Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uakari.primate.wisc.edu!ames!skipper!shafer From: shafer@skipper.dfrf.nasa.gov (Mary Shafer) Newsgroups: sci.space.shuttle Subject: Re: Liftoff Question Message-ID: Date: 14 Sep 90 22:44:32 GMT References: <52900004@uxa.cso.uiuc.edu> <36104@eerie.acsu.Buffalo.EDU> Sender: shafer@skipper.dfrf.nasa.gov Organization: NASA Dryden, Edwards, Cal. Lines: 40 In-reply-to: v055mvw3@ubvmsb.cc.buffalo.edu's message of 14 Sep 90 12:20:26 GMT In article <36104@eerie.acsu.Buffalo.EDU> v055mvw3@ubvmsb.cc.buffalo.edu (Gregory J Schaffer) writes: In article <52900004@uxa.cso.uiuc.edu>, sfn20715@uxa.cso.uiuc.edu writes... > >When the shuttle lifts off, what is used to make it turn and roll? >(roll/pitch? turn/yaw? you know what I mean...) >I would assume that the orbiter's aerodynamic surfaces are not used, >as they are not directly exposed to the air, and its not going !!!!They AREN'T???!!! What ARE they exposed to? :) >_that_ fast when it clears the tower and starts the turn, and I would >assume that the SSME's are not vectored, right? Which one of these >is wrong? The Space Shuttle's Main Engines have the capability to swivel (I believe the correct term is GIMBLE), and I think, to a *VERY* small degree, so can the SRB skirts. The nozzles gimble, not the SSMEs. The aerodynamic surfaces (here, the WING) do produce a force component opposite in direction to the external tank as the shuttle flies. I don't know if this, or any movement of the rudder, are used in the roll maneuver. The whole shuttle is an aerodynamic surface producing lift (your force opposite in direction to the external tank) out the top of the shuttle (can you say "lifting body"?) which is a better way of referring to it than as opposite the external tank. This lift isn't dependent on the location of the external tank, so it's confusing to phrase it this way. Did you mean control surfaces (ailerons, rudder, and body flap) were used in the roll? The lift would, at most, produce a pitching moment, not a rolling moment. -- Mary Shafer shafer@skipper.dfrf.nasa.gov ames!skipper.dfrf.nasa.gov!shafer NASA Ames Dryden Flight Research Facility, Edwards, CA Of course I don't speak for NASA "A MiG at your six is better than no MiG at all"--Unknown US fighter pilot