, they were relatively low on actual flight time hours with Discovery at 39 missions and Endeavor at only 25 missions. Sorry if it's been addressed before.
I can't answer, but maybe you'll be interested in this paper I saw on NTRS a few years ago and thankfully it is back on NTRS (because I can't remember which backup hard drive I originally stored it on):  "Space Shuttle Operations and Infrastructure: A Systems Analysis of Design Root Causes and Effects" by Carey M. McCleskey (NASA/TP—2005–211519)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050172128.pdf

There's a lot of interesting data, including some chronological detail on a single ground processing flow (for STS-86, in 1997) in Appendix D.
Title: Re: Shuttle Q&A Part 5
Post by: mako88sb on 07/07/2015 09:09 am
I've done some searching but not having much luck. What I'm curious about is the maintenance breakdown of the Space Shuttle system. Just how many man hours of it were required between launches? How much percentage wise did it increase for each shuttle as they got older. Considering they were designed for at least a 100 missions each, they were relatively low on actual flight time hours with Discovery at 39 missions and Endeavor at only 25 missions. Sorry if it's been addressed before.
I can't answer, but maybe you'll be interested in this paper I saw on NTRS a few years ago and thankfully it is back on NTRS (because I can't remember which backup hard drive I originally stored it on):  "Space Shuttle Operations and Infrastructure: A Systems Analysis of Design Root Causes and Effects" by Carey M. McCleskey (NASA/TP—2005–211519)
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050172128.pdf

There's a lot of interesting data, including some chronological detail on a single ground processing flow (for STS-86, in 1997) in Appendix D.

Thanks for the link. Skimmed through it real quick and definitely looks interesting. Hopefully I can find some time this week to go over it some more.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 08/20/2015 02:31 am

STS-125 launch. ASA 1 failure. CAPCOM calls up, "bypass across the board".
Is that an instruction to do something, if so, what? Or was it informational and if so what did it mean?

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Graham on 08/20/2015 03:10 pm

STS-125 launch. ASA 1 failure. CAPCOM calls up, "bypass across the board".
Is that an instruction to do something, if so, what? Or was it informational and if so what did it mean?

Thanks!
I'm sure someone will correct me if I'm wrong, but I believe it meant that ASA 1 was being bypassed since it had failed. In fact I believe the next call up was "No action required".
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/21/2015 03:10 am

STS-125 launch. ASA 1 failure. CAPCOM calls up, "bypass across the board".
Is that an instruction to do something, if so, what? Or was it informational and if so what did it mean?

Thanks!
I'm sure someone will correct me if I'm wrong, but I believe it meant that ASA 1 was being bypassed since it had failed. In fact I believe the next call up was "No action required".

ASA = Aerosurface Servo Amplifier.   There are four of these (ASAs) that act like the brain of the hydraulic actuators used to move the orbiter's aerosurfaces (elevons, speedbrake, and rudder).  Each actuator has 4 servo valves (or ports) and a single ASA (1,2,3 or 4) is assigned to each one of those 4 servo valves on each of the hydraulic actuators.  In other words, each actuator is redundantly controlled by 4 ASAs.

During ignition and liftoff of Atlantis on STS-125, the power to ASA 1 failed and all the ports assigned to that ASA on each actuator were bypassed to effectively take ASA 1 out of the loop and allow the remaining ASAs (2,3, and 4) to continue to do their job.  A message was displayed to the crew by the GPC (general purpose computers) and Scott Altman (Scooter) reported that fact to Houston right as the roll maneuver was being performed.  They confirmed that all the ports on ASA 1 bypassed.  As long as all the ports automatically bypass, then the procedures require no action by the crew.

A single ASA failure was considered a loss of redundancy, more than that, depending on the number and timing of the failures, and you could potentially be talking about an abort or terminating the mission early (i.e. next PLS - Primary Landing Site opportunity).

Mark
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 08/21/2015 02:33 pm
Thank you Graham and Mark.

If I remember correctly, this occurred during SSME ignition before SRB ignition. Why then, didn't the launch abort before liftoff?

Thank you!
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/22/2015 03:44 am
I really don't remember.  It was presumably a function of how and when the LCC (Launch Commit Criteria) for this system's parameters were monitored.  Could be it was only a launch limit violation up to T-31 seconds or T-10 seconds.

Mark
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 08/28/2015 06:22 pm
In regards to my previous questions re STS-125 ASA 1, this is the mission control ascent vid;
https://www.youtube.com/watch?v=O7q34Rpgvqw

-What is "2 stage" (after liftoff and before in the bucket) ?
-What does booster mean when he says;
"3 fids are all invalid, invalid family and delimiter. Good norm. Crew has no insight"?
"impact the crew calling an engine out behind a data path"?

Oh, and if there is backroom audio ala STS-93 I'd love to hear that.

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: hamzah on 08/31/2015 03:38 am
hi guys i'm new to the forum,and i have a question on the space shuttle pumping system, i'm a mechanical engineer who worked on hydraulic efficiency pump improvement research at the university were we improved the efficiency of heart assistant device (VBA) and Berkeley pump by simulations and real testing.I'm getting ready to apply our theory/methods of improvement on space pump put before i can apply it i need to know what type of pumps the space shuttle uses in space ? and what forces the pumps experience while operating in space ? and if possible the schismatic of the pumps used and the pumping system?  :)           
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/31/2015 12:21 pm
Pumps for what systems?. There were many pumps on the shuttle
Title: Re: Shuttle Q&A Part 5
Post by: hamzah on 09/04/2015 03:15 pm
sorry i didn't specify, i want any pumping system and type pump schamatic that is used in shuttle while flying in space, and if it possible to specify the use of it so i could simulate it in detail using the sofware  :)
Title: Re: Shuttle Q&A Part 5
Post by: baldusi on 09/04/2015 05:32 pm
sorry i didn't specify, i want any pumping system and type pump schamatic that is used in shuttle while flying in space, and if it possible to specify the use of it so i could simulate it in detail using the sofware  :)
Do you mean the pumps on the rocket engines turbopump? The pumps on the heat rejection system? The onboard water supply pumps? The hydraulic actuators' pump? The pneumatic pressurization pump?
In space nothing flows by gravity. Any fluid will need to be moved by a pump or blade.
Title: Re: Shuttle Q&A Part 5
Post by: hamzah on 09/04/2015 06:23 pm
actully all those pumps will work in my software  :D, and if possible my professor wants to know were can he apply and who he needs to contact for NASA grants to fund the research ?
Title: Re: Shuttle Q&A Part 5
Post by: ZachS09 on 09/20/2015 07:59 pm
According to a PDF file dating back to June 2001 (www.nasa.gov/pdf/2254main_tm210880.pdf (http://www.nasa.gov/pdf/2254main_tm210880.pdf)), there were five previous shuttle missions including STS-95 that featured the first SRB-intertank cameras. Is there any way to obtain the SRB cam footage from the other four:

STS-93
STS-96
STS-101
STS-103

I would appreciate it.
Title: Re: Shuttle Q&A Part 5
Post by: hamzah on 09/20/2015 10:39 pm
can anyone give me the schismatic of the onboard water supply pumps that is used on the shuttle to simulate please? :D
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/20/2015 10:51 pm
can anyone give me the schismatic of the onboard water supply pumps that is used on the shuttle to simulate please? :D

There wasn't pumps used to move water.  It just use pressure and diaphragms.
Title: Re: Shuttle Q&A Part 5
Post by: Johnnyhinbos on 12/25/2015 02:24 pm
Not sure where this is best posted, but here's an interesting article on a proposed conversion of the shuttle's main engines to a full flow staged conversion version. A conversion that never happened.

I find it of particular interest when used as a metric for engine reuse and the issues and expense that the SSME had. Therefore this may best be placed in the SpaceX thread on reuse...

http://www.eaglehill.us/programs/journals/spaevo/2015a1/



Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 12/30/2015 12:30 am
I met these two fine people during the media tour of Discovery in the OPF before the STS-134 launch, but I've lost my notes about who they are. I know there are people here who do.....



TIA
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 12/30/2015 01:16 am
I think the woman on the left is Stephanie Stilson, Discovery's flow director.
Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 12/30/2015 01:44 am
I think the woman on the left is Stephanie Stilson, Discovery's flow director.

That's her, thanks.

The gentleman had something to do with security. Before entering the OPF we had been given very precise instructions to stay within the red lines on the floor. At one point I wanted to try to lean over the line and see if I could see Discovery's name and get an image of it.  I explained what I was doing to him and got a quiet nod, while I was doing so another person thought I was pushing the boundary a bit too far and came over to give me a warning. I accepted the warning, and promised to be good. A couple minutes later he came over and demanded my camera. My heart sank but I handed it over and he disappeared, telling me to stay put. A few minutes later he returned and handed my camera back without a word. He had gone up and taken the two images below for me.

Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/07/2016 07:21 pm
What kind of temperatures are experienced by the Shuttle during ascent?

After MECO, what composes the various particles/debris that are seen escaping from the Orbiter?

How long after MECO are the payload bay doors opened?

TIA
Title: Re: Shuttle Q&A Part 5
Post by: tminus9 on 01/07/2016 08:30 pm
How long after MECO are the payload bay doors opened?

According to the STS-135 mission report, MECO was at 00/00:08:24 MET and payload bay doors were opened at 00/01:34:16 MET, so in that case it was roughly 90 minutes after MECO. I don't know how that varied over the program's history, but I'd suspect it was similar since the orbiter can't stay in orbit long without opening the doors.

Title: Re: Shuttle Q&A Part 5
Post by: Lee Jay on 01/07/2016 08:34 pm
After MECO, what composes the various particles/debris that are seen escaping from the Orbiter?

A good bit is ice peeling off of the SSMEs.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/07/2016 09:02 pm
After MECO, what composes the various particles/debris that are seen escaping from the Orbiter?

A good bit is ice peeling off of the SSMEs.
As in water ice from combustion?
Title: Re: Shuttle Q&A Part 5
Post by: Graham on 01/08/2016 11:21 am
How long after MECO are the payload bay doors opened?

TIA

I seem to recall that, at least on STS 1, if the PLBD were not opened during the first orbit there would be an immediate abort.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/08/2016 05:00 pm
How long after MECO are the payload bay doors opened?

TIA

I seem to recall that, at least on STS 1, if the PLBD were not opened during the first orbit there would be an immediate abort.
Excellent!

This discussion jogged my memory and I went and looked up the Mission Events Lists in the Historical section of L2.

STS-1  35minutes:29 seconds after MECO
MECO        12:08:36:8
PLBD open 12:44:05:3

STS -69    34:17 after MECO
MECO                  250:15:17:30.171
PBD RIGHT OPEN 250:16:51:47
PBD LEFT OPEN    250:16:53:06

STS-132- roughly 24:29 after MECO
MECO                134:18:28:34
PLBD open right 134:19:52:53
                 left   134:19:54:11

Thanks everyone.
Title: Re: Shuttle Q&A Part 5
Post by: mtakala24 on 01/09/2016 12:18 pm
Space Shuttle checklists say that if the contingency/manual procedures to drive the payload bay doors open would not work, the next step is to go to deorbit next PLS (Primary Landing Site) checklist. I'm guessing that the mission length would be 2 or 3 orbits that way.
Title: Re: Shuttle Q&A Part 5
Post by: ludo on 01/20/2016 12:18 pm
Hi
Have a quick question that I can't seem to find an answer for. I know there I radiation in space and am wondering does that radiation dissipate when the shuttle enters back into earth's atmosphere or does it stick to the space shuttle when it's back on planet earth? Or does the re entry wipe the shuttle clean? Thanks in advance.
Title: Re: Shuttle Q&A Part 5
Post by: rocx on 01/20/2016 12:32 pm
Hello ludo,

Radiation does not stick to things. Solar and cosmic radiation in space consists of very small very energetic particles (protons, electrons, rarely a larger nucleus). It is possible that radiation impacts a nucleus on the spacecraft and changes it to a radioactive isotope. In this case going through reentry won't wash it away. I think that spacecraft design generally tries to avoid using materials that can turn into radioactive istopes on the outside of the ship, but I'm not sure.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 01/31/2016 04:40 pm
How had the Lockheed ejection seats been tested, which were installed for the OFT missions? I know their envelope was up to Mach 2.7 and 80'000 ft, but how was this tested? Which methods were used?
Also: Had the seats actually been tested together with the EES suits? If so, how?

The ejection seats for Buran had been tested together with the Strizh suits during five Progress launches in addition to the usual ground tests on rocket sleds and test aircraft.
Was something similar done with the Shuttle seats?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/31/2016 07:21 pm
How had the Lockheed ejection seats been tested, which were installed for the OFT missions? I know their envelope was up to Mach 2.7 and 80'000 ft, but how was this tested? Which methods were used?
Also: Had the seats actually been tested together with the EES suits? If so, how?
There was sled testing and they used SR-71 suits.
Title: Re: Shuttle Q&A Part 5
Post by: GigaG on 02/01/2016 03:24 am
For a school project, I need a list of every shuttle mission's payload weight. Somewhere other than Wikipedia. Does this exist? Where can I find it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/01/2016 01:54 pm
For a school project, I need a list of every shuttle mission's payload weight. Somewhere other than Wikipedia. Does this exist? Where can I find it?

http://www.spaceflight.nasa.gov/shuttle/reference/green/cargsumm.pdf
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 02/02/2016 01:57 pm
For a school project, I need a list of every shuttle mission's payload weight. Somewhere other than Wikipedia. Does this exist? Where can I find it?

http://www.spaceflight.nasa.gov/shuttle/reference/green/cargsumm.pdf
Anything that includes STS-89 through STS-135.  That was a nice document Jim.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 02/08/2016 11:37 pm
For a school project, I need a list of every shuttle mission's payload weight. Somewhere other than Wikipedia. Does this exist? Where can I find it?

http://www.spaceflight.nasa.gov/shuttle/reference/green/cargsumm.pdf
Anything that includes STS-89 through STS-135.  That was a nice document Jim.


This Space Shuttle Mission Summary book has payload weights for all the program's missions.


http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf

Mark


Title: Re: Shuttle Q&A Part 5
Post by: Hog on 03/02/2016 01:48 pm
For a school project, I need a list of every shuttle mission's payload weight. Somewhere other than Wikipedia. Does this exist? Where can I find it?

http://www.spaceflight.nasa.gov/shuttle/reference/green/cargsumm.pdf
Anything that includes STS-89 through STS-135.  That was a nice document Jim.


This Space Shuttle Mission Summary book has payload weights for all the program's missions.


http://www.jsc.nasa.gov/history/reference/TM-2011-216142.pdf

Mark
Thank you IMOM, I appreciate the link.  A "LIKE" for you!
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 04/25/2016 10:00 pm
When the Soviets had their own Shuttle program, one of their concerns was a possible negative influence on the piloting skills of the cosmonauts during a mission, i.e. their ability to fly and precisely land Buran after staying in zero-gravity for more than a week. To address this concern and simulate these conditions, both Igor Volk and Anatoliy Levchenko, right after landing of their respective Soyuz missions, had to fly the Tu-154LL Buran training aircraft back to Zhukovsky to perform a Buran style approach and landing. After that, they had to fly right back to Baykonur in a MiG-25 to do some more Buran profile landings there.

Had there been any similar concerns for the US Space Shuttle astronauts? If so, how were these concerns addressed and dealt with?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 04/25/2016 10:15 pm
When the Soviets had their own Shuttle program, one of their concerns was a possible negative influence on the piloting skills of the cosmonauts during a mission, i.e. their ability to fly and precisely land Buran after staying in zero-gravity for more than a week. To address this concern and simulate these conditions, both Igor Volk and Anatoliy Levchenko, right after landing of their respective Soyuz missions, had to fly the Tu-154LL Buran training aircraft back to Zhukovsky to perform a Buran style approach and landing. After that, they had to fly right back to Baykonur in a MiG-25 to do some more Buran profile landings there.

Had there been any similar concerns for the US Space Shuttle astronauts? If so, how were these concerns addressed and dealt with?

The shuttle flew a laptop and hand controller in the 90's for long duration missions to maintain proficiency.   But even before that, there was no real concern.  Apollo astronauts were in control for all entries.
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 04/25/2016 10:16 pm
When the Soviets had their own Shuttle program, one of their concerns was a possible negative influence on the piloting skills of the cosmonauts during a mission, i.e. their ability to fly and precisely land Buran after staying in zero-gravity for more than a week. To address this concern and simulate these conditions, both Igor Volk and Anatoliy Levchenko, right after landing of their respective Soyuz missions, had to fly the Tu-154LL Buran training aircraft back to Zhukovsky to perform a Buran style approach and landing. After that, they had to fly right back to Baykonur in a MiG-25 to do some more Buran profile landings there.

Had there been any similar concerns for the US Space Shuttle astronauts? If so, how were these concerns addressed and dealt with?

Yes, particularly for the Extended Duration Orbiter (EDO) missions. 

The timing was completely different in that Shuttle didn't overlap Apollo, so there was no way for the U.S. to fly astronauts on a different vehicle to find out how they would perform on Shuttle.  Instead the idea was to build-up to longer flights to make sure that there wasn't a negative impact (a cliff or gradual build-up) due to microgravity.

There was also a tool, called PILOT, put onboard for practicing crew coordination and piloting during landing. A cross-program team worked on that in 1992/1993 and it first flew on STS-58.

http://articles.orlandosentinel.com/1993-10-22/news/9310220155_1_shuttle-pilot-astronauts

The unique suitcase-sized computer that PILOT used originally was replaced by the standard PGSC in the late-1990s or early-2000s.

Finally, had it been needed, the orbiter had an autoland capability as long the pilot (PLT) could deploy the gear and CDR/PLT could apply the brakes.  There were ways to automate the gear deploy and braking but the program didn't feel it was necessary and history shows that was correct.

Andy




Title: Re: Shuttle Q&A Part 5
Post by: Hog on 05/01/2016 03:07 pm
How had the Lockheed ejection seats been tested, which were installed for the OFT missions? I know their envelope was up to Mach 2.7 and 80'000 ft, but how was this tested? Which methods were used?
Also: Had the seats actually been tested together with the EES suits? If so, how?

The ejection seats for Buran had been tested together with the Strizh suits during five Progress launches in addition to the usual ground tests on rocket sleds and test aircraft.
Was something similar done with the Shuttle seats?
The upper limits were educated guesses, there was no certification at Mach 3 or 80,000-100,000ft.

Here is footage of a Mach 3+ M-21 Blackbird breakup.  Both the Pilot and the Launch Control Officer(LCO-backseater) ejected successfully while the LCO drowned after his suit filled with water after he opened his faceshield.

There was the A-12(1 seater CIA spy plane), M-21 (M for Mother which launched the D-21 drone D for Daughter) the 3 YF-12(interceptor which fired missiles) and finally the least rare SR-71 spy plane-2 seater

http://www.youtube.com/watch?v=GMyC2urCl_4
Title: Re: Shuttle Q&A Part 5
Post by: drnscr on 05/05/2016 01:35 am
Actually, all SR71s were two seaters (one pilot, one RSO).  However, I think you're referring to the SR71 pilot training aircraft which is a totally bizarre looking variant.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 05/07/2016 10:34 pm
Actually, all SR71s were two seaters (one pilot, one RSO).  However, I think you're referring to the SR71 pilot training aircraft which is a totally bizarre looking variant.
Like I wrote "the LEAST rare SR-71 spy plane 2 seater", meaning the most common of the Blackbirds was the 2 seat SR-71(32 built), as there were more 2 seat SR-71s built than 1 seat A-12s(13 built, plus 2 M-21s and 3 YF-12 models being built-the YF-12 has no chines on its nose to allow a radar suite to be installed, this forced designers to include a single fin that is retractable under the fuselage as well as a fin under each engine nancelle)

The bizarre looking twin cockpit trainer aircraft was a SR-71B model(2 of the 32 SR-71s were built as  dual control, elevated and offset rear cockpit B models).  The SR-71B also had the ventral fins of the YF-12.
The A-12 trainer had 2 sets of controls, like the SR71-B. The A-12 trainer was called the "Titanium Goose.".
There was also an SR-71-C built which was the front section of the Static Test Article and the rear section was the back section of a crashed YF-12.

Pic #1  SR-71 trainer with raised 2nd cockpit slightly offset
Pic #2 YF-12A Interceptor notice the chine-less nose that houses the fire control radar to track AIM-47 missiles
Pic #3 Good pic of a YF-12A in NASA livery, notice the 3 ventral fins, 1 in the center, and 1 under each engine.  Also carrying a "cold tube" experiment for NASA.
Pic #4 Pic of SR-71 C model, front is SR-71 test article, rear was a crashed YF-12A, so it has the fully chined front coupled with the 3 ventral finned rear fuselage This craft was nicknamed "The Bastard" as it supposedly yawed slightly during its high Mach cruise.
Pic #5 A-12 trainer with its dual cockpit, used to train CIA Pilots, no "Geneva Conventions" card for these Pilots, it was a covert mission, the SR-71 was the overt mission. This trainer retained the J-75 engines and maxxed out at Mach 1.6.  Proper A-12's being the smallest and lightest of the Blackbirds also had the smaller fuel load of just 64,000lbs, the SR-71 took 80,000pounds of JP-7.  One A-12 mission saw 94,780ft in altitude.
Title: Re: Shuttle Q&A Part 5
Post by: rtphokie on 06/08/2016 04:28 pm
How much do these things weigh? Specifically the older design before the crossover was added to ensure both sides blew simultaneously.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/08/2016 04:55 pm
How much do these things weigh? Specifically the older design before the crossover was added to ensure both sides blew simultaneously.

I believe the crossover was just wiring and would have not appreciably affected the weight.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/08/2016 05:07 pm
Subject: Flight Readiness Firings

1)  Were the LOX and LH2 tanks filled to flight levels/pressures?
2) I found a reference that states that the FRF for Columbia STS-1 had a burn duration of about 20 seconds.  Were the other 6 FRFs of approximately the same duration?


Flight Readiness Firing History

Orbiter Vehicle                Flight Readiness Firing(s)        Launch Date & Mission
OV-102-Columbia    Feb 20, 1981                         Apr 12, 1981 STS-1
OV-099-Challenger  Dec 18, 1982/Jan 25, 1983     Apr 04, 1983 STS-6
OV-103-Discovery   June 02, 1984/Aug 04, 1988   Aug 30, 1984 STS-41-D/STS-26 (12th&26th mission)
OV-104-Atlantis       Sept 12, 1985                       Oct 03, 1985 STS-51-J (21st STS mission)
OV-105-Endeavour  Apr 06, 1992                         May 07, 1992 STS-49
OV-101-Enterprise   nil                                        Feb 15, 1977-Oct 26, 1977  15 Approach Landing Tests


(Edit: to include the omitted STS-26 Atlantis FRF-5 spaceworthy Orbiters, each performing a single FRF with Challenger & Discovery performing 2 FRF each-big thanks to Andy!)
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/08/2016 05:12 pm
Paul, I remember the FRFs had different duration times (matter of seconds difference) as the program matured.  There were other differences such as having specially patched software on the early FRFs and using I-Load changes for the later ones.

Also, don't forget there was an STS-26 FRF.  That was a good day - it felt like we were going to fly soon.

Andy
Title: Re: Shuttle Q&A Part 5
Post by: rtphokie on 06/08/2016 05:25 pm
I'm wondering about the nut itself.  Goes on a 28 inch long, 3.5 inch diameter bolt.  I've seen them on display but not seen any details.  It's the biggest frangible nut I know of.
Title: Re: Shuttle Q&A Part 5
Post by: Nerull on 06/09/2016 08:40 am
Anyone know the context for the missing tiles in this photo? Service panel access? Access behind those tiles wasn't a normal part of launch prep, was it?

Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/09/2016 11:13 am
Anyone know the context for the missing tiles in this photo? Service panel access? Access behind those tiles wasn't a normal part of launch prep, was it?

Larger region is a Purge and Drain Access Panel (monomethylhydrazine & helium)
Smaller one is a Service Access Panel (also monomethylhydrazine & helium)

It also looks like a tank relief vent (monomethylhydrazine) has had something taped over it (the white rectangular taped area above top panel)

Not routinely removed during normal pad flow.  I'm sure someone will know the reason why they were opened.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/09/2016 11:24 am
Anyone know the context for the missing tiles in this photo? Service panel access? Access behind those tiles wasn't a normal part of launch prep, was it?

Larger region is a Purge and Drain Access Panel (monomethylhydrazine & helium)
Smaller one is a Service Access Panel (also monomethylhydrazine & helium)

It also looks like a tank relief vent (monomethylhydrazine) has had something taped over it (the white rectangular taped area above top panel)

Not routinely removed during normal pad flow.  I'm sure someone will know the reason why they were opened.
The Purge, Drain and Servicing panels had their TPS removed in readiness for S0024, Prelaunch Propellant Loading. During rollover and VAB ops, the panels are covered with a green fabric cover. This cover is removed after arrival at the pad. The photo above was most likely taken at a time the RSS had been retracted for Payload Canister ops before S0024.

So yes, these panels are routinely removed during the pad flow for servicing of the FRCS propellant tanks (MMH and NTO).
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/09/2016 11:31 am
Anyone know the context for the missing tiles in this photo? Service panel access? Access behind those tiles wasn't a normal part of launch prep, was it?

Larger region is a Purge and Drain Access Panel (monomethylhydrazine & helium)
Smaller one is a Service Access Panel (also monomethylhydrazine & helium)

It also looks like a tank relief vent (monomethylhydrazine) has had something taped over it (the white rectangular taped area above top panel)

Not routinely removed during normal pad flow.  I'm sure someone will know the reason why they were opened.
The Purge, Drain and Servicing panels had their TPS removed in readiness for S0024, Prelaunch Propellant Loading. During rollover and VAB ops, the panels are covered with a green fabric cover. This cover is removed after arrival at the pad. The photo above was most likely taken at a time the RSS had been retracted for Payload Canister ops before S0024.

So yes, these panels are routinely removed during the pad flow for servicing of the FRCS propellant tanks (MMH and NTO).

See, I knew someone would know  :) .  Thanks for the correction Dave.
Title: Re: Shuttle Q&A Part 5
Post by: Kansan52 on 06/10/2016 10:08 pm
I'm wondering about the nut itself.  Goes on a 28 inch long, 3.5 inch diameter bolt.  I've seen them on display but not seen any details.  It's the biggest frangible nut I know of.


Not lots of info but fun when they gave Colbert one:

http://www.collectspace.com/ubb/Forum23/HTML/002702.html
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 06/10/2016 11:35 pm
I'm wondering about the nut itself.  Goes on a 28 inch long, 3.5 inch diameter bolt.  I've seen them on display but not seen any details.  It's the biggest frangible nut I know of.

The attached document gives detailed design dimensions of the nut, plus some other info (pre-crossover implementation).  It is made of Inconel 718 whose density is around 0.30 lbs/in3 (8.2 g/cm3).  So in principle the mass of the nut could be calculated from the drawing!
Title: Re: Shuttle Q&A Part 5
Post by: rtphokie on 06/11/2016 04:53 am
I'm wondering about the nut itself.  Goes on a 28 inch long, 3.5 inch diameter bolt.  I've seen them on display but not seen any details.  It's the biggest frangible nut I know of.

The attached document gives detailed design dimensions of the nut, plus some other info (pre-crossover implementation).  It is made of Inconel 718 whose density is around 0.30 lbs/in3 (8.2 g/cm3).  So in principle the mass of the nut could be calculated from the drawing!

Awesome thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Torten on 06/14/2016 04:39 pm
I wouldn't be suprised to find out that this question has been asked in the past, but as this website doesn't seem to have a search function, I shall ask it here.

STS-107 seems to have flown about 1.5 years later than STS-108. While shuttle launches would often have completely out of synch numbers, that was because the numbers were allocated when the missions were funded? So what happened for the mission to take so long between funding and launch? I would also guess that STS-107 was the last non station/hubble launch planned?
Title: Re: Shuttle Q&A Part 5
Post by: rtphokie on 06/14/2016 04:56 pm
I wouldn't be suprised to find out that this question has been asked in the past, but as this website doesn't seem to have a search function, I shall ask it here.

STS-107 seems to have flown about 1.5 years later than STS-108. While shuttle launches would often have completely out of synch numbers, that was because the numbers were allocated when the missions were funded? So what happened for the mission to take so long between funding and launch? I would also guess that STS-107 was the last non station/hubble launch planned?

numbering was as manifested, not as flown.  Missions flew out of sequence sometimes according to payload needs/constraints. 
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 06/16/2016 04:46 pm
I wouldn't be suprised to find out that this question has been asked in the past, but as this website doesn't seem to have a search function, I shall ask it here.

STS-107 seems to have flown about 1.5 years later than STS-108. While shuttle launches would often have completely out of synch numbers, that was because the numbers were allocated when the missions were funded? So what happened for the mission to take so long between funding and launch? I would also guess that STS-107 was the last non station/hubble launch planned?
I wouldn't be suprised to find out that this question has been asked in the past, but as this website doesn't seem to have a search function, I shall ask it here.

STS-107 seems to have flown about 1.5 years later than STS-108. While shuttle launches would often have completely out of synch numbers, that was because the numbers were allocated when the missions were funded? So what happened for the mission to take so long between funding and launch? I would also guess that STS-107 was the last non station/hubble launch planned?

numbering was as manifested, not as flown.  Missions flew out of sequence sometimes according to payload needs/constraints. 


Exactly.  Mission numbers represented the manifest order -- which changed greatly sometimes with flown order.  STS-107 was not a high priority mission given the ISS assembly schedule.  When schedule slips happened, STS-107 got pushed.

Also, we does have a "search function."  On the top navigation bar (see attached screencap for reference).
Title: Re: Shuttle Q&A Part 5
Post by: Becker67 on 06/29/2016 07:38 pm
1. I was reading STS-115 Orbit Operations checklist and on page 12-89 is DEORBIT Manager Initialization . I see from the checklist it's a software application which I imagine is run on a laptop. I was wondering if the software is the same or the parent to this? https://www.nasa.gov/centers/johnson/techtransfer/technology/MSC-24639-1-tsa-dops.html#.V3QgpvkrJqM

2. I know mission control sorts out the data for deorbit but would the crew use this software routinely or was it simply a back-up?

