Path: utzoo!attcan!uunet!cadnetix.COM!cadnetix!beres
From: beres@cadnetix.COM (Tim Beres)
Newsgroups: sci.space.shuttle
Subject: Re: Discovery's launch: Am I imagining things?
Message-ID: <4305@cadnetix.COM>
Date: 30 Sep 88 14:52:36 GMT
References: <1104@cfa237.cfa250.harvard.edu>
Sender: news@cadnetix.COM
Reply-To: beres@cadnetix.COM (Tim Beres)
Organization: Cadnetix Corp.,  Boulder, CO
Lines: 28

Jonathan McDowell writes:
>BUT....  At about 80 to 90 seconds into the flight, I and several
>friends independently thought we saw flame coming out of the right hand
>(no, right on the TV screen, so I guess that must mean its really the
>"left hand") SRB at the case-to-nozzle joint (where the cylindrical
>booster starts to flare toward the bottom). Did anyone else see this?
>The commentators didnt mention it. I hope I'm wrong.
>
I saw the same thing.  Pretty scary, but it turns out it was just a trick
of physics.  The Rocky Mtn. News today devoted a couple of paragraphs to 
this "sighting".  I'll paraphrase (so as not to upset Eugene by using
info without permission :-).  This question was asked of Royce Mitchell
of Marshall, he said it was due to a physics principle called reverse flow
seperation.  As the orbiter rolls, the SRB's exhausts get mixed together
creating a collision of hot particles.  These collisions give the effect
of the plume riding up the side of the SRB.  

I really wish that didn't happen though!  Still seems like the outside casing
of the SRB would get very hot, possibly causing other nasty effects.  Anybody
know more of this reverse flow seperation thingy?

			Tim


..words to memorize  words hypnotize  words make my mouth exercise  words all
fail the magic prize... -- VF
Tim Beres   Cadnetix, 5775 Flatirons Pkwy, Boulder, CO 80301  
            beres@cadnetix.com  {uunet,boulder,nbires}!cadnetix!beres