Author Topic: Shuttle Questions Q and A (2)  (Read 190692 times)

Offline Pointman 7

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RE: Shuttle Questions Q and A (2)
« Reply #40 on: 04/26/2006 12:12 AM »
Quote
astrobrian - 25/4/2006  7:06 PM

Its the aft  External Tank connections to the Shuttle if what I am seeing is correct

LOL. Yeah, I think I worked that out ;)

I want to know what each electrical connections aft port connectors I'm seeing here.

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #41 on: 04/26/2006 01:11 AM »
Quote
Pointman 7 - 25/4/2006  7:12 PM

Quote
astrobrian - 25/4/2006  7:06 PM

Its the aft  External Tank connections to the Shuttle if what I am seeing is correct

LOL. Yeah, I think I worked that out ;)

I want to know what each electrical connections aft port connectors I'm seeing here.


I'll give it a try;

On the left:  The big silver colored circle at the top is the 17 inch LH2 (Liquid Hydrogen) feedline disconnect, the dark circle immediately below and to the right is the 2 inch LH2 pressurization disconnect, to the left of that with the redish color is the 4 inch LH2 recirculization line connection, and the big circle at the bottom is the electrical monoball - this is where the electrical interfaces between the orbiter and the ET are made, examples would be the low level ECO sensor instrumentation as well as all the other LH2 liquid level sensors, pressurization, vent and flow control valves etc...


On the right:  The big silver circle is the 17 inch LO2 (Liquid Oxygen) feedline disconnect, the dark circle immediately below and to the left is the 2 inch LO2 pressurization disconnect,  below that is the electrical monoball umbilical - again this is the electrical interface between the orbiter and ET, examples would be the liquid level sensors for the LO2 tank (the LO2 ECO sensors are not actually in the tank like the LH2 ECO sensors are, they are on the orbiter side of the 17 inch disconnect), valve operation etc...

The holes for the ET/Orbiter tie bolts are not really visible in this picture, but you have three around each of the 17 inch feedline diconnects one at the bottom (6 o'clock postition) and the other at the 10 and 2 o'clock.

Aside from the ET intrumentation, SRB related instrumentation also goes thru these connection points.

Mark Kirkman
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Offline Jim

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RE: Shuttle Questions Q and A (2)
« Reply #42 on: 04/26/2006 01:40 AM »
The red covers on the right (and partial extreme left) are the aft ET structure connections (balls) to the Orbiter (sockets)

Offline dmc6960

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RE: Shuttle Questions Q and A (2)
« Reply #43 on: 04/26/2006 03:56 PM »
Why are both the LH2 and LO2 feedlines 17 inches if the engines require 6 times the amount of hydrogen than they do oxygen?
-Jim

Offline Jim

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RE: Shuttle Questions Q and A (2)
« Reply #44 on: 04/26/2006 04:09 PM »
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dmc6960 - 26/4/2006  11:56 AMWhy are both the LH2 and LO2 feedlines 17 inches if the engines require 6 times the amount of hydrogen than they do oxygen?

That is by weight, but there still a volumetric difference

But the design was for ease.  Only one disconnect needed to be designed. 

Offline GLS

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RE: Shuttle Questions Q and A (2)
« Reply #45 on: 04/28/2006 01:44 PM »
I have a couple more questions (actually I have more, but I'll ask them later...):
1) I was giving a quick read at the CAIB report the other day, and on STS 107 there was a 2.08sec, window protect maneuver at T+127.7 using RCS F1U, F2U, F3U. WHAT IS THIS???
2) On cameras ET207 and ET208, there's some *lines* in the image at about 60-90sec into the flight. Is that a reflection or what?
GLS is go for main engine start!

Offline psloss

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RE: Shuttle Questions Q and A (2)
« Reply #46 on: 04/28/2006 01:54 PM »
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GLS - 28/4/2006  9:44 AM

I have a couple more questions (actually I have more, but I'll ask them later...):
1) I was giving a quick read at the CAIB report the other day, and on STS 107 there was a 2.08sec, window protect maneuver at T+127.7 using RCS F1U, F2U, F3U. WHAT IS THIS???

