Path: utzoo!utgpu!water!watmath!clyde!bellcore!faline!thumper!ulysses!andante!princeton!udel!gatech!mandrill!tut.cis.ohio-state.edu!mailrus!ames!elroy!devvax!lwall
From: lwall@devvax.UUCP
Newsgroups: sci.space.shuttle
Subject: Re: Orbiter/SRB separation
Message-ID: <2170@devvax.JPL.NASA.GOV>
Date: 4 Jun 88 00:06:00 GMT
References: <50665@ti-csl.CSNET>
Reply-To: lwall@devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA.
Lines: 14
Posted: Fri Jun  3 20:06:00 1988

In article <50665@ti-csl.CSNET> DMeyer@mips.csc.ti.com (Dane Meyer) writes:
: Why?  The SSME's *are* throttlable, and there is some on-board fuel which 
: normally is used for final insertion into orbit, as well as the subsequent
: de-orbit burn.  So, the SSME's could be throttled down to some suitable
: level, and be allowed to burn while the disconnect/separation is accomplished.

No doubt there will be others who say this, but the on-board fuel is
hypergolic and is not fed to the SSME's.  If you look carefully you'll see
a couple extra nozzles sticking out the back.  The SSME's must be shut
down before separation or their various components will diverge when the first
bubble comes through and the turbos suddenly have nothing to slow them down.

Larry Wall
lwall@jpl-devvax.jpl.nasa.gov