3. Lastly if there is any other information/screenshots of this software, other than what is on the checklist, could anyone point me in the right direction?
Title: Re: Shuttle Q&A Part 5
Post by: alk3997 on 06/29/2016 07:58 pm
1. I was reading STS-115 Orbit Operations checklist and on page 12-89 is DEORBIT Manager Initialization . I see from the checklist it's a software application which I imagine is run on a laptop. I was wondering if the software is the same or the parent to this? https://www.nasa.gov/centers/johnson/techtransfer/technology/MSC-24639-1-tsa-dops.html#.V3QgpvkrJqM

2. I know mission control sorts out the data for deorbit but would the crew use this software routinely or was it simply a back-up?

3. Lastly if there is any other information/screenshots of this software, other than what is on the checklist, could anyone point me in the right direction?

MCC was prime for deorbit calculations.  The results were the burn targets which were uplinked to the flight computers directly.  The crew then read-back the parameters to the ground to verify the uplink.

In the event of a loss of comm or an emergency the deorbit manager could be used.  The crew would have to type the parameters into the GPCs from deorbit manager screen (the PGSC laptops).

Andy
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 07/02/2016 01:02 pm
Not sure where I can find this information, so I'll post it for the "experts" here...during the time that MIR was permanently manned by U.S. astronauts (from STS-76 through STS-91) there were 9 other shuttle flights that flew independent missions.
Did each of those (independent) flights (albeit briefly) communicate with the U.S. MIR crew member?
Thank you.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 07/02/2016 01:37 pm
Not sure where I can find this information, so I'll post it for the "experts" here...during the time that MIR was permanently manned by U.S. astronauts (from STS-76 through STS-91) there were 9 other shuttle flights that flew independent missions.
Did each of those (independent) flights (albeit briefly) communicate with the U.S. MIR crew member?
Thank you.

not each one.
Title: Re: Shuttle Q&A Part 5
Post by: TJL on 07/03/2016 02:51 pm
Not sure where I can find this information, so I'll post it for the "experts" here...during the time that MIR was permanently manned by U.S. astronauts (from STS-76 through STS-91) there were 9 other shuttle flights that flew independent missions.
Did each of those (independent) flights (albeit briefly) communicate with the U.S. MIR crew member?
Thank you.

not each one.
As always, thanks, Jim...are there links available for those flights that did communicate?
Tom
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 07/17/2016 02:17 pm
It's only been 10 years, but someone posted video of the STS-31 post-launch press conference on YouTube, which covers the LO2 outboard F/D valve issue (sounds more like a software/process issue) that stopped the terminal count at T-31 seconds for a short time. 
https://www.youtube.com/watch?v=kh_kNbvaI0U

Aside from John's help with this way back when (quoted below), the only other description of the issue was in Harry Kolcum's contemporary story in AW&ST.  There's a little extra background in the opening remarks from Bob Sieck and George Sasseen and the Q&A.  The briefing stars at about 2 hours and 30 minutes into the video.

Quote
Orbiter Obvious - 7/11/2006  8:37 PM

Quote
jcopella - 25/7/2006  1:50 PM

Quote
psloss - 25/7/2006  6:20 AM

Quote
jcopella - 25/7/2006  12:44 AM

P.S.  Prerequisite Control Logic (PCL) is a little GOAL subroutine that console engineers could associate with a particular command.  The idea was you would put safety checks inside the PCL sequence to ensure that the command never resulted in an unsafe situation.  In this case, MPS apparently made some kind of procedural change which caused the PCL (which would normally allow the command to go thru) to block the command.  I remember a little bit of a fire drill after this incident to hunt down all the GLS-issued commands that had PCL sequences associated with them so we wouldn't be quite so surprised if it ever happened to us again.
Thanks, John.  On the comm loop that was broadcast on NASA Select, SPE says it was PCL sequence 18 (if I'm hearing right).  Also sounds like Ms. Pape's voice at the GLS console.

Yep.  GCL18.  That's the PCL sequence for V41K1515XL, the LO2 outboard f/d valve close command (I still have my GLS "brain book" here in the office, which I keep around for sentimental reasons.  Never thought I'd have to use it to look up a PCL sequence again!  LOL)

How long does it take someone to train up and know all these sequences like this?

The short answer is, years.  But you should keep in mind a couple of things.  Not everyone in a given system knows every single PCL sequence for that system cold.  Usually only the system specialists (very small number of very senior people) had that sort of in-depth knowledge, and even they relied on source code listings and other reference material to supplement their grey matter.

I was a GLS engineer, and we executed a lot of commands on behalf of the subsystems, and we were software weenies anyway, so we were sort of expected to have that sort of knowledge.  But even we realied on our "brain books" for this sort of thing, and of course that knowledge is supplemented by messages and displays that we saw in real-time on launch day.

On my first tour thru KSC, I worked with GLS for about 4 years, and at the end of that 4 years I felt like I was just starting to really know what I was doing.  At that time (early 90s), we had a training and certification program for new engineers that generally took about a year to complete, depending on what the launch schedule was like -- you had to complete X number of S0044s, X number of S0017s and X number of S0007s (both as early shift support, backup operator, and primary operator).  There were also classes you were required to attend, and we had some assignments and tests as well.  That was on top of your daily job assignments which would've included software development & maintenance, data review, paperwork, attending meetings (yay!!), etc.  After your training was complete, you really needed a few (3 or 4 years) of hard experience before things really settle in and you get confident in the role.

Maybe some of the other Shuttle vets who worked on the hardware can chime in on what sort of training they received and how long it took them to get comfortable with the job.  And if they worked console for any length of time, and dealt with high energy systems, I'll be they even remember some of their PCL sequences!  LOL
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/10/2016 05:36 pm
Is anyone here familiar with the changes to the Orbiter Docking System from the Shuttle-Mir missions to the ISS missions if any?
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 11/08/2016 02:23 pm
GLS is go for main engine start at T-10 seconds but I note that unlike at other points in the GLS sequence below T-9 minutes this was not marked as auto in S0007.  Was an action required by CGLS to allow the RSLS to start the engines?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/08/2016 02:39 pm
GLS is go for main engine start at T-10 seconds but I note that unlike at other points in the GLS sequence below T-9 minutes this was not marked as auto in S0007.  Was an action required by CGLS to allow the RSLS to start the engines?
It was a software command, see the chart that Mark posted here:
https://forum.nasaspaceflight.com/index.php?topic=10600.msg263210#msg263210

(The conversation around that post is relevant, too.)

Belated edit to highlight this specific post from former GLS jcopella in that conversation:
https://forum.nasaspaceflight.com/index.php?topic=10600.msg263266#msg263266
Quote
At this point GLS & RSLS run in parallel, interacting directly only when there's a countdown clock hold/resume (e.g., the T-9m built-in hold), and at T-31 sec and T-10 sec when the two LPS "go" flags (auto sequence start & SSME start, respectively) are sent.
Title: Re: Shuttle Q&A Part 5
Post by: Zoe on 11/08/2016 04:08 pm
Thanks, I'm still curious though as to why the RSLS auto sequence start at T-31 seconds is marked as auto whereas the main engine start at T-10 seconds is not if both commands were sent automatically from the GLS to the RSLS.
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 12/09/2016 03:04 am
Does anyone know what the upmass used on a Hubble Servicing Mission was?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 12/12/2016 01:37 pm
Does anyone know what the upmass used on a Hubble Servicing Mission was?
Which one?
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 12/24/2016 02:56 pm
Which one?
Any generic one (a rough total mass for a generic Hubble servicing), but all if possible. I looked in L2, but the documentation I found is very in depth on the systems carried up while not actually mentioning total mass.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 01/02/2017 07:02 pm
Which one?
Any generic one (a rough total mass for a generic Hubble servicing), but all if possible. I looked in L2, but the documentation I found is very in depth on the systems carried up while not actually mentioning total mass.
This is all stuff from Wikipedia and isn't consistent in format.  Some is detailed payload breakdown, while some is simply launch mass and landing mass of the Orbiter.  I think there was some very detailed documentation on payloads earlier on in this very thread.  Perhaps a quick read in this thread may reveal some answers.  Perhaps this will pique some others input?

STS-31-Discovery Launch mass 11,110 kg (24,490 lb)

STS-61 Endeavour had a payload mass of 10,949 kg (24,138 lb)

STS-82-Discovery-Servicing Mission 2

STS-103-Discovery-Servicing Mission 3A

Launch mass
112,493 kilograms (248,005 lb)
Landing mass
95,768 kilograms (211,132 lb)

STS-109-Columbia-Service Mission 3B

Launch mass
116,989 kg (257,917 lb)
Landing mass
100,564 kg (221,706 lb)

STS-125-Atlantis-Servicing Mission 4  https://en.wikipedia.org/wiki/STS-125
As per Wikipedia, the total upmass of payload for STS-125, the last Hubble Service Mission, was 13,104 kilograms (28,889 lb).

Bays 1–2 Orbiter Docking System
EMUs 3006, 3004, 3015, 3017 1,800 kilograms (4,000 lb)
 ~480 kilograms (1,060 lb)

Bay 3P Shuttle Power
 Distribution Unit (SPDU) ~17 kilograms (37 lb)

Bays 4–5 SLIC /COPE with
 Wide Field Camera 3 2,990 kilograms (6,590 lb)

Bays 7–8 ORUC COS/RSU/FGS
 Cosmic Origins Spectrograph
 Fine Guidance Sensor, Gyros 3,339 kilograms (7,361 lb)

Bay 10P GABA/MFR ~50 kilograms (110 lb)

Bay 10P GABA/PFR ~50 kilograms (110 lb)

Bay 11 HST-FSS/BAPS/SCM
 Berthing and Positioning Sys
 Soft Capture Mechanism 2,177 kilograms (4,799 lb)

Bay 12 MULE
 RNS, NOBL blankets 1,409 kilograms (3,106 lb)

Starboard Sill Orbiter Boom Sensor System ~382 kilograms (842 lb)
Port Sill Canadarm 301 410 kilograms (900 lb)
 
Total: 13,104 kilograms (28,889 lb)


Title: Re: Shuttle Q&A Part 5
Post by: smn on 05/21/2017 04:17 pm
Hi there,

I'm new to this site and hope this question hasn't been asked before:

What are the hinges of the Payloadbay Doors and the surroundings of the FRCS thrusters made of? It looks like a metallic material, is it Inconnel?
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 05/22/2017 04:12 am
Can anyone provide links to audio/video/transcript/articles of instances when an orbiter burn was not responded to with "no trim required"...and needed to be trimmed?  Curious as to what instructions were given, what corrections were made to meet the targets, and any other information.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/28/2017 06:02 pm
Can anyone provide links to audio/video/transcript/articles of instances when an orbiter burn was not responded to with "no trim required"...and needed to be trimmed?  Curious as to what instructions were given, what corrections were made to meet the targets, and any other information.


I can’t think of any examples from a real mission off the top of my head, but hearing something different certainly wouldn’t be nominal.  It would mean the crew missed a step in the procedure or the resulting burn didn’t go as planned (e.g. flight control problems, premature cutoff, etc.).
“trimming out the residuals" is the last step of the burn procedure.

Burn Procedure 101:
Any burn (OMS or RCS) is obviously monitored very closely by the crew.  For a typical OMS burn the workload is divided as follows:

PLT (Pilot) will monitor the health of the burn (i.e. the engines)
-   Engine chamber pressure (Pc)
-   Helium and Propellant tank pressures
-   Position of the engine ball valves
-   Oxidizer and fuel engine inlet pressures
-   Fuel injector temperature

CDR (Commander) will monitor where the orbiter is going
-   Burn attitude (are we pointed in the right direction and is the attitude stable).  This is done primary by looking at the error and guidance steering needles on the ADI (attitude direction indicator or “8 ball”)
-   Shape of the current orbit versus the new targeted orbit - this is done by tracking the Perigee and Apogee altitudes, HP and HA, they should be changing as the burn progresses.  For a de-orbit burn the HP would be a value well within the atmosphere
-   Duration of the burn and remaining Delta V to go.

Let’s say you are conducting a deorbit burn with a target Delta V of 321 feet per second and an OMS burn duration of 3 minutes 18 seconds.  The crew would see the TGO (time to go) counting down to zero from 3:18 and the Delta VTOT (total delta v required) counting down.  Ideally both values will get to zero at the same time and the engine burn will stop.  Any “residual” velocity components along any of the orbiter’s axis (X, Y and Z) would be indicative of the sloppiness of the burn.  This information was displayed to the crew as VGOs (velocity to go) for each axis.  In reality the guidance and flight control systems were very good and these values were quite small - within 10ths of a foot per second.

The last step of the burn card/procedure was to trim out the residuals to within defined limits (based on the type of burn) this was done by manually moving the THC (translational hand controller) in the direction needed to reduce these velocity components.  Which direction to move the controller for a given axis (ex: push in versus pull out for the x-axis) was based on the sign (plus or minus) of the VGO.

I have attached an image of the Maneuver Display where this information was provided to the crew (in the box at the top right corner) and a copy of an OMS 2 Burn Card.  At the bottom of the card you will see that 2 seconds after cutoff (this allowed time for a purge) the crew would take the OMS engine switches to off and then trim out any residuals to within the limits specified.


Mark Kirkman
"Space Shuttle Hugger"
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 05/29/2017 06:02 am
Mark,
Thank for the info and the burn card.  I know the guidance and flight control systems were exceptionally good and accurate.  I couldn't remember any burn that wasn't responded to with "no trim required."  Would still like to hear audio or read a transcript of what happened if trim was required.  Would the ground communicate residuals to be trimmed and give some type of PAD?  Would the CDR and PLT just trim it on their own, without direction?
Title: Re: Shuttle Q&A Part 5
Post by: billshap on 07/21/2017 04:13 am
Listening to some old Shuttle audio, before the full TDRSS network was operational.  The Orbiter was instructed to "Configure LOS" and "Configure AOS" as its orbital path moved from ground station to ground station...and TDRSS.  What did these procedures entail?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 07/23/2017 02:32 pm
Listening to some old Shuttle audio, before the full TDRSS network was operational.  The Orbiter was instructed to "Configure LOS" and "Configure AOS" as its orbital path moved from ground station to ground station...and TDRSS.  What did these procedures entail?


As you probably already know, Mission Control can uplink commands from the ground to the orbiter.  These commands are received onboard via the communication system (S-band or Ku) and forwarded to the shuttle's general purpose computers (GPCs).  To protect against the possibility of receiving so called "spurious" commands while the orbiter was crossing a gap between tracking stations, the crew would "configure for LOS" (loss of signal) by blocking the GPCs from accepting commands from the comm system.  When acquisition of signal occurred (AOS) as the orbiter came into range of the next tracking station, the crew would "configure AOS" by enabling the GPCs to accept commands thru the comm system again.

This blocking and enabling can be done either with a switch located near the aft portion of the center console (C-3) or by selecting the appropriate item entry with a GPC Data Processing System Utility Display known as SPEC 1.


Mark Kirkman

Title: Re: Shuttle Q&A Part 5
Post by: billshap on 07/23/2017 03:23 pm
Mark,
Thanks for the info, and the enlightenment.  Was trying to figure out what would have to be configured comm-wise, and why; overlooked the GPC aspect.
Title: Re: Shuttle Q&A Part 5
Post by: brad2007a on 07/30/2017 10:22 pm
Forgive me if this rather simple question was asked and answered already, but...

My understanding is that Discovery was to be assigned to Vandenberg for the polar launches. Would Discovery have stayed there, or been "shuttled" to KSC for other missions?
Title: Re: Shuttle Q&A Part 5
Post by: ChrisGebhardt on 07/30/2017 10:40 pm
Forgive me if this rather simple question was asked and answered already, but...

My understanding is that Discovery was to be assigned to Vandenberg for the polar launches. Would Discovery have stayed there, or been "shuttled" to KSC for other missions?

According to the list of Shuttle missions cancelled in the wake of Challenger, Discovery would have gone back and forth. 

Example:
STS-62A - first flight from Vandenberg - 1 July 1986 - Discovery
STS-61N - DOD flight from Kennedy - 4 Sept. 1986 - Discovery
STS-62B - DOD flight from Vandenberg - 29 Sept. 1986 - Discovery
Title: Re: Shuttle Q&A Part 5
Post by: dosobo on 08/26/2017 12:30 pm
hi everybody!

i often remember the amazing manned missions in the past and these days there is nothing like this (except iss-transfers).
yes, iss is a fulltime manned mission and absolutely great but what i mean is something big like Space Shuttle and alle the incredible projects before.

so that took me to the point to shout out a question online:

https://when-do-we-hear-the-next.doublesonicboom.com (https://when-do-we-hear-the-next.doublesonicboom.com)  ;)

do you think like me or am i alone with all these memories and wishes for the future?

bye and greetings!
Title: Re: Shuttle Q&A Part 5
Post by: spacenut on 08/26/2017 12:50 pm
I turned 16 the day they landed on the moon.  I was hoping for us to go to Mars by the mid-1980's.  Shuttle was OK, but instead of building a space station, maybe they should have built a Nautilus-X type spacecraft so we could use it as a shuttle to and from Mars or the moon.  It would have at least kept our exploration going. 

Hopefully SpaceX will be the first to get a larger ITS spacecraft into orbit and be able to land it.  Then go beyond LEO. 
Title: Re: Shuttle Q&A Part 5
Post by: eric z on 08/26/2017 12:58 pm
 Hi Dosobo, Welcome and have fun here! You ask a great question...sometimes we can get so lost in the trees, we don't see the forest, or vice-versa! There are many reasons we are where we are today, and you are about to be flooded with a lot of well-informed opinions, and maybe even some not-so well informed. Let's see what you think a few pages into this thread after getting hopefully thoughtful and diverse views. Keep an open mind, I've certainly had my eyes opened here, and have changed my mind on some things, but also have renewed strength in other things I believe in. Also, if you can, and maybe you already have, join L2 for even more extensive FUN!  8)
Title: Re: Shuttle Q&A Part 5
Post by: Weasel Pilot on 09/15/2017 10:38 pm
Both the LOX tank and the LH2 tank had four sensors at the 100% level - a low sensor, two (assumedly) median sensors and a high sensor (plus other sensors at the 98% and overfill levels). Does anybody know how much space there was between the 100% low sensor and the 100% high sensor?  In other words how much vertical space did 1% of propellant take up in the tank?  Obviously due to the tank shapes this would vary with location in the tank, but at the top (100% level) does anyone know what this was?

Dave
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 09/15/2017 11:23 pm
6 inches for the LOX tank, 8 for the LH2 tank
Title: Re: Shuttle Q&A Part 5
Post by: Weasel Pilot on 09/20/2017 12:16 am
Thanks! Awesome response!!
Title: Re: Shuttle Q&A Part 5
Post by: Weasel Pilot on 09/20/2017 05:58 pm
Which begets another question...or actually five -
1. The tank fill schedule (as I understand it) was low flow to 2% then high flow (5,000 gal/min) til 98% then low flow again to 100%
      a. What was the low flow rate?
      b. How do it know?  No 2% sensor...
2. The feed lines openings were offset (as I measure it, 10 degrees for LOX and 6 degrees for LH2). 
      a. I ASSUME that this was to make up for gravity effect, si or no?
      b. Why are these not the same? (density delta twix LO2 & LH2?)
      c. Was the offset towards or away from the orbiter?

Dave
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/20/2017 06:52 pm
Which begets another question...or actually five -
1. The tank fill schedule (as I understand it) was low flow to 2% then high flow (5,000 gal/min) til 98% then low flow again to 100%
      a. What was the low flow rate?
      b. How do it know?  No 2% sensor...
Dave


There is a lot packed into those questions, so let me take the first one since I can answer that pretty quickly and easily.  If someone else doesn't beat me to it, I will try and come back with a good answer to the second question later.

Slow Fill for LO2 to 2% level was based on time (about 11 minutes) at a flow rate of about 270 gallons per minute.
Fast Fill for LO2 to 98% level sensor was at around 1300+ gallons per minute.
LO2 Topping occurred at approximately 800 gallons per minute.
LO2 Replenish was in the neighborhood of 100 gallons per minute.

The launch vehicle was "designed to accept" 5000 gallons of LO2 per minute.  This was from a DOD requirement for so called "rapid response" launching of the shuttle.  However, the facility at KSC was only capable of delivering about 1400 gpm.

Slow Fill for LH2 to 5% occurred at a flow rate of 1200 gallons per minute until the 5% sensor was wet.
Fast Fill commenced at around 6900 gallons per minute until about the 85% level, then switched to "Reduce Fast Fill" until the 98% sensors were wet.
LH2 Topping to the 100% sensor occurred at about 600 gallons per minute.
LH2 Replenish was approximately 200 gallons per minute.

Mark Kirkman
Space Shuttle Hugger and NASA Geek
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/20/2017 07:58 pm

2. The feed lines openings were offset (as I measure it, 10 degrees for LOX and 6 degrees for LH2). 
      a. I ASSUME that this was to make up for gravity effect, si or no?
      b. Why are these not the same? (density delta twix LO2 & LH2?)
      c. Was the offset towards or away from the orbiter?

Dave

No, they were offset due to orbiter hanging off the side of the ET and creating an offset CG and hence, the centerline of thrust was not parallel to the centerline of the ET

Towards the orbiter
Title: Re: Shuttle Q&A Part 5
Post by: Weasel Pilot on 09/21/2017 08:01 pm
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/21/2017 08:16 pm
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?

Thrust (acceleration) vector. It's not "straight up" through the ET.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/22/2017 01:22 pm
Thanks again!  Excellent response/info.

I'm trying to get my (very) limited grey matter wrapped around the offset CG thing - I realize why the CG was offset, but did the offset cause/require a pitch that in turn caused the feed ports to be "canted"?

If the thrust vector does not go through the CG, then there is a moment and the vehicle rotates. 
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/28/2017 03:21 am
For the first few shuttle flights, the CDR executed a +Y translation following the normal +Z translation away from the ET. My question is, when did the +Y translation morph into the +X translation maneuver we’re familiar with?
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 09/30/2017 03:21 pm
Why didn't the shuttle external tank have LOX/LH2 common bulkhead - unlike Saturn S-II ? they were of similar sizes and volumes.
I thought it could have made the E.T lighter, helping the shuttle performance a little ? by 1979 the Air Force was considering strapping Titan engines or solid rocket motors to improve performance.

Could a common bulkhead external tank have been fitted to shuttles as an upgrade ?
Title: Re: Shuttle Q&A Part 5
Post by: Welsh Dragon on 09/30/2017 04:58 pm
SRB thrust beam needed to go between the tanks, didn't it? Guess you could have made a circumferential thrust ring of some description, but that would probably wipe out the weight saving of the common bulkhead.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/30/2017 11:03 pm
Why didn't the shuttle external tank have LOX/LH2 common bulkhead - unlike Saturn S-II ? they were of similar sizes and volumes.
I thought it could have made the E.T lighter, helping the shuttle performance a little ? by 1979 the Air Force was considering strapping Titan engines or solid rocket motors to improve performance.

Could a common bulkhead external tank have been fitted to shuttles as an upgrade ?

Those were NASA studies
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 10/01/2017 07:45 am
Recently was looking at old mission pictures and the images of Challenger post landing and actually in the preflare on 61a gave me a start! The browned burn from nose cap up to the cabin window was striking. I've never seen the shuttle look like that in that area. Was is a different reentry plan? High inclined orbit?
My other question was regarding I believe sts 8 or maybe 9. I read that there was tile slumping. I don't know what that is and what would cause it?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/02/2017 12:26 am
Recently was looking at old mission pictures and the images of Challenger post landing and actually in the preflare on 61a gave me a start! The browned burn from nose cap up to the cabin window was striking. I've never seen the shuttle look like that in that area. Was is a different reentry plan? High inclined orbit?


No, just waterproofing material burning off.  no different entry


My other question was regarding I believe sts 8 or maybe 9. I read that there was tile slumping. I don't know what that is and what would cause it?

I believe it was in the elevon area.  Slumping is melting.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/02/2017 01:06 am
Recently was looking at old mission pictures and the images of Challenger post landing and actually in the preflare on 61a gave me a start! The browned burn from nose cap up to the cabin window was striking. I've never seen the shuttle look like that in that area. Was is a different reentry plan? High inclined orbit?


No, just waterproofing material burning off.  no different entry

Yes. What they used pre-Challenger was stock 3M ScotchGuard that was sprayed directly onto the orbiter. It was later found that the ScotchGuard wasn’t working too well with the adhesive used to bond the tiles to the orbiter. This caused alot tiles to debond and was what was really behind the “TPS issues” with Challenger that forced her substitution with Discovery for STS-51C. In fact the problems were so severe that they removed Challenger’s original body flap and used the one intended for Atlantis. The body flaps were never changed back prior to the loss of Challenger so even to this day, Atlantis still have the refurbished body flap from Challenger.
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 10/02/2017 07:20 am
Great, thanks for the quick response gang! I knew someone here had the answer. I love this site.
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 10/02/2017 04:03 pm
Neat. Was there any other major hardware from Challenger/Columbia that made it to the end of the program? I seem to recall something about a custom payload mounting structure actually being recovered from Columbia's debris and studied for use on a later mission, don't think it happened though
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 10/03/2017 12:39 am
Here is a link to an AIAA paper on the Orbiter TPS:  https://arc.aiaa.org/doi/abs/10.2514/6.2011-7308
that Wayne Hale also mentioned in his L2 post:  https://forum.nasaspaceflight.com/index.php?topic=29231.msg1611589#msg1611589

Yes. What they used pre-Challenger was stock 3M ScotchGuard that was sprayed directly onto the orbiter. It was later found that the ScotchGuard wasn’t working too well with the adhesive used to bond the tiles to the orbiter. This caused alot tiles to debond and was what was really behind the “TPS issues” with Challenger that forced her substitution with Discovery for STS-51C. In fact the problems were so severe that they removed Challenger’s original body flap and used the one intended for Atlantis. The body flaps were never changed back prior to the loss of Challenger so even to this day, Atlantis still have the refurbished body flap from Challenger.
Title: Re: Shuttle Q&A Part 5
Post by: AJA on 11/14/2017 08:00 pm
First post back in a long time... and that too when I realised that I already knew a place where someone would have an answer for the question I'd ask.


I was catching up on Wayne Hale's posts - and then scrolled down to see the post on the PAL Ramps.


Then it struck me.


Was the possibility of spraying the protective foam on the underside of the orbiter ever mooted? It could have been manually/automatically discarded once the shuttle achieved orbit (chucked into a decay orbit), or even once it was out of a bulk of the atmosphere (perhaps at altitudes where expendables shed the payload fairing) - on the way uphill, after ET Sep.


That'd have made the stack a little more immune to foam IMPACTS on the TPS?


(It might have exacerbated some other problem - like impacts to the SSME nozzles/boosters, or may have made the aerodynamics very very untenable?)


Can someone point me in the way of the material that did the analysis of this mitigation possibility?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/19/2017 10:12 pm
Any Shuttle Entry FDOs left around here? If so, what was generally the de-orbit burn targets like? I'm thinking of Hp and de-orbit burn to EI angles.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 12/04/2017 12:43 am
Some of the Forward RCS tank support struts on STS-1 buckled because of the SRB ignition overpressure. 

Some light discussion in the archives is at https://forum.nasaspaceflight.com/index.php?topic=10600.msg231831#msg231831

Is there any more information (photos, diagrams, reports) on this little-known incident?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 12/04/2017 05:22 am
All I could find was the following in the STS-1 IFA List:

Quote
DISCUSSION: The forward RCS oxidizer aft Z strut failed in Euler buckling due to the lift-off dynamic response from the SRB overpressure.  The forward and
aft Z axis tank struts on both the fuel and the oxidizer tanks were replaced with struts reinforced by plies of boron/epoxy.  The rod end diameter of the fuel tank struts was
increased by 1/16 in. to be the same as the diameter of the oxidizer struts.   
The base heat shield left and right struts were reinforced and replaced.  All other large mass support systems were reassessed for positive margins.   CONCLUSION: Z axis
accelerations exceeded design limits due to SRB overpressure which resulted in deformation of the forward RCS oxidizer tank aft Z strut.    CORRECTIVE_ACTION:
Forward RCS struts were modified and replaced.  Base heat shield left and right struts were reinforced and replaced.  All large mass structures were analyzed and found to
have positive margins of safety.   CAR ANALYSIS: Descriptions of damage, causes, and corrective actions are defined in the preceding. [not included in original problem
report]   EFFECTS_ON_SUBSEQUENT_MISSIONS: None   

Its listed as IFA STS-1-V-58, but google turned up nothing more interesting. No other information or pictures are in the final Mission Report either.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 12/04/2017 12:10 pm
Thanks, the Final Mission Report showed up in my search too. I should have called this a poorly-documented incident, rather than of a little-known one.  For a major structural failure that could have resulted in LOC, there is a surprising lack of documentation on what the heck happened. 

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: Galactic Penguin SST on 12/30/2017 10:24 am
Re-posting a question I have from the Shuttle-Centaur thread:

A theoretical question: What is the maximum payload the Shuttle with Centaur (both versions) could have pushed to a standard GTO (*) or to a trans-Mars trajectory?

(*) I know that most of such missions would had smaller satellites doing direct injection to geostationary, but just let's say that we have the satellite making the circulation burns here.  ;)

Also what is the maximum size of the volume that can be allocated to the payload in the Shuttlr Orbiter cargo bay?

The figures I have seen are only for direct geostationary insertion missions, and they don't give out the payload volume that can be used (which looked rather small).
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/30/2017 07:48 pm
Re-posting a question I have from the Shuttle-Centaur thread:

A theoretical question: What is the maximum payload the Shuttle with Centaur (both versions) could have pushed to a standard GTO (*) or to a trans-Mars trajectory?

