Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/5/84; site mmm.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!stolaf!mmm!allen
From: allen@mmm.UUCP (Kurt Allen)
Newsgroups: net.space
Subject: Re: Shuttle Ditching
Message-ID: <467@mmm.UUCP>
Date: Thu, 6-Feb-86 10:30:40 EST
Article-I.D.: mmm.467
Posted: Thu Feb  6 10:30:40 1986
Date-Received: Sun, 9-Feb-86 07:36:28 EST
References: <8602032227.AA10998@s1-b.arpa>
Reply-To: allen@mmm.UUCP (Kurt Allen)
Organization: 3M Company, St. Paul, Minn.
Lines: 49
Summary: 

In article <8602032227.AA10998@s1-b.arpa> ac%mit-oz@MIT-MC.ARPA writes:

>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

This type of action is exactly what is practised time and time again
in the simulaters. I really doubt that the pilot in command is going
to 'freeze'. Test pilots are trained to react. Listen to cockpit tapes
of planes going down and listen to what the crew say while the plane
is destroying itself.

>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.

The shuttle was appx 50,000 feet in the air, and traveling at over 2000
miles an hour. A large part of this vecter was straight up, so their
altitude would continue to increase after seperation from the srb's and main
tank. They would probably require the use of the attitude rockets to point
the shuttle in the right direction, as at 50,000+ feet the control
surfaces will not have a great deal of effectiveness. Given that I think
that it would have been able to enter a glide. They might have trouble
dumping onboard fuel before impact, but they should have several minutes
before impacting the ocean.

Since the landing speed of the shuttle is (I think) around 150 - 200
kts (fairly high for a plane that size ) the impact with the ocean could
be a problem, but with a carefull pilot the shuttle should be able to
maintain structural integrity. Whether the shuttle would float afterwords,
or even be able to skip on top of the water after impact instead of
diving into the water and 'flying' down to a depth of several hundred feet
below the surface (as happens to many fighter aircraft) I don't know.

All in all I don't think their chances would have been too bad. But the
shuttle would probably have needed to be mostly rebuilt, or even scrapped.
Aircraft that have been overstressed are often never quite the same
afterword, and NASA probably doesnt have any mechanism for getting
a shuttle out of the water and onto a ship quickly. The electronics
would surely suffer.

-- 
	Kurt W. Allen
	3M Center
	ihnp4!mmm!allen