# 3 Space Shuttle questions
**URL:** https://boards.straightdope.com/t/3-space-shuttle-questions/573964
**Category:** Factual Questions
**Created:** [March 8, 2011, 8:58pm UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964 "2011-03-08T20:58:45Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)
#### Post date: [March 8, 2011, 8:58pm UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/1 "2011-03-08T20:58:45Z")
Over on Mindless Stuff…,\*\* Bijou Drains\*\* offered this link to an excellent video:
Space shuttle launch video - from on solid rocket
[http://www.youtube.com/watch?v=fvSRnOJ8x38](http://www.youtube.com/watch?v=fvSRnOJ8x38)
I have three quick questions:
1. The “intertank” sequence (from about 15 to 20 mins) has sound. I was surprised that there’s enough air for there to be sound, at the altitude of separation. Or are we hearing sound transmitted right through the metal to the camera, or something?
2. For how much time after the separation do the boosters continue to go “up” due to momentum? From the videos, it feels to me like at least a minute or two.
3. What are those things we see hitting the water a good five seconds or so before the booster itself splashes down?
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### Author:  [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)
#### Post date: [March 8, 2011, 9:32pm UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/2 "2011-03-08T21:32:18Z")
> [@JKellyMap](#):
>
> 1. The “intertank” sequence (from about 15 to 20 mins) has sound. I was surprised that there’s enough air for there to be sound, at the altitude of separation. Or are we hearing sound transmitted right through the metal to the camera, or something?
Separation altitude is 150K feet. There isn’t much air up there, but given the ludicrous speeds involved, it seems reasonable to expect some wind noise. Even after the chunks of debris stop hitting the booster, you can hear air rushing past it.
> [@](#):
>
> 1. For how much time after the separation do the boosters continue to go “up” due to momentum? From the videos, it feels to me like at least a minute or two.
75 seconds. They separate at an altitude of 150K feet, and coast by themselves up to a peak altitude of 220K feet before beginning their descent. [(source: Space Shuttle News Reference Manual)](http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html)
> [@](#):
>
> 1. What are those things we see hitting the water a good five seconds or so before the booster itself splashes down?
In the [Space Shuttle News Reference Manual,](http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/srb.html#srb-recovery) I see the following:
> [@SSNRM](#):
>
> …the low-altitude baroswitch at an altitude of 5,975 feet 248 seconds after separation…The nozzle extension is severed by pyrotechnic charge either at apogee or 20 seconds after low baroswitch operation.
> Water impact occurs 295 seconds after separation at a velocity of 81 feet per second.
Taking all of that together, I infer that the nozzle extension separates from the SRB about 40 seconds before splashdown. Maybe that’s what we see being jettisoned and hitting the water?
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### Author:  [@thirdname](https://boards.straightdope.com/u/thirdname)
#### Post date: [March 8, 2011, 11:10pm UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/3 "2011-03-08T23:10:57Z")
I have a question. When the external tank separates, what carries it away from the shuttle? It’s the fuel source for the main engines, so I would think that they would shut down when it separates, and both the tank and shuttle would just continue on the same ballistic trajectory. Does the shuttle have fuel for the main engines left in it after separation, or does it use maneuvering thrusters, or what?
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### Author:  [@AndrewL](https://boards.straightdope.com/u/AndrewL)
#### Post date: [March 8, 2011, 11:35pm UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/4 "2011-03-08T23:35:40Z")
The shuttle main engines are exclusively fueled by the main fuel tank and shut down before it’s jettisoned, so those can’t help to separate it. The shuttle has a second set of engines, the two OMS engines, which draw fuel from tanks inside the orbiter. Those are used after main engine shutdown and tank separation to push the orbiter the rest of the way into orbit, while the tank is left on a sub-orbital ballistic trajectory and falls back into the atmosphere.
Actual separation between the tank and the shuttle is also assisted by firing the RCS maneuvering engines to push the orbiter away from the tank, and residual fuel in the tank venting through the supply lines to push the tank away from the orbiter.
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### Author:  [@JKellyMap](https://boards.straightdope.com/u/JKellyMap)
#### Post date: [March 9, 2011, 2:06am UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/5 "2011-03-09T02:06:12Z")
Great, thanks, folks! Boondoggle or not, I’m gonna miss those lovely beasts.
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### Author:  [@Zakalwe](https://boards.straightdope.com/u/Zakalwe)
#### Post date: [March 9, 2011, 3:04am UTC](https://boards.straightdope.com/t/3-space-shuttle-questions/573964/6 "2011-03-09T03:04:53Z")
> [@JKellyMap](#):
>
> Over on Mindless Stuff…,\*\* Bijou Drains\*\* offered this link to an excellent video:
Well thanks to both you and Bijou. That is, hands down, one of the coolest fucking things I’ve ever seen. I love the bounces when the SRBs splash down.