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From: jer@peora.UUCP (J. Eric Roskos)
Newsgroups: net.columbia
Subject: Re: AW&ST on 51L
Message-ID: <2036@peora.UUCP>
Date: Tue, 18-Mar-86 22:48:31 EST
Article-I.D.: peora.2036
Posted: Tue Mar 18 22:48:31 1986
Date-Received: Fri, 21-Mar-86 03:51:26 EST
References: <6511@utzoo.UUCP>
Organization: Concurrent Computer Corporation, Orlando, Fl
Lines: 33

> 73.175  Massive cloud of oxygen or hydrogen gas streaming aft along tank
>         from rupture caused by booster nose.  [This is visible in one of
>         the photos AW&ST has printed.]  Some gas at bottom of tank too;
>         tank starting to break up?

This raises a question which I had not mentioned in here previously,
because of the requests not to have people "speculating"; but I still
haven't seen any comment on it, and I am curious.

In the original "NASA Select" photos made with the remote tracking camera
(the one which shows the closeup of the shuttle), at the time that the
visible vapors begin moving down parallel to the "bottom" surface of the
external tank, it appears that a substantial structural failure also
occurs at the aft end of the tank, near where the left SRB is attached.
Specifically, it *appears* that a curved rectangular strip of the tank
breaks away, allowing a very dense layer of vapors to come out the left
side of the tank wall slightly ahead of the aft end of the tank.  These
vapors come out over the *external* surface of the rectangular strip I
mentioned, suggesting that there is a gap in the wall of the tank at that
point. (If some vapors had just appeared trailing from the aft end,
you would have to try to see whether they were visible along the
left side of the spherical bottom of the tank to be able to decide their
general point of origin; but these clearly seem to come from the left
side wall of the tank on the cylindrical part of the tank instead.)

However, in all the published descriptions, all I've seen are statements
that the *right* supporting strut breaks away.  Are the supporting struts
(or the sides of the tank) tied together structurally in such a way
that the loads from the SRBs are balanced, such that when the right one
came loose, it would cause the left one to pull the aft left side of the
external tank off?
-- 
E. Roskos