Newsgroups: sci.space.shuttle
Path: utzoo!henry
From: henry@utzoo.uucp (Henry Spencer)
Subject: Re: What happened?  Could risk be higher?
Message-ID: <1989Nov29.163242.1165@utzoo.uucp>
Organization: U of Toronto Zoology
References: <wZQjNdy00WBKQ0oJB9@andrew.cmu.edu> <5082@jane.uh.edu>
Date: Wed, 29 Nov 89 16:32:42 GMT
Expires: Feb 28 11:30:45 EST 1990

In article <5082@jane.uh.edu> ST9@jane.uh.edu (Rich Bainter AKA Pug) writes:
>I was told recently by a person who *might* know that the reason they pushed so
>hard for a shuttle capsule escape system was that the crew of the challenger
>had not only survived the explosion but that they were alive for the two
>minutes until the shuttle hit the ocean.  Supposedly the cockpit had been blown
>intact apart from the rest of the shuttle and was intact until it hit the
>ocean.

Here's a piece I posted a while ago on this subject:

The most relevant document here is the medical and forensic report from
the team headed by (astronaut and MD) Joe Kerwin.  The stresses involved
in the disintegration of the orbiter and external tank were well within
normal human limits, and are quite unlikely to have caused either death
or major injury of the astronauts.  (The external tank did not explode,
it came to pieces and the propellants burned rapidly.  The orbiter,
somewhat damaged, was thrown out of control and was torn apart by the
hypersonic slipstream.)  The crew cabin survived as a single unit and
hit the ocean slightly battered but basically intact.  Several of the
emergency air packs, intended to provide breathing during an emergency
escape on the pad, had been activated.  It appears vanishingly unlikely
that this could have been caused by anything but human action.  It is
impossible to avoid concluding that most or all of the crew survived
the orbiter breakup, and at least some of them were conscious for at
least a few seconds afterward.  Almost certainly they were killed by
impact with the ocean, not by the accident itself.  (There were no voice
or other recorders running for more than a fraction of a second after
breakup, the cabin was badly smashed by the water impact, and the bodies
were under water for weeks before recovery, so it is hard to be positive 
of most of this.)

One remaining uncertainty is whether the crew were conscious all the way
down.  The key question is whether the cabin held pressure.  The emergency
packs held *air*, not *oxygen*, and would not have prevented quick loss
of consciousness at the breakup altitude.  Consciousness probably would
not have been regained before impact, once lost.  Kerwin's team worked
very hard to try to determine whether the cabin had held pressure, but
ultimately could not be sure -- the impact damage was just too great.
In particular, it was not possible to determine with certainty whether
any of the windows had broken during the breakup.  If one had to guess,
the best guess [in my opinion -- Kerwin's team did not guess] is that the
cabin lost pressure quickly and the astronauts rapidly lost consciousness,
but certainty is not possible.
-- 
That's not a joke, that's      |     Henry Spencer at U of Toronto Zoology
NASA.  -Nick Szabo             | uunet!attcan!utzoo!henry henry@zoo.toronto.edu