If you're referring to the forward RCS firing at SRB separation, I believe that's done to minimize the amount of SRB separation motor exhaust deposited on the orbiter windows -- if you recall the ET camera video from STS-112, which was essentially in the line of fire of the right SRB, the camera's window was "fogged over" by the separation motor plume.  Early in the program, some crews remarked right after SRB sep about how much "crud" was left on the windows (I believe that was the word used by Paul Weitz on STS-6).  If I recall correctly, someone noted that re-entry tended to "clean" that film off the windows.

Someone here can probably say how long ago the FRCS firing was put into use, but it predates 107.

Edit: Looking at the 112 ET cam footage again, I'm not sure I see the FRCS firing.

Philip Sloss

Offline GLS

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RE: Shuttle Questions Q and A (2)
« Reply #47 on: 04/28/2006 02:09 PM »
Very smart thing... the FRCS plume shields the windows from the BSM plumes/stuff.... thanks!!!

EDIT: Wait a minute, I doesn't shield anything because the burn is after SRB sep.... It just cleans the windows...
GLS is go for main engine start!

Offline Zoomer30

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RE: Shuttle Questions Q and A (2)
« Reply #48 on: 04/28/2006 04:07 PM »
Looks like they need a BPS like the Apollo caps had.  Course they would not be able to SEE till the thing was dropped off (dont ask how that woudl work)

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #49 on: 04/28/2006 04:22 PM »
I forget which flight was the first to use the up firing jets at SEP.  It was sometime in 2000 when we first did it.  I remember being at an Ascen/Entry Flight Techniques meeting in Houston with a couple of other instructors when someone made the presentation on this...we all looked at each other with a "They want to do what during SRB SEP...they have lost their damn minds!!!!"

The idea of possibly inducing a pitch rate...in the direction that the SRBs are traveling when they seperate...took some getting used to.

That aside, the technique works very well and has reduced the windshield glare for entry and landing that used to be caused by the residue from the SRB SEP motors.  Glare is a big factor the STA (Shuttle Training Aircraft) pilot considers when evaluating approaches at the shuttle runway prior to every launch for RTLS or prior to the deorbit burn for End of Mission landings.  It goes without saying you really need to be able to see the runway.  With that residue on the window the sun could really cause some glare according to some commanders.

Mark Kirkman
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Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #50 on: 04/28/2006 07:07 PM »
Bump from another thread:

Quote
Jim - 28/4/2006  12:20 PM

Quote
Zoomer30 - 28/4/2006  12:14 PMCant find the post for some reason, but one thing that was not mentioned was that the shuttle, no matter what orbital declination it will be in, MUST go to orbit "heads down, wing level" until SRB sep. Or in other words, upside down.  The reason is its the only safe way to get rid of the SRBs.  If they shuttle flew on top of the stack, the SRBs would slam into the wings.  A few mins after SRB sep the shuttle does that roll that does place the ship on top, thats so they can tap into the TDRS sat for ground comm (they started that in '98 I think, so they could close ground stations that are used during ascent).I think the previous poster thought the shuttle was the only ship to do a roll after launch.  All rockets have done this, its just more visable with the shuttle.

It has nothing to do the SRB's.    It is to reduce the loads on the wings.  The roll back to orbiter on top is to increase performance, a better TDRSS link was just a fallout.

The Shuttle Q &A thread is were questions like this go


The roll to heads down after liftoff has many side benefits but the primary reason for it is to minimize structural loads between the ET and the orbiter.  The heads down attitude does provide a slight negative angle of attack which minimizes loads while not sacrificing too much performance.

There is no reason SRB SEP can not occur from the heads up attitude other than a loss in overall performance (up mass).

The roll back to heads up which occurs at about five and a half minutes into the flight was primarily driven by the closure of the Bermuda tracking station.  It provides an early handoff from MILA to TDRS East.  The second roll is actually a slight performance loss.  The first flight to do this was STS-87.  Rolling back to heads up was always part of the TAL procedures but additional study and certification was needed prior to incorporating it into Nominal Ascents.  In fact the shuttle is no longer certified to stay heads down on a Nominal Ascent!!!

OTHER benefits of the Roll to Heads down is: visible horizon for the crew (helps with abort and manual flying procedures), G-loading on crew is more favorable, communication with the ground stations is not blocked by the ET.

Mark Kirkman
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Offline Chris Bergin

RE: Shuttle Questions Q and A (2)
« Reply #51 on: 04/28/2006 10:54 PM »
Good man Mark. I'm making both Shuttle Q and A thread sticky.

