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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.columbia
Subject: Re: orbiter ascent attitude
Message-ID: <6404@utzoo.UUCP>
Date: Thu, 20-Feb-86 15:08:05 EST
Article-I.D.: utzoo.6404
Posted: Thu Feb 20 15:08:05 1986
Date-Received: Thu, 20-Feb-86 15:08:05 EST
References: <999@burl.UUCP> <6357@utzoo.UUCP>, <510@iham1.UUCP>
Organization: U of Toronto Zoology
Lines: 17

> > As I understand it, it's simply so that the tank and SRB's don't block
> > line-of-sight for radio communications between the orbiter and the ground.
> 
> But, why the role?  Why doesn't it just fly straight onto its back?

The attitude at launch is constrained by the structure of the launch site.
Things like the flame trenches were originally set up for the Saturn V,
and rebuilding the pads totally for the shuttle wasn't thought reasonable.
So the shuttle lifts off in an attitude that's different from what's wanted
in flight.  Hence the roll.

Incidentally, it has nothing to do with getting the thrust line to pass
through the center of gravity, since that depends on which way the nozzles
point *with respect to the vehicle* and has nothing to do with attitude.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry