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From: eder@ssc-vax.UUCP (Dani Eder)
Newsgroups: net.space
Subject: Re: reentry of paper airplanes?
Message-ID: <742@ssc-vax.UUCP>
Date: Wed, 15-May-85 14:10:38 EDT
Article-I.D.: ssc-vax.742
Posted: Wed May 15 14:10:38 1985
Date-Received: Thu, 16-May-85 23:59:36 EDT
References: <1631@mordor.UUCP> <3000002@pbear.UUCP> <581@mnetor.UUCP>
Organization: Boeing Aerospace Co., Seattle, WA
Lines: 28

> >
> >I'm sorry, I should have stated that when someone was on an EVA, take
> >the paper airplane and THROW it toward the ground and against the orbit.
> >Peter Barada
> 	From a practical standpoint, the astronaut would have to have an
> awefully good arm. Depending on the orbit, the paper plane would
> need a velocity of several thousand miles per hour with respect
> to the spacecraft. I can't see the plane being thrown faster than
> 20 or 30 mph. considering that the thrower would be in a space suit.
> Even if you postulate a mechanical throwing device, it would probably
> destroy a paper plane, ( I think certainly, but I won't go overboard).

     Let us assume the Orbiter is at 150 Mautical Miles.  Your astronaut
throws the airplane at 20 mph or 10 meters/second aft.  Aft is defined
as opposite your orbital motion.  The airplane will now have a perigee
of 140 Nautical Miles and an apogee of 150 Nautical Miles.

     A piece of 20-lb bond 8.5x11 inches weighs .01 lb.  When folded
into a paper airplane and flying stably it has a cross section of 0.5
inches square.  This gives it a ballistic coefficient (weight/area) of
3 lbs/ft^2.  It will decay from orbit in about 40 days.

     If the paper airplane has a blunt nose (0.1 foot radius), then
the peak heating on re-entry will be 70 BTU/ft^2/sec (795 kW/m^2).
This means the peak temperature, assuming the paper is black, will
be 1900 Kelvin (2973 F).

Dani Eder / ssc-vax!eder / Boeing Company