Path: utzoo!dciem!nrcaer!scs!cognos!geovision!alastair
From: alastair@geovision.uucp (Alastair Mayer)
Newsgroups: sci.space.shuttle
Subject: Re: Discovery's launch: Am I imagining things?
Message-ID: <417@geovision.UUCP>
Date: 4 Oct 88 14:00:24 GMT
Article-I.D.: geovisio.417
References: <1104@cfa237.cfa250.harvard.edu> <3811@phoenix.Princeton.EDU>
Reply-To: alastair@geovision.UUCP (Alastair Mayer)
Organization: GeoVision Corp, Ottawa, Canada
Lines: 21

> [several comments about the apparent 'flame' coming off the side of
> the SRB during the Discovery launch]

Yeah, I saw it too.  But if you recall (or go back and watch if you
taped it), that flame is at the *base* of the external tank (not partway
up the side as in 51-L).   Now, do any of you recall seeing the photos
taken during STS-1 or STS-2 of the external tank after separation?  The
charring (easy to see against the white paint of the tank) around the
base of the ET is very clear.  This charring is caused (I beleive) by
radiant heat from the SRB exhaust plumes - and is one of the reasons
the ET is insulated.

While the 'flames' at the base of the ET were unsettling, I put them
down to smoke & gases coming off the ET insulation as it charred,
and illuminated by the SRB exhaust plumes.  Given the blunt aft end
of the ET, and the 'pocket' formed there by the Orbiter body and SRBs,
you'd expect gases to tend to stagnate there a bit rather than being
instantly dispersed in the slipstream.

All of which makes me a bit skeptical about some proposed designs
for 'aft cargo carriers' to be attached at the base of the ET.