Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!zaphod.mps.ohio-state.edu!wuarchive!mit-eddie!rutgers!umn-d-ub!umn-cs!meccts!viper!dave
From: dave@viper.Lynx.MN.Org (David Messer)
Newsgroups: sci.space.shuttle
Subject: Re: last launch - check your tapes
Keywords: shuttle curious visual
Message-ID: <2998@viper.Lynx.MN.Org>
Date: 11 Dec 89 01:30:27 GMT
References: <3352@husc6.harvard.edu>
Reply-To: dave@viper.Lynx.MN.Org (David Messer)
Organization: Lynx Data Systems, Eagan, MN
Lines: 22

In article <3352@husc6.harvard.edu> seth@vax.ftp.com (Seth D. Hollub) writes:
 >I noticed something during the last launch and was wondering if
 >anyone else saw it.
 >
 >Ok, the most recent launch of the shuttle, between about 80,000 feet and
 >about 110,000 feet. The bottom of the external tank looks like it's,
 >um, "flaming".

There was a long discussion of this effect after it was
noticed on the first shuttle flight after Challenger (people
were watching THAT one pretty closely.)

Basically, what happens is that when the atmospheric pressure
drops off, as the shuttle ascends, the pressure in the exhaust
plume forces some of the gases forward.  This will happen on
any type of rocket but it is much more noticable with the
shuttle because of the distance between the SRBs.

Don't worry about it.
-- 
Remember Tiananmen Square.           | David Messer       dave@Lynx.MN.Org -or-
                                     | Lynx Data Systems  ...!bungia!viper!dave