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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)
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.