Author Topic: Shuttle Q&A Part 5  (Read 1103440 times)

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #2600 on: 04/24/2012 03:16 pm »
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Offline Prober

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Re: Shuttle Q&A Part 5
« Reply #2601 on: 04/24/2012 03:28 pm »
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.
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Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #2602 on: 04/24/2012 03:37 pm »
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.


What is its weight, attach methods, and how does it come off, nominally and in aborts?

Its weight would reduce payload by the same amount.
Its drag would reduce payload also.
« Last Edit: 04/24/2012 03:39 pm by Jim »

Offline MP99

Re: Shuttle Q&A Part 5
« Reply #2603 on: 04/24/2012 05:05 pm »
What temperature are the gasses fed into the ET as pressurant?

Prelaunch

Helium for the LH2 tank and I think nitrogen for the LOX tank
During flight, the SSME provide heated gases.

Thanks.

What temp are the gases from the SSMEs at the point they're injected?

Cheers, Martin

Offline Prober

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Re: Shuttle Q&A Part 5
« Reply #2604 on: 04/24/2012 07:19 pm »
Would the Space shuttle have benefited from the use of a fairing during assent?



Where would be the fairing?

Thinking of an upside down L shapped fairing.   Designed to cover the heat shield bottom to top, and the crew compartment.   The fairing would be flaired and end near the payload bay doors.

Not sure of the space available between the orbiter bottom and the fuel tank. Hope the idea would not involve adding say 6 inches of needed space.


What is its weight, attach methods, and how does it come off, nominally and in aborts?

Its weight would reduce payload by the same amount.
Its drag would reduce payload also.

drag should be reduced (if designed right).  We have gotten better since the shuttle was designed.

weight would be an issue

2017 - Everything Old is New Again.
I have not failed. I've just found 10,000 ways that won't work. ~ by Thomas Alva Edison

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #2605 on: 04/24/2012 07:25 pm »

drag should be reduced (if designed right).  We have gotten better since the shuttle was designed.

No, it will be more than the existing shuttle.  It will have a larger profile and some of the shuttle is still exposed.

Offline wolfpack

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Re: Shuttle Q&A Part 5
« Reply #2606 on: 04/24/2012 07:40 pm »

Since the shuttle blanks much of the effect of the vertical stabilizer could we assume the rudder is also somewhat blanked and hence engine power is used to aid in turns (yaw)?

I believe there is still enough control authority in the rudder. 

Probably way more than enough. Stomping on rudder pedals has the effect of separating the vertical stabilizer from the fuselage in normal aircraft. :)

Offline Fequalsma

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Re: Shuttle Q&A Part 5
« Reply #2607 on: 04/25/2012 02:48 am »
From the SLWT system definition handbook, vol. I (section-page):

 - The LO2 and LH2 tanks are pressurized with dry GN2 at 6 psig (+/-1) after fabrication at MAF and during shipment to KSC (3-2). 

 - After the stack is assembled on the MLP, both tanks are purged with GHe prior to and during prop loading (3-4, 9-6).

 - Pre-launch, both tanks are pressurized with GHe, the LO2 tank at T-155 sec, and the LH2 tank at T-106 sec (3-5).  Pressurization is autogenous after T-6 sec (9-7).

 - Heated GN2 is used to purge the Intertank and nose cap (9-3, 9-7), and GHe is injected into the LO2 feedline aft elbow to suppress/prevent geysering (9-6).

From the LWT system definition handbook, vol. III (1988):

 - GO2 ullage gas temperature is 600 deg F max at the diffuser inlet, and an average of 390 deg F at the ET/Orbiter interface.

 - GH2 ullage gas temperature is 100 deg F max at the diffuser inlet, and an average of -10 deg F at the ET/Orbiter interface.



What temperature are the gasses fed into the ET as pressurant?

Prelaunch

Helium for the LH2 tank and I think nitrogen for the LOX tank
During flight, the SSME provide heated gases.

Thanks.

What temp are the gases from the SSMEs at the point they're injected?

Cheers, Martin
« Last Edit: 04/25/2012 02:50 am by Fequalsma »

Offline e of pi

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Re: Shuttle Q&A Part 5
« Reply #2608 on: 04/25/2012 12:41 pm »
Someone the other day was asking me if there were ever any issues with wind levels during roll-out of Shuttle to the pad. What were the wind limits like for rollout and then for remaining on the pad? I know they usually rolled back to the VAb in the face of hurricane threats, but can someone lay out the actual critieria involved?

Offline iskyfly

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Re: Shuttle Q&A Part 5
« Reply #2609 on: 04/26/2012 06:23 pm »
In this article;

http://www.nasaspaceflight.com/2011/07/atlantis-down-processing-mer-review-notes-flawless-return/

 “performed flawless, bar typical GPC (General Purpose Computer) errors during rollout.”


What are these errors, causes and where can I find out more about this?

