Author Topic: Q&A - Space Shuttle Roll  (Read 1565 times)

Offline Diskovery

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Q&A - Space Shuttle Roll
« on: 03/30/2017 07:28 PM »
First, please forgive me if this is posted in the wrong section, or posting this is not allowed for some reason - I just have nowhere else to post this thread and ask these questions and I figured this would be the place, if any, to do so! :D

So let's get on to the question.

My question is, why exactly does the space shuttle roll during ascent? I get it is for a few different reasons, but what are the main ones and can you please explain them to me in detail? I get that one reason is to set the orbiter on the right track for the ISS, that one is simple, but the ones I don't get are to increase the orbital altitude, and to increase maximum dynamic pressure.

On the matter of increasing dynamic pressure, wouldn't you want to decrease dynamic pressure, as more pressure on the vehicle would be a bad thing? Or do I have that completely misunderstood?

Thanks and Rest in Peace to the glorious shuttle program!!!

Offline wolfpack

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Re: Q&A - Space Shuttle Roll
« Reply #1 on: 04/02/2017 01:40 AM »
Roll program establishes launch azimuth and aligns the thrust vector with the CG. More than that I'm not aware of.

Offline AnalogMan

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Online edkyle99

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Re: Q&A - Space Shuttle Roll
« Reply #3 on: 04/03/2017 12:09 AM »
This is a good time perhaps to point out that most (not all) launch vehicles do a "roll program" similar to STS, but without the wing-loading reason!  Mostly it has to do with the guidance platform orientation, the position of antennas, and the like.  This allows the launch vehicle to have the same upward and downward facing orientation regardless of launch azimuth  (use a pencil to test the idea).

 - Ed Kyle
« Last Edit: 04/03/2017 12:23 AM by edkyle99 »