(*) I know that most of such missions would had smaller satellites doing direct injection to geostationary, but just let's say that we have the satellite making the circulation burns here.  ;)

Also what is the maximum size of the volume that can be allocated to the payload in the Shuttlr Orbiter cargo bay?

The figures I have seen are only for direct geostationary insertion missions, and they don't give out the payload volume that can be used (which looked rather small).

40 feet for G, 34 for G'
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 01/04/2018 12:25 pm
Does anybody have access to a hi-res photo of the large NASA plaques as seen on the seatbacks of the seats inside Endeavour? https://www.nasa.gov/sites/default/files/endeavour_closeout-_full_1.jpg

Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: damnyankee36 on 01/04/2018 07:13 pm
Sorry to hijack your post, but I am surprised at the potential FOD this tech is wearing.  Watch, bracelet, pen in pocket...

Maybe in this particular image this was a retired orbiter or otherwise not space-bound.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/04/2018 07:25 pm
Sorry to hijack your post, but I am surprised at the potential FOD this tech is wearing.  Watch, bracelet, pen in pocket...

Maybe in this particular image this was a retired orbiter or otherwise not space-bound.
This photo was taken during Endeavour's T&R processing. Otherwise there would be a mandatory bunny suit requirement for when working inside the crew module and payload bay. This requirement was dropped once the T&R processing began as the orbiter wouldn't fly again, ever.
Title: Re: Shuttle Q&A Part 5
Post by: john57sharp on 01/16/2018 07:19 pm
Good evening all, we have just watched the 2 Mission Control documentaries on YouTube and we wondered whether there were always film crews in Mission Control or where they there because there was a whiff of an issue, this relates particularly to the SLS-107 disaster, which seemed to have been covered by a number of cameras in amongst the controllers at a very critical time, or is it perhaps clever editing is existing footage to provide pictures for the r3corded audio?

I hope I’m mak8ngbsome sense?

Cheers
John
Title: Re: Shuttle Q&A Part 5
Post by: cebri on 02/19/2018 07:14 pm
Hello, yet another question.  ;D

In my understanding, in the original design of SRB joints, Zinc Chromate was used to seal the joint so the fuel wouldn't reach the O-Rings in the first place. Yet, O-Ring erosion was present since the second flight. Did the Zinc Chromate Putty ever worked?  Or this wasn't its function at all?

Thanks¡
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/19/2018 08:21 pm
Good evening all, we have just watched the 2 Mission Control documentaries on YouTube and we wondered whether there were always film crews in Mission Control or where they there because there was a whiff of an issue, this relates particularly to the SLS-107 disaster, which seemed to have been covered by a number of cameras in amongst the controllers at a very critical time, or is it perhaps clever editing is existing footage to provide pictures for the r3corded audio?

I hope I’m mak8ngbsome sense?

Cheers
John

There are always crews in there for major events.
Title: Re: Shuttle Q&A Part 5
Post by: IanThePineapple on 02/19/2018 09:40 pm
Popping in here to ask a quick question: what happened/will happen to the Apollo/Shuttle MLPs? I know SLS had its own MLP built, but what happened or will happen to the original 3 Shuttle ones?

Thanks!
-Ian
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 02/20/2018 01:20 am
OrbitalATK has one of them for NGL, if that ever flies. The other 2 are still sitting around waiting for use, been a few studies by different companies but no firm plans
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 02/23/2018 12:37 pm
unpacking after moving house, i came accross two old Shuttle manifests. Going through them, i stumbled over an Inmarsat payload manifested for the 4th quarter of 1994.
A late 1991 version of the manifest, has the Inmarsat payload removed and the secondary objective (SFU-RETR) moved to 1995. There is an empty Atlantis for STS-68 manifested for August '94 so maybe that was supposed to be the Inmarsat flight.

Obviously, there was never an Inmarsat that was deployed by Shuttle but i have not yet heared about one of their payloads being switched from Shuttle to an ELV. Was it just an experiment carried aboard (although, it appears to be a primary payload in the manifest)? Can an anyone shed light on that? Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 02/23/2018 01:22 pm
unpacking after moving house, i came accross two old Shuttle manifests. Going through them, i stumbled over an Inmarsat payload manifested for the 4th quarter of 1994.
A late 1991 version of the manifest, has the Inmarsat payload removed and the secondary objective (SFU-RETR) moved to 1995. There is an empty Atlantis for STS-68 manifested for August '94 so maybe that was supposed to be the Inmarsat flight.

Obviously, there was never an Inmarsat that was deployed by Shuttle but i have not yet heared about one of their payloads being switched from Shuttle to an ELV. Was it just an experiment carried aboard (although, it appears to be a primary payload in the manifest)? Can an anyone shed light on that? Thanks!

What is the source and date of the manifest?  It isn't a NASA document.  It may be an error.
Title: Re: Shuttle Q&A Part 5
Post by: thomasafb on 02/23/2018 04:13 pm

What is the source and date of the manifest?  It isn't a NASA document.  It may be an error.


i received it from NASA as a kid. Among a load of "Information Summaries" brochures.

EDIT: on second thought, i might have gotten these two documents together with the STS press kits i requested before each flight from JSC (mail code AP-4).
As for the date, i must have been in '91 - i remember having them pinned on my wall and editing them as the years unfolded.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 03/06/2018 10:11 pm
Below is a picture of OV-105 Endeavour on display at the California Science Center.

If I came across an Orbiter that had just ditched in a lake and was resting in a few feet of water, "assuming" a perfect water landing(I've seen the water landing testing in the wave pool)

The Yellow arrow with the word "RESCUE" in black letters appears to point at a small red dot.

1) What is the red dot?

2)   Could I open the hatch from the outside?

3) Is there any way for a rescuer to access the Orbiter without tools?
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 03/06/2018 10:53 pm
The red dot is a cover over the fitting for the "External Side Hatch Opening/Closing Device". It also is compatible with a 1/2" or 5/8" drive with a 12 inch extension. The cover is designed to be punched through by the tool.

There is no way to open the orbiter without tools without crew assistance (if the crew is able to actuate the hatch themselves though, or use the hatch/Window 8 jettison, then it can be done tool-free. But all those are only controllable from inside)
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 03/09/2018 03:20 pm
Contingency abort planning only required local emergency crews to establish a minimum 2,500' perimeter around the vehicle and keep people away. There was no requirement to attempt to rescue the crew. Let them do their jobs and egress. If they can't, then it's over.

Contingency aborts were all pretty thin.
Title: Re: Shuttle Q&A Part 5
Post by: Zero-G on 03/13/2018 03:50 pm
What is a "sawtooth doubler"? This piece of equipment is mentioned in the book "Bringing Columbia Home", but the author gives only a rudimentary description (page 164):
Quote
This two-foot by two-foot plate -roughly in the shape of the orbiter itself- had been bonded underneath the orbiter and then covered with tiles.
What is its correct designation and its actual function and purpose? Where exactly was it mounted and what is its actual shape? Was this piece unique to Columbia or did every orbiter have it?
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 03/14/2018 12:13 am
I've been looking through all the Shuttle manufacturing pictures I can find and can't find anything looking like this on any orbiter, though in fairness it is hard to find good shots of the underside before TPS application. A doubler is typically a repair patch though, basically a metal plate attached over a damaged section of a structure. A quick search turned up several Orbiter repairs of this type using that term, so it probably means the same here. Only thing I can guess was that the orbiter was damaged at some point prior. The terminology used ("had been bonded onto") kinda-sorta supports this.
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 03/14/2018 12:50 am

What is the source and date of the manifest?  It isn't a NASA document.  It may be an error.


i received it from NASA as a kid. Among a load of "Information Summaries" brochures.

EDIT: on second thought, i might have gotten these two documents together with the STS press kits i requested before each flight from JSC (mail code AP-4).
As for the date, i must have been in '91 - i remember having them pinned on my wall and editing them as the years unfolded.

These look like manifests that were printed on the back cover of the JSC News Roundup from that period. I may still have some in my collection somewhere. Don't recall them being a standalone product, but JSC PAO works in mysterious ways.

STS-68 ended up getting the second flight of Space Radar Laboratory. I vaguely recall Inmarsat being on the manifest, but it must not have ever gotten within L-24 months, else someone from my group would have been assigned to design the deploy trajectory. (I worked IBSS deploy/retrieve on STS-39, and ORFEUS-SPAS deploy/retrieve on STS-51, re-manifested from STS-54.)
Title: Re: Shuttle Q&A Part 5
Post by: wally on 03/23/2018 07:32 am
Can someone help me with the SSMEs serial numbers for STS-134 and STS-135? All I have is this chart (http://www.collectspace.com//review/sts133_ssmechart-lg.jpg), but it's not updated for the last two missions. Thank you.

Also, as a follow-up question, why does some engines have two or three numbers? Like 2012 | 2107 or 2036 | 2045?

Edit: I've found the answer to my first question: 2059, 2061 and 2057 for STS-134 and 2047, 2060, 2045 for STS-135.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 03/23/2018 10:59 am

Also, as a follow-up question, why does some engines have two or three numbers? Like 2012 | 2107 or 2036 | 2045?


SSMEs were given a new serial number whenever there was a major upgrade to a new Phase or Block.

For the examples you gave:

2012 / 2107   Phase I / Phase II
2036 / 2045   Block I / Blocks IIA  & II
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 03/23/2018 02:45 pm
Can someone help me with the SSMEs serial numbers for STS-134 and STS-135? All I have is this chart (http://www.collectspace.com//review/sts133_ssmechart-lg.jpg), but it's not updated for the last two missions. Thank you.

Also, as a follow-up question, why does some engines have two or three numbers? Like 2012 | 2107 or 2036 | 2045?

Edit: I've found the answer to my first question: 2059, 2061 and 2057 for STS-134 and 2047, 2060, 2045 for STS-135.
Don't forget the 2010 build E-2062 and the 2014 build E-2063.

ME-2063 was first hotfired on October 19, 2017.  3 month build condensed into 2 minutes.
http://www.youtube.com/watch?v=HtE_61ZR67Y

Both are scheduled to support SLS-2.
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 03/24/2018 04:52 am
One question that popped into my mind last night was, what was the payload weight penalty for having the obss installed? Was the ability to throttle to 104.5% able to claw some of the weight back?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 04/16/2018 05:56 am
Wow, I expected someone would have an answer since you are all super fast! Usually it's answered as I hit post lol
Title: Re: Shuttle Q&A Part 5
Post by: MKremer on 04/16/2018 03:05 pm
One question that popped into my mind last night was, what was the payload weight penalty for having the obss installed? Was the ability to throttle to 104.5% able to claw some of the weight back?
Found this reference:

      "OBSS boom mass is listed as 536 lbs (243.1255 Kg) for STS-124 on "SPACE SHUTTLE MISSIONS SUMMARY" (NASA/TM–2011–216142)."

here: https://sourceforge.net/p/shuttleultra/tickets/49/
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 04/16/2018 04:25 pm
One question that popped into my mind last night was, what was the payload weight penalty for having the obss installed? Was the ability to throttle to 104.5% able to claw some of the weight back?

The OBSS flight kit (MV0092A) is listed as 842 lb in Shuttle Payload Integration Cargo Evaluation (SPICE) documents. These are available in L2 for STS-130 thru STS-133.

See also:

http://www.wiki-zero.com/index.php?q=aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnL3dpa2kvU1RTLTExOQ (http://www.wiki-zero.com/index.php?q=aHR0cHM6Ly9lbi53aWtpcGVkaWEub3JnL3dpa2kvU1RTLTExOQ)

which also gives this mass (this is for the whole system, not just the boom)
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 04/17/2018 05:34 am
Awesome information thanks!
Title: Re: Shuttle Q&A Part 5
Post by: capcomespace on 04/19/2018 05:00 pm
I don't know if this question was in previous thread:
What is first mission STS tobe used the new RPSF at KSC for checkout the SRM motor ?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 04/20/2018 06:08 am
My memory is a little wacky but I believe it was sts-26, but don't quote me on it.
Title: Re: Shuttle Q&A Part 5
Post by: capcomespace on 04/22/2018 05:05 am
Think you, SRM of STS 26 was checked in RPSF, It's sure. I thinked any mission before in 1985.
Title: Re: Shuttle Q&A Part 5
Post by: rayleighscatter on 05/13/2018 03:19 pm
Shortly before launch there was always the step of clearing the caution/warning memory. Does this mean that during the pre-launch phase caution/warning messages were routine? And does anyone know what sorts of warnings would show up that needed to be cleared before launch?
Title: Re: Shuttle Q&A Part 5
Post by: HelixSpiral on 05/15/2018 07:40 pm
Cabin pressure for one. It was tested every time. There may have been nuisance alarms, or even real alarms that were then resolved by the crew and/or LCC. The memory was cleared to remove any "is that a new fault or that one from before liftoff?" moments. I recall from some in-cabin videos crews noting that there was nothing to clear during that step (they still performed the step anyway).
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/26/2018 06:54 pm
Were there potential Shuttle crewmembers that refused to fly on proposed Shuttle-Centaur missions(Galileo, Ulysses, Magellan)?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 06/27/2018 04:50 am
I don't think any of the astronauts would refuse an assignment. To do so, especially under George Abbey, would be career suicide.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/28/2018 11:51 am
I don't think any of the astronauts would refuse an assignment. To do so, especially under George Abbey, would be career suicide.
So long as it wasn't a Return To Launch Site trial for STS-1.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/05/2018 05:32 pm
Anyone know the clocking of the holddown posts on the SRB Aft Skirt in relation to the Booster Z axis?
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 07/05/2018 05:45 pm
With regards to the above, is the clocking the same for the SLS boosters?

(Working on an RSRM model right now)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 07/06/2018 01:04 am
DaveS, is this what you're looking for?
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: zubenelgenubi on 07/06/2018 02:38 am
Were there potential Shuttle crewmembers that refused to fly on proposed Shuttle-Centaur missions (Galileo, Ulysses, Magellan)?

Flights of the ‘Death Star’
written by Chris Bergin October 26, 2005
https://www.nasaspaceflight.com/2005/10/flights-of-the-death-star/

Quote
In early January 1986, [STS-61F commander Fred] Hauck recalled, "we were working an issue to do with redundancy in the helium actuation system for the liquid oxygen [and] liquid hydrogen dump valves and it was clear that the [Shuttle management] was willing to compromise on the margins in the propulsive force being provided by the pressurised helium. We were very concerned about it."

(STS-61F was to launch Ulysses.)

Quote
"We had discussions about it with the technical people, but we went to a [review] board to argue why this was not a good idea to compromise on this feature. The board turned down the request. I went back to the crew office and said to my crew, in essence, 'NASA is doing business differently from the way it has in the past. Safety is being compromised and, if any of you want to take yourself off this flight, I will support you.'"

Two Shuttles, Two Launches, One Planet…and a Five-Day Goal
By Ben Evans, May 17, 2012
http://www.americaspace.com/2012/05/17/two-shuttles-two-launches-one-planetand-a-five-day-goal/

John Fabian was announced as a member of the STS-61G (Galileo launch) crew in May 1985, and resigned from the mission a few months later.  (He resigned from NASA, effective January 1, 1986.)

Quote
One of the reasons for Fabian’s departure was his conviction that NASA prized commercial respectability above operational flight safety. He spent enough time with the 61G crew to see a technician clambering onto the Centaur with an untethered wrench in his back pocket and another smoothing out a weld, then accidentally scarring the booster’s thin skin with a tool. In Fabian’s mind, it was bad enough that the Shuttle was carrying a volatile booster with limited redundancy, without adding new worries about poor quality control oversight and a lax attitude towards safety.

Considering his post-NASA career, according to his NASA bio, last updated in December 1993, Fabian proceeded to
Quote
become Director of Space, Deputy Chief of Staff, Plans and Operations, Headquarters USAF.

Colonel Fabian retired from the USAF in June 1987 and joined Analytic Services Inc (ANSER), a non-profit aerospace professional services firm in Arlington, Virginia, where he is now President and Chief Executive Officer.
https://www.jsc.nasa.gov/Bios/htmlbios/fabian-jm.html
Title: Re: Shuttle Q&A Part 5
Post by: IanThePineapple on 07/10/2018 05:52 pm
Which mobile launcher umbilical towers became the fixed service structures at 39A and 39B? I know ML-1's umbilical tower was scrapped, but I don't know which pads ML-2 and 3's umbilical towers went to.

Thanks for the help!
Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 07/11/2018 06:44 pm
None? The fixed service structures have been there since the start of the Shuttle program, they're part of the pad not the MLPs
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/11/2018 07:06 pm
None? The fixed service structures have been there since the start of the Shuttle program, they're part of the pad not the MLPs
The Fixed Service Structures were created by disassembling the old Saturn V LUTs and trucking them, segment-by-segment to the pads. Pad A's FSS was created from the LUT on ML-2 and the FSS on Pad B was the ML-1 LUT. ML-3's LUT went into the "LUT Bone Yard" in the KSC Industrial Area after it had been removed from ML-3 in order to convert ML-3 into MLP-3 for the shuttle program.

Only the Rotating Service Structures were new builds.
Title: Re: Shuttle Q&A Part 5
Post by: IanThePineapple on 07/11/2018 07:52 pm
None? The fixed service structures have been there since the start of the Shuttle program, they're part of the pad not the MLPs
The Fixed Service Structures were created by disassembling the old Saturn V LUTs and trucking them, segment-by-segment to the pads. Pad A's FSS was created from the LUT on ML-2 and the FSS on Pad B was the ML-1 LUT. ML-3's LUT went into the "LUT Bone Yard" in the KSC Industrial Area after it had been removed from ML-3 in order to convert ML-3 into MLP-3 for the shuttle program.

Only the Rotating Service Structures were new builds.

Wasn't ML-1 renamed MLP-3 since it was the last to be reconfigured for Shuttle? I thought I read ML-1 became MLP-3 and ML-3 became MLP-1, with ML-2 becoming MLP-2.

So, would it be:

ML-1 (MLP-3): LUT disassembled, scrapped in 2004
ML-2 (MLP-2): LUT became 39A FSS
ML-3 (MLP-1): LUT became 39B FSS

Is that right?
Thanks for the help!
Title: Re: Shuttle Q&A Part 5
Post by: whitelancer64 on 07/12/2018 04:36 pm
None? The fixed service structures have been there since the start of the Shuttle program, they're part of the pad not the MLPs
The Fixed Service Structures were created by disassembling the old Saturn V LUTs and trucking them, segment-by-segment to the pads. Pad A's FSS was created from the LUT on ML-2 and the FSS on Pad B was the ML-1 LUT. ML-3's LUT went into the "LUT Bone Yard" in the KSC Industrial Area after it had been removed from ML-3 in order to convert ML-3 into MLP-3 for the shuttle program.

Only the Rotating Service Structures were new builds.

Wasn't ML-1 renamed MLP-3 since it was the last to be reconfigured for Shuttle? I thought I read ML-1 became MLP-3 and ML-3 became MLP-1, with ML-2 becoming MLP-2.

So, would it be:

ML-1 (MLP-3): LUT disassembled, scrapped in 2004
ML-2 (MLP-2): LUT became 39A FSS
ML-3 (MLP-1): LUT became 39B FSS

Is that right?
Thanks for the help!

Yes, that is correct.

Shuttle MLP-1 was formerly Apollo ML-3, and Shuttle MLP-3 was Apollo ML-1. ML-1 was the last ML converted for the Shuttles because it was used for Skylab crew launches, and the ASTP. In fact, MLP-3 wasn't used for Shuttle launches until 1990.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/04/2018 10:47 pm
Anyone know the depth of the ET umbilical wells on the orbiter? I'm thinking of the full depth of them from the edges to the very top of the keel beams from which the ET Door Drive Mechanism (DDM) linkages protrude from.

Any schematics that show the various elements of the umbilical wells are appreciated!
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 08/09/2018 05:36 pm
https://www.youtube.com/watch?v=JLU4CK7UHd4


In this 17 second clip of what appears to be a pre launch Q&A of STS-1 John Young says in response to a question about ejecting when on the solids, "You just pull the little handle". Does anyone know if the entire Q&A available to watch?

Thank you
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 08/10/2018 05:46 am
Two questions here. On sts-1 there was apparently damage to one of the landing gear doors and some damage to the underside of that door. Any pictures and how that happened?

On sts-3 or 4 I can't remember now, there was damage to the tiles on the front top of the nose area and was seen via the canadarm. That caused this damage?

Thank you
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/10/2018 10:57 am
Penguin have you seen the STS-1 post flight report?

https://www.jsc.nasa.gov/news/columbia/anomaly/STS1.pdf

It’s STS-1-V-49 on page 33, but unfortunately no photos. 
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 08/11/2018 04:54 am
No I haven't. Thank for the reading material for tonight!
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 08/24/2018 05:19 am
OK that was a great read. Thank you.

Now, as I said before sts 3 or 4 had tile damage to the upper nose area above the frcs and below the cabin window. Any idea on what was going on there?

Also I read sts83 had the record for heaviest landing weight but Columbia was not given upgrades to the 6.0 loads. Was there any post landing issues?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/07/2018 01:51 pm

"Roll Program" - What is the crew looking for to cue them to say "Roll Program" and "Roll Program Complete"?
What "triggers" the Roll Program? MET? Velocity? Altitude?

STS-1

-Pre launch I thought I heard the phrase, "up arrow, down arrow"?
-Did the SRB's ignite at T + 3 seconds? I can hear a voice in the nasa feed counting up, "T+1, T+2, T+3".
-What is being called down by the crew at approx. 1:04:00 in the video feed. It is shortly after, "Go at 40". Sounded to me like, "434 max q 48" ???

-Final approach. Chase goes underneath to look at the tiles at approx. 11,000 feet and radios, "Looks real good underneath". I guess that is good to know, a warm and fuzzy? I mean, if it doesn't look good and they are this far already are they going to think about it and decide whether to eject or not?

-When chase is counting down the number of feet to TD where is that altitude coming from? Radar on the chase? Same thing for airspeed?


https://www.youtube.com/watch?v=cT4ADwS66X0&t=3245s

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/07/2018 02:36 pm

What "triggers" the Roll Program? MET? Velocity? Altitude?


Velocity


-Did the SRB's ignite at T + 3 seconds? I can hear a voice in the nasa feed counting up, "T+1, T+2, T+3".


For STS-1, yes. The T-0 time was not adjusted for the "twang" to settle out, as that was characterized late in the program by ground vibrational testing at Stennis using Enterprise, inert boosters, and an ET filled with water. The T-0 time was fixed for STS-2 and all later flights.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/07/2018 02:41 pm

-When chase is counting down the number of feet to TD where is that altitude coming from? Radar on the chase?


Visual
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/07/2018 03:34 pm
I'm in a bit of discussion about whether or not the orbiter was at an slight angle when it was mated to the ET. Based on measurements of the separation planes (FWD and aft) it seems like the orbiter would have to be at an angle to be properly mated to both the FWD and aft points (EO-1 through EO-3).
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/07/2018 07:13 pm

"Roll Program" - What is the crew looking for to cue them to say "Roll Program" and "Roll Program Complete"?
What "triggers" the Roll Program? MET? Velocity? Altitude?

STS-1

-Pre launch I thought I heard the phrase, "up arrow, down arrow"?
-Did the SRB's ignite at T + 3 seconds? I can hear a voice in the nasa feed counting up, "T+1, T+2, T+3".
-What is being called down by the crew at approx. 1:04:00 in the video feed. It is shortly after, "Go at 40". Sounded to me like, "434 max q 48" ???


The roll program was initiated by the flight software at a relative velocity of 127 feet per second.  Up to this point the vehicle was in the "vertical rise" phase.  As the roll program began, the crew would have observed this on the ADI (attitude direction indicator) as well as on the digital readouts of Roll Pitch and Yaw on the BFS version of the Ascent Trajectory Display.  For STS-1, if the crew did not see this taking place as expected, the crew would have taken over manually with the throttle and control stick.  For later shuttle missions, if the roll didn't occur as planned, the first action was to engage the BFS (backup flight software).

You will have to be specific about where/when you heard the reference to "up and down arrows".   Generally, these were depicted on the various GPC CRT Displays to reflect an out of limit condition for a specific parameter.

Yes, for STS-1, lift off was not at T-0 in the countdown.  The auto sequence began at T-28 seconds (versus T-31 for all later flights) and the main engine start sequence began at T-3.4 (iirc) seconds (versus 6.6 for all later launches) and resulted in SRB Ignition after T-0 in the countdown.  MET was set to zero at SRB Ignition.

John called out 434 referencing the airspeed in KEAS (knots equivalent airspeed - pronounced "keys").  This was a surrogate for max dynamic pressure.  On STS-1, it was supposed to be 435 EAS at T+53 seconds.

Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/07/2018 10:05 pm
Drawings in the SLWT System Definition Handbook Vol. 2 show that the FWD attachment point is 16.285 inches above the AFT attachment points.  The FWD and AFT attachment points are 843.60 inches apart, so ARCTAN(16.285/843.60) = 1.106 degrees.
F=ma


I'm in a bit of discussion about whether or not the orbiter was at an slight angle when it was mated to the ET. Based on measurements of the separation planes (FWD and aft) it seems like the orbiter would have to be at an angle to be properly mated to both the FWD and aft points (EO-1 through EO-3).
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 09/08/2018 01:49 am
Drawings in the SLWT System Definition Handbook Vol. 2 show that the FWD attachment point is 16.285 inches above the AFT attachment points.  The FWD and AFT attachment points are 843.60 inches apart, so ARCTAN(16.285/843.60) = 1.106 degrees.
F=ma

For a dry tank or a fueled tank? The ET shrank something like a foot in the vertical direction when cryo-loaded. So that would rotate the forward bipod a bit.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 03:51 am
See Figure III-21. The FWD attachment moved axially by 5.5 inches when the tank was fueled, and the bipod rotated by ARCTAN(5.5/56.341) = 5.576 degrees. I cannot find any loaded dimensions for the AFT attachments.  Either way, the 1.1 degree angle of the Orbiter relative to the ET did not change significantly for a loaded ET. 
F=ma


Drawings in the SLWT System Definition Handbook Vol. 2 show that the FWD attachment point is 16.285 inches above the AFT attachment points.  The FWD and AFT attachment points are 843.60 inches apart, so ARCTAN(16.285/843.60) = 1.106 degrees.
F=ma

For a dry tank or a fueled tank? The ET shrank something like a foot in the vertical direction when cryo-loaded. So that would rotate the forward bipod a bit.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2018 01:10 pm
The meat of the question is now what if any AoA did the orbiter have when mated to the ET?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 02:07 pm
https://www.aiaa.org/uploadedFiles/About-AIAA/History_and_Heritage/Final_Space_Shuttle_Launches/Why_the_Wings_Stay_On.pdf
F=ma


The meat of the question is now what if any AoA did the orbiter have when mated to the ET?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2018 02:17 pm
https://www.aiaa.org/uploadedFiles/About-AIAA/History_and_Heritage/Final_Space_Shuttle_Launches/Why_the_Wings_Stay_On.pdf
F=ma


The meat of the question is now what if any AoA did the orbiter have when mated to the ET?
I meant when while stationary on the MLP, not in-flight. Was the axes of the orbiter and ET/SRB stack different or were they inline with each other?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 02:23 pm
As you know, there are several coordinate systems.  When stacked, the centerline of the Orbiter Payload Bay and the centerline of the ET are parallel, and separated by 336.5 inches.  (edited - 336.5, not 400)
F=ma

https://history.nasa.gov/rogersrep/v3o5.htm
https://history.nasa.gov/rogersrep/v3o6.htm


https://www.aiaa.org/uploadedFiles/About-AIAA/History_and_Heritage/Final_Space_Shuttle_Launches/Why_the_Wings_Stay_On.pdf
F=ma


The meat of the question is now what if any AoA did the orbiter have when mated to the ET?
I meant when while stationary on the MLP, not in-flight. Was the axes of the orbiter and ET/SRB stack different or were they inline with each other?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2018 02:29 pm
Did the orbiter have a pitch bias (positive or negative) when mated to the ET like it when it was mated to the OTS/SCA? When it was mated to either of those two, it was always pitched up by 3°s(6°s for the ALTs). That is what I am trying find out, if it had a positive or negative pitch angle (AKA Angle of Attack) when mated to the ET like it did for everything else it could be mated to.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 05:15 pm
https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/

Scaling from this drawing of the Orbiter/SCA, its FWD attachment is 4.5 feet above the AFT attachments, so the attachment point plane is inclined +3.4 degrees relative to the SCA reference plane (windows/body stripe), or 2.3 degrees higher than the Orbiter/ET stack (1.1 degrees). The Orbiter reference plane (Payload Bay Door sill) is inclined +1.8 degrees relative to the SCA waterline plane, or 1.8 degrees higher than on the Orbiter/ET stack (zero). 

Since this drawing is not CAD or a known scale, these angles are probably not accurate, but if you average them, the Orbiter sits 2 degrees (3 versus 1) more nose-high on the SCA than on the ET. What AOA between the Orbiter and ET are you looking for? The angle of the wings relative to the ET?  If so, then at the root?  At the chine? 
F=ma


Did the orbiter have a pitch bias (positive or negative) when mated to the ET like it when it was mated to the OTS/SCA? When it was mated to either of those two, it was always pitched up by 3°s(6°s for the ALTs). That is what I am trying find out, if it had a positive or negative pitch angle (AKA Angle of Attack) when mated to the ET like it did for everything else it could be mated to.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2018 05:22 pm
https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/ (https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/)

Scaling from this drawing of the Orbiter/SCA, its FWD attachment is 4.5 feet above the AFT attachments, so the attachment point plane is inclined +3.4 degrees relative to the SCA reference plane (windows/body stripe), or 2.3 degrees higher than the Orbiter/ET stack (1.1 degrees). The Orbiter reference plane (Payload Bay Door sill) is inclined +1.8 degrees relative to the SCA waterline plane, or 1.8 degrees higher than on the Orbiter/ET stack (zero). 

