Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: How do they get it pointing up?
Message-ID: <1989Nov29.192322.6761@utzoo.uucp>
Organization: U of Toronto Zoology
References: <1989Nov23.165606.27671@utzoo.uucp> <117.UUL1.3#5131@mvac23.UUCP>
Date: Wed, 29 Nov 89 19:23:22 GMT

In article <117.UUL1.3#5131@mvac23.UUCP> mvac23!thomas@udel.edu writes:
>I assume that one of the reasons that shuttle's engines start before the
>solid boosters is to help counteract the tendency of the whole thing to
>fall on the orbiter's back?

Yup.  The other reason is that you can abort a launch if problems occur
in the orbiter's engines, but once the SRBs fire you are committed, so
it makes sense to light the orbiter engines slightly early and see if
they work.  (There have been one or two aborts at that point.)
-- 
That's not a joke, that's      |     Henry Spencer at U of Toronto Zoology
NASA.  -Nick Szabo             | uunet!attcan!utzoo!henry henry@zoo.toronto.edu