Ask A Scientist© Engineering Archive

Index Key:   ENG015
Author:      andre
Subject:     Why does the Shuttle turn on launch?
Text:        I would like to know why the Shuttle, as soon as the launch 
starts, turns around its vertical axis and assumes an oblique position and 
flies "upside-down."

Response #:  1 of 4
Author:      bobs
Text:        I am not really sure, but here is one possibility.  Missile 
systems like this have to be guided into orbit.  They must be lined up 
properly in azimuth (angle) and then they need to be tilted over to eventually  
become tangent to the earth and "inserted" into an orbit.  The guidance 
systems are sophisticated, but not so much that they can be driven.  It is 
very likely, for example, that the machine can only tilt in one direction, 
like you and I.  We can bend straight over from the waist.  If we want to tilt 
in another direction, we have to rotate on our vertical axis and then tilt.  
This is what I think is going on with the shuttle.  Why not orient the launch 
tower so that they do not have to rotate?   I assume it is because there is 
more than one orbit that shuttles go into depending on the mission, so they 
cannot line up the launch tower with more than one.  It is easier to rotate 
the missile than it is to rotate the launch tower.  But this is just a guess 
based on the way military missile systems work, or at least the way they used 
to work.  There may not be anyone on this network/system that is currently 
working on the shuttle, but you could write to any NASA organization and I am 
sure you will get the right answer, and perhaps a lot more information as 
well. 



Response #:  2 of 4
Author:      sysop
Text:        You might also try asking NASA from NEWTON.  This can be done by 
choosing 4) Network ?)NASA from the main menu.  This feature allows you to 
connect to NASA's BBS, where you could follow-up on this question.

Response #:  3 of 4
Author:      John Hawley
Text:        The reason the shuttle rotates is so the pilots can see the 
horizon in case they need to abort.

Response #:  4 of 4
Author:      sysop
Text:        Combine the horizon answer with the fixed tower/different orbits 
problem should do it.