Since this drawing is not CAD or a known scale, these angles are probably not accurate, but if you average them, the Orbiter sits 2 degrees (3 versus 1) more nose-high on the SCA than on the ET. What AOA between the Orbiter and ET are you looking for? The angle of the wings relative to the ET?  If so, then at the root?  At the chine?
The orbiter X-axis which goes through the nose. I have attached a schematic of Discovery at a level attitude. Is that how the how the orbiter would sit on the ET or would it be at an angle relative to the X axis?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 05:50 pm
My assessment is yes. The Orbiter X-axis in your image runs through the centerline of the Orbiter Payload Bay, and is parallel to the centerline of the ET, separated by 336.5 inches (see Reply #3546).
F=ma

https://history.nasa.gov/rogersrep/v3o5.htm



https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/ (https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/)

Scaling from this drawing of the Orbiter/SCA, its FWD attachment is 4.5 feet above the AFT attachments, so the attachment point plane is inclined +3.4 degrees relative to the SCA reference plane (windows/body stripe), or 2.3 degrees higher than the Orbiter/ET stack (1.1 degrees). The Orbiter reference plane (Payload Bay Door sill) is inclined +1.8 degrees relative to the SCA waterline plane, or 1.8 degrees higher than on the Orbiter/ET stack (zero). 

Since this drawing is not CAD or a known scale, these angles are probably not accurate, but if you average them, the Orbiter sits 2 degrees (3 versus 1) more nose-high on the SCA than on the ET. What AOA between the Orbiter and ET are you looking for? The angle of the wings relative to the ET?  If so, then at the root?  At the chine?
The orbiter X-axis which goes through the nose. I have attached a schematic of Discovery at a level attitude. Is that how the how the orbiter would sit on the ET or would it be at an angle relative to the X axis?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/08/2018 05:58 pm
My assessment is yes. The Orbiter X-axis in your image runs through the centerline of the Orbiter Payload Bay, and is parallel to the centerline of the ET, separated by 336.5 inches (see Reply #3546).
F=ma

https://history.nasa.gov/rogersrep/v3o5.htm



https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/ (https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/)

Scaling from this drawing of the Orbiter/SCA, its FWD attachment is 4.5 feet above the AFT attachments, so the attachment point plane is inclined +3.4 degrees relative to the SCA reference plane (windows/body stripe), or 2.3 degrees higher than the Orbiter/ET stack (1.1 degrees). The Orbiter reference plane (Payload Bay Door sill) is inclined +1.8 degrees relative to the SCA waterline plane, or 1.8 degrees higher than on the Orbiter/ET stack (zero). 

Since this drawing is not CAD or a known scale, these angles are probably not accurate, but if you average them, the Orbiter sits 2 degrees (3 versus 1) more nose-high on the SCA than on the ET. What AOA between the Orbiter and ET are you looking for? The angle of the wings relative to the ET?  If so, then at the root?  At the chine?
The orbiter X-axis which goes through the nose. I have attached a schematic of Discovery at a level attitude. Is that how the how the orbiter would sit on the ET or would it be at an angle relative to the X axis?
So the difference in heights of the attachment points (FWD vs aft) doesn't make the orbiter X-axis have an angle?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/08/2018 06:06 pm
I'd bet you a krona that they designed it that way.
F=ma


My assessment is yes. The Orbiter X-axis in your image runs through the centerline of the Orbiter Payload Bay, and is parallel to the centerline of the ET, separated by 336.5 inches (see Reply #3546).
F=ma

https://history.nasa.gov/rogersrep/v3o5.htm



https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/ (https://www.the-blueprints.com/blueprints/modernplanes/modern-sa-st/56557/view/space_shuttle_boeing_747/)

Scaling from this drawing of the Orbiter/SCA, its FWD attachment is 4.5 feet above the AFT attachments, so the attachment point plane is inclined +3.4 degrees relative to the SCA reference plane (windows/body stripe), or 2.3 degrees higher than the Orbiter/ET stack (1.1 degrees). The Orbiter reference plane (Payload Bay Door sill) is inclined +1.8 degrees relative to the SCA waterline plane, or 1.8 degrees higher than on the Orbiter/ET stack (zero). 

Since this drawing is not CAD or a known scale, these angles are probably not accurate, but if you average them, the Orbiter sits 2 degrees (3 versus 1) more nose-high on the SCA than on the ET. What AOA between the Orbiter and ET are you looking for? The angle of the wings relative to the ET?  If so, then at the root?  At the chine?
The orbiter X-axis which goes through the nose. I have attached a schematic of Discovery at a level attitude. Is that how the how the orbiter would sit on the ET or would it be at an angle relative to the X axis?
So the difference in heights of the attachment points (FWD vs aft) doesn't make the orbiter X-axis have an angle?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 09/13/2018 12:19 am
Thank you Wolfpack, Jim and Mark!
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 09/14/2018 02:10 am
Did the orbiter have a pitch bias (positive or negative) when mated to the ET like it when it was mated to the OTS/SCA? When it was mated to either of those two, it was always pitched up by 3°s(6°s for the ALTs). That is what I am trying find out, if it had a positive or negative pitch angle (AKA Angle of Attack) when mated to the ET like it did for everything else it could be mated to.
I recall that the attachment angle used for actual transport flights was different than the angle used for the Approach and Landing Test.  For ferry flights, the Orbiter was mounted at 3º

"The forward support assembly consisted of two 8’-6” long tubes, which allowed the
orbiter to be mounted at a three-degree angle-of-attack to reduce drag during ferry flights."

Note that these tubes were 13 feet long during the ALT program, giving the Orbiter(Enterprise) a higher Angle of Attack of 7º.

Attachments
#1 Copy of SCA Report
2) Pic Orbiter Vehicle ferry flight front attachment(8-1/2 feet  long-3º)
3) OV Approach and Landing Test front attach (13' long 7º)
4) OV-101 Enterprise stacked atop 905 prior to ALT-14(Freefligh#4) test Oct 12, 1977-Test #4 with Joe Engle and Richard Truly
5) Great view of attach struts during ALT-14(free flight#4)
6) OV-101 Enterprise in ferry flight configuration with shorter 8-1/2  foot long attach struts 3 weeks later November 13, 1977
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 10/29/2018 05:20 pm
Currently trying to wrap my mind around the orbiter weight breakdown.

First, did I got the basic numbers right

- Orbiter weight without the SSME and no payload: 151 000 pounds.

- With the SSME added: 171 000 pounds.

- Maximum landing weight: 240 000 pounds (does that includes a 60 000 pounds full payload bay ?)

Well, is there, somewhere, a detailed breakdown of those 151 000 pounds of empty weight ? The two OMS pods weight 30 000 pounds by themselves, TPs was also pretty heavy - 20 000 pounds. What else ?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 10/30/2018 12:26 am
Archibald, check out the Orbiter weights starting on page D-81 of:

W. Heineman Jr..: “Design Mass Properties II: Mass Estimating and Forecasting for Aerospace Vehicles Based on Historical Data,” Report No. JSC-26098, NASA Johnson Space Center, Houston, TX, November 1994.

http://www.alternatewars.com/BBOW/Space/JSC-26098_Design_Mass_Properties_II.pdf

F=ma

Edit - I uploaded the report, because I can never find the darn thing...
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/30/2018 07:23 am
Does anyone know the Xo locations of the 16 PLBD C/L latches? I have the locations of latches 3 through 16 but I'm lacking the locations of the two forward-most latches.
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 10/30/2018 09:22 am
Archibald, check out the Orbiter weights starting on page D-81 of:

W. Heineman Jr..: “Design Mass Properties II: Mass Estimating and Forecasting for Aerospace Vehicles Based on Historical Data,” Report No. JSC-26098, NASA Johnson Space Center, Houston, TX, November 1994.

http://www.alternatewars.com/BBOW/Space/JSC-26098_Design_Mass_Properties_II.pdf

F=ma
thank you !!
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/30/2018 03:46 pm
Currently trying to wrap my mind around the orbiter weight breakdown.

First, did I got the basic numbers right

- Orbiter weight without the SSME and no payload: 151 000 pounds.

- With the SSME added: 171 000 pounds.

- Maximum landing weight: 240 000 pounds (does that includes a 60 000 pounds full payload bay ?)

Well, is there, somewhere, a detailed breakdown of those 151 000 pounds of empty weight ? The two OMS pods weight 30 000 pounds by themselves, TPs was also pretty heavy - 20 000 pounds. What else ?

27klb of OMS/RCS propellants
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 10/30/2018 03:58 pm
Whew. 27 000 pounds ? Should be 13 metric tons. Thank you Jim.
Well, that make some sense. The orbiter was quite a big and heavy spacecraft, nearly thrice as heavy as an Apollo CSM. Takes a lot of storable propellants to move such a big object across the sky.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 10/30/2018 11:30 pm
You're welcome.  It's a handy report.  Did it answer all your questions?

F=ma


Archibald, check out the Orbiter weights starting on page D-81 of:

W. Heineman Jr..: “Design Mass Properties II: Mass Estimating and Forecasting for Aerospace Vehicles Based on Historical Data,” Report No. JSC-26098, NASA Johnson Space Center, Houston, TX, November 1994.

http://www.alternatewars.com/BBOW/Space/JSC-26098_Design_Mass_Properties_II.pdf

F=ma
thank you !!
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 10/31/2018 04:31 am
Yes it did. Never realized before how heavy were the RCS/OMS systems + their propellants. More or less 1/3 of an orbiter mass by themselves.
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 10/31/2018 12:51 pm
Yes it did. Never realized before how heavy were the RCS/OMS systems + their propellants. More or less 1/3 of an orbiter mass by themselves.

Note this is why the program adopted burning the OMS engines for about a minute shortly after SRB sep--improve upmass, reduce on-orbit mass and improve down mass.
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 10/31/2018 06:25 pm
Yes it did. Never realized before how heavy were the RCS/OMS systems + their propellants. More or less 1/3 of an orbiter mass by themselves.

Note this is why the program adopted burning the OMS engines for about a minute shortly after SRB sep--improve upmass, reduce on-orbit mass and improve down mass.

I'm left wondering, was the OMS/RCS oversized for some reason (safety, something else), or was it the absolute right / minimum size for such a big vehicle ?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 10/31/2018 06:45 pm

I'm left wondering, was the OMS/RCS oversized for some reason (safety, something else), or was it the absolute right / minimum size for such a big vehicle ?

It was sized for flexibility and before direct insertion was developed.
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 11/01/2018 08:57 am
(browsed direct insertion) So they found that the SSMEs could do the final push into orbit better than the OMS pods. Interesting.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/01/2018 01:15 pm
(browsed direct insertion) So they found that the SSMEs could do the final push into orbit better than the OMS pods. Interesting.

Due to ISP difference and acceptable ET disposal location.
Title: Re: Shuttle Q&A Part 5
Post by: Archibald on 11/01/2018 02:37 pm
Yeah, sure, at 450 seconds the SSMEs bury the OMS pods - 315 seconds - any time of the week. And of course their propellant tank is jettisoned (the E.T) and not part of the orbiter. On top of that all this OMS propellant can now be used for orbital manoeuvering.
How much did they gained ? I red somewhere the orbiter had 300 m/s of delta-v to manoeuver in orbit. I wonder with what kind of insertion was this calculated.

Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 11/02/2018 08:27 pm
(browsed direct insertion) So they found that the SSMEs could do the final push into orbit better than the OMS pods. Interesting.

I think they always knew that, but the SSMEs on the first flights were at 100% RPL. 104.5% wasn't certified yet. Hence the OMS-1 burn.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 11/02/2018 10:36 pm
(browsed direct insertion) So they found that the SSMEs could do the final push into orbit better than the OMS pods. Interesting.

I think they always knew that, but the SSMEs on the first flights were at 100% RPL. 104.5% wasn't certified yet. Hence the OMS-1 burn.

Had nothing to do with thrust level.   It was a redesign of the trajectory.  Direct insertion could be done with 100% RPL.  BTW, 104.5% didn't come around until the ISS era.   104% was the standard after STS-6 or so.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/13/2018 03:14 am
DaveS, here are the Xo coordinates that I found.  How do they compare with yours?
F=ma

602.3, 647.3, 692.3, 737.3
783.6, 828.3, 873.0, 917.7
966.4, 1011.1, 1055.8, 1100.5
1144.2, 1184.2, 1224.2, 1264.2

Does anyone know the Xo locations of the 16 PLBD C/L latches? I have the locations of latches 3 through 16 but I'm lacking the locations of the two forward-most latches.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/13/2018 03:10 pm
DaveS, here are the Xo coordinates that I found.  How do they compare with yours?
F=ma

602.3, 647.3, 692.3, 737.3
783.6, 828.3, 873.0, 917.7
966.4, 1011.1, 1055.8, 1100.5
1144.2, 1184.2, 1224.2, 1264.2

Does anyone know the Xo locations of the 16 PLBD C/L latches? I have the locations of latches 3 through 16 but I'm lacking the locations of the two forward-most latches.
Thanks, your coordinates agrees with the one I have found for latches 3-16. You don't happen to have the Yo coordinates for the inboard edges of the door rib beams? I mean the ones that the latches and passive shear fittings are attached to.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/13/2018 11:57 pm
Yes but I need to go back in to the drawings.  Stand by...  OK found them...

At the OML, the starboard (active) PLBD sill beam is Yo = +7.05 inches.  The port (passive) PLBD is Yo = -3.94 inches.

F=ma


DaveS, here are the Xo coordinates that I found.  How do they compare with yours?
F=ma

602.3, 647.3, 692.3, 737.3
783.6, 828.3, 873.0, 917.7
966.4, 1011.1, 1055.8, 1100.5
1144.2, 1184.2, 1224.2, 1264.2

Does anyone know the Xo locations of the 16 PLBD C/L latches? I have the locations of latches 3 through 16 but I'm lacking the locations of the two forward-most latches.
Thanks, your coordinates agrees with the one I have found for latches 3-16. You don't happen to have the Yo coordinates for the inboard edges of the door rib beams? I mean the ones that the latches and passive shear fittings are attached to.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/09/2018 04:05 am
How was the velocity scale of MM103 ASCENT TRAJ 2 handled for HST missions? I'm asking because the scale only goes between 25K and 26K, with the MECO velocity for HST missions going slightly beyond the 26K maximum of the scale. Was it pegged OSH for the last few seconds on those missions or was the scale adjusted for those missions only?
Title: Re: Shuttle Q&A Part 5
Post by: DMeader on 12/11/2018 12:08 am
Yes it did. Never realized before how heavy were the RCS/OMS systems + their propellants. More or less 1/3 of an orbiter mass by themselves.

Note this is why the program adopted burning the OMS engines for about a minute shortly after SRB sep--improve upmass, reduce on-orbit mass and improve down mass.

If they planned on burning the OMS engines to save weight, why not simply load that much less propellant?
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 12/11/2018 02:29 pm


If they planned on burning the OMS engines to save weight, why not simply load that much less propellant?

We don't know that they didn't, certainly for specific missions.  And there is a difference between "saving weight" and performance.
As well, remember the prop tanks in the OMS pods also supported the aft RCS, so there is more to the equations than one might think.  Being able to maneuver and do de-orbit burn(s) are crit1, and of course there are ISS reboosts too.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 12/12/2018 11:53 pm
How was the velocity scale of MM103 ASCENT TRAJ 2 handled for HST missions? I'm asking because the scale only goes between 25K and 26K, with the MECO velocity for HST missions going slightly beyond the 26K maximum of the scale. Was it pegged OSH for the last few seconds on those missions or was the scale adjusted for those missions only?

Although I’ve stared at that particular display a million times, after all these years I really don’t remember how that was dealt with.  Since the MECO target for Hubble was so close to 26,000 (26,088 fps on STS-125) I believe the Cutoff Bug (CO) was placed right next to the 26.  For most of the Space Shuttle Program, until around 2007, the nominal use of that portion of the Trajectory Display was only available in the BFS.  In 2007 the OI-32 software update included modified Trajectory displays for the PASS. Up to that point in time, as contradictory as it sounds, a Nominal MECO was monitored by using the BFS displays.  The original (pre 2007) PASS version of TRAJ 2 (the 2nd stage display) was really only used for monitoring RTLS Aborts and provided very little useful information for a Nominal Ascent.

The last few seconds prior to MECO that bug would start moving.  This usually resulted in a standard call out within the cockpit of “Bug’s Alive”.  Crew’s were trained to verify a Nominal MECO by observing that bug stopped at the CO (cutoff) position which approximated the Inertial Velocity target. Simultaneously, they would feel the nearly instantaneous reduction in G forces from 3 to zero.  They would also see the Chamber Pressure Meters for all 3 engines drop to 0%, illumination of each of the 3 red Engine Status lights, and illumination of the DAP (digital auto pilot) panel lights.

Side note:  I seem to remember that because of hardware/software limitations, the original version of the display overlay was fixed.  And since it was too difficult to change it, we lived with the 25 to 26 on the display even when it wasn’t appropriate.  For example, the display was rescaled for TAL MECO velocities during a TAL abort, but the 25 and 26 labels were still there.  After the new OI-32 software in 2007, I believe they were able to get rid of that issue.  However, as I said earlier I really don’t remember for sure, and I could be talking out of my Butt!

I’ve attempted to attach some screen shots of the original PASS and BFS Displays, followed by a screen shot of the 2 new PASS displays.  The original PASS display was essentially the same for both first and second stage.  The new versions included a separate first and second stage like the BFS always had.

Mark Kirkman
"Space Shuttle Hugger"
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/16/2018 02:34 am
Thanks Mark for the detailed answer. Now on to something different: Did Atlantis retain the additional cameras and TCS that was mounted to the External Airlock truss throughout the Shuttle-Mir program until Discovery and Endeavour flew out the program and Atlantis went to Palmdale to ready her for the ISS assembly missions?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/04/2019 11:33 am
Does anyone know the MET of Ku band antenna deployment on STS-95?
Title: Re: Shuttle Q&A Part 5
Post by: daschmid on 01/15/2019 08:27 pm
What did the Shuttle GLS user interface look like?


I'm building a simulator for the CCMS.  I have a lot very detailed info on the OS and base applications (including the GOAL executor and FEPs) and even a pretty good idea how the GLS works (based on S0007 and the various GLSDD's that are floating around).  Surprisingly, there's virtually no information out there about what the actual screens the console operators interacted with look like.  I've found a single youtube video that briefly shows half of a barely visible screen here:


https://youtu.be/R8aByl2fK5I?t=720 (https://youtu.be/R8aByl2fK5I?t=720)   (skip to 12 minutes in)


From this video and a bit of guesswork I've reconstructed the display in the attached image.  Does anyone know how accurate this is, and what should be on the right side of the screen?


A couple more specific questions:


- It looks to me like the top section with the timers is constant across all GLS displays, and the lower section is replaced depending on the particular GOAL program you're interacting with (SLP07 in this case).  Is this right?


- what do the marks under the VFY/MIP/LIP columns signify?  I'm assuming the columns correspond to the state of mainline verifies, the mainline interrupt processor and LCC interrupt processors? Does it signify if there's a violation for that milestone?


- what does 'ML REVERIFICATION' do?  Is it a user invokable action?


- I'm guessing the 'BFS' and the top center is indicating the current ops?  Should there be a matching 'PASS' mode next to it?


- Although it's hard to see in the source image, above 'LAST HOLD' it looks like 'CPERS', which would be 'contingent performs'?  Is that indicating whether any CPERS are currently running?


- similar to CPERS, I *think* that's 'TB0' in the lower right box, which would be 'Timebase zero'?  is that just a display, or is it indicating something else?


These are pretty obscure details to be worrying about, but I'm basically looking for any info to make this as accurate as possible.   Any insight on what this or other GLS screens should look like or how they behave is greatly appreciated.


Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: Bismuth on 01/16/2019 10:18 pm
Topic, this is hard to explain.
I'm looking for information on the skylab-like units they put in the shuttle bay which they could connect to the hatch and work in a pressurized environment.   These units stay in the shuttle bay.  Am I thinking incorrectly here and the shuttles launched satellites and/or connected to mir/ISS every mission?
Title: Re: Shuttle Q&A Part 5
Post by: Rocket Science on 01/16/2019 10:23 pm
https://www.nasa.gov/mission_pages/station/structure/elements/spacehab.html
http://science.ksc.nasa.gov/shuttle/missions/sts-90/images/images.html
https://directory.eoportal.org/web/eoportal/satellite-missions/s/spacelab
Title: Re: Shuttle Q&A Part 5
Post by: Bismuth on 01/16/2019 10:30 pm
Perfect!  I think it would be way too much to ask to pressurize the whole bay so I'd think they had units to fit in the bay that were pressurized.   Also I've seen the shuttle cockpit and the "locker" room below, so it would be nice to stretch your legs in that sucker.
Title: Re: Shuttle Q&A Part 5
Post by: Rocket Science on 01/16/2019 10:37 pm
Perfect!  I think it would be way too much to ask to pressurize the whole bay so I'd think they had units to fit in the bay that were pressurized.   Also I've seen the shuttle cockpit and the "locker" room below, so it would be nice to stretch your legs in that sucker.
One of our NSF members Jim worked the Spacehab missions 8)
Title: Re: Shuttle Q&A Part 5
Post by: ngilmore on 01/16/2019 10:49 pm
A SpaceHab module is on display at the California Science Center in Los Angeles.

https://californiasciencecenter.org/exhibits/air-space/space-shuttle-endeavour/spacehab
Title: Re: Shuttle Q&A Part 5
Post by: ngilmore on 01/16/2019 10:54 pm
Of interest to the OP:

Quote
On some missions, two modules were flown together to make a SPACEHAB Logistics Double Module, providing more room for experiments and storage.

https://californiasciencecenter.org/exhibits/air-space/space-shuttle-endeavour/spacehab
Title: Re: Shuttle Q&A Part 5
Post by: woods170 on 01/17/2019 11:55 am
Topic, this is hard to explain.
I'm looking for information on the skylab-like units they put in the shuttle bay which they could connect to the hatch and work in a pressurized environment.   These units stay in the shuttle bay.  Am I thinking incorrectly here and the shuttles launched satellites and/or connected to mir/ISS every mission?

I've noticed you've begun asking lots of question all over this forum. And you create a thread for each question.
No offense, but that is not how this forum works.
Specifically for the type of questions you aks there is a Questions & Answers section in this forum: https://forum.nasaspaceflight.com/index.php?board=36.0

I strongly suggest you take your questions there.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/19/2019 12:37 am
SpaceHAB related question: On which missions was either or both of the XO576 bulkhead CCTV cameras (A/D) moved to the aft bulkhead of the SpaceHAB? Two missions I'm aware of are STS-95 (both cameras relocated) and STS-107 (camera D relocated the left camera platform of the SpaceHAB), but where there any others? And what was the reason for relocating these cameras?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 01/21/2019 07:45 pm
SpaceHAB related question: On which missions was either or both of the XO576 bulkhead CCTV cameras (A/D) moved to the aft bulkhead of the SpaceHAB? Two missions I'm aware of are STS-95 (both cameras relocated) and STS-107 (camera D relocated the left camera platform of the SpaceHAB), but where there any others? And what was the reason for relocating these cameras?

STS-57, 60, 63, 77.   The module blocked the view of the cameras for items behind the module
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/22/2019 01:48 am
SpaceHAB related question: On which missions was either or both of the XO576 bulkhead CCTV cameras (A/D) moved to the aft bulkhead of the SpaceHAB? Two missions I'm aware of are STS-95 (both cameras relocated) and STS-107 (camera D relocated the left camera platform of the SpaceHAB), but where there any others? And what was the reason for relocating these cameras?

STS-57, 60, 63, 77.   The module blocked the view of the cameras for items behind the module
Thanks for the answers. Was there anything special they wanted to keep an eye on during those missions? On a similar tangent: The RMS end effector camera, was it different in any way from the other cameras that were mounted on PTUs? Or was it bog standard, just not mounted on a PTU?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/08/2019 08:57 pm
Can someone confirm that the forward-most edge of the PLBD forward curvature are located at XO576 and the aft-most edge where they meet the mid-fuselage is at XO582?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 02/08/2019 09:03 pm
I can at least confirm that where they meet at mid-fuselage is indeed  Xo582
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 02/09/2019 01:23 am
SpaceHAB related question: On which missions was either or both of the XO576 bulkhead CCTV cameras (A/D) moved to the aft bulkhead of the SpaceHAB? Two missions I'm aware of are STS-95 (both cameras relocated) and STS-107 (camera D relocated the left camera platform of the SpaceHAB), but where there any others? And what was the reason for relocating these cameras?

STS-57, 60, 63, 77.   The module blocked the view of the cameras for items behind the module
Thanks for the answers. Was there anything special they wanted to keep an eye on during those missions?

Payloads to be deployed/retrieved by the RMS, for which the cameras gave orthogonal views during berthing/unberthing and capture:
57 - EURECA
60 - WSF
63 - SPARTAN
77 - SPARTAN/IAE

Quote
On a similar tangent: The RMS end effector camera, was it different in any way from the other cameras that were mounted on PTUs? Or was it bog standard, just not mounted on a PTU?

IIRC, the EE camera was mostly bog-standard except that it also had fixed zoom, to avoid confusing the RMS capture cues. The PTU-mounted cameras had variable zoom.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 02/09/2019 12:03 pm
Thanks for the answers Jorge. When you say that the EE camera had a fixed zoom do you mean that its FoV couldn't be altered? I'm pretty sure that it could as I have seen EE camera do this on numerous occasions.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/17/2019 06:02 pm
Forward PLBD apex Xo=574.2, base Xo=583.4. Aft apex/base Xo=1306.9
F=ma

EDIT: this TM reports these numbers: Forward PLBD apex Xo=574.09, base Xo=579.30.
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19920011434.pdf

Can someone confirm that the forward-most edge of the PLBD forward curvature are located at XO576 and the aft-most edge where they meet the mid-fuselage is at XO582?
Title: Re: Shuttle Q&A Part 5
Post by: matain on 03/03/2019 06:58 am
I seem to remember soome footage of a Big Wing Canberra that was going to be monitoring Discovery's descent--flying 'chase'. (https://www.viki.com/users/ppornnapa01_632/about/)Anyone have any links?
Title: Re: Shuttle Q&A Part 5
Post by: joema on 03/10/2019 10:50 pm
I seem to remember soome footage of a Big Wing Canberra that was going to be monitoring Discovery's descent--flying 'chase'. (https://www.viki.com/users/ppornnapa01_632/about/)Anyone have any links?


STS-114 ascent video by a WB-57F at 50,000 ft: https://www.youtube.com/watch?v=zLsSh3AYtFY

https://commons.wikimedia.org/wiki/File:NASA_WB-57F_(NASA_928)_with_WB-57_Ascent_Video_Experiment.jpg
https://airbornescience.nasa.gov/instrument/WAVE
https://en.wikipedia.org/wiki/Martin/General_Dynamics_RB-57F_Canberra

For such a specialized effort, it doesn't look that good. They were apparently having stabilization problems.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/15/2019 10:51 am
Anyone know what happened to Atlantis's ET umbilical well doors? They were removed in the OPF and a Ferry Flight Door set was installed in their place but what became of the actual flight ET umbilical well doors? I have attached the very last photo of them after they had been disconnected and removed from the orbiter.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 03/25/2019 08:16 pm
And SRM question: The case stiffener rings that were on the aft motor segment, were they pre-installed at the factory or at the launch site? The foam and the large outer rings were just additional covering correct? These were not going to present on the FWC aft motor segments, is this also correct?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 04/28/2019 05:19 am
Question about rcs. I've noticed on the control panel that has a low-z selection. I know that this was used on docking to iss. How exactly does this work?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 04/28/2019 05:39 am
Question about rcs. I've noticed on the control panel that has a low-z selection. I know that this was used on docking to iss. How exactly does this work?

“The LOW Z pbi (push button indicator) inhibits all up-firing jets from firing to prevent jet plumes from damaging payloads or Extravehicular Activity (EVA) crewmembers.  If a +Z translation is required, +X and -X jets are commanded to fire since they have a small +Z thrust component.  The -Z translations use the same six downfiring jets whether HIGH, LOW, or NORM Z is selected.  The LOW Z pbi can be toggled on or off, is mutually exclusive with HIGH Z, and can be used regardless of the selection in the other translation axes.”


Mark Kirkman
Space Shuttle Hugger
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 04/29/2019 05:01 am
Amazing. Thanks a lot! After all these years I had no idea that the +X and - X had a slight +Z to them.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 04/30/2019 10:30 am
Ah got it now - I always wondered why there were no upfiring verniers. 
F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/03/2019 03:41 pm
Can someone clarify where the jettison line is for the Ku band DA? I have attached a photo of the DA of OV-103 with two lines, one red and one green. Which one is the correct one?
Title: Re: Shuttle Q&A Part 5
Post by: dror on 06/03/2019 04:14 pm
What would a shuttle mission cost in CRS + CCTCap  prices?
Title: Re: Shuttle Q&A Part 5
Post by: SWGlassPit on 06/03/2019 04:30 pm
What would a shuttle mission cost in CRS + CCTCap  prices?

I'm not sure I really understand the question -- it doesn't make a whole lot of sense to me.

Kind of like asking how many calories an apple would have if you made it out of bananas.
Title: Re: Shuttle Q&A Part 5
Post by: dror on 06/03/2019 06:40 pm
What would a shuttle mission cost in CRS + CCTCap  prices?

I'm not sure I really understand the question -- it doesn't make a whole lot of sense to me.

Kind of like asking how many calories an apple would have if you made it out of bananas.
;D sorry,
Assuming
1. shuttle could carry 20 ton to ISS, AND 7 crew members*
2. CRS prices are about 60-70$ million per ton*
3. CCTCap prices are between 30-50$ million per seat *

So a full shuttle mission would "worth" 1410-1750$ million.
If Shuttle prices were lower than that, does it mean that shuttle was more cost effective than COTS ?!

* My estimates are mostly unsubstantiated. I couldn't find formal prices or capabilities.
So I ask for better opinions

Title: Re: Shuttle Q&A Part 5
Post by: brickmack on 06/05/2019 04:26 pm
What would a shuttle mission cost in CRS + CCTCap  prices?