Thanks

Offline MP99

Re: Shuttle Q&A Part 5
« Reply #2610 on: 04/26/2012 06:39 pm »
Fequalsma,

great - thanks.

cheers, Martin

Offline sivodave

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Re: Shuttle Q&A Part 5
« Reply #2611 on: 04/30/2012 08:37 pm »
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide

Offline DaveS

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Re: Shuttle Q&A Part 5
« Reply #2612 on: 05/03/2012 12:18 am »
Is each bay of the orbiter payload bay of equal length or does they vary in length?
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Offline Fequalsma

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Re: Shuttle Q&A Part 5
« Reply #2613 on: 05/03/2012 01:48 am »
Is each bay of the orbiter payload bay of equal length or does they vary in length?

From the Space Shuttle Systems Summary, 1980.
« Last Edit: 05/03/2012 01:50 am by Fequalsma »

Offline DaveS

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Re: Shuttle Q&A Part 5
« Reply #2614 on: 05/03/2012 03:05 am »
Is each bay of the orbiter payload bay of equal length or does they vary in length?

From the Space Shuttle Systems Summary, 1980.
Thanks. That is the kind of schematic I was looking for. It answers the question nicely with the fuselage station numbers.
"For Sardines, space is no problem!"
-1996 Astronaut class slogan

"We're rolling in the wrong direction but for the right reasons"
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Offline HelixSpiral

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Re: Shuttle Q&A Part 5
« Reply #2615 on: 05/07/2012 02:12 am »
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide

ASCENT TRAJ was the display used by PASS for both first and second stage. ASCENT TRAJ 1 and 2 were the respective BFS displays for first and second stage. Starting with the OI-32 software version (STS-120), PASS used similar displays to the BFS and were also called ASCENT TRAJ 1 and 2.

The old ASCENT TRAJ display was designed mainly to assist RTLS aborts and wasn't very useful for nominal ascents.

Offline Fequalsma

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Re: Shuttle Q&A Part 5
« Reply #2616 on: 05/09/2012 01:51 am »
Does anyone have diagrams of the forward RCS module?  I'd like to know where the struts supporting the prop tanks are connected, and which one buckled during STS-1. 

Thanks,
F=ma

Offline DaveS

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Re: Shuttle Q&A Part 5
« Reply #2617 on: 05/09/2012 02:04 am »
Anyone know the clearance between PLB Camera B and the SRMS End Effector? Based on photos I would estimate it's no more than 3". This is with the SRMS stowed and the camera in 0/0.
"For Sardines, space is no problem!"
-1996 Astronaut class slogan

"We're rolling in the wrong direction but for the right reasons"
-USA engineer about the rollback of Discovery prior to the STS-114 Return To Flight mission

Offline alk3997

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Re: Shuttle Q&A Part 5
« Reply #2618 on: 05/13/2012 01:43 pm »
In this article;

http://www.nasaspaceflight.com/2011/07/atlantis-down-processing-mer-review-notes-flawless-return/

 “performed flawless, bar typical GPC (General Purpose Computer) errors during rollout.”


What are these errors, causes and where can I find out more about this?

Thanks

It wasn't an error in some ways but an expected condition.  At this point in the flight, the orbiter was stopped near the end of the runway.  Entry guidance was still running in OPS 3.  As you can imagine entry guidance was designed for a forward moving vehicle not one that should be stopped.

If the crew jumped up and down (excited crew) or the wind caused the vehicle to bounce up and down on the landing gear while stopped (vertical motion but no horizontal motion), entry guidance would generate a message saying we went through a math issue (tan 90 or divide by zero, I forget).  The GPC software's math routines handled the issue and there was never a real problem. 

We could have easily have changed this to not have messages occur (we wouldn't have changed the math), but why tinker with code that was working fine for a part of "flight" that really wasn't flight?  As soon as we went to OPS 9, the messages stopped since OPS 9 was designed for being stopped near the end of the runway.

So, not an oversight and not an error in reality.  It also gave the on-console folks a chance to guess how many "error messages" would be received, which depended upon winds, crew exhuberance and time in OPS 3 while stopped.

As far as I know, unless you find the user note (which says to ignore the messages), there is no other documentation available.
« Last Edit: 05/13/2012 02:09 pm by alk3997 »

Offline alk3997

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Re: Shuttle Q&A Part 5
« Reply #2619 on: 05/13/2012 01:51 pm »
Hi all.

From the "Ascent Guidance and Flight Control Workbook", available on L2, it shown that there were difference ascent displays. In particular it is shown an ASCENT TRAJ 1, ASCENT TRAJ 2 and an ASCENT TRAJ display.

I'm getting confused because I don't understand when the ASCENT TRAJ display was used. If there were two displays already, one for first and one for second stage, why having a general ASCENT TRAJ display?

thanks very much

Davide

ASCENT TRAJ was the display used by PASS for both first and second stage. ASCENT TRAJ 1 and 2 were the respective BFS displays for first and second stage. Starting with the OI-32 software version (STS-120), PASS used similar displays to the BFS and were also called ASCENT TRAJ 1 and 2.

The old ASCENT TRAJ display was designed mainly to assist RTLS aborts and wasn't very useful for nominal ascents.

The newer PASS Ascent Traj displays were collectively known as 6X Traj (or XXXXXX TRAJ) since the XXXXXX could be changed from ASCENT to an abort name.  RTLS TRAJ was significantly different than ASCENT TRAJ.  The newer displays were an attempt to implement some of what had been planned with CAU display work.

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