Author Topic: Shuttle Q&A Part 5  (Read 1067829 times)

Offline HelixSpiral

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Re: Shuttle Q&A Part 5
« Reply #2620 on: 05/13/2012 02:16 PM »
Thanks, alk. Being a computer guy, the software and GPCs had always interested me and I always like reading your posts.

Online DaveS

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Re: Shuttle Q&A Part 5
« Reply #2621 on: 05/14/2012 12:52 AM »
Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
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Offline Fequalsma

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Re: Shuttle Q&A Part 5
« Reply #2622 on: 05/14/2012 01:25 AM »
305 or 308.4 per the diagram above.  it says the longerons are at 414...


Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
« Last Edit: 05/14/2012 01:26 AM by Fequalsma »

Offline alk3997

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Re: Shuttle Q&A Part 5
« Reply #2623 on: 05/14/2012 02:45 AM »
Thanks, alk. Being a computer guy, the software and GPCs had always interested me and I always like reading your posts.

Your welcome and I'm glad you find the appends interesting.  Sorry I don't get too much time anymore to answer these (now) historical questions.

Andy

Online DaveS

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Re: Shuttle Q&A Part 5
« Reply #2624 on: 05/14/2012 03:30 AM »
305 or 308.4 per the diagram above.  it says the longerons are at 414...


Anyone know the Zo coordinates for the bottom of the PLB bays?  I don't mean the floor of the midbody, but just the bays that give the payload bay the familiar semi-circular shape. According to the Mechanical Systems Workbook, the sill longerons are at Zo410.00.
I don't think Zo414.0 is for the longerons but rather payload bay door hinge line. Based on my research the PLBD door hinge lines are at Yo95 with the longerons at Yo90. And the shape of the longerons from bottom to top roughly corresponds to a 5" square.
"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

Online DaveS

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Re: Shuttle Q&A Part 5
« Reply #2625 on: 05/15/2012 11:37 PM »
Anyone know if the encircled brackets in the attached photo is equally spaced along the length of the PLB longerons or if it varies? Also, any ideas what the metal cylinder in the photo is for? I'm thinking it's a drive rod of sorts for the MPMs.
« Last Edit: 05/15/2012 11:39 PM by DaveS »
"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 NavySpaceFan

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Re: Shuttle Q&A Part 5
« Reply #2626 on: 05/21/2012 10:09 PM »
Was the solar array that slipped its tensioning cables during STS-97 the same one that jammed during 116 and tore during 120?
<----First launch of DISCOVERY, STS-41D!!!!

Offline sivodave

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Re: Shuttle Q&A Part 5
« Reply #2627 on: 05/24/2012 09:10 AM »
Hi All.

Question of the day is: was there any difference between the APDS used for docking to the MIR and the one used for docking to the ISS?

Thanks very much

Davide

Offline iskyfly

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Re: Shuttle Q&A Part 5
« Reply #2628 on: 05/24/2012 07:18 PM »
Thank you alk3997 for your reply re: GPS errors during roll out.


Offline Spaceguy5

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Re: Shuttle Q&A Part 5
« Reply #2629 on: 06/08/2012 08:40 PM »
Why are the blankets in the aft of Endeavour's payload bay different from the rest of the orbiters?

For example, this blanket (VO70-362609-058): If you look at one up close, it has a velcro flap, a set of flaps with snap buttons, and a snap-shut hole in the middle. The blanket on the opposite side also has similar features.

Similarly, this blanket (VO70-362610-042) as well as it's twin... if you look up close, they both also have a velcro flap.
« Last Edit: 06/08/2012 08:44 PM by Spaceguy5 »

Offline Archer

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Re: Shuttle Q&A Part 5
« Reply #2630 on: 06/11/2012 06:59 PM »
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #2631 on: 06/11/2012 07:02 PM »
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.

Offline Archer

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Re: Shuttle Q&A Part 5
« Reply #2632 on: 06/11/2012 07:46 PM »
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.
Thank you!
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline Archer

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Re: Shuttle Q&A Part 5
« Reply #2633 on: 06/11/2012 10:08 PM »
How much time does it take to inspect Space Shuttle TPS tiles after the flight and repair it (damaged ones are replaced I guess)?