I'm not sure I really understand the question -- it doesn't make a whole lot of sense to me.

Kind of like asking how many calories an apple would have if you made it out of bananas.
;D sorry,
Assuming
1. shuttle could carry 20 ton to ISS, AND 7 crew members*
2. CRS prices are about 60-70$ million per ton*
3. CCTCap prices are between 30-50$ million per seat *

So a full shuttle mission would "worth" 1410-1750$ million.
If Shuttle prices were lower than that, does it mean that shuttle was more cost effective than COTS ?!

* My estimates are mostly unsubstantiated. I couldn't find formal prices or capabilities.
So I ask for better opinions

Dragon-F9 is like 120 million total, for 6 tons to ISS, thats like 20 million per ton. That'd make a Shuttle flight "worth" more like 610-750 million, about the actual price of a Shuttle flight. Its probably a wash overall. If the CC/CRS vehicles flew as often, their price would probably come down though. Shuttle was definitely cheaper than equivalent Soyuz plus Progress/HTV/ATV cargo flights
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/06/2019 10:07 pm
Q on the gussets that are on the sides of longerons of the orbiter PLB that connect with the Xo576 bulkhead: I'm having a hard time determining if they're are angled outboard at the points where they connect to the bulkhead. I have circled the structures in question, if there's any confusion as to what I am referring to.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 07/12/2019 02:59 pm
Post STS-51-L, was their contingency plans that would have allowed crews to survive a Challenger type incident?   
This is post 51-L so the crew is now in a pressure suit and would have been concious for the rest of the ride up and down.
Were there actual cue cards that would have instructed the crew to blow the hatch and egress a falling crew compartment?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/12/2019 03:55 pm
Post STS-51-L, was their contingency plans that would have allowed crews to survive a Challenger type incident?   
This is post 51-L so the crew is now in a pressure suit and would have been concious for the rest of the ride up and down.
Were there actual cue cards that would have instructed the crew to blow the hatch and egress a falling crew compartment?

https://www.nasa.gov/centers/johnson/pdf/567068main_ASC_135_F_1.pdf

LOC/BREAK-UP cue card (PDF page 215)
Title: Re: Shuttle Q&A Part 5
Post by: jcopella on 07/14/2019 03:33 am
What did the Shuttle GLS user interface look like?


I'm building a simulator for the CCMS.  I have a lot very detailed info on the OS and base applications (including the GOAL executor and FEPs) and even a pretty good idea how the GLS works (based on S0007 and the various GLSDD's that are floating around).  Surprisingly, there's virtually no information out there about what the actual screens the console operators interacted with look like.  I've found a single youtube video that briefly shows half of a barely visible screen here:


https://www.youtube.com/watch?v=R8aByl2fK5I?t=720 (https://www.youtube.com/watch?v=R8aByl2fK5I?t=720)   (skip to 12 minutes in)


From this video and a bit of guesswork I've reconstructed the display in the attached image.  Does anyone know how accurate this is, and what should be on the right side of the screen?

It's very accurate. What's on the right side, if memory serves, are a few additional cursor targets to invoke other GLS tasks. I'd have to go back to my brain book to get the details.

I have some printed copies of the GOAL display skeletons (the static part of the display) that I can dig up if you're still interested in pursuing this project.

(I was a GLS operator during mid-life of the Shuttle program, 1989 thru 1993)

Quote
A couple more specific questions:


- It looks to me like the top section with the timers is constant across all GLS displays, and the lower section is replaced depending on the particular GOAL program you're interacting with (SLP07 in this case).  Is this right?

Yes.


Quote
- what do the marks under the VFY/MIP/LIP columns signify?  I'm assuming the columns correspond to the state of mainline verifies, the mainline interrupt processor and LCC interrupt processors? Does it signify if there's a violation for that milestone?

That's correct. Each hash represents the state of a discrete pseudo function designator (FD) representing whether an inhibit (hold) against the given milestone has been flagged. These hashes were associated with cursor control points on the screen (tab stops, basically) so the operator could "cursor control" (tab) to them and turn them on/off manually, if needed. In practice, we never, ever had to do this, except in cases of software debug/test.


Quote
- what does 'ML REVERIFICATION' do?  Is it a user invokable action?

I'm not 100% sure of this, because if memory serves (it has been a while), this was little-used, but yes, it was a user-invokable action. I believe what it did was scan all of the bookkeeping variables (these were 16-bit "digital pattern" pseudo FDs) for each milestone category to see if any inhibits (holds) were indicated in that category. Don't quote me on that, though -- my vague recollection is this was a feature that may have been needed in the early days but as the software and Shuttle itself matured, we outgrew the need for it.


Quote
- I'm guessing the 'BFS' and the top center is indicating the current ops?  Should there be a matching 'PASS' mode next to it?

You would think so, wouldn't you? I'll check my printed copies and see if that section is accurate/complete.


Quote
- Although it's hard to see in the source image, above 'LAST HOLD' it looks like 'CPERS', which would be 'contingent performs'?  Is that indicating whether any CPERS are currently running?

Precisely.


Quote
- similar to CPERS, I *think* that's 'TB0' in the lower right box, which would be 'Timebase zero'?  is that just a display, or is it indicating something else?

Yes, that's the downlisted RSLS timebase zero value -- the number of seconds remaining until T-0, as determined by RSLS.

Quote
These are pretty obscure details to be worrying about, but I'm basically looking for any info to make this as accurate as possible.   Any insight on what this or other GLS screens should look like or how they behave is greatly appreciated.


Thanks!

Sorry I'm just seeing this now -- had to do a search on GLSDD for another reason and found this post. Like I said, I have some hardcopies of the display skeletons that may be helpful to you if you are still engaged in this project.

p.s. Kudos to you on reverse engineering the semantics of that display from that grainy video and S0007. If you have access to Vol IV, you might find the GLS subsystem section which might provide some additional detail for not only SLP07, but the other GLS displays. As you've correctly surmised, SLP07 was just one of several.
Title: Re: Shuttle Q&A Part 5
Post by: daschmid on 07/16/2019 09:24 pm
What did the Shuttle GLS user interface look like?

From this video and a bit of guesswork I've reconstructed the display in the attached image.  Does anyone know how accurate this is, and what should be on the right side of the screen?

It's very accurate. What's on the right side, if memory serves, are a few additional cursor targets to invoke other GLS tasks. I'd have to go back to my brain book to get the details.

I have some printed copies of the GOAL display skeletons (the static part of the display) that I can dig up if you're still interested in pursuing this project.

(I was a GLS operator during mid-life of the Shuttle program, 1989 thru 1993)


Sweet!  It's great to hear from someone with first hand experience.  Some of your previous posts have been invaluable in figuring this stuff out.


I'm definitely still (slowly) working on it, and every bit of information is appreciated. I'm currently putting together a GOAL compiler/executor and using code automatically generated from parts of the GLSDD as my main test case.  Of course, I'm entirely unsure that the code I'm generating is correct.  I suspect, for example, that the VFY/CVFYs should be in tables rather than separate statements.  GOAL is a weird language.


FYI for those interested, you can find electronic versions of GLSDDs for more than a dozen flights in the wayback machine here:


https://web.archive.org/web/19970609012138/http://lpsweb.ksc.nasa.gov/GLS/Dds/ddmenu.html (https://web.archive.org/web/19970609012138/http://lpsweb.ksc.nasa.gov/GLS/Dds/ddmenu.html)

Quote
p.s. Kudos to you on reverse engineering the semantics of that display from that grainy video and S0007. If you have access to Vol IV, you might find the GLS subsystem section which might provide some additional detail for not only SLP07, but the other GLS displays. As you've correctly surmised, SLP07 was just one of several.


Thanks! And--yup. I've done several trawls through S0007 including Vol IV.  Since the procedures are extremely detailed I've been able to glean quite a bit about the programs, screen contents, PFPK functions, etc.  I've got a list of SAP, SGP and SLP programs I think are all part of GLS. (I'm not sure what they all do yet, but it's a start!)


Another high level question I've had: is the GLSDD the input that's used to generate the executable code, or is there a separate input file that generates both the GLSDD and executable code?  I ask because there's enough variation that it's not always clear to me how to map entries in the GLSDD to GOAL statements.  On the other hand, there are comments like "DELAY 2 SECONDS" that map directly.


Thanks again for your response; this is great!
Title: Re: Shuttle Q&A Part 5
Post by: jcopella on 07/23/2019 10:46 pm
What did the Shuttle GLS user interface look like?

From this video and a bit of guesswork I've reconstructed the display in the attached image.  Does anyone know how accurate this is, and what should be on the right side of the screen?

It's very accurate. What's on the right side, if memory serves, are a few additional cursor targets to invoke other GLS tasks. I'd have to go back to my brain book to get the details.

I have some printed copies of the GOAL display skeletons (the static part of the display) that I can dig up if you're still interested in pursuing this project.

(I was a GLS operator during mid-life of the Shuttle program, 1989 thru 1993)


Sweet!  It's great to hear from someone with first hand experience.  Some of your previous posts have been invaluable in figuring this stuff out.


I'm definitely still (slowly) working on it, and every bit of information is appreciated. I'm currently putting together a GOAL compiler/executor and using code automatically generated from parts of the GLSDD as my main test case.  Of course, I'm entirely unsure that the code I'm generating is correct.  I suspect, for example, that the VFY/CVFYs should be in tables rather than separate statements.  GOAL is a weird language.

Yes, they are in tables, but perhaps not quite in the way you think -- see the rest of my reply, below.

Quote
Another high level question I've had: is the GLSDD the input that's used to generate the executable code, or is there a separate input file that generates both the GLSDD and executable code?  I ask because there's enough variation that it's not always clear to me how to map entries in the GLSDD to GOAL statements.  On the other hand, there are comments like "DELAY 2 SECONDS" that map directly.


Thanks again for your response; this is great!


In terms of automated code generation, the GLSDD was the input file to those tools; there was no other precursor file or automated process that produced the DD itself. Instead, the DD came about via the process of interpreting the LCC&B, the OMRSD, and the KSC LCC Implementation Plan. It was originally authored, and subsequently edited, entirely manually.

However, it's important to understand that the DD didn't generate *all* of the GLS, nor was all of the DD consumed by automated tools -- it was a hybrid kind of thing. The way the DD served automation of the GLS software was primarily in two areas: generation of the MIPs & LIPs and their associated "Lookup" programs (this was the infrastructure that supported the CVFY function), and generation of the GLS mainline (CMD and VFY and most of the activities that occurred between T-26m and post-launch securing).

Other parts of the GLS software -- for example, Safing -- were not automatically generated by the DD at all. The DD still served as the source of requirements, but Safing was entirely hand-coded.

Because of all this, you shouldn't think of a line item in the GLSDD as mapping onto a single GOAL statement; instead you should think of each GLSDD line item mapping onto a chunk of GLS architecture, which might be a single statement (as in the case of a delay), or many statements, potentially distributed across applications and processors (consoles). The latter was particularly true for CVFYs, which could get quite complicated and affected the Interrupt Processors (MIPs and LIPs), which ran at Backup, and the Lookups, which ran at Integration.
Title: Re: Shuttle Q&A Part 5
Post by: jcopella on 07/24/2019 02:56 am
Here are a couple of photos I snapped of pages in my brain book that might be helpful --

The first is of SDP01, the display skeleton for SLP07. Most elements should be obvious based on what you've been able to puzzle out so far, but if not, let me know and I'll try to help.

The second is kind of a "cheat sheet" or table of contents for all the GLS GOAL applications -- it might be helpful to associate a function with a program name you might see in the S0007 OMI, or whatever.

Good luck, and let me know how the project turns out!
Title: Re: Shuttle Q&A Part 5
Post by: fl1034 on 08/10/2019 07:59 pm
Can someone explain why are there bellows on the turbine ends of HPFTP and HPOTP (in SSMEs of course)? What exactly are they loading onto the turbine? Is the whole stationary aft section free to shift axially inside the turbine housing, which includes the turbine inlet struts and all the stator blades? Then how is the clearance between this aft section and the turbine disc maintained? Through hydraulic pressure vs seal clearance?

Another quick follow-on, are all the turbines and stators uncooled and thus as hot as the fuel-rich gas? I've heard from non-authoritative sources that all these blades are coated with gold to mitigate hydrogen embrittlement. Is this true?
Title: Re: Shuttle Q&A Part 5
Post by: SWGlassPit on 08/14/2019 02:01 pm
Can someone explain why are there bellows on the turbine ends of HPFTP and HPOTP (in SSMEs of course)? What exactly are they loading onto the turbine? Is the whole stationary aft section free to shift axially inside the turbine housing, which includes the turbine inlet struts and all the stator blades? Then how is the clearance between this aft section and the turbine disc maintained? Through hydraulic pressure vs seal clearance?

I don't have design knowledge, but from looking at illustrations, it appears the bellows serves the purpose of strain relief to allow for thermal expansion.

Quote
Another quick follow-on, are all the turbines and stators uncooled and thus as hot as the fuel-rich gas? I've heard from non-authoritative sources that all these blades are coated with gold to mitigate hydrogen embrittlement. Is this true?

The high pressure turbopump turbines are cooled with GH2, which is discharged into the turbine outlet.
Title: Re: Shuttle Q&A Part 5
Post by: fl1034 on 08/18/2019 07:43 am
I don't have design knowledge, but from looking at illustrations, it appears the bellows serves the purpose of strain relief to allow for thermal expansion.

That's what I thought also.

The high pressure turbopump turbines are cooled with GH2, which is discharged into the turbine outlet.

How are the turbines cooled? Through internal labyrinthine GH2 passages? Or just by the GH2 leaked through the various seal between the shaft and the stators?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/22/2019 11:21 pm
Quick question to settle a discussion I'm having: The forward edges of the orbiter midbody sidewalls are perfectly vertical when seen from the side, is this correct? There's no angle to them? I'm talking about where the midbody joins with the lower forward fuselage half.
Edit:To make the question a bit more clear, is the interpretation of the attached schematic correct? Teal vertical line being the bottom of the Xo576 bulkhead, green horizontal line the PLBD hinge line at Zo420 and the red diagonal line the tilted upper section of the Xo576 bulkhead.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/29/2019 01:21 am
Pretty sure that the entire Xo 576 bulkhead is flat, not angled above Zo 420.  See photo of 576 without the insulation liner.
F=ma 

Quick question to settle a discussion I'm having: The forward edges of the orbiter midbody sidewalls are perfectly vertical when seen from the side, is this correct? There's no angle to them? I'm talking about where the midbody joins with the lower forward fuselage half.
Edit:To make the question a bit more clear, is the interpretation of the attached schematic correct? Teal vertical line being the bottom of the Xo576 bulkhead, green horizontal line the PLBD hinge line at Zo420 and the red diagonal line the tilted upper section of the Xo576 bulkhead.

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/29/2019 02:48 pm
Pretty sure that the entire Xo 576 bulkhead is flat, not angled above Zo 420.  See photo of 576 without the insulation liner.
F=ma 
It has to be to account the canted upper forward fuselage aft face. Or are you saying that the entire bulkhead is angled in the X-Z plane?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 08/30/2019 04:02 pm
During STS-107, COlumbia had her internal airlock, then furthur aft there is a tunnel running back to the Spacehab Research Double Module (RDM).

In the case of an on-orbit rescue, who would astros have exitted and entered Columbia?


attachments  a wiki diagram of the RDM SPaceHab. Is that round "cover" on top of the mid deck to Spacehab, a hatch cover?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 08/31/2019 04:50 am
There is an airlock in the top section of the jog (the connecting tunnel) to allow EVA in case of unforseen issues. You can see the top hatch on the right.
Title: Re: Shuttle Q&A Part 5
Post by: Ilikeboosterrockets on 09/12/2019 10:13 pm
Random question, apologies if it's been asked before.

How much control authority do the flight control surfaces (especially the vertical tail) have at high aoa and reentry velocity+altitude? I've read that the shuttle pulls high alpha S-turns in early stages of reentry, but I can't imagine the control surfaces are especially effective in that regime. I was specifically wondering about the vertical tail, as it almost seems like it would be in the "shadow" of the leading edge of the wing+the fuselage, especially if there's flow separation?

Thanks
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 09/12/2019 11:21 pm
Random question, apologies if it's been asked before.

How much control authority do the flight control surfaces (especially the vertical tail) have at high aoa and reentry velocity+altitude? I've read that the shuttle pulls high alpha S-turns in early stages of reentry, but I can't imagine the control surfaces are especially effective in that regime. I was specifically wondering about the vertical tail, as it almost seems like it would be in the "shadow" of the leading edge of the wing+the fuselage, especially if there's flow separation?

Thanks


For most of the entry phase (starting at Mach 25 and 400,000 feet in altitude) the orbiter is at a high 40 degree angle of attack (alpha) - which as you surmised, washes out the tail.  The angle of attack begins to ramp down beginning at around Mach 10 as the orbiter aerodynamics change from separated flows to the more conventional laminar flows that we are accustomed to with traditional airplane flight.
When the orbiter performs a roll reversal at the higher Mach numbers it is really a yaw maneuver because the orbiter is rolling around the velocity vector.  Remember the 40 degree alpha means that the velocity vector is 40 degrees away from the the orbiters roll axis.
So, to answer your question, these rolls around the velocity vector are initiated by a combination of yaw jets and - and as the altitude decreases and dynamic pressure builds up - deflection of the elevons (used to intentionally induce adverse yaw).
Beginning at Mach 10 (which occurs in the neighborhood of 170,000 to 165,000 feet in altitude) the angle of attack is slowly reduced, and the speed-brake function of the rudder assembly is used as a trim/stability device.  Both sides of the rudder panels deploy which produces a pitch up moment.  This pitch up moment also increases the effectiveness of the elevons (hence the trim function).
At about Mach 5 (~ 115,000 feet in altitude), and an alpha of around 22 degrees and slowly decreasing,  the rudder/speed-brake assembly transitions to a more conventional rudder function.


Mark Kirkman
“Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: TMI on 09/15/2019 10:38 am
I watched a video some time ago from a man that worked at or with NASA at the beginning of the Shuttle program, he talked about the data bus, programming in high level vs assembler and the tests they ran at the time, and how they simulated the rocket to test computer systems.

I recall a brown stage area and that it was some kind of official NASA talk, but that could be wrong.

Does anyone know what this video was and is it available to the public?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 11/01/2019 01:25 pm
This question sort of relates to a question previous dealing with the split tail/speedbrake and it being "washed out" at high AoA's.
After the main landing gear(MLG) settles down on the runway, the parachute is deployed before the nose landing gear(NLG) touches down.  As the parachute reefs, is there an off center force experienced by the orbiter that wants to pull the nose of upwards?
Was the parachute "reefing" perceptible to the crew?
As I understand it, the chute is deployed and the commander uses the "trim" controls to bring the nose down rather than using the stick to bring the nose down.  Does the parachute force affect this trimming prior to NLG touchdown?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 12/15/2019 11:40 pm
Does someone know the Xo coordinates of the two points on the attached photo?
Title: Re: Shuttle Q&A Part 5
Post by: amirghanbariir on 12/19/2019 01:38 pm
I seem to remember soome footage of a Big Wing Canberra that was going to be monitoring Discovery' (https://www.triptoday.ir)s descent--flying ' (http://www.rahkarenovin.net)chase' (http://www.rahkarenovin.com).Anyone have any links?


 :o  ???  ;)
طراحی سایت (http://www.rahkarenovin.com) هاست لینوکس (http://www.rahkarenovin.net/web-hosting/) ثبت دامنه (http://www.rahkarenovin.net/domains/)  میزبانی وب (http://www.rahkarenovin.net/) بلیط هواپیما (https://www.triptoday.ir/)

Title: Re: Shuttle Q&A Part 5
Post by: JAFO on 01/09/2020 03:34 pm
Was any thought ever given to doing STS as an inline vehicle from scratch, with the SSMEs on the ET?


Now that I think about it, it would have meant losing the SSMEs along with the ET, defeating the purpose/selling point of a near fully reuseable vehicle, so I doubt it was ever considered. Bummer, as it would have given a better system from the beginning.
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 01/09/2020 03:36 pm
Was any thought ever given to doing STS as an inline vehicle from scratch, with the SSMEs on the ET?


Now that I think about it, it would have meant losing the SSMEs along with the ET, defeating the purpose/selling point of a near fully reuseable vehicle, so I doubt it was ever considered. Bummer, as it would have given a better system from the beginning.

The "original" design called for the core to be recoverable (usually as a winged first stage) with the orbiter stacked on top as the orbital stage--so yes, early designs were in-line and fully recoverable.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/18/2020 04:00 am
I need some light on a shuttle GN&C term here. When talking about a certain attitude, in some cases it has the prefix of "Bias". What is this and how was it determined? For example, some of the attitudes flown during STS-107 was "BIAS -ZLV -XVV"? How did this attitude differ from a regular "-ZLV -XVV" attitude?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 01/18/2020 04:30 pm
I need some light on a shuttle GN&C term here. When talking about a certain attitude, in some cases it has the prefix of "Bias". What is this and how was it determined? For example, some of the attitudes flown during STS-107 was "BIAS -ZLV -XVV"? How did this attitude differ from a regular "-ZLV -XVV" attitude?

Unfortunately, there's no simple answer for this because it depends on the purpose of the bias. For example, while docked to ISS, the shuttle was in a BIAS -XLV -ZVV attitude. In this case, the purpose of the bias was to put the shuttle-ISS stack in a torque equilibrium attitude to minimize ISS prop usage. STS-107 didn't dock so that's not it, obviously, but unless you know the purpose of the bias (comm? thermal? payloads?) you won't know how it was determined.
Title: Re: Shuttle Q&A Part 5
Post by: libra on 02/26/2020 08:33 am
I seem to remember soome footage of a Big Wing Canberra that was going to be monitoring Discovery' (https://www.triptoday.ir)s descent--flying ' (http://www.rahkarenovin.net)chase' (http://www.rahkarenovin.com).Anyone have any links?


 :o  ???  ;)
طراحی سایت (http://www.rahkarenovin.com) هاست لینوکس (http://www.rahkarenovin.net/web-hosting/) ثبت دامنه (http://www.rahkarenovin.net/domains/)  میزبانی وب (http://www.rahkarenovin.net/) بلیط هواپیما (https://www.triptoday.ir/)

Should be one of NASA RB-57F, the B-57 being a US Canberra and the F having a huge span. Could fly as high or even higher than a U-2.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/01/2020 11:11 pm
Anyone know if this screenshot from STS-131 shows the Ku band antenna dish in the MIP (Master Index Pulse) position?
Title: Re: Shuttle Q&A Part 5
Post by: pilecarls8 on 05/04/2020 03:54 pm
Though the space shuttle accomplished quite a bit, we all know that the Shuttle was a grand fiasco in design, safety, and especially cost. It was responsible in the end for NASA decisively losing the rocket battle to the private sector. But given that NASA consists of thousands of people with as much expertise in spaceflight as anyone (and more than anyone else in the 70s), I'm left wondering how it all stacked up like this.

I heard that back in the 70s, they wanted a reusable spacecraft to cheapen the costs of spaceflight. Did not the NASA people realize that the Shuttle might cost more than a low cost expendable system, and/or that for a reusable design the shuttle was an odd and extremely inefficient way to go? Or was this nothing more than a cosmic miscalculation and failure by NASA?(I know it's because in those days there was no KSP)
Title: Re: Shuttle Q&A Part 5
Post by: nacnud on 05/04/2020 04:04 pm
There are a lot of threads on this, it's a fascinating story. I suggest taking a look through the many many threads on this already.
Title: Re: Shuttle Q&A Part 5
Post by: Kansan52 on 05/04/2020 04:06 pm
Hubris.

In my opinion.

Cost pressures were intense. Apollo, Apollo Test follow ons, upgraded Saturn V, NERVA, ect. were chopped. Human Spaceflight was on the chopping block and self delusion said the Space Transportation System would save HSF.
Title: Re: Shuttle Q&A Part 5
Post by: Svetoslav on 05/04/2020 04:06 pm
We've had this discussion numerous times so I'm not sure if it's good to open this topic again. After all, most of the people would agree that:

1. If we judge the Space Shuttle by the original goals of the program - safety, frequent launches, and affordability so not only government astronauts would fly to space, but also ordinary people... yes, the program was a failure.

2. If we judge the Space Shuttle by things accomplished, especially when compared to other crewed programs - total number of people launched to space, Spacelab missions, construction of the ISS and Hubble servicing missions - the program was highly successful.

But then you ask : "Did not the NASA people realize that the Shuttle might cost more than a low cost expendable system?" - I think you're missing a point. Pursuing the goal itself isn't bad. Choosing reusability vs low cost expendable systems is a noble goal - but we may agree that the way NASA tried to do it, via the Space Shuttle, was not an optimal/affordable approach. I don't think many people here will disagree. And most of them won't disagree that Elon Musk's approach towards reusability, which we see with the Falcon rockets and later with Starship, has a bigger potential to succeed.
Title: Re: Shuttle Q&A Part 5
Post by: whitelancer64 on 05/04/2020 04:44 pm
There are indeed tons of threads on this. There were a whole bunch of inputs that pushed the Shuttle's design away from being something that might actually have been lower cost and more efficient in operations. There is not one single simple explanation.

One of the big problems is that the reusable shuttle was designed essentially by committee - the DOD had a lot of input on the design requirements for the payload bay that made the shuttle much larger and heavier than originally conceived.

But there were many others. I agree with the previous posts that reading up on the topic would help tremendously.
Title: Re: Shuttle Q&A Part 5
Post by: Coastal Ron on 05/04/2020 05:05 pm
Congratulations on your first post!

That said, welcome to reality, which in this case is someone disagreeing with you. I think you are starting out with a number of flawed assumptions, which will lead you to bad conclusions.

And yes, let's not debate the topic here, as there are TONS of threads that deal with this topic. But let me point out what I think your flawed assumptions are, since they might help you on future discussions.

Though the space shuttle accomplished quite a bit, we all know that the Shuttle was a grand fiasco in design, safety, and especially cost.

The term "grand fiasco" has no way to be measured, it is an emotional description, so there is no way to come to an unbiased conclusion. If you wanted to ask if it met its goals on payload, or per flight cost, those are quantifiable.

Quote
It was responsible in the end for NASA decisively losing the rocket battle to the private sector.

Again, a conclusion that is based on emotion and not facts. And why is depending on the private sector "bad"?

Quote
But given that NASA consists of thousands of people with as much expertise in spaceflight as anyone (and more than anyone else in the 70s), I'm left wondering how it all stacked up like this.

Again, a flawed assumption - NASA contracts for the vast amount of their hardware, and the aerospace knowledge for designing things like the Shuttle is predominately held in the private sector, not NASA. The Shuttle vehicle was designed and built by Rockwell International based on a design competition that NASA held. NASA did not come up with the idea that Rockwell International ultimately built, though obviously NASA validated the design and provided assistance. But assuming that all spacecraft knowledge emanates from NASA is wrong.

Quote
I heard that back in the 70s, they wanted a reusable spacecraft to cheapen the costs of spaceflight. Did not the NASA people realize that the Shuttle might cost more than a low cost expendable system, and/or that for a reusable design the shuttle was an odd and extremely inefficient way to go? Or was this nothing more than a cosmic miscalculation and failure by NASA?(I know it's because in those days there was no KSP)

If you are truly interested in the history of the Shuttle then I recommend you read books on the topic. There are lots of them out there, and you can find recommendations on NSF. Because the Shuttle was a product of many things, including politics, and not just engineering choices. So until you understand those factors, you won't understand the answers you get.

My $0.02
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 05/04/2020 06:18 pm
Thank you Ron.
Title: Re: Shuttle Q&A Part 5
Post by: Tony Trout on 05/17/2020 03:59 pm
The question is probably self-explanatory but....I was looking at a picture of shuttle Atlantis, I believe, at KSC on display and noticed that not all of the wing is there with the display...in other words, it was removed, I guess you could say. 

Why was this done to these legendary orbiter(s)?!?!?!?  I would think that KSC, at least, would want a complete orbiter to display????? 

Any answers are welcome!!

(BTW, if I put this in the wrong place, my apologies.  Someone can move it if they wish)
Title: Re: Shuttle Q&A Part 5
Post by: Hobbes-22 on 05/17/2020 04:51 pm
What are you referring to? In all of the images I've seen, the wings are complete.

(https://attractionsmagazine.com/wp-content/uploads/2014/02/image002.jpg)

The port wing is partially hidden by the walkway.

(http://www.collectspace.com/images/news-062913a-lg.jpg)
Title: Re: Shuttle Q&A Part 5
Post by: Tony Trout on 05/17/2020 06:34 pm
That second image is the one I was referring to.  I should have searched to find it to add it to my original message. 

I guess, due to my bad eyesight, I didn't see the rest of the wing and thought that they had somehow removed it. 
Title: Re: Shuttle Q&A Part 5
Post by: rlandmann on 05/19/2020 09:46 pm
Hi all — Obscure question about Enterprise from a scale modeller's perspective... were/are her elevon flapper doors made from Inconel? In photos during ALT, they seem much lighter in colour, even a light grey. But in subsequent photos (integration test at KSC, European tour ’83, World’s Fair ’84) they’re the expected black.

Were they originally a different material and then replaced? Or maybe just later painted black? Or are the ALT photos just a trick of the harsh Californian sunlight and they were Inconel all along? (Although I can’t remember photos of the X-15 looking light grey!)
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/19/2020 11:13 pm
Hi all — Obscure question about Enterprise from a scale modeller's perspective... were/are her elevon flapper doors made from Inconel? In photos during ALT, they seem much lighter in colour, even a light grey. But in subsequent photos (integration test at KSC, European tour ’83, World’s Fair ’84) they’re the expected black.

Were they originally a different material and then replaced? Or maybe just later painted black? Or are the ALT photos just a trick of the harsh Californian sunlight and they were Inconel all along? (Although I can’t remember photos of the X-15 looking light grey!)