Offline psloss

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RE: Shuttle Questions Q and A (2)
« Reply #52 on: 04/28/2006 11:18 PM »
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mkirk - 28/4/2006  3:07 PM

OTHER benefits of the Roll to Heads down is: visible horizon for the crew (helps with abort and manual flying procedures), G-loading on crew is more favorable, communication with the ground stations is not blocked by the ET.
(Hope it's OK to bring this over from the locked thread...)

Hi Mark,

Weren't some studies done/consideration given to a heads-up ascent? I want to say this was associated with other ascent changes using the 5-segment SRBs (like ATO off the pad), but maybe it's unconnected...have to go do some digging for references...

This reference is only available offline, though the first page (w/abstract) can be downloaded:
http://www.aiaa.org/content.cfm?pageid=406&gTable=japaperimportPre97&gID=25979

And an interesting old Usenet thread (not sure about the accuracy); here's one post:
http://groups.google.com/group/sci.space.shuttle/msg/590bae76a518a1ac

(I'd be interested in anything you know about this.)

Thanks,

Philip Sloss

Offline hyper_snyper

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RE: Shuttle Questions Q and A (2)
« Reply #53 on: 04/28/2006 11:53 PM »
I have a quick shuttle question.

During STS-121 or any other subsequent mission, there are going to be cameras on the ground and on the tank to spot falling foam.  If a big chunk of foam flies free and hits the orbiter and damages the TPS (heaven forbid) during the early stages of ascent and it's spotted by the cameras nice and clear do the mission controllers have the option of telling the crew to abort TAL or RTLS?  If it's obvious damage has been done, I don't see how it would be a good idea to let them continue to orbit.

Offline psloss

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RE: Shuttle Questions Q and A (2)
« Reply #54 on: 04/29/2006 12:11 AM »
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hyper_snyper - 28/4/2006  7:53 PM

I have a quick shuttle question.

During STS-121 or any other subsequent mission, there are going to be cameras on the ground and on the tank to spot falling foam.  If a big chunk of foam flies free and hits the orbiter and damages the TPS (heaven forbid) during the early stages of ascent and it's spotted by the cameras nice and clear do the mission controllers have the option of telling the crew to abort TAL or RTLS?  If it's obvious damage has been done, I don't see how it would be a good idea to let them continue to orbit.
I can't give a straight answer, but I'd always assumed that Columbia's RCC damage would have been catastrophic even in a TAL entry given its similarity to a regular entry -- and actually, I believe some low-energy TALs can be more extreme thermally...not sure about RTLS (though it has it's own risks).

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #55 on: 04/29/2006 06:01 PM »
Quote
psloss - 28/4/2006  6:18 PM

Quote
mkirk - 28/4/2006  3:07 PM

OTHER benefits of the Roll to Heads down is: visible horizon for the crew (helps with abort and manual flying procedures), G-loading on crew is more favorable, communication with the ground stations is not blocked by the ET.
(Hope it's OK to bring this over from the locked thread...)

Hi Mark,

Weren't some studies done/consideration given to a heads-up ascent? I want to say this was associated with other ascent changes using the 5-segment SRBs (like ATO off the pad), but maybe it's unconnected...have to go do some digging for references...

This reference is only available offline, though the first page (w/abstract) can be downloaded:
http://www.aiaa.org/content.cfm?pageid=406&gTable=japaperimportPre97&gID=25979

And an interesting old Usenet thread (not sure about the accuracy); here's one post:
http://groups.google.com/group/sci.space.shuttle/msg/590bae76a518a1ac

(I'd be interested in anything you know about this.)

Thanks,

Philip Sloss


I sat in on a few meetings in the 1999-2000 timeframe concerning 5 Segment Bossters.  Nobody ever metnioned heads up profile to my knowledge.  The biggest concerns I recall involved getting the vehicle recertifed for the new ascent trajectory.  Structural changes to the tank would be needed, new aerodynamic modeling (since for example, the SRB nose cones would be higher relative to the current stack which in trun meant the shock waves would be hitting the tank in a different location), processing was a concern since you would have extra segements in the VAB (increased risk, processing to stacks would have exceeded the current certification for the VAB in terms of allowable propellant).

