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From: irwin@uiucdcs.CS.UIUC.EDU
Newsgroups: net.columbia
Subject: Re: Challenger SRBs
Message-ID: <8500024@uiucdcs>
Date: Mon, 10-Feb-86 10:19:00 EST
Article-I.D.: uiucdcs.8500024
Posted: Mon Feb 10 10:19:00 1986
Date-Received: Wed, 12-Feb-86 08:13:14 EST
References: <4270@mhuxd.UUCP>
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Nf-ID: #R:mhuxd.UUCP:4270:uiucdcs:8500024:000:2482
Nf-From: uiucdcs.CS.UIUC.EDU!irwin    Feb 10 09:19:00 1986


>>/* Written  3:29 pm  Feb  7, 1986 by lmc@cisden.UUCP in uiucdcs:net.columbia */
>> In fact, according to the Monday Boston Globe, "James Mizell, a retired NASA
>> engineer working as a consultant to the space agency, said yesterday that in
>> a ''thrust termination'' procedure, explosive charges were used to ''cut the
>> top and bottom off, disableing the rockets.'' [PARAGRAPH] Under the procedure
>> burning fuel then fires from both ends, Mizell said, stopping the rocket's
>> forward motion."

>I think this is highly improbable.  The nose cone of the SRB contains all
>the electronics that the SRB possesses (destruct system, pyrotechnics
>control, recovery beacon, etc.) and the *huge* parachute recovery system.
>Thrust from both ends of the SRB would not slow down the SRB; it has
>already burned out when it is jettisoned, and even if it were, such a
>tactic would probably result in extreme tumbling of the rocket, making
>parachute deployment impossible.  It seems to me that the top and bottom
>of the SRB is it's most valuable parts; the rest is *just* stovepipe.

>Lyle McElhaney
>...hao!cisden!lmc
>/* End of text from uiucdcs:net.columbia */

Lyle, in your response to lmc@cisden.UUCP, I do not think you absorbed
what you read!

Note "thrust termination". This is an abnormal abort, BEFORE the SRBs
have burned out, and YES, it will stop the forward motion of the "stovepipe".

Ever thought what would happen to a four wheel drive vehicle, if you put
the front wheels in reverse and the rear wheels in a forward gear, (not
that it can be done) and let them have a tug of war?

["I think this is highly improbable" (Lyle)]. This is EXACTLY what is done.
The nose and tail of the SRB are blasted loose, and no consideration is
given to the parachute deployment, they are trying to stop the flight of
the SRB, not RECOVER it.

CBS showed a strip of animated film the other day, which explained the
proceedure that the Range Safety Officer had taken. It showed the nose
and tail of the SRB being separated from the rest of the SRB, and as it
happened, one of the separated nose cones of one of the units had the
chute deploy, carrying down only the nose cone. By the way, on the news
last night, it was stated that NASA had decided to give up on the search
for the remainder of the SRBs (stovepipes). They could have verified the
blown seal theory had they found them, but it appears they will not be
found.

Al Irwin      puree!uiucdcs!irwin   irwin@a.CS.UIUC.EDU