I’ve never given it any though until now, but it wouldn’t have made sense to do that.  Enterprise was not exposed to any thermal environments that would have necessitated the additional expense and hassle of working with the Inconel material.


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/29/2020 01:24 am
Was avionics bay 3B used in the final Shuttle flights?  Is there a diagram that shows which black boxes are located in each bay?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/29/2020 01:42 am
Was avionics bay 3B used in the final Shuttle flights?  Is there a diagram that shows which black boxes are located in each bay?

F=ma



Here are diagrams of Bay 1, 2, 3A & 3B:


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/29/2020 02:19 am
Thanks mkirk.  What's the source of these images?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 05/30/2020 01:04 am
Thanks mkirk.  What's the source of these images?

F=ma

The drawings showed up in a lot of the training documentation, but I grabbed these from the IFM (In-Flight Maintenance) Checklist.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 05/31/2020 04:13 pm
Good info thanks mkirk.  I saw in one of Wayne Hale's posts that the RSB is closed at 15 percent. Do you know why 15 and not 0?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 06/01/2020 04:21 am
He said don't ask why!  ;D
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/01/2020 05:57 pm
Good info thanks mkirk.  I saw in one of Wayne Hale's posts that the RSB is closed at 15 percent. Do you know why 15 and not 0?

F=ma

Like penguin44 said, Wayne told you not to ask.  What the heck?   Lol

Keeping it simple - the lower limit of the speed brake was 15 degrees.  So if either auto guidance or the crew manually commanded the speed brake to the close position during entry - it was actually at 15 degrees. This was to help prevent physical binding of the mechanical linkages when the rudder is deflected  (remember both speed brake panels moved as a combine unit to perform the rudder function)  and to improve rudder effectiveness. 

This “software limit” became effective once the speed brake was commanded open - in other words, this didn’t apply during launch since the speed brake was not used then.


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 06/01/2020 06:49 pm
I know he said don't ask - but I couldn't help myself!  And he answered on the other thread...

Thanks again for your insight mkirk. 

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/01/2020 07:01 pm
I know he said don't ask - but I couldn't help myself!  And he answered on the other thread...

Thanks again for your insight mkirk. 

F=ma

What other thread?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 06/01/2020 07:23 pm
https://forum.nasaspaceflight.com/index.php?topic=22791.msg2090787#msg2090787

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: AS_501 on 06/04/2020 08:50 pm
Been watching close-up/high speed imagery of SSME and SRB launch events on NASA TV.  Always wondered why the SSME nozzles pulled toward each other (while at full thrust) just before SRB ignition.  Final check of engine controller?  Final check of gimbaling?  Thanks!
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 06/04/2020 09:00 pm
Been watching close-up/high speed imagery of SSME and SRB launch events on NASA TV.  Always wondered why the SSME nozzles pulled toward each other (while at full thrust) just before SRB ignition.  Final check of engine controller?  Final check of gimbaling?  Thanks!

That is the RS-25s moving to actual launch position--they are slightly splayed as they spin up to full thrust to avoid hitting each other during start-up transients.  (that is, to keep the nozzles from hitting each other--that would make for a very bad day)

EDIT:  not sure which imagery you've been watching, but I've seen super high res/super slo-mo imagery where one can see not just the large-scale transients (engines shaking visibly), but also the harmonics in the nozzles themselves--subtle oscillations much like a ringing bell.  Amazing stuff!
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 06/05/2020 03:35 pm
Been watching close-up/high speed imagery of SSME and SRB launch events on NASA TV.  Always wondered why the SSME nozzles pulled toward each other (while at full thrust) just before SRB ignition.  Final check of engine controller?  Final check of gimbaling?  Thanks!

That is the RS-25s moving to actual launch position--they are slightly splayed as they spin up to full thrust to avoid hitting each other during start-up transients.  (that is, to keep the nozzles from hitting each other--that would make for a very bad day)

EDIT:  not sure which imagery you've been watching, but I've seen super high res/super slo-mo imagery where one can see not just the large-scale transients (engines shaking visibly), but also the harmonics in the nozzles themselves--subtle oscillations much like a ringing bell.  Amazing stuff!
Way upthread, I was making the same discussion about SSME in Position 2 and 3(left and right engine positions).  And while having  engine 2 and 3's nozzles splayed further apart for the "start" position was perhaps a small part of the reason, primarily the start position was to control thrust vector in an attempt to reduce of center loading of the stack.  An effect was a reduced "twang" effect which at the same time reduced that amount of movement in the SRB joints. The SRB joints elusively allow for the "twang" movement as the SRB nozzles are bolted hard-down to the MLP .

A quote from JIM discussing flight and start SSME positions.
http://forum.nasaspaceflight.com/index.php?topic=2030.525
"They are spaced apart to allow for motion during  the start transient.  They might bang together if they were in the flight position."


From M Kirkman reply 3160 of this thread
https://forum.nasaspaceflight.com/index.php?topic=17437.3160
"While it is true that keeping the engine bells from colliding is an important consideration, the “start position” (as it was explained to me) is really about loads management of the entire stack (i.e. twang) during the thrust buildup.  The other day I just happened to have a discussion over lunch about thrust buildup with some of the folks involved in evaluating/quantifying the “Twang” pre and post STS-1.  As it turns out, the timing of those events did not go quite as expected or planned for STS-1.

Mark Kirkman"


Twang motion at the External Tank top end, where the Gaseous Oxygen beanie cap resides before launch.
https://youtu.be/xmLeGBIj6kw

The twang motion continues on for quite some time follow the conclusion of a Flight Readiness Firing(FRF) and/or a Redundant Set Launcher Sequencer(RSLS) Aborts.  RSLS aborts occur after the engine start command given at T minus 6.6 seconds but before the redundant frangible nuts and SRB ignition firing chain is triggered at T Zero. These were the worst cases of "Launchus Interuptus". The astros feel the engines startup and running, but fail to feel the 2 SRBs fire off. This is followed by the astronauts keenly listening for what type of egress is needed. Hoping to not hear Mode-1, which means pop your belts and get out of the orbiter as quickly as possible and getting to the slidewire gaskets.

This video of STS-68 RSLS Launch Pad Abort OTV Camera 071 shows the startup sequence with engines 2 and 3 in the start position then following start they immediately slew together into the "launch" position then immediatley splay apart once again as an RSLS abort was commanded.
https://youtu.be/ekDTXQet_as

 Nozzle "bending" during startup.  The flow separation and other dynamics within the engine nozzle is fascinating.
https://youtu.be/hDCCBgppG4s
Title: Re: Shuttle Q&A Part 5
Post by: cebri on 06/09/2020 12:11 pm
Now that the discussion is focused on the SSME, I do have one question. I read sometime ago, can't remember where, that the in the early days of the space shuttle, the turbo pumps came back is such bad conditions after each flight that sometimes they could not be dismounted for refurbishment and they actually needed to be literally sawed from the rest of the engine. Is there any truth to this? 
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 06/20/2020 05:05 pm
Any orbiter C&T techs or engineers around? If so, maybe you could help me out with the attached wire diagram? It is of the Ku band reflector horn. On the main structure there's a rectangular box with 4 connectors/wires coming out of it and I want to know how they connect with the main cube that also have 4 connectors on it. The connectors on the "box" have the prefix of "E" and the ones on the horn cube have the prefix of "H". I want to know how each connects like E1 connects with H3 for example.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/28/2020 02:17 pm
Space Shuttle Training Briefings

Throughout this Space Shuttle Q&A Thread/Forum, the subject of shuttle aborts has come up numerous times.  Since before STS-1 even flew, there were (and still are) countless myths regarding how the shuttle was actually flown/operated, and how it would have been flown in various nominal, off-nominal, and contingency abort scenarios  - particularly with regard to expected survivability.

The links below are to some recently produced Briefing on the topic of Shuttle Ascent / Abort procedures and techniques.  They are presented by Andy Foster, a former Space Shuttle Training Instructor in the same group that I would ultimately end up working in for a while.  He presents these briefings in essentially the same fashion as we presented the initial academics to Astronauts before beginning their Shuttle Mission Simulator (SMS) training.

Andy is still conducting the remaining briefings every Tuesday night via the Webex Meeting app at 7:00 central time.  You can still sign up for free to participate in the remaining briefings by sending an email to:  [email protected]

The remaining briefs will cover Contingency Aborts - by far the most complex and “scariest” aspects of shuttle flight operations.  Can the space shuttle ditch in the ocean?  When and how would the crew bailout?  What if all 3 engines fail during first or second stage?
Once those are recorded I will update this post with links to them as well.

Space Shuttle Ascent Overview:

https://m.youtube.com/watch?v=fKlZ9iqtvAk


Space Shuttle Ascent Aborts - Return to Launch Site (RTLS):

https://m.youtube.com/watch?v=bAEjgvSYi-E



Space Shuttle Ascent Aborts - Transoceanic Abort Landing (TAL):

https://m.youtube.com/watch?v=JoTJvbsKl2k



Space Shuttle Contingency Aborts Part 1:

https://www.youtube.com/watch?v=9Ijf0Yx7OEE



Space Shuttle Contingency Aborts Part 2:

https://www.youtube.com/watch?v=kzKSf60uork



Here is a link to a Space Shuttle Ascent briefing Andy presented to the news media prior to the first flight (STS-26) after the Challenger Accident :

https://m.youtube.com/watch?v=zkAvE2FGeUM



Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 07/06/2020 11:20 pm
Does anyone know the angle of the PLB flood-lights WRT horizontal? From my observations, the look to be pointed approx. 40° upwards, is this correct?
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 07/11/2020 12:32 pm
Space Shuttle Training Briefings

Throughout this Space Shuttle Q&A Thread/Forum, the subject of shuttle aborts has come up numerous times.  Since before STS-1 even flew, there were (and still are) countless myths regarding how the shuttle was actually flown/operated, and how it would have been flown in various nominal, off-nominal, and contingency abort scenarios  - particularly with regard to expected survivability.

The links below are to some recently produced Briefing on the topic of Shuttle Ascent / Abort procedures and techniques.  They are presented by Andy Foster, a former Space Shuttle Training Instructor in the same group that I would ultimately end up working in for a while.  He presents these briefings in essentially the same fashion as we presented the initial academics to Astronauts before beginning their Shuttle Mission Simulator (SMS) training.

Andy is still conducting the remaining briefings every Tuesday night via the Webex Meeting app at 7:00 central time.  You can still sign up for free to participate in the remaining briefings by sending an email to:  [email protected]

The remaining briefs will cover Contingency Aborts - by far the most complex and “scariest” aspects of shuttle flight operations.  Can the space shuttle ditch in the ocean?  When and how would the crew bailout?  What if all 3 engines fail during first or second stage?
Once those are recorded I will update this post with links to them as well.


Space Shuttle Ascent Aborts - Return to Launch Site (RTLS):

https://m.youtube.com/watch?v=bAEjgvSYi-E



Space Shuttle Ascent Aborts - Transoceanic Abort Landing (TAL):

https://m.youtube.com/watch?v=JoTJvbsKl2k



Space Shuttle Contingency Aborts Part 1:

https://www.youtube.com/watch?v=9Ijf0Yx7OEE



Space Shuttle Contingency Aborts Part 2:

https://www.youtube.com/watch?v=kzKSf60uork



Here is a link to a Space Shuttle Ascent briefing Andy presented to the news media prior to the first flight (STS-26) after the Challenger Accident :

https://m.youtube.com/watch?v=zkAvE2FGeUM



Mark Kirkman
“NASA Space Shuttle Hugger”

I am a user who reads all NSF posts via the "Unread Posts" menu.  As such I was NOT que'd into M Kirks addition of the newest of Andy Fosters Abort talks.  I am giving his post a BUMP as the Contingency Aborts talk is now up.

Thank you to all involved.  I've got some video to peruse.

Paul S-alphabet-horn
"NASA Space Shuttle Hugger"
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/02/2020 02:07 am
Hey Folks-

Some fellow SMS (Shuttle Mission Simulator) Instructors posted some videos of an Integrated Sim for STS-135 in another group forum.  They said I could link those videos here as well.
This Integrated Simulation was conducted on 6/16/2011 for STS-135.

What you will see is a video for each of the 4 runs they conducted this particular day.  The video shows 4 cameras that usually monitored the PFD (primary flight display) in the shuttle simulator cockpit, another camera showing a PASS (primary) GPC (general purpose computer) display,  a third showing a BFS (backup flight system) display, and a 4th that is usually looking out the commander’s side window.  All of the audio is from within the cockpit as Chris Ferguson, Doug Hurley, Sandra Magnus, and Rex Walheim work through the problems and talk to CAPCOM Butch Wilmore.

I will also post a pdf link at the very bottom to the Sim Instructor Script used that day.  You will notice that it mentions 5 runs, but iirc, only 4 were done that day.

FYI; the PFD shows, (from left to right), MACH/VELOCITY, ANGLE OF ATTACH (ALPHA), the attitude of the shuttle with regard to the earth horizon, ALTITUDE (in thousands of feet) and rate of climb (H-dot in feet per second).

Unfortunately the cameras used for this cutoff the tops of each display - what you would normally see up on the top would be the GPC Modes, Display Title, and Mission Elapsed Time.

VIDEO 1
Is from Run #1 of the script, a “TAL - Cabin Leak” scenario:

https://m.youtube.com/watch?v=XTJ2pCK5Apw


VIDEO 2
Is from Run #4 of the script; a “ATO - Launch hold, BFS engage for GPC failures” scenario:

https://m.youtube.com/watch?v=nbeAbWzyYDs


VIDEO 3
Is from Run #2 of the script; a “Stuck droop - 1 engine throttle stuck and 1 engine shutdown” scenario:

https://m.youtube.com/watch?v=UBeHeuKmETM


VIDEO 4
Is from Run #3 of the script; a “Systems AOA - loss of 2 H2O loops” scenario:

https://m.youtube.com/watch?v=nIvGBd0SHOQ



Here’s a link to a pdf of the Sim Script

https://ia601400.us.archive.org/16/items/sts-135-ascent-3/STS-135%20Ascent%203.pdf


Mark Kirkman
“NASA Space Shuttle Hugger”

Title: Re: Shuttle Q&A Part 5
Post by: psloss on 08/02/2020 01:32 pm
Some fellow SMS (Shuttle Mission Simulator) Instructors posted some videos of an Integrated Sim for STS-135 in another group forum.  They said I could link those videos here as well.
This Integrated Simulation was conducted on 6/16/2011 for STS-135.
Nice.  Thanks, Mark.

This is the ascent simulation day that media was invited to watch from Building 5 and then Building 30.  It is interesting to see some of the displays, but especially to hear the crew intercom.  On the day, the flight director loop was available.

Are there any Booster-FIDO sim runs out there? :)
Title: Re: Shuttle Q&A Part 5
Post by: Gingin on 08/05/2020 08:45 am
That are some incredible footages, and deeply interesting scenarios and pdf
The AOA for H2O loop failure is very interesting, especially with the Systems AOA procedures FDF that we can find on L2 section.

Thanks for the highlight.
Can we share those videos or is it just for forum members?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/06/2020 10:04 pm

Thanks for the highlight.
Can we share those videos or is it just for forum members?



Yes, you can share.


Mark Kirkman
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/06/2020 10:27 pm
Here is another set of videos - this time from an Integrated Entry Sim for STS-135 on Jun 15, 2011

Once again the screen montage seems somewhat random, but typically it consists of a PASS (primary system) GPC, a BFS (backup flight system) GPC, an out the window view, and a PFD (primary flight display).

I will include a link to a pdf of the Simulation Script used by the Instructor Team at the bottom of this post.

The PFD screen shot depicts (from left to right) MACH/Relative Velocity in thousands of feet per second (knots equivalent airspeed is in the box at the bottom of the tape, ALPHA (angle of attack), orbiter attitude with respect to the horizon, H (altitude in nautical miles until below 65 nm, then it is altitude in thousands of feet), H Dot (is vertical velocity in feet per second).


VIDEO 1
Begins about 28 minutes prior to the Deorbit Burn and runs through landing

https://m.youtube.com/watch?feature=youtu.be&v=FYdkVLeo-1Y


VIDEO 2
Labeled ENTRY 3 - Begins when the orbiter has descended through 200,000 feet

https://m.youtube.com/watch?feature=youtu.be&v=DRczw5lG29A


VIDEO 3
Labeled ENTRY 4 - Begins when the orbiter has descended through 200,000 feet

https://m.youtube.com/watch?v=sI5_2vqsde0


VIDEO 4
Labeled ENTRY 5 - Begins when the orbiter has descended through 200,000 feet

https://m.youtube.com/watch?v=nB3GPvNSZcY


Pdf of the STS-135 Integrated Entry #2 Simulation Script:

https://ia801401.us.archive.org/4/items/sts-135-entry-2/STS-135%20Entry%202.pdf


Mark Kirkman
“NASA Space Shuttle Hugger”

Title: Re: Shuttle Q&A Part 5
Post by: Gingin on 08/07/2020 10:08 am

Yes, you can share.


Mark Kirkman

Perfect.

Last one is very interesting also.
Thanks for sharing those stuffs
So entertaining when you spent hours reading SCOM etc
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 08/09/2020 04:52 am
Sitting here reading a bit about sts-48. Amazing work, but I was wondering why the need for a 3 person Eva? Would it not have been better to spin Endeavour to match the sat and then just use the rms?
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/09/2020 10:55 pm
I think you mean STS-49.  The 3-crew EVA was done because they were DESPERATE for a solution, as the capture bar approach was a complete non-starter. 

Think about what you're proposing to do.  Let's just spin up the WHOLE orbiter to # RPM, and then grab Intelsat with the RMS.  Probably rip the dam thing right off the Orbiter.

F=ma

Sitting here reading a bit about sts-48. Amazing work, but I was wondering why the need for a 3 person Eva? Would it not have been better to spin Endeavour to match the sat and then just use the rms?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/10/2020 01:55 am
I think you mean STS-49.  The 3-crew EVA was done because they were DESPERATE for a solution, as the capture bar approach was a complete non-starter. 

Think about what you're proposing to do.  Let's just spin up the WHOLE orbiter to # RPM, and then grab Intelsat with the RMS.  Probably rip the dam thing right off the Orbiter.

F=ma

Sitting here reading a bit about sts-48. Amazing work, but I was wondering why the need for a 3 person Eva? Would it not have been better to spin Endeavour to match the sat and then just use the rms?

Agreed, STS-49. Intelsat was spin-stabilized and there was quite a bit of analysis between the second and third rendezvous attempts as to exactly what the spin rate should be, to strike the best compromise between stability (minimize "coning" motion) and ability of the EVA crewmen to grab the spinning Intelsat. The "knee" in the curve for Intelsat, as it turned out, was 0.25 RPM (1.5 deg/s).

A matched-rate flyaround with Endeavour wouldn't have literally ripped the RMS off, but the in-flight experience of STS-87 showed that 2 deg/s was definitely not doable, and STS-87 post-flight investigation showed that the realistic upper limit was around 0.5 deg/s, assuming the target satellite rotation was *stable*... Intelsat definitely wouldn't have been stable at 0.5 deg/s. But assuming you could match rates, then what? As Fequalsma says, the capture bar *simply didn't work*. "...then just use the RMS" is a ridiculous answer... what, exactly, does the RMS grapple onto if the capture bar doesn't work?

Source: me. I worked both missions.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/10/2020 10:34 pm
Good additional information, Jorge.  A colleague supported another experiment on STS-49, and told me about the Intelsat simulator used to practice the capture in the WETF. Apparently the capture bar worked perfectly in the pool.

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: gosha_space on 08/17/2020 01:57 am
Hey Folks-

Some fellow SMS (Shuttle Mission Simulator) Instructors posted some videos of an Integrated Sim for STS-135 in another group forum.  They said I could link those videos here as well.
This Integrated Simulation was conducted on 6/16/2011 for STS-135.

What you will see is a video for each of the 4 runs they conducted this particular day.  The video shows 4 cameras that usually monitored the PFD (primary flight display) in the shuttle simulator cockpit, another camera showing a PASS (primary) GPC (general purpose computer) display,  a third showing a BFS (backup flight system) display, and a 4th that is usually looking out the commander’s side window.  All of the audio is from within the cockpit as Chris Ferguson, Doug Hurley, Sandra Magnus, and Rex Walheim work through the problems and talk to CAPCOM Butch Wilmore.

I will also post a pdf link at the very bottom to the Sim Instructor Script used that day.  You will notice that it mentions 5 runs, but iirc, only 4 were done that day.

FYI; the PFD shows, (from left to right), MACH/VELOCITY, ANGLE OF ATTACH (ALPHA), the attitude of the shuttle with regard to the earth horizon, ALTITUDE (in thousands of feet) and rate of climb (H-dot in feet per second).

Unfortunately the cameras used for this cutoff the tops of each display - what you would normally see up on the top would be the GPC Modes, Display Title, and Mission Elapsed Time.

VIDEO 1
Is from Run #1 of the script, a “TAL - Cabin Leak” scenario:

https://m.youtube.com/watch?v=XTJ2pCK5Apw


VIDEO 2
Is from Run #4 of the script; a “ATO - Launch hold, BFS engage for GPC failures” scenario:

https://m.youtube.com/watch?v=nbeAbWzyYDs


VIDEO 3
Is from Run #2 of the script; a “Stuck droop - 1 engine throttle stuck and 1 engine shutdown” scenario:

https://m.youtube.com/watch?v=UBeHeuKmETM


VIDEO 4
Is from Run #3 of the script; a “Systems AOA - loss of 2 H2O loops” scenario:

https://m.youtube.com/watch?v=nIvGBd0SHOQ



Here’s a link to a pdf of the Sim Script

https://ia601400.us.archive.org/16/items/sts-135-ascent-3/STS-135%20Ascent%203.pdf


Mark Kirkman
“NASA Space Shuttle Hugger”

This is the most unique material! Thank you so much! I am currently practicing a shuttle landing and noticed that the motion model + atmosphere model is not correct thanks to your videos.
How accurate are the mathematical motion models used in this simulator?

Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/17/2020 02:18 am
One would hope 100% accurate.  Wouldn't be worth much if they weren't.

F=ma


How accurate are the mathematical motion models used in this simulator?
Title: Re: Shuttle Q&A Part 5
Post by: gosha_space on 08/17/2020 04:26 am
An error occurs when trying to load a display format GPC MEMORY. What to do? What is the reason?
(https://cdn.discordapp.com/attachments/694153756870443059/744773550006861964/unknown.png)
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 08/17/2020 05:37 am
An error occurs when trying to load a display format GPC MEMORY. What to do? What is the reason?
(https://cdn.discordapp.com/attachments/694153756870443059/744773550006861964/unknown.png)

The MDU lost comm with the IDP via the 1553 bus.

If this were on a real shuttle or a flight-realistic simulator, I'd suggest working MAL PROC DPS 5.6d, 'BIG ‘X’ ACROSS MDU AND/OR
‘POLL FAIL’, p 5-47. I think the answers to blocks 1-3 are NO so you can start in block 10 on p 5-48.

https://www.nasa.gov/centers/johnson/pdf/359891main_125_MAL_G_J_2_E1.pdf

Since I have no idea what fidelity the sim you're running is, I have no idea if this procedure will work.
Title: Re: Shuttle Q&A Part 5
Post by: Gingin on 08/18/2020 10:05 am
An error occurs when trying to load a display format GPC MEMORY. What to do? What is the reason?


Looks like you are using FG Shuttle.
I think you are driving a SM major function by assigning a GPC that contains GNC OPS 2 guidance, hence the poll error.
Or you modded the IDP 2 to OPS 0 then switched to SM function.

I got the same thing than you when messing up in the Spec 0 display format

(https://imagizer.imageshack.com/img923/2600/HhDPM5.jpg)

Have a look there if you want for proper OPS 1/2 transition, based on real FDF

http://wiki.flightgear.org/Flying_the_Shuttle_-_Launch_And_Post_Insertion_Advanced#Post_Insertion:_Advanced_GPC_reconfiguration (http://wiki.flightgear.org/Flying_the_Shuttle_-_Launch_And_Post_Insertion_Advanced#Post_Insertion:_Advanced_GPC_reconfiguration)


Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/18/2020 05:53 pm
can someone explain to me what it is PREBANK
Title: Re: Shuttle Q&A Part 5
Post by: Gingin on 08/20/2020 05:12 pm
can someone explain to me what it is PREBANK


It is usually used for underburn during deorbit or during Abort Once Around .
It is associated in general with propellant failure, or limited DeltaV for those burns.

By Banking the Orbiter before the Entry Interface , vertical component of the lift vector will be decreased slighlty.
It will then cause a steeper entry trajectory early on.
Steeper entry angle = increased drag = Delta V dissipated faster, helping to recover from a shallow entry angle.

Prebank value will depend by how far is the current perigee after deorbit burn compared to the forecasted one.
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/25/2020 10:15 am
can someone explain to me what it is PREBANK


It is usually used for underburn during deorbit or during Abort Once Around .
It is associated in general with propellant failure, or limited DeltaV for those burns.

By Banking the Orbiter before the Entry Interface , vertical component of the lift vector will be decreased slighlty.
It will then cause a steeper entry trajectory early on.
Steeper entry angle = increased drag = Delta V dissipated faster, helping to recover from a shallow entry angle.

Prebank value will depend by how far is the current perigee after deorbit burn compared to the forecasted one.

thanks for the good answer
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/25/2020 11:20 am
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?

Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 08/25/2020 11:36 am
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?


It's just HDOT or Height Delta Over Time, AKA vertical velocity. In normal aviation terms it would climb rate/sink rate.
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 08/25/2020 12:47 pm
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?


It's just HDOT or Height Delta Over Time, AKA vertical velocity. In normal aviation terms it would climb rate/sink rate.

Surely H-double-dot is the rate of change of vertical velocity, i.e., the vertical acceleration?
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/25/2020 04:26 pm

It's just HDOT or Height Delta Over Time, AKA vertical velocity. In normal aviation terms it would climb rate/sink rate.
I wanted to know about H-double-dot :)
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 08/25/2020 06:09 pm
While "DOT" makes a nice backronym, it is simply engineering shorthand notation for the time derivative of a quantity, d(...)/dt.  So Hdot = dH/dt, and H-double-dot = d(dH/dt)/dt.

F = mdv/dt = md(dx/dt)/dt

Source: my engineering degree(s)


It's just HDOT or Height Delta Over Time, AKA vertical velocity. In normal aviation terms it would climb rate/sink rate.
I wanted to know about H-double-dot :)
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/25/2020 07:41 pm
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?




H double dot is altitude acceleration
H dot is altitude rate (analogous to rate of climb or descent in an airplane)

H double dot is a very valuable tool for flying a manual entry.


Background:

For a Space Shuttle entry, range to the landing site is controlled by managing drag. You manage drag by controlling altitude.  You control altitude by adjusting roll. 

For example; if you are high energy and need to slow down so you don’t go zipping by the runway at the landing site; you obviously want to increase your current drag in order to reduce your high total energy condition.
Where can you find more drag???? 
Well, right below you in the thicker part of the atmosphere.
If you roll the orbiter, the vertical component of lift is reduced and the orbiter begins to descend (fall) faster into the thicker part of the atmosphere.

This is somewhat counter intuitive from a piloting point of view because in a traditional airplane you manage altitude by pitching up or down.  Unfortunately, the shuttle had a very small alpha (angle of attack) envelope during entry of only +/- 3 degrees.  If you exceeded that alpha it would result in loss of control and you’d  “burn the wings off”.

The amount of roll needed to achieve the desire descent rate (H dot) to get you to the desire drag - was provided by the GPC (general purpose computer) displays.  If that wasn’t available or couldn’t be trusted, the astronauts could do a little math in public and use the formula Hdot Desired = Hdot + 20 * (Drag current - Drag desired)......sounds like a great job for the Flight Engineer (MS2).

H double dot provided a means for the pilot to evaluate the amount of roll being used.  An H double dot of close to zero meant you had a stable H dot.

All of the above is an overly simplistic explanation, but it hopefully gives you a little insight.

Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Gingin on 08/25/2020 08:12 pm
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?

If you have a L 2 subscription, you can have a look to the Entry TAEM, Approach Landing Guidance Workbook to have even more informations.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 08/26/2020 12:32 am
So if you are controlling H dot with roll angle, are you applying counter yaw to keep the ground track "straight" or are you allowing the Orbiter to turn and then counter-rolling later to get back on track?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/26/2020 06:25 am
So if you are controlling H dot with roll angle, are you applying counter yaw to keep the ground track "straight" or are you allowing the Orbiter to turn and then counter-rolling later to get back on track?

When you use bank angle to control descent rate, the nose of the orbiter starts to track away from the intended landing site.  We let this “DELAZ” (delta azimuth) - defined as the angle between the landing site and the direction of the orbiter’s nose - build up to between 10.5 degrees and 17.5 degrees. 

After the DELAZ gets to those values, you then reverse the orbiter’s bank angle (i.e. a roll reversal) to the opposite direction.  Doing this allows the orbiter’s nose to track back in the opposite direction until it again gets to 10.5 to 17.5 degrees of DELAZ.  Although you don’t point the orbiter directly at the landing site (DELAZ of zero), you keep it within a manageable tolerance of 17.5 degrees for most of the entry.

This entire process of roll reversals is referred to as cross range control.

Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/26/2020 06:43 am
for Mark Kirkman


very impressive video

what does H-double dot mean?
how astronauts use H-double dot when performing manual control?

If you have a L 2 subscription, you can have a look to the Entry TAEM, Approach Landing Guidance Workbook to have even more informations.

Yes, I have Entry TAEM, Approach Landing Guidance Workbook, but I do not understand many points because I have to translate into my own language.
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/26/2020 08:11 am
for Mark Kirkman







H double dot is altitude acceleration
H dot is altitude rate (analogous to rate of climb or descent in an airplane)

H double dot is a very valuable tool for flying a manual entry.


Background:

For a Space Shuttle entry, range to the landing site is controlled by managing drag. You manage drag by controlling altitude.  You control altitude by adjusting roll. 

