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From: v071pzp4@ubvmsd.cc.buffalo.edu (Craig L Cole)
Newsgroups: sci.space.shuttle
Subject: RE: Liftoff Question
Message-ID: <36479@eerie.acsu.Buffalo.EDU>
Date: 17 Sep 90 16:39:19 GMT
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A couple of comments on the following thread:

1) Both the SSMEs and SRMs gimble - if you watch NASA select before
   a launch, they'll show the gimble test. The SSMEs move quite a bit!

2) The shuttle DOES use its aerodynamic surfaces to help stabilize
   the launch trajectory. In the Roger's Report, Challenger's
   aerodynamic surfaces were trying in vain to keep the stack
   together as the stack ripped apart due to stress.

3) As I understand it, the shuttle roll is to alter the shuttle's
   orbital inclination. The "standard" shuttle inclination is 
   about 28 degrees above the equator. The shuttle can reach over
   60 degrees. The roll helps point it in the right direction.

   A shuttle can obtain its usual upside-down position 
   without rolling. Stand upright, call your front the shuttle,
   your back the ET. At launch, all you'd have to do to have the
   shuttle upside down is bend over forward.

   Say you're facing east and want to head north. Turn at the same
   time as you bend forward and you'll have just imitated a typical
   shuttle roll!

4) I know the shuttle has to fly upside down to reduce stresses,
   but I'm not sure where the stress are lowered. My guess is, the
   ET takes the brunt of the shock wave the stack creates, letting
   the shuttle ride in its "wake." Which would explain why the shuttle
   can't pop off of the ET before the SRB's are spent whithout
   aerodynamic stresses ripping the shuttle apart (like Challenger).

I don't work for NASA or anything (yet) so I'm not 100% sure of any
of this. But I like to think some of its right!

                                    Craig Cole
                                    University at Buffalo
                                    V071PZP4@UBVMS.BITNET
                                    V071PZP4@UBVMS.CC.BUFFALO.EDU