There was a preliminary belief that with 5 segment boosters Black Zones would be significantly reduced but I don't think they would have been eliminated.  Single engine failure in first stage would have resulted in an ATO capability I believe.


I read your Usenet thread and that doesn't seem to ring true to me.  I will read the AIAA paper in a couple days and see if that makes sense...I can say I never heard anyone discuss heads up as a performance advantage but that paper is pretty old (1988) so I'll look into it.

Mark Kirkman
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Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #56 on: 04/29/2006 06:29 PM »
Quote
hyper_snyper - 28/4/2006  6:53 PM

I have a quick shuttle question.

During STS-121 or any other subsequent mission, there are going to be cameras on the ground and on the tank to spot falling foam.  If a big chunk of foam flies free and hits the orbiter and damages the TPS (heaven forbid) during the early stages of ascent and it's spotted by the cameras nice and clear do the mission controllers have the option of telling the crew to abort TAL or RTLS?  If it's obvious damage has been done, I don't see how it would be a good idea to let them continue to orbit.

No, that is definately not an option and actually although it sounds on the suface like it might be a good idea, it is actually a very dangerous and bad idea.

Ascent is only 8.5 minutes long, during that time someone would have to see the foam debris, assess it size, mass, velocity, density, and total impact energy.  Then you would have to determine if it hit a critical area of the orbiter or not.  Then you have to decide if the impact actually caused damage or is a safety of flight issue...what systems affected?, do you have potential control issues?, do you have thermal issues?

Then even if you could do all that you have to pass the abort request up to the crew in a timely manner.  

Tha abort profiles the shuttle uses are well trained and understood, but they all impose significant trade offs in risk.  RTLS for example is less thermally severe than a TAL but it is far more dynamic than most TALs.  If you have critical systems affeceted by the impact such as impending lose of hydraulics then you want to get on the ground quickly...loss of a thermal window pain means you want a less thermally severe profile.  My point is you would have to evaluate all of this "on the fly" and hope you don't make your situation worse.

The right thing to do is fly with our current abort philosophy and if performance and systems allow it, you go to orbit and then evaluate the situation.  Lets say there is significant damage to the vehicel structure...you would rather think thru exactly how you want to fly (control issues, thermal, or opt for safe haven on ISS) and then return as opposed to attempting an abort without a complete understanding of the vehicle's status and your ability to survive the profile.

Going to space so you can "reconfigure" is exactly what you would want to do!!!!  Contrary to Ascent and Entry, on orbit operations give you time to think and evaluate.  This is similar to the airplane pilot's desire to gain altitude when a problem occurs...altitude gives you time to evaluate...Shuttle does this to the extreme...

Another point:  The flight control team in the MCC (mission control center) does not watch the video in real time.  There are some TV monitors in the room but everyone is trained to look at their data.  The video can deceive you!!!  On top of that the very high quality video is not transmitted in real time...it is recorded and evaluated frame by frame by many engineers on the photo analysis team about a day after launch.

Mark Kirkman
Mark Kirkman

Offline GLS

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RE: Shuttle Questions Q and A (2)
« Reply #57 on: 04/29/2006 07:24 PM »
And can anyone anwser the second question?
2) On cameras ET207 and ET208, there's some *lines* in the image at about 60-90sec into the flight. Is that a reflection or what?
GLS is go for main engine start!

Offline Jim

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RE: Shuttle Questions Q and A (2)
« Reply #58 on: 04/29/2006 07:33 PM »
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GLS - 29/4/2006  3:24 PMAnd can anyone anwser the second question?2) On cameras ET207 and ET208, there's some *lines* in the image at about 60-90sec into the flight. Is that a reflection or what?

Where are we to view these videos?

Offline mkirk

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RE: Shuttle Questions Q and A (2)
« Reply #59 on: 04/30/2006 12:06 AM »
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GLS - 29/4/2006  2:24 PM

And can anyone anwser the second question?
2) On cameras ET207 and ET208, there's some *lines* in the image at about 60-90sec into the flight. Is that a reflection or what?

Over the years I have talked to some of the engineers on the Photo Analysis working groups about that and similar effects.  Believe me you and I are not the first to ask about these.  It is a result of a combination of things such as optics and lighting, aerodynamic effects changing the light refraction and so on...the head of the team told me you could probably earn a PhD by studying the phenomenon.

Mark Kirkman
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