For example; if you are high energy and need to slow down so you don’t go zipping by the runway at the landing site; you obviously want to increase your current drag in order to reduce your high total energy condition.
Where can you find more drag???? 
Well, right below you in the thicker part of the atmosphere.
If you roll the orbiter, the vertical component of lift is reduced and the orbiter begins to descend (fall) faster into the thicker part of the atmosphere.

This is somewhat counter intuitive from a piloting point of view because in a traditional airplane you manage altitude by pitching up or down.  Unfortunately, the shuttle had a very small alpha (angle of attack) envelope during entry of only +/- 3 degrees.  If you exceeded that alpha it would result in loss of control and you’d  “burn the wings off”.

The amount of roll needed to achieve the desire descent rate (H dot) to get you to the desire drag - was provided by the GPC (general purpose computer) displays.  If that wasn’t available or couldn’t be trusted, the astronauts could do a little math in public and use the formula Hdot Desired = Hdot + 20 * (Drag current - Drag desired)......sounds like a great job for the Flight Engineer (MS2).

H double dot provided a means for the pilot to evaluate the amount of roll being used.  An H double dot of close to zero meant you had a stable H dot.

All of the above is an overly simplistic explanation, but it hopefully gives you a little insight.

Mark Kirkman
“NASA Space Shuttle Hugger”



Mark thanks for your answer.

The ENTRY TRAJ has a Phugoid scale.
 Is this scale used for manual control?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/29/2020 01:07 am



Mark thanks for your answer.

The ENTRY TRAJ has a Phugoid scale.
 Is this scale used for manual control?


It helped provide situational awareness on how auto guidance was doing, but it also could be used as a “fly to” indicator during manual control of the orbiter during entry.  It would start flashing, and the needle would deflect, to signal to the crew when a roll reversal was needed.

Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/31/2020 02:08 pm


After the DELAZ gets to those values, you then reverse the orbiter’s bank angle (i.e. a roll reversal) to the opposite direction.  Doing this allows the orbiter’s nose to track back in the opposite direction until it again gets to 10.5 to 17.5 degrees of DELAZ.  Although you don’t point the orbiter directly at the landing site (DELAZ of zero), you keep it within a manageable tolerance of 17.5 degrees for most of the entry.

This entire process of roll reversals is referred to as cross range control.

Mark Kirkman
“NASA Space Shuttle
Hugger”

I've heard two versions of what roll reversals look like.
1.This is a roll around the X axis
2. This is yaw turn around the velocity vector.
3. What does it look like in reality?

Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 08/31/2020 05:12 pm


After the DELAZ gets to those values, you then reverse the orbiter’s bank angle (i.e. a roll reversal) to the opposite direction.  Doing this allows the orbiter’s nose to track back in the opposite direction until it again gets to 10.5 to 17.5 degrees of DELAZ.  Although you don’t point the orbiter directly at the landing site (DELAZ of zero), you keep it within a manageable tolerance of 17.5 degrees for most of the entry.

This entire process of roll reversals is referred to as cross range control.

Mark Kirkman
“NASA Space Shuttle
Hugger”

I've heard two versions of what roll reversals look like.
1.This is a roll around the X axis
2. This is yaw turn around the velocity vector.
3. What does it look like in reality?




The roll reversals are rolls around the velocity vector.  Because of the orbiter’s very high angle of attack (40 degrees for most of the entry until below Mach 10), this roll maneuver is actually a body axis yaw.
If viewed externally, it would look like the orbiter is yawing from side to side.
Title: Re: Shuttle Q&A Part 5
Post by: Albert Lapatin on 08/31/2020 08:02 pm


After the DELAZ gets to those values, you then reverse the orbiter’s bank angle (i.e. a roll reversal) to the opposite direction.  Doing this allows the orbiter’s nose to track back in the opposite direction until it again gets to 10.5 to 17.5 degrees of DELAZ.  Although you don’t point the orbiter directly at the landing site (DELAZ of zero), you keep it within a manageable tolerance of 17.5 degrees for most of the entry.

This entire process of roll reversals is referred to as cross range control.

Mark Kirkman
“NASA Space Shuttle
Hugger”




The roll reversals are rolls around the velocity vector.  Because of the orbiter’s very high angle of attack (40 degrees for most of the entry until below Mach 10), this roll maneuver is actually a body axis yaw.
If viewed externally, it would look like the orbiter is yawing from side to side.

Thanks Mark.
The "Shuttle Crew Operations Manual" mentions additional displays called "Bearing Displays - SPEC 54".
Нave they been used on at least one Shuttle flight?
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 09/01/2020 02:15 pm
Dumb question: what prevented the Shuttle's SRB's from filling with water and sinking after ocean impact?  Were balloons used?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/01/2020 03:03 pm
Dumb question: what prevented the Shuttle's SRB's from filling with water and sinking after ocean impact?  Were balloons used?
No balloons. The SRBs were naturally buoyant. The first task in SRB recovery was to install a Diver Operated Plug (DOP) that would allow the booster to switch from from the vertical splashdown orientation to the horizontal tow orientation by "de-watering" the boosters, IE by pumping out the water from the inside. That caused the boosters to rise until they fell over and were ready for the tow back to Port Canaveral.
Title: Re: Shuttle Q&A Part 5
Post by: Proponent on 09/01/2020 05:03 pm
So the boosters naturally floated in a vertical, nozzle-down orientation after splashdown?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/01/2020 05:17 pm
So the boosters naturally floated in a vertical, nozzle-down orientation after splashdown?
Yes. Their natural orientation the water was vertical as they then were just water-filled steel tubes.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 09/01/2020 08:19 pm
They were partially filled with water after splashdown.  The trapped air was what made them buoyant in "spar mode".  After the Diver-Operated Plug was installed, and the SRB de-watered, they were towed back in "log mode".

F=ma


So the boosters naturally floated in a vertical, nozzle-down orientation after splashdown?
Yes. Their natural orientation the water was vertical as they then were just water-filled steel tubes.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/20/2020 07:44 pm
Could someone detail the "standard" set ascent Performance Enhancements used in the latter half of the program?
Title: Re: Shuttle Q&A Part 5
Post by: usn_skwerl on 10/10/2020 01:00 am
I can't seem to find it, but I'm curious about the orbiter's tire pressures?
Title: Re: Shuttle Q&A Part 5
Post by: Hobbes-22 on 10/10/2020 06:58 am
340 psi (main gear) and 300 psi (nose gear). (from an article on the Nasa site that's no longer there, unfortunately).
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/10/2020 10:41 am
There are slightly different pressures given in the Shuttle Crew Operations Manual (from 2008):

Prior to launch tires are inflated with nitrogen as follows:

Nose landing gear 350 psi (rated for max load of 45,000 lbs per tire and 217 knots max landing speed, can be reused once)

Main landing gear 370 psi (rated for max load of 132,000 lbs per tire and 225 knots max landing speed, life of one landing only)

Manual can be downloaded here (1161 pages, 41.2MB):
https://www.nasa.gov/centers/johnson/pdf/390651main_shuttle_crew_operations_manual.pdf (https://www.nasa.gov/centers/johnson/pdf/390651main_shuttle_crew_operations_manual.pdf)
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/11/2020 10:26 pm
I've learned that when Entreprise was at Pad 39-A, her External Tank was filled "through Enterprise’s mock Main Propulsion System – with hundreds of thousands of gallons of Liquid Hydrogen and Liquid Oxygen. Source: https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/

Does anybody know more about this "mock Main Propulsion System"? Did Enterprise had External Tank umbilicals?
Thanks in advance.

Edit: corrections.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/12/2020 05:07 pm
I've learned that when Entreprise was at Pad 39-A, her External Tank was filled "through Enterprise’s mock Main Propulsion System – with hundreds of thousands of gallons of Liquid Hydrogen and Liquid Oxygen. Source: https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/ (https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/)

Does anybody know more about this "mock Main Propulsion System"? Did Enterprise had External Tank umbilicals?
Thanks in advance.

Edit: corrections.
There was none. Enterprise only had fake SSME nozzles made from cast iron. The only umbilicals that Enterprise ever had were for interfacing with the SCA during the ALTs. She didn't ever have any T0 umbilical panels on her aft engine compartment where the TSMs on the then unfinished MLP-1 would have interfaced with the orbiter. As far as I know, Enterprise's check out of KSC was all mechanical in nature, very similar to the so called Facility Checkouts she did in the mid-80's of Vandenberg's shuttle facilities.
I have attached a photo taken during the rollout of the LOX TSM showing that the area in question on Enterprise is void of any umbilicals extending from the TSM. So they couldn't have loaded any cryos at the pad, it was physically impossible.
I've also attached a photo of the same TSM and area of Columbia taken during the STS-1 rollout showing the umbilicals in place.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 10/12/2020 05:44 pm
If they could load no cryogens, how/when were the "beanie cap" requirements first noticed?

https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/

"She was then rolled out to launch pad 39A on 1 May 1979. During rollout, Enterprise was driven at various speeds to measure and note the various vibration strains on the fully-mated Shuttle stack. This was used to determine an optimal rollout speed for operational Space Shuttle missions.
Once at the pad, Enterprise helped validate launch pad procedures – with her biggest test and benefit to the ground processing operations coming during the full-up Wet Countdown Dress Rehearsal when she helped simulate External Tank fueling operations for launch.
During the test, Enterprise’s ET was filled – through Enterprise’s mock Main Propulsion System – with hundreds of thousands of gallons of Liquid Hydrogen and Liquid Oxygen.
During this time, the venting capabilities of the gaseous hydrogen vent line/system were tested.
However, something quite disturbing was discovered during this test – ICE was building up at the top of the External Tank where the gaseous oxygen was being allowed to vent directly from the tank.
This posed a significant problem as ice was already understood to be a serious hazard to the Shuttle orbiter’s Thermal Protection System tiles and panels.
With the maiden voyage of the Shuttle just under two years away, NASA needed a solution to this newly-discovered problem."

Interesting.  Hmm.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/12/2020 06:05 pm
If they could load no cryogens, how/when were the "beanie cap" requirements first noticed?
Interesting.  Hmm.
Probably through model testing, not using Enterprise.
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/13/2020 12:04 am
If they could load no cryogens, how/when were the "beanie cap" requirements first noticed?
Interesting.  Hmm.
Probably through model testing, not using Enterprise.
Thank you all for your answers. Maybe they found a way to fill the ET bypassing Enterprise and TSM.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/13/2020 12:17 am
If they could load no cryogens, how/when were the "beanie cap" requirements first noticed?
Interesting.  Hmm.
Probably through model testing, not using Enterprise.
Thank you all for your answers. Maybe they found a way to fill the ET bypassing Enterprise and TSM.
That would be a no-go as the pad cryo facilities tie into the cryo lines on the exterior of the MLP which enter the MLP on Side 1 (south side when it is at the pad) and is routed up through the TSMs. And the fill/drain of the ET is where the orbiter is mated to it (aft structure), so they're blocked off when the orbiter is mated to it.
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/13/2020 12:37 am
Would it be possible to route the LH2 and LOX plumbing through Aft Fuselage Access Doors? But since you said that Enterprise didn't have ET propellant umbilicals, it would be no use.

Title: Re: Shuttle Q&A Part 5
Post by: jbirdav8r on 10/13/2020 04:01 pm
I believe the ET used for the Enterprise facilities verification at KSC was a boilerplate. I think it was likely the same ET that was used in the MGVT program at Marshall. It only had a notional LOX feedline, no pressurization lines, and I don't even think it had any LH2 feedline at all...maybe a stub. Importantly, I don't even think it had any foam insulation. Even if you could fill it, it wouldn't be a very good idea.

There would be opportunities to catch the LOX vent ice issues in real-world tests. Importantly, the Main Propulsion Test Article (MPTA) tests at NSTL (later Stennis). The MPTA had an actual, functioning, insulated external tank that was filled and drained through an actual orbiter aft compartment. Whether or not such an issue was identified in the tests, I don't know, but it was possible.

I think the article you've referenced is just incorrect.

As an aside, MPTA-098 still exists...at least as of several years ago. I was walking through the Space and Rocket Center back lawn in Huntsville and came across it, sitting on the dirt like an old utility shed. There wasn't any signage or anything. What a piece of hardware! You could get close enough to touch it, and probably crawl into it (no, I didn't). The external tank from those tests holds the "Pathfinder" mockup, also there in Huntsville.

Edit to add: Two photos. One is Enterprise stacking ops in the VAB. The other is stacking for the MGVT at Marshall. I'm almost positive it's the same tank.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/13/2020 07:09 pm
An article from NASA also says that the Enterprise stack was used for cryogenic tests on the ET:

"Roll out to Launch Pad 39A occurred on May 1, and again KSC employees and their families were invited to view the event. With Enterprise mated to its ET and SRBs perched on the MLP, a total mass of about 11 million pounds, and riding atop the Mobile Transporter, technicians drove the stack at varying speeds to determine the optimum velocity to minimize vibration stress on the vehicle. The rollout process took about eight hours to complete.  Once at the pad, engineers used Enterprise to conduct fit checks and to validate launch pad procedures. The most critical step was a countdown demonstration test during which the ET was filled with super-cold liquid hydrogen and liquid oxygen. A significant discovery that ice built up at the top of the ET during this process led to the addition of the gaseous oxygen vent hood (familiarly known as the “beanie cap”) to the launch pad facility and a procedure to retract it just a few minutes before liftoff. This prevented the dangerous buildup of ice during the countdown and was perhaps Enterprise’s greatest contribution as a test vehicle during its time at the launch pad."

https://www.nasa.gov/feature/40-years-ago-space-shuttle-enterprise-rolls-to-the-pad (https://www.nasa.gov/feature/40-years-ago-space-shuttle-enterprise-rolls-to-the-pad)
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/13/2020 10:17 pm
It seems that we have contradictory information. I found an article on collectspace.com (http://www.collectspace.com/news/news-020817a-michoud-tornado-shuttle-external-tank.html) that says that the External Tank used with Enterprise at KSC was the same that was used on the Mated Vertical Ground Vibration Test performed at Marshall. The ET in question was the "ET-GVTA" (external tank-ground vibration test article):

Quote
ET-GVTA was one of the first three external tanks that was manufactured at Michoud. Built to represent a flight article, it was not covered in insulating foam like those that would later launch to space, but was painted white.
"ET-GVTA played a critical role in the early testing for the space shuttle," said Dennis Jenkins, the author of the new book, "Space Shuttle: Developing an Icon, 1972-2013" and a former project manager for the space shuttle program. "It was the subject of several iconic photos."

First used with the prototype orbiter Enterprise for a series of vibration tests at NASA's Marshall Space Flight Center in Alabama, ET-GVTA helped establish the bending modes and nodal crossing points to validate various analyses and locate the rate gyros and accelerometers used by the flight control system.

It was then moved to the Kennedy Space Center in Florida for a series of facility verification tests, culminating with it being paired with two solid rocket boosters and mounted to Enterprise in the Vehicle Assembly Building and moving to Launch Complex 39A for the first time.

ET-GTVA was subsequently shipped back to Louisiana for its possible refurbishment into a flight tank, but that did not happen. Instead, it was disassembled and its liquid oxygen and liquid hydrogen tanks, as well as its interstage, were put into storage, eventually being parked outside Building 103, the facility's main manufacturing building.



Photo credits: Dennis Jenkins.



Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/13/2020 11:44 pm
There would be opportunities to catch the LOX vent ice issues in real-world tests. Importantly, the Main Propulsion Test Article (MPTA) tests at NSTL (later Stennis). The MPTA had an actual, functioning, insulated external tank that was filled and drained through an actual orbiter aft compartment. Whether or not such an issue was identified in the tests, I don't know, but it was possible.
ET-MPTA was delivered to NSTL in September, 1977, and had gone through several initial tanking cycles and firing tests through 1978 while mated with MPTA-098 in the B-2 Test Stand.  (Those MPTA tests continued into early 1981.)

What may be getting conflated is the testing of GOX vent system designs that began in the LETF in late Summer of 1979.

Unfortunately, it's harder to find contemporaneous information to connect the proverbial dots since this history significantly predates the WWW.

There's an NTRS paper from 1982 that talks about development of the GOX vent system but doesn't provide background how the issue came up originally.
Title: Re: Shuttle Q&A Part 5
Post by: woods170 on 10/14/2020 04:58 pm
If they could load no cryogens, how/when were the "beanie cap" requirements first noticed?

https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/ (https://www.nasaspaceflight.com/2012/04/space-shuttle-enterprise-the-orbiter-that-started-it-all/)

"She was then rolled out to launch pad 39A on 1 May 1979. During rollout, Enterprise was driven at various speeds to measure and note the various vibration strains on the fully-mated Shuttle stack. This was used to determine an optimal rollout speed for operational Space Shuttle missions.
Once at the pad, Enterprise helped validate launch pad procedures – with her biggest test and benefit to the ground processing operations coming during the full-up Wet Countdown Dress Rehearsal when she helped simulate External Tank fueling operations for launch.
During the test, Enterprise’s ET was filled – through Enterprise’s mock Main Propulsion System – with hundreds of thousands of gallons of Liquid Hydrogen and Liquid Oxygen.
During this time, the venting capabilities of the gaseous hydrogen vent line/system were tested.
However, something quite disturbing was discovered during this test – ICE was building up at the top of the External Tank where the gaseous oxygen was being allowed to vent directly from the tank.

This posed a significant problem as ice was already understood to be a serious hazard to the Shuttle orbiter’s Thermal Protection System tiles and panels.
With the maiden voyage of the Shuttle just under two years away, NASA needed a solution to this newly-discovered problem."

Interesting.  Hmm.

Emphasis mine.

Don't know where Chris G. (the author of the linked NSF article) got this from but it is a load of incorrect.

Enterprise never had a mock Main Propulsion System. Neither was a tanking test ever performed with Enterprise, while sitting on the pad:

Quote from: Dennis R. Jenkins
During April 1979, OV-101 was mated to a pair of inert solid rocket boosters and the ET (serial number 2) scheduled to be used on STS-1. The stack was transported atop MLP #1 to Pad 39A on 1 May 1979. During almost three months at the pad, Enterprise would help verify that maintenance platforms mated to the vehicle in the correct locations, and that crew escape procedures worked properly. On 23 July 1979, Enterprise was rolled back to the VAB to be demated from the SRBs and ET.

Dennis R. Jenkins is generally recognized as THE expert on Space Shuttle history. The mere fact that his description of Enterprise's stint at LC-39A does not mention any tanking test is clear evidence that such rumoured tanking test never took place.

And when one contemplates other evidence, it becomes clear that such a rumoured tanking test did indeed never take place.
On L2 are several high resolution images available of Enterprise, including the area where the main connections to the STA and ET are. Particularly that image shows very clearly that there is NO hookup for the LOX feedline present. NO hookup for the LH2 feedline either. Other images on L2 show the interior of Enterprise's aft area. Again no feedlines for LOX or LH2. Publically available images of Enterprise show clearly that there are no hookups for the TSMs present on Enterprise. And high resolution images of Enterprise's rollout (again in L2) to LC-39A again clearly show that the TSM umbilicals were NOT hooked up to Enterprise's aft section.

There is also other circumstantial evidence that points to Enterprise not having a mock Main Propulsion System. Dennis R. Jenkins points out that Enterprise was again used as a facilities checkout vehicle at Vandenburg pad SLC-6 in 1985. He also notes that in early 1986 OV0192 (Columbia) was scheduled to arrive at SLC-6 "to conduct tanking tests".

Why would Vandenberg need Columbia for tanking tests? The answer is simple: because Enterprise does not contain the systems necessary to conduct a tanking test.


It is correct that NASA, in 1979, became aware of the ice build-up issue around the GOX vent. But this was due to tanking tests on ground-test articles of the ET, likely the MPTA-ET tests at Stennis. Those tests took place with a tanking test-article of the ET, connected to the Main Propulsion Test Article (MPTA) and had a functioning GOX vent. It was likely those tests that resulted in the recognition of the problem which led to the late development of the GOX vent arm.
The discovery of this problem was in fact so late into development that the GOX vent arm was not ready in time to support STS-1 as originally intended. Problems with the GOX vent seals during tanking tests and the FRF eventually led to the GOX vent hood being used in an "umbrella" mode only for STS-1, providing heated GN2 to prevent ice buildup. The GOX was allowed to escape in the air around the ET.Not until STS-2 did the GOX vent arm become operational as intended.
Title: Re: Shuttle Q&A Part 5
Post by: AnalogMan on 10/14/2020 07:40 pm
A near contemporary source document Chronology of KSC and KSC Related Events for 1979 dated September 22, 1980 has the following entry for the arrival of Enterprise at KSC on April 10, 1979:

[... looking to future events following arrival]

"Pad operations using the Enterprise would include checks of the sound suppression system, flowing the super-cold liquid oxygen and liquid hydrogen propellants, verification tests for the Orbiter Access Arm and Rotating Service Structure, and others. [...]"

So if they were not planning to load the External Tank, where were they going to flow cryogenic propellants to/from and why was the shuttle stack needed, or was it just the need for an MLP?

I could not find any other references to this type of test in the Chronology.  It can be downloaded here: https://ntrs.nasa.gov/api/citations/20060017819/downloads/20060017819.pdf (https://ntrs.nasa.gov/api/citations/20060017819/downloads/20060017819.pdf)
Title: Re: Shuttle Q&A Part 5
Post by: jbirdav8r on 10/15/2020 03:41 pm
I thought this would be a fairly easy and straightforward question to answer but it's turned into an interesting "deep dive."

I found this great paper on lessons learned in external tank development. If you are a fan of the External Tank, it's one of the best resources I've ever seen on the ET.

https://case.edu/cps/sites/case.edu.cps/files/2019-05/2241main_shuttle_et_lesson_021030.pdf

Page 18 mentions the GOX vent ice problem, and specifically ties it to the MPTA tests, as I suspected. Another technical paper I came across gives the background to the GOX vent program arising from a problem identified in the "summer of 1979."

Further research indicates that indeed the same tank was used for the ground vibration tests at Marshall and the Enterprise rollout at KSC, the Ground Vibration Test Article (ET-GVTA). This tank was shipped back to Michoud for rebuilding into a flight article, but this never happened. The tank was eventually destroyed in the 2017 Michoud tornado.

I still strongly suspect a true all-up tanking test at the pad never happened until Columbia arrived out there for STS-1, and that the story of Enterprise being tanked and somehow heroically finding this hitherto unknown ice issue is an apocryphal one.
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/15/2020 06:56 pm
User Ares67 wrote on a post about Enterprise that they load the LH2 and LOX, but up to the Tail Service Master, since Enterprise didn't have a Main Propulsion System, it couldn't flow the propellant to the External Tank.
This user mentioned a "Orbiter Mid-body umbilicals". Does anybody know what are those?

Quote
Once at the pad, Enterprise supported checks of the sound suppression system, as well as loading of the super-cold liquid oxygen and liquid hydrogen propellants. Orbiter mid-body umbilicals were attached to the vehicle. Cryogenic propellants were to flow from storage facilities through the Mobile Launcher Platform into the Tail Service Masts, though these liquefied gases did not go further, for Enterprise lacked the appropriate plumbing.

Verification tests of the Orbiter Access Arm and Rotating Service Structure were conducted. The payload ground-handling mechanism for transfer of an assembled payload from the Rotating Service Structure into the shuttle’s cargo bay also demonstrated its readiness. A 20,000-pound concrete weight, representing a spacecraft, arrived within a sealed canister. With the RSS well away from the shuttle, workers hoisted the canister into the PCR, removed its dummy payload, then rotated the RSS to lie against the back of Enterprise for payload installation within the cargo bay. All this was done under strict environmental control, to prevent contamination of the “spacecraft.”

From May 1 to July 23, 1979, Enterprise completed extensive mechanical fit checks of Kennedy’s checkout and launch operations before she was rolled back to the VAB. “By using Enterprise, we were able to work out a lot of things on a noninterference basis, making the entire effort worthwhile,” Talone said.
https://forum.nasaspaceflight.com/index.php?topic=35828.msg1272680#msg1272680
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 10/15/2020 07:16 pm
The Orbiter Mid-Body Umbilical Unit (OMBUU) was located on the RSS. It was used to fill/drain the Power Reactant Storage and Distribution (PRSD) storage tanks located below the payload bay. The OMBUU had a large umbilical that connected to an umbilical panel on the orbiter (large green rectangle in photo 2). It was mated during the S0009 Pad Validation operations that took place following rollout. It was demated from the orbiter once servicing of the PRSD had been completed during the launch countdown. Photo 3 shows the midbody umbilical panel on orbiter with the cover removed in the OPF.
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/15/2020 11:20 pm
I thought this would be a fairly easy and straightforward question to answer but it's turned into an interesting "deep dive."

When I first read that, I thought: "how did they manage to fill the External Tank?" When you see pictures of Enterprise at LC-39A you can see that there are no umblicals connected to her. I'm glad this doubt has clarified this subject. Thank you all.


The Orbiter Mid-Body Umbilical Unit (OMBUU) was located on the RSS. It was used to fill/drain the Power Reactant Storage and Distribution (PRSD) storage tanks located below the payload bay. The OMBUU had a large umbilical that connected to an umbilical panel on the orbiter (large green rectangle in photo 2). It was mated during the S0009 Pad Validation operations that took place following rollout. It was demated from the orbiter once servicing of the PRSD had been completed during the launch countdown. Photo 3 shows the midbody umbilical panel on orbiter with the cover removed in the OPF.

Thanks, DaveS!
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/16/2020 12:09 am
User Ares67 wrote on a post about Enterprise that they load the LH2 and LOX, but up to the Tail Service Master, since Enterprise didn't have a Main Propulsion System, it couldn't flow the propellant to the External Tank.
NASA KSC did a similar test at Pad 39B late last year to get ready to load propellants on their new vehicle and NASA Stennis did the same in 2018 using turnaround tools as stand-ins.
Title: Re: Shuttle Q&A Part 5
Post by: maia125 on 10/16/2020 12:15 am
So we can assume that's probably what happened when Enterprise was at the pad 39A, right?
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 10/16/2020 12:35 am
So we can assume that's probably what happened when Enterprise was at the pad 39A, right?
It's plausible, but I'd rather see documentation that's more definitive.

FWIW, an old Shuttle chronology has a nice conflation, attributed to "The HSV-TIMES,07/24/79":
https://ntrs.nasa.gov/citations/19910005807

Quote
Twelve weeks of ground tests on the lockup orbiter Enterprise ended.
test series was deemed a complete success. Although the ground tests were
successful, a new problem was discovered with the vehicle--there was a
possibility of ice forming on the outside of the fuel tanks, which could
falloff during launch and damage other parts of the ship.

It would be, of course, interesting to read that story from I guess an edition of the Huntsville Times published on 24 July 1979, but it might be involved in this misdemeanor on history.
Title: Re: Shuttle Q&A Part 5
Post by: woods170 on 10/16/2020 01:43 pm
I found this great paper on lessons learned in external tank development. If you are a fan of the External Tank, it's one of the best resources I've ever seen on the ET.

https://case.edu/cps/sites/case.edu.cps/files/2019-05/2241main_shuttle_et_lesson_021030.pdf (https://case.edu/cps/sites/case.edu.cps/files/2019-05/2241main_shuttle_et_lesson_021030.pdf)

Page 18 mentions the GOX vent ice problem, and specifically ties it to the MPTA tests, as I suspected. Another technical paper I came across gives the background to the GOX vent program arising from a problem identified in the "summer of 1979."

Excellent find! This specifically ties in the discovery, of the GOX vent ice build-up problem, with the MPTA-ET tests at Stennis.

I still strongly suspect a true all-up tanking test at the pad never happened until Columbia arrived out there for STS-1, and that the story of Enterprise being tanked and somehow heroically finding this hitherto unknown ice issue is an apocryphal one.

You suspect correctly. The first true all-up tanking test at the pad took place with Columbia, prior to the Flight Readiness Firing.
It is reasonable to assume that the incorrect narrative - of tanking tests with Enterprise revealing the GOX vent issue - came into existence because someone added one snippet of information to another snippet of information and drew the wrong conclusion.
The fact that both Enteprise's stint at LC-39A and the discovery of the GOX vent issue (on MPTA-ET) occurred in the (early) summer of 1979 is probably why the wrong conclusions were drawn.
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 11/07/2020 04:54 pm
Does anyone have any good images of the aft middeck panel that was removed to install or remove the internal airlock on the orbiters? I know I've seen one of the panel off from the cargo bay during processing/overhaul, but I can't find it again at the moment.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/07/2020 07:05 pm
Here are some photos.
F=ma

Edit - should be Xo 576 bulkhead, not 578
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 11/08/2020 02:17 pm
Thanks, that's exactly what I was thinking of!
Title: Re: Shuttle Q&A Part 5
Post by: Seamurda on 11/08/2020 09:28 pm
Fagets original concept for the fully reusable Shuttle had it entering fully stalled in a near 90 degree angle of attack.

This allowed it to slow down higher in the atmosphere for a lower heat load. This was at the cost of lower cross range.

Was the shuttle as designed capable of entering using this profile and was it considered when the cross range requirement was no longer particularly useful?
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 11/08/2020 09:40 pm
Fagets original concept for the fully reusable Shuttle had it entering fully stalled in a near 90 degree angle of attack.

This allowed it to slow down higher in the atmosphere for a lower heat load. This was at the cost of lower cross range.

Was the shuttle as designed capable of entering using this profile and was it considered when the cross range requirement was no longer particularly useful?

No and no.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/10/2020 12:49 am
Does anyone recognize this piece of hardware?  I found these in with some Orbiter build photos, but it may not be on the OV?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 01:31 am
That's the Tunnel Adapter Assembly (TAA) that was used to link the orbiter airlock with either Spacelab or SpaceHAB when either of those were flown. Those are some rare photos of the interior of the TAA. Most photos only show the exterior.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/10/2020 05:46 pm
Cool! DaveS can you post an exterior photo of the TAA with this part circled? I'm having a hard time picturing where the large opening at the top is on the TAA. Is it the zig-zag tunnel?

