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Thread: How was the Shuttle roll program executed?

  1. #1
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    How was the Shuttle roll program executed?

    How was the US shuttle roll program executed? Was it done by gimballing the shuttle engines, as in the Saturn V, or was it done aerodynamically using the shuttle wing controls? Or some other mechanism?

    Seems like using the shuttle's wing control surfaces might put excessive forces on the shuttle attachment points.

  2. #2
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    Iím almost certain it was done with the engines. My recollection is that the control surfaces were not active until reentry.
    As above, so below

  3. 2020-Mar-21, 02:14 AM
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  4. #3
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    It's achieved by gimbling the main engines itself – the three SSME – the main engines – and also by gimbling the two solid rocket booster nozzles to achieve that roll profile.
    https://www.nasa.gov/mission_pages/s...-leinbach.html
    (One hopes he's better at launch direction than he is at spelling, grammar and composition.)

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    https://www.nasa.gov/mission_pages/s...-leinbach.html
    (One hopes he's better at launch direction than he is at spelling, grammar and composition.)

    Grant Hutchison
    Well, it's a transcript of a Q&A podcast with Leinbach, so it's spoken word vs. written. But the actual podcast seems to have vanished.

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    Quote Originally Posted by Tucson_Tim View Post
    Seems like using the shuttle's wing control surfaces might put excessive forces on the shuttle attachment points.
    That's an odd thing to suppose.

    I mean: an odd thing to suppose that - structures whose purpose is solely and expressly to provide lift, aerodynamic stability and attitude control and aerobraking at Mach 25 by interacting with the atmosphere - would experience excessive forces by doing so.

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    How was the Shuttle roll program executed?

    Quote Originally Posted by DaveC426913 View Post
    That's an odd thing to suppose.

    I mean: an odd thing to suppose that - structures whose purpose is solely and expressly to provide lift, aerodynamic stability and attitude control and aerobraking at Mach 25 by interacting with the atmosphere - would experience excessive forces by doing so.
    Itís not odd. Itís not that the structures are weak but rather that they might rip the orbiter from the external tank, with potentially undesirable consequences.
    As above, so below

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    Aha. I'm such a fool.

    When the OP wrote "roll", I somehow thought "pitch". I thought s/he was asking about the flip prior to reentry.

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    Quote Originally Posted by DaveC426913 View Post
    Aha. I'm such a fool.
    Oh Carol
    I am because we are
    (African saying)

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    Quote Originally Posted by schlaugh View Post
    Well, it's a transcript of a Q&A podcast with Leinbach, so it's spoken word vs. written. But the actual podcast seems to have vanished.
    Ah, that makes more sense, thanks; it was a really weird sentence construction. My apologies to Leinbach. I hadn't realized it was a transcript.
    Still, you'd have hoped that a transcriber used by NASA would have ... ahem ... a lock on the spelling of "gimbal".

    Grant Hutchison

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    Quote Originally Posted by Jens View Post
    It’s not odd. It’s not that the structures are weak but rather that they might rip the orbiter from the external tank, with potentially undesirable consequences.
    Thanks for setting him straight! I thought I was quite specific and clear with my question and concerns.

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    Quote Originally Posted by grant hutchison View Post
    and also by gimbling the two solid rocket booster nozzles
    Thanks for that. I wasn't aware the solid booster nozzles were capable of gimbaling.
    Last edited by Tucson_Tim; 2020-Mar-22 at 07:13 PM.

  13. #12
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    Quote Originally Posted by Tucson_Tim View Post
    Thanks for that. I wasn't aware the solid booster nozzles were capable of gimbling.
    Watch an SRB gimbal test here.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Watch an SRB gimbal test here.

    Grant Hutchison
    Thanks!

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    As an aside. This picture shows the size of the Rocketdyne F1 engine, of which there were five on the first stage of the Saturn V rocket. The four outer F1 engines could be gimbled but the center was stationary. 1.5 million pounds of thrust each. 7.5 million pounds total.

    F1-rocket-engine.jpg

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    Quote Originally Posted by Tucson_Tim View Post
    Thanks for setting him straight! I thought I was quite specific and clear with my question and concerns.
    In my defense, - with the single exception of the word "roll" - there is nothing in your OP to indicate what maneuver you are talking about.

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    Quote Originally Posted by DaveC426913 View Post
    In my defense, - with the single exception of the word "roll" - there is nothing in your OP to indicate what maneuver you are talking about.
    I referenced the Saturn V roll program. Three other posters knew what I was talking about -- BEFORE YOUR POST.

    You are offering up a very weak defense, after calling my comment "odd" with no apology to me.

    BTW, I don't see how you could infer I was talking about "reentry" when mentioning the Saturn V vehicle as I did.

    For those that graciously answered my question, I thank you.
    Last edited by Tucson_Tim; 2020-Mar-23 at 04:29 AM.

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    Now I didn't know that the SRB had the ability to gimbal its nozzles. Old dogs learn new tricks from time to time.

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