Most of the time between missions.
What takes more time: inspection or repairs?
The future is better than the past. Despite the crepehangers, romanticists, and anti-intellectuals, the world steadily grows better because the human mind, applying itself to environment, makes it better. With hands...with tools...with horse sense and science and engineering. (c) R. A. Heinlein

Offline sivodave

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Re: Shuttle Q&A Part 5
« Reply #2634 on: 06/13/2012 06:51 PM »
Hi all.

one question about deorbit burn.

Which is the reason for which during the deorbit the Orbiter was placed with the belly up? As long as you have tail-first is shouldn't be important if the belly is up or down, right?

My guess is that in this was, at completion of the burn it would have been faster maneuvering to the entry attitude of 40 degrees of angle of attack and that maybe in this way the pilots had a better situation awarness.

What do you think?

Thanks very much

Davide

Offline wolfpack

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Re: Shuttle Q&A Part 5
« Reply #2635 on: 06/13/2012 07:22 PM »
Hi all.

one question about deorbit burn.

Which is the reason for which during the deorbit the Orbiter was placed with the belly up? As long as you have tail-first is shouldn't be important if the belly is up or down, right?

My guess is that in this was, at completion of the burn it would have been faster maneuvering to the entry attitude of 40 degrees of angle of attack and that maybe in this way the pilots had a better situation awarness.

What do you think?

Thanks very much

Davide

If the deorbit burn is roughly halfway around the planet from entry interface, then the "belly-up" burn will have the Orbiter in (or near) the proper reentry attitude.

At burn = Orbiter "top" towards Earth
At halfway point = Orbiter "nose" towards Earth
At EI = Orbiter "belly" towards Earth

Remember the only reason the Orbiter orbits the Earth with its "top" pointed toward Earth is because it has been imparted with a pitch motion with period equal to the orbital period. Without that it would be a cycle of "nose"/"top"/"tail"/"belly" (or the reverse).

I hope that wasn't too basic of an answer due to me misunderstanding the question.

Offline sivodave

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Re: Shuttle Q&A Part 5
« Reply #2636 on: 06/13/2012 10:09 PM »
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide

Offline wolfpack

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Re: Shuttle Q&A Part 5
« Reply #2637 on: 06/15/2012 02:10 PM »
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide

Perhaps the maneuver was done such that the attitude was for a completely +x burn at TIG? I'm not sure, this will have to be answered by Jorge or someone else with the expertise.

My assumption (which is probably incorrect) is that things are done to minimize propellant consumption.

Offline SiameseCat

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Re: Shuttle Q&A Part 5
« Reply #2638 on: 06/17/2012 01:30 PM »
Hi wolfpack.

I kept reading a little bit about this subject and I think I've now understood what you are saying. So if my understanding is correct, the reason is that for all duration of coasting from deorbit burn to EI, the Orbiter kept an inertial attitude.

If this is the case, I've though another question. Maneuvering to burn attitude was done 20 minutes before the burn. If the orbiter kept this attitude inertially, does this not mean that the burn was not completely along the +x axis, but had also a +z component?

or the inertial attitude was kept only AFTER the deorbit burn, while up to the deorbit burn the Orbiter had a LVLH attitude?

Thanks very much

Davide

Perhaps the maneuver was done such that the attitude was for a completely +x burn at TIG? I'm not sure, this will have to be answered by Jorge or someone else with the expertise.

My assumption (which is probably incorrect) is that things are done to minimize propellant consumption.
That's correct; a constant inertial attitude means that the shuttle is always rotating in an LVLH frame. The inertial burn attitude will result in the correct LVLH attitude at TIG.

I think an inertial burn is actually more efficient than an LVLH burn, because you're always thrusting in the same direction. If you think about an LVLH burn, the direction is changing, so the thrust at the end of the burn partially cancels out the thrust at the start of the burn.

For deorbit burns, it's possible to deliberately waste propellant by burning out-of-plane. This reduces the shuttle's landing weight.
« Last Edit: 06/17/2012 01:38 PM by SiameseCat »

Offline sivodave

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Re: Shuttle Q&A Part 5
« Reply #2639 on: 06/20/2012 08:32 AM »
Thanks SiameseCat. I think now I've understood how it worked the deorbit burn.

Davide

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