F=ma

That's the Tunnel Adapter Assembly (TAA) that was used to link the orbiter airlock with either Spacelab or SpaceHAB when either of those were flown. Those are some rare photos of the interior of the TAA. Most photos only show the exterior.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 05:52 pm
This is a photo of the TAA in the Bay 1 position for STS-107. Left is forward where it connects to Xo576 bulkhead and right is where it connects to the SpaceHAB Short Transfer Tunnel. The EVA hatch is on the top of the main cylindrical body of the TAA. The TAA is more or less a shortened internal airlock without all the pressurization and EVA support equipment like the Servicing/Cooling Umbilicals (SCUs) used by the EVs before going on to internal suit power and consumables.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 06:04 pm
This screenshot shows STS-106 MS Ed Lu opening the upper EVA hatch to begin the one and only EVA of the mission.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/10/2020 08:15 pm
Thanks DaveS.  But where is the part that is in the photos that I posted?

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 08:39 pm
Thanks DaveS.  But where is the part that is in the photos that I posted?

F=ma
What part? The only photos I see is the ones in the pdf file.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/10/2020 09:27 pm
Where is this dome in/on the TAA?  I can't picture it...

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 10:06 pm
That photo is of the interior of the TAA looking down the longitudinal axis. The hatchway for the EVA hatch is on the top and hatchway where the engineer is for the aft hatchway. So if you're moving to from orbiter to module, then it is just a straight shot. The TAA in the photo(s) is lacking the forward conical transition segment where it would interface with the orbiter airlock.
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/10/2020 10:35 pm
This photo of the TAA being installed into the PLB of Endeavour for STS-89 shows the interior somewhat. The External Airlock with the ODS on it can be seen to the extreme right in the photo.
Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 11/10/2020 10:45 pm
Right, that makes sense now.  The top opening in my photos didn't look like the EVA hatch, so I wasn't seeing it.

F=ma
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 11/12/2020 08:52 pm
Anyone know the thickness of the midbody ring frames and if it varies? I mostly interested in the XO582 ring frame.
Title: Re: Shuttle Q&A Part 5
Post by: psloss on 11/12/2020 08:55 pm
This photo of the TAA being installed into the PLB of Endeavour for STS-89 shows the interior somewhat. The External Airlock with the ODS on it can be seen to the extreme right in the photo.
Another point of view I believe for one of those units; this is in between STS-83 and STS-94.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 02/26/2021 02:17 pm
Does anyone have handy any pictures or diagram of what a Shuttle stack would look like with 5 segment boosters being used instead of the typical 4 segment boosters?

Title: Re: Shuttle Q&A Part 5
Post by: Fequalsma on 02/26/2021 04:07 pm
Figure 23 in https://www.aiaa.org/docs/default-source/uploadedfiles/about-aiaa/history-and-heritage/shuttlevariationsfinalaiaa.pdf?sfvrsn=b8875e90_0

https://ntrs.nasa.gov/api/citations/20020023401/downloads/20020023401.pdf

F=ma


Does anyone have handy any pictures or diagram of what a Shuttle stack would look like with 5 segment boosters being used instead of the typical 4 segment boosters?


Title: Re: Shuttle Q&A Part 5
Post by: Hog on 02/26/2021 04:46 pm
Figure 23 in https://www.aiaa.org/docs/default-source/uploadedfiles/about-aiaa/history-and-heritage/shuttlevariationsfinalaiaa.pdf?sfvrsn=b8875e90_0

https://ntrs.nasa.gov/api/citations/20020023401/downloads/20020023401.pdf

F=ma


Does anyone have handy any pictures or diagram of what a Shuttle stack would look like with 5 segment boosters being used instead of the typical 4 segment boosters?


Wow, thank you very much!  There's a couple gems there that I will need to study.   96"/8 feet=2.44m is the difference in height, to the tips of the SRBs and to the tip of the External Tank.  That's is closer to the same elevation than I was guessing.
There was 616" 34-1/2 feet/10.57m difference in height between the 4 segment boosters and the Shuttle External Tank.
The ARES-V 5.5 segment SRBs would have extended beyond the External Tank.  Yikes?

Also leads me to realize why the road from reusable to expendable for the SLS 5 segment SRB was an easy one.  To retain reusability in the 5 segment configuration would have required a new parachute system.  The parachute systems designed for the 4 segment RSRM(Redesigned Solid Rocket Motor) nor the FWC(Filament Wound Case) SRB for Polar launches out of Vandenberg would not suffice.  Also launch cadence of 1 per year doesn't help the economics of reusability in this particular case.

Thanks again, I really appreciate it!
Title: Re: Shuttle Q&A Part 5
Post by: PahTo on 02/26/2021 04:58 pm

Also leads me to realize why the road from reusable to expendable for the SLS 5 segment SRB was an easy one.  To retain reusability in the 5 segment configuration would have required a new parachute system.  The parachute systems designed for the 4 segment RSRM(Redesigned Solid Rocket Motor) nor the FWC(Filament Wound Case) SRB for Polar launches out of Vandenberg would not suffice.  Also launch cadence of 1 per year doesn't help the economics of reusability in this particular case.

Thanks again, I really appreciate it!

Indeed, as evidenced by the parachute "failure" on the Ares 1 test flight, it demonstrated in real terms that much more robust 'chutes would be required, adding so much mass as to eat in to the performance gained by 5-seg boosters in the first place.  I put failure in quotes due to the fact the 'chutes didn't fail so much as being asked to do way more than that for which they were designed.  Even empty segments are incredibly heavy...
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/18/2021 11:09 pm

Also leads me to realize why the road from reusable to expendable for the SLS 5 segment SRB was an easy one.  To retain reusability in the 5 segment configuration would have required a new parachute system.  The parachute systems designed for the 4 segment RSRM(Redesigned Solid Rocket Motor) nor the FWC(Filament Wound Case) SRB for Polar launches out of Vandenberg would not suffice.  Also launch cadence of 1 per year doesn't help the economics of reusability in this particular case.

Thanks again, I really appreciate it!

Indeed, as evidenced by the parachute "failure" on the Ares 1 test flight, it demonstrated in real terms that much more robust 'chutes would be required, adding so much mass as to eat in to the performance gained by 5-seg boosters in the first place.  I put failure in quotes due to the fact the 'chutes didn't fail so much as being asked to do way more than that for which they were designed.  Even empty segments are incredibly heavy...
Only four segments had live propellant in them. The fifth segment was inert, a mass simulator for launch just like the upper stage and Orion/LAS. So what was launched was essentially a regular STS RSRM. So the chutes had to deal with the extra mass of not only the fifth segment but also its inert propellant that was still in the case. Only the lower four segments were empty at the time. I think the splashdown would have been successful if the fifth segment had been empty and not carrying a couple of hundreds of thousands pounds of inert propellant.

Ares-1X was an ascent experiment, not a full up demonstration of the entire first stage flight from launch to splashdown.
Title: Re: Shuttle Q&A Part 5
Post by: wolfpack on 04/19/2021 07:35 pm
If the Shuttle landed SLF RWY33, how did it get turned around to head back to the VAB? Or were all the landings RWY15?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 04/19/2021 08:00 pm
If the Shuttle landed SLF RWY33, how did it get turned around to head back to the VAB? Or were all the landings RWY15?
They just turned around on the runway and headed down the runway.
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 05/27/2021 11:49 pm
Flight deck audio of ALT-5. Haise was quite angry at himself.

https://youtu.be/rjPMqtYET_A
Title: Re: Shuttle Q&A Part 5
Post by: AS_501 on 05/27/2021 11:59 pm
That was the only shuttle landing where I thought they would lose control.
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 05/28/2021 05:04 am
Indeed. He wa# sounding like he wasn't already having a good day before sep!
Title: Re: Shuttle Q&A Part 5
Post by: rlandmann on 06/12/2021 05:17 am
In every photo I've seen of Enterprise, her overhead windows appear white. I'm wondering whether actual windows were ever fitted to these frames (and the photos show them with shades in place), or whether they were just blanked off?
Title: Re: Shuttle Q&A Part 5
Post by: iskyfly on 06/16/2021 02:14 am
No aft and rear windows.

https://space.stackexchange.com/questions/45408/how-space-ready-was-space-shuttle-prototype-enterprise/45409#45409
Title: Re: Shuttle Q&A Part 5
Post by: kidpagorn on 06/17/2021 07:29 pm
In Kathy Sullivan podcast recently, during her first mission, STS 41-G (Challenger), after MECO, the commander, Bob Crippen made a routine radio call to MCC. But, it turned out it not MCC who reply, but an RAF pilot somewhere in GB (Challenger was over GB at the moment). So, they needed to change radio frequency on the Shuttle very often? or they had a fixed radio frequency for entire duration? 
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 06/17/2021 07:31 pm
In Kathy Sullivan podcast recently, during her first mission, STS 41-G (Challenger), after MECO, the commander, Bob Crippen made a routine radio call to MCC. But, it turned out it not MCC who reply, but an RAF pilot somewhere in GB (Challenger was over GB at the moment). So, they needed to change radio frequency on the Shuttle very often? or they had a fixed radio frequency for entire duration? 

Fixed.

And I doubt that happened.
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 06/17/2021 07:52 pm
In Kathy Sullivan podcast recently, during her first mission, STS 41-G (Challenger), after MECO, the commander, Bob Crippen made a routine radio call to MCC. But, it turned out it not MCC who reply, but an RAF pilot somewhere in GB (Challenger was over GB at the moment). So, they needed to change radio frequency on the Shuttle very often? or they had a fixed radio frequency for entire duration? 

For UHF communications, there were a couple of switches above the Commander’s head that allowed the selection of 2 different Frequencies (296.8 & 259.7).  The selection of “Guard” (243.0) was also an option via the rotary switch.

This image is how the switch looked back then.
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 09/25/2021 01:41 am
Can anyone link me to any images or tours of Shuttle servicing _before_ the final flights? I found a couple tours like this outside the vehicles (https://www.youtube.com/watch?v=UsTqVSg_HOk) and some like this inside, but mostly after each orbiter's final flight: http://www.nycaviation.com/2012/01/photos-on-the-flight-deck-of-space-shuttle-atlantis/18911

(http://www.nycaviation.com/newspage/wp-content/uploads/2012/01/middeck-atlantis.jpg)

I'm curious how much the "stripped" look was typical for flight-to-flight turnaround vs end-of-program.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 09/25/2021 02:42 am
The mid deck was stripped after every flight.
It looked like that most of time.
Title: Re: Shuttle Q&A Part 5
Post by: e of pi on 09/25/2021 06:01 pm
The mid deck was stripped after every flight.
It looked like that most of time.
Thanks for the confirmation, I thought I'd read that but was having trouble finding specific documentation.
Title: Re: Shuttle Q&A Part 5
Post by: Kyra's kosmos on 09/28/2021 11:29 pm
Where were the two-digit relay addresses assigned for the APC (Autonomous Payload Controller)*?

*Worked with GAS payloads, the IMAX and certain "secondary" PLB payloads (SSBUV).

On the APS's display the center two digits were the relay number the two digits to either side were alpha-numeric. ("A" "E" "L" Etc. What did these codes mean?

Were there other or backup off-nominal functions an APC could perform? There seemed to be a "generic" list of commands imprinted on the controllers that changed throughout the program.

Title: Re: Shuttle Q&A Part 5
Post by: MDMoery on 12/03/2021 04:07 am
I have a quick question that I have had no luck finding an answer to.

I know that in August 2000, STS-106 became the first Shuttle stack to ever roll into VAB High Bay 2.  Were there ever any subsequent Shuttle stacks that took refuge in High Bay 2?  As in SRB/ET/Orbiter stacks on an MLP, not Orbiters on the floor.  Or for that matter, were there ever any SRB and/or ET partial stacks in HB2?

So far as I can find, the only stacks that have ever been in HB2 in the 55 year history of the building are:
* Apollo 10 (full stacking)
* Apollo 13 (Launch vehicle stacking only, CSM/LM spacecraft stacked in HB1)
* Skylab 1 (full stacking of space station)
* STS-106 (Shuttle stacking not possible, refuge only)

Thanks.
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 12/03/2021 11:37 am
Where were the two-digit relay addresses assigned for the APC (Autonomous Payload Controller)*?

*Worked with GAS payloads, the IMAX and certain "secondary" PLB payloads (SSBUV).

On the APS's display the center two digits were the relay number the two digits to either side were alpha-numeric. ("A" "E" "L" Etc. What did these codes mean?

Were there other or backup off-nominal functions an APC could perform? There seemed to be a "generic" list of commands imprinted on the controllers that changed throughout the program.



no off nominal functions.
Flight software and payload bay wiring is where the addresses were assigned
Title: Re: Shuttle Q&A Part 5
Post by: Kyra's kosmos on 12/11/2021 06:49 am
Thank you, Jim.

The APC was used on many missions and deserved a mention.
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 08/26/2022 03:31 pm
Good day, I have just been challenged as to my reasoning of exactly why the Shuttle's main engines ignition was staggered by 120 milliseconds

I've always understood that it was to reduce loads throughout the Main Propulsion System(MPS).
or
Was the 120 millisecond staggered ignition to reduce the shockwave leaving the aft section in an effort to reduce the wear/tear on the SSME exhaust tunnel(to keep the fire bricks from flying around)?

or some combination of both or neither?
Title: Re: Shuttle Q&A Part 5
Post by: Jim on 08/26/2022 03:36 pm
Good day, I have just been challenged as to my reasoning of exactly why the Shuttle's main engines ignition was staggered by 120 milliseconds

I've always understood that it was to reduce loads throughout the Main Propulsion System(MPS).
or
Was the 120 millisecond staggered ignition to reduce the shockwave leaving the aft section in an effort to reduce the wear/tear on the SSME exhaust tunnel(to keep the fire bricks from flying around)?

or some combination of both or neither?

To keep the nozzles from banging into each other. 

SSME exhaust was nothing like the SRBs and there was no shockwave since the SSMEs took 3 seconds to come up to thrust.
Title: Re: Shuttle Q&A Part 5
Post by: daschmid on 09/02/2022 07:19 pm
Obscure and very specific questions about the Flight Software:


I've been slowly reconstructing HAL/S source based on available FSW specifications.   The specifications only go so far.  Obviously I have no info on comment lines and CR history, but I'm also left with questions of style. I know it's a long shot, but if anyone in the world knows the answers to these questions there's a good chance they're hanging around this forum.


Here's a link to a couple of reconstructed functions for reference:


https://gist.github.com/ColanderCombo/3b28cc7c934c801ee5b37db8152a01a6


Questions:
- How close do these reconstructions look to the original code?  I already know that the original was extensively annotated, tying individual lines of code to the Change Request they are associated with.  Excluding this annotation, how verbose were comments?  In these files I have relatively few comments, but maybe text from the source specification should be included?
- HAL/S supports Fortran-style 'C' line comments and the surprisingly modern looking '/* */' inline comment.  Were inline comments common?
- HAL/S flow control statements like IF/THEN/ELSE take a single statement.  The equivalent to C's  '{}' block is a 'DO; END;' block.  I've omitted the DO;/END; in cases where the code looked cleaner without it. Is this reasonable, or were there stricter rules?
- COMPOOL variables: in general, I've been accessing shared COMPOOL variables directly throughout functions.  I've seen some implications in the specs that inputs are copied into local variables at the top of functions so the values will be consistent throughout.  Similarly, outputs might get set in a single batch at the end of the function.  Any insights?
- SM2_OPS makes use of the user interface grammar, which isn't part of the HAL/S language and is implemented using macros.  Does it look right?
- SSP_EXEC plays a little fast and loose with HAL's NAME() feature. (equivalent to a pointer/addressof in other languages). Does this seem legit?


If you're able to help out with these questions or if you have any other notes, thanks much!

Title: Re: Shuttle Q&A Part 5
Post by: Hog on 09/09/2022 07:20 pm
Do any of our Shuttle-minded members have any memories of Flight Termination System(FTS) batteries being changed at the pad?

I remember a video showing a man/men pushing a cart with a battery or batteries loaded on it.  The very careful manner in which these people were pushing the cart led me to think that they were very important and/or delicate and had some weight to them..  The commentators were talking about battery temperatures and battery life.

I was watching the video online, so that precludes any of the missions Return To Flight#1 (RTF#1) STS-26 that I was watching live via NASA-Select(now NASA-TV) via C band satellite. Unless it was recorded and then I watched it later, online.

If this indeed was a FTS battery change event, was it common?
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/09/2022 07:55 pm
Do any of our Shuttle-minded members have any memories of Flight Termination System(FTS) batteries being changed at the pad?

I remember a video showing a man/men pushing a cart with a battery or batteries loaded on it.  The very careful manner in which these people were pushing the cart led me to think that they were very important and/or delicate and had some weight to them..  The commentators were talking about battery temperatures and battery life.

I was watching the video online, so that precludes any of the missions Return To Flight#1 (RTF#1) STS-26 that I was watching live via NASA-Select(now NASA-TV) via C band satellite. Unless it was recorded and then I watched it later, online.

If this indeed was a FTS battery change event, was it common?
No, what you most likely saw was recorded KSC PAO footage of the HST battery removal and recharge and subsequent re-installation following the first scrub of STS-31. The HST batteries required a 120 hr recharging period following any launch scrubs and they had to it in the VAB Battery Lab which batteries like this are stored in a special refrigerator which chills the batteries which allows them to take on a stronger charge. This was all done in tandem with the APU R&R that caused the launch scrub.

Video can seen here:
https://www.youtube.com/watch?v=fQlPPOZTOxw
Title: Re: Shuttle Q&A Part 5
Post by: Hog on 09/09/2022 10:12 pm
Do any of our Shuttle-minded members have any memories of Flight Termination System(FTS) batteries being changed at the pad?

I remember a video showing a man/men pushing a cart with a battery or batteries loaded on it.  The very careful manner in which these people were pushing the cart led me to think that they were very important and/or delicate and had some weight to them..  The commentators were talking about battery temperatures and battery life.

I was watching the video online, so that precludes any of the missions Return To Flight#1 (RTF#1) STS-26 that I was watching live via NASA-Select(now NASA-TV) via C band satellite. Unless it was recorded and then I watched it later, online.

If this indeed was a FTS battery change event, was it common?
No, what you most likely saw was recorded KSC PAO footage of the HST battery removal and recharge and subsequent re-installation following the first scrub of STS-31. The HST batteries required a 120 hr recharging period following any launch scrubs and they had to it in the VAB Battery Lab which batteries like this are stored in a special refrigerator which chills the batteries which allows them to take on a stronger charge. This was all done in tandem with the APU R&R that caused the launch scrub.


Excellent and thank you, that was great to watch another shuttle video.  That was exactly the video I was asking about.
Interesting tidbit:  1:35 Each "set" consists of 6 batteries and each set weighs 400lbs. There were 2 sets of batteries on HST.
Title: Re: Shuttle Q&A Part 5
Post by: John2375 on 01/22/2023 01:26 pm
In the earlier days, of many Edwards AFB landings- why were some fights landed on the lakebed and others on the concrete runway??
For example: STS-36 landed on lakebed runway 23. Why?? The previous flight landed on concrete runway 22.. 
I understand in the very early days they wanted the extra margin the lakebed runways allowed for, but in the above example it was 1990..
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/22/2023 02:00 pm
In the earlier days, of many Edwards AFB landings- why were some fights landed on the lakebed and others on the concrete runway??
For example: STS-36 landed on lakebed runway 23. Why?? The previous flight landed on concrete runway 22.. 
I understand in the very early days they wanted the extra margin the lakebed runways allowed for, but in the above example it was 1990..


The simple answer is the decision came down to which runway had the optimal “anticipated” and “observed” approach and landing conditions.

Which runway had the best winds (direction and magnitude)?
Would the orbiter experience turbulence or shear layers?
Were there cloud decks obscuring the approach path (i.e. maybe clouds to the north or east, but clear to the south or west)?
Is there rain/moisture or lightning from one direction versus another?

What about sun angle and glare:
Is the sun in the crew’s eyes? 
Is it creating shadows that obscure the runway marking or lighting, or making depth perception a challenge?

What about ground fog:
Is it obscuring the view of the approach lighting?

What about runway condition:
Is one end of the runway still covered by puddles from recent rains?
Expected braking action and rollout margins?



I hope that gives you insight into some of the thought process.  Keep in mind, the decision on landing sight had to be made a little over 90 minutes prior to the expected touchown in order to accommodate the deorbit burn.  After the burn, it was possible under certain conditions, but certainly not ideal, to change the runway for a particular landing sight.


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/22/2023 11:02 pm
Question on the post-MECO ET Sep translation maneuver that was done by the CDR: On the early missions it seems like it wasn't a a +X maneuver but rather a -Y maneuver given the PAO's comments on STS-1 that the orbiter was "moving to north of the External Tank" and that Young should have been "able to see it out of his window". Is this correct and when wasn't it changed to the +X maneuver that was used through the rest of the program?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/23/2023 12:24 am
Question on the post-MECO ET Sep translation maneuver that was done by the CDR: On the early missions it seems like it wasn't a a +X maneuver but rather a -Y maneuver given the PAO's comments on STS-1 that the orbiter was "moving to north of the External Tank" and that Young should have been "able to see it out of his window". Is this correct and when wasn't it changed to the +X maneuver that was used through the rest of the program?


For STS-1 it was indeed an “out of plane” maneuver.  In the case of STS-1 it was a +Y burn.  The exact direction was determined by the exact roll attitude of the orbiter at ET Sep (which was supposed to be 180 degrees).  As you can see in my attached image, if the roll attitude was less than 170, then they would perform a -Y burn.

The idea was this got the Orbiter safely away from the ET by being out of plane - keep in mind the orbiter did an automatic -Z translation right at ET Sep - this Y translation was in addition to that.  It was also hoped that, depending on burn direction and. exact orbiter roll attitude, either the CDR or PLT would be able to view the tank.

If my memory is correct, this procedure was changed to the standard +X maneuver for STS-2.  My copy of the STS-2 Checklist does not have the Y maneuver in it.  I was just a kid at the time, but if my memory isn’t failing me, I actually recall the news coverage making a big deal about this.  They talked about how the +X translation would allow the ET Umbilical Well Camera to obtain imagery of the condition of the tank from bottom to top as the orbiter moved along the length of the separating tank.


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 01/23/2023 05:39 am
Mark: thanks for the answer. It was something that had been on my mind on and off again for a few years. In my mind up until now was that the "north" that the MCC PAO stated was in relation to the orbiter coordinate system where "north" was +X.

Another DPS question: Did MM104 OMS-1 MNVR EXEC take in account the additional dV of the MPS propellant dump when calculating the dV targets?
Title: Re: Shuttle Q&A Part 5
Post by: mkirk on 01/24/2023 02:50 pm
Mark: thanks for the answer. It was something that had been on my mind on and off again for a few years. In my mind up until now was that the "north" that the MCC PAO stated was in relation to the orbiter coordinate system where "north" was +X.

Another DPS question: Did MM104 OMS-1 MNVR EXEC take in account the additional dV of the MPS propellant dump when calculating the dV targets?


Yes, but not directly in the OMS 1 Targets, but in how the orbiter achieved the desired Targets.

The OMS 1 Burn was conducted using a “closed loop” guidance scheme known as PEG 4 (powered explicit guidance).  PEG 4 was trying to achieve specific vertical and horizontal velocity changes (Delta V) over a certain point above the earth.  Closed loop guidance meant the orbiter knew where it was at the start of the burn (state vector at the time of ignition) and where it wanted to be (state vector at the end of the burn).  During the burn, sensed accelerations (i.e. IMU data) were used to update the current state vector - this was then compared to the desired OMS cutoff conditions.

On a “Standard Insertion”  mission like STS-1, the “Automatic” MPS Dump started at OMS 1 Ignition.  If I recall correctly, the Dump contributed about 10 to 11 feet per second of Delta V. 
Btw, the rule of thumb was that 2 fps of Delta V contributed 1 nautical mile to the Perigee Altitude (Hp).

So, if the Dump occurred as planned during the OMS 1 Burn, the continuously updated OMS cutoff conditions needed to achieve the desired target conditions, would occur slightly earlier than if the Dump was not taking place.



(Someone like Jorge - if he still lurks within these threads - would probably be able to give you a much better explanation.)


Mark Kirkman
“NASA Space Shuttle Hugger”
Title: Re: Shuttle Q&A Part 5
Post by: John2375 on 01/27/2023 07:58 pm
Thanks, Mark -  I understand what you’re saying and it especially makes sense when determining runway 17 vs 23, for example. And I know sometimes at KSC they’d accept  a little tailwind component so the sun angle wasn’t a factor.
I was just curious about my example of STS-36: runway 23 vs 22- the winds component would be similar, sun angle as well, and the previous flight STS-32 used 22.

Also- STS-37 had some issues with the upper level winds not being as forecast on the HAC. Eileen  Collins writes in her book that STS-63 had stronger winds on the HAC than they excepted.. we’re there any other flights you know of that had to do some good piloting to get the orbiter to the runway?!
Title: Re: Shuttle Q&A Part 5
Post by: John2375 on 02/21/2023 07:47 pm
https://www.americaspace.com/2021/01/03/stopping-the-shuttle-remembering-the-drag-chute-30-years-on/

First paragraph.. references a landing that “almost bounced…” ? Any idea which flight that refers to?
Title: Re: Shuttle Q&A Part 5
Post by: penguin44 on 02/22/2023 02:07 am
Either the final landing test of Enterprise or sts-3 perhaps
Title: Re: Shuttle Q&A Part 5
Post by: John2375 on 02/23/2023 02:14 pm
most likely- and certainly STS-51D for the seized brakes/blown tire (why didn’t the orbiter have nose wheel steering from the get-go?

STS-91 kind of bounced, not hard but there are 2 distinct main gear  touchdowns ..
Title: Re: Shuttle Q&A Part 5
Post by: Nicolas PILLET on 06/03/2023 02:01 pm
I've seen this replica in storage in Steven F. Udvar-Hazy Center two months ago. Someone knows from which display model it comes ?
Title: Re: Shuttle Q&A Part 5
Post by: AS_501 on 07/18/2023 11:14 pm
I'm curious about one aspect of the radiators inside the payload bay doors.  When the orbiter was flying on its own (i.e. not docked to Mir or ISS), was the payload bay oriented away from the Sun as often as possible to minimize Solar heating of the radiators?  When the bay was facing the Sun, did the radiators lose some of their cooling efficiency?  I'm not well versed in the underlying physics of the radiators.
Thx
Title: Re: Shuttle Q&A Part 5
Post by: Jorge on 07/19/2023 02:28 am
I'm curious about one aspect of the radiators inside the payload bay doors.  When the orbiter was flying on its own (i.e. not docked to Mir or ISS), was the payload bay oriented away from the Sun as often as possible to minimize Solar heating of the radiators?  When the bay was facing the Sun, did the radiators lose some of their cooling efficiency?  I'm not well versed in the underlying physics of the radiators.
Thx

The TL; DR answer is that soon after the start of the program the "free-flight" attitude standardized on payload bay toward Earth with one wing pointed at the velocity vector. Later in the program the standard was payload bay to Earth, tail to velocity vector.

Long answer: It was a balance between thermal, comm, and orbital debris concerns. On early flights it was learned that pointing one axis of the Orbiter at the sun for too long caused too much of a thermal imbalance between the sunlit and shaded sides, resulting in difficulty closing the payload bay doors before deorbit. Payload bay to Earth maintained thermal balance for closing the doors while still providing adequate heat rejection through the radiators. Once TDRSS was available, wing to velocity vector (therefore nose out of plane) ensured that at least one S-band antenna (arranged around the nose) was pointed at a TDRS satellite for near-continuous comm. Later, when orbital debris became more of a concern, tail to velocity vector was chosen to shield the cabin from MMOD. By this time TDRS-Z was available to mitigate the comm loss due to S-band blockage "off the tail".
Title: Re: Shuttle Q&A Part 5
Post by: John2375 on 07/20/2023 12:50 pm
I’ve tried searching but to no avail;  I recall somewhere on here, there was a dramatic photo of the forward fire team “caught” outside their bunker during launch.. I think the story was that a hold was called for T-31 so they went outside.. then the hold was cancelled and they didn’t have time to get back inside..  there was talk on here of which launch it was but idk if it was ever determined ?
Title: Re: Shuttle Q&A Part 5
Post by: Thorny on 07/21/2023 05:54 pm
I’ve tried searching but to no avail;  I recall somewhere on here, there was a dramatic photo of the forward fire team “caught” outside their bunker during launch.. I think the story was that a hold was called for T-31 so they went outside.. then the hold was cancelled and they didn’t have time to get back inside..  there was talk on here of which launch it was but idk if it was ever determined ?

I'm not sure if it was ever identified as to which mission it was, but here is the photo...

https://www.thedrive.com/content-b/message-editor%2F1642726676274-lzajden.jpeg?auto=webp&optimize=high&quality=70&width=1440
Title: Re: Shuttle Q&A Part 5
Post by: joncz on 07/21/2023 06:07 pm

I'm not sure if it was ever identified as to which mission it was, but here is the photo...

https://www.thedrive.com/content-b/message-editor%2F1642726676274-lzajden.jpeg?auto=webp&optimize=high&quality=70&width=1440

Quote
Yes, the carrier vehicle is outside the pad's perimeter fence. This was M-113/Hard Top One's astronaut rescue vehicle and team (I think Unit #HE-704-080) on station at A/B 4, just under a mile from the shuttle on Pad B, during the launch of STS-26/Discovery in Sept. 1988. I think the photo seen is one that had been autographed by one of the 12-member astronaut pad rescue teams that Bob had gotten from me long ago.

From http://www.collectspace.com/ubb/Forum29/HTML/001965.html
Title: Re: Shuttle Q&A Part 5
Post by: DaveS on 09/23/2023 07:08 am
Can someone with a bit more knowledge than me, explain how the PLBD NO-GO diagram is supposed to be read in terms of the position assessment outlined in the STS-1 Post Insertion checklist? Crippen reported that it was "Position 1A" that was determined during the PLBD latch and cycle tests.