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From: acourt@BBN-VAX.ARPA ("Anthony J. Courtemanche")
Newsgroups: net.space
Subject: Shuttle Ditching
Message-ID: <8602032227.AA10998@s1-b.arpa>
Date: Mon, 3-Feb-86 16:45:00 EST
Article-I.D.: s1-b.8602032227.AA10998
Posted: Mon Feb  3 16:45:00 1986
Date-Received: Wed, 5-Feb-86 05:02:22 EST
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: ac%mit-oz@MIT-MC.ARPA
Organization: The ARPA Internet
Lines: 48

Although, as said earlier, it is doubtful whether the Shuttle could
survive the deceleration of landing in the Atlantic, it is interesting
to think about what the possible abort scenarios would entail.

First, the media (& NASA photos) say that an abnormal plume eminated
from the right SRB at least 15 seconds before the deadly external tank 
explosion.  Is 15 seconds long enough to initiate an abort?  At least
three events would have to occur:

1) Ground crew interprets visual data, determines that the situation is
deadly, and tells shuttle commander to abort.  My guess is that this
could take up a very significant part of 15 seconds.

2) Shuttle commander receives abort message and initiates abort
sequence.  I don't know how well the Shuttle pilots are trained to
respond to such frightening news, but I would guess that the commander
wouldn't freeze for more than say 0.5 seconds.   Now as far as
initiating the abort sequence, I've heard that this consists of pulling
a lever and pressing a button.  If this is true, I would guess that
this could be done within a second.

3) Shuttle breaks away from external tank soon enough to survive the
explosion.  I have no idea how different the trajectories of the
shuttle and the ET/SRB assembly can be made to be during an abort.
I would guess that in any case, to survive the explosion, the
ET/SRB-Shuttle separation would have to be at least a thousand feet or
so.  Even at this distance, any shock wave effects could still be
dangerous.

Now, even if all the above could be done in time and the Shuttle remain
intact, could the Shuttle obtain an aerodynamic trajectory before
hitting the ocean?  I don't remember the altitude that the Shuttle was
at when the explosion happened, but the Shuttle was on it's back and
this is not a graceful way to start gliding.  Also, correct me if I'm
wrong, but I don't think that any sort of engines are available to help
re-orient the orbiter during the abort (could the de-orbit engines be used?).
Hence, only the control surfaces on the Shuttle could be used to
establish a gliding (as opposed to plummeting) trajectory.

To me, it seems doubtful that an abort could have succeeded in saving
the lives of 7 astronauts or the orbiter.

I am welcome to have any comments on my above reasoning, and I'd like
to know if, in light of what I've said above, there was any reasonable
chance for a safe abort.

--Anthony Courtemanche
ac%mit-oz@mit-mc