Author Topic: Shuttle Q&A Part 5  (Read 1542517 times)

Offline Oberon_Command

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Re: Shuttle Q&A Part 5
« Reply #720 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?

Offline Sesquipedalian

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Re: Shuttle Q&A Part 5
« Reply #721 on: 10/17/2009 04:32 am »
Following the Wikipedia ET page to this Lockheed Martin page 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%?

Offline spaceshuttle

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Re: Shuttle Q&A Part 5
« Reply #722 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 to this Lockheed Martin page 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.
T-10...9...8...7...we're go for main engine start...4...3...2...1...0 and liftoff of Shuttle Daedalus as the National Aerospace System celebrates its 25th mission.

Offline psloss

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Re: Shuttle Q&A Part 5
« Reply #723 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.

Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #724 on: 10/17/2009 11:22 am »
Following the Wikipedia ET page to this Lockheed Martin page 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
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Online DaveS

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Re: Shuttle Q&A Part 5
« Reply #725 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.
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Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #726 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.

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Offline psloss

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Re: Shuttle Q&A Part 5
« Reply #727 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.

Offline Danny Dot

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Re: Shuttle Q&A Part 5
« Reply #728 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?

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Offline psloss

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Re: Shuttle Q&A Part 5
« Reply #729 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.
« Last Edit: 10/17/2009 10:56 pm by psloss »

Offline Jorge

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Re: Shuttle Q&A Part 5
« Reply #730 on: 10/18/2009 02:38 am »
Following the Wikipedia ET page to this Lockheed Martin page 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.
JRF

Offline kraisee

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Re: Shuttle Q&A Part 5
« Reply #731 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.
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Re: Shuttle Q&A Part 5
« Reply #732 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?
« Last Edit: 10/25/2009 10:59 pm by mmeijeri »
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Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #733 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

Online DaveS

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Re: Shuttle Q&A Part 5
« Reply #734 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.
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Offline mkirk

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Re: Shuttle Q&A Part 5
« Reply #735 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.


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Re: Shuttle Q&A Part 5
« Reply #736 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.
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Offline Jorge

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Re: Shuttle Q&A Part 5
« Reply #737 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.
JRF

Offline Jim

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Re: Shuttle Q&A Part 5
« Reply #738 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

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Re: Shuttle Q&A Part 5
« Reply #739 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.
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