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From: KFL@MIT-MC.ARPA ("Keith F. Lynch")
Newsgroups: net.space
Subject: Shooting into orbit
Message-ID: <[MC.LCS.MIT.EDU].762987.851220.KFL>
Date: Fri, 20-Dec-85 22:25:29 EST
Article-I.D.: <[MC.LCS.MIT.EDU].762987.851220.KFL>
Posted: Fri Dec 20 22:25:29 1985
Date-Received: Fri, 17-Jan-86 04:53:40 EST
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The ARPA Internet
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    From: Nicholas.Spies@h.cs.cmu.edu

    Perhaps rail guns (like Tom Swift's Electric Gun) could be used to
    shoot materials into space ... [Is air friction too much to allow orbital
    velocities?]

  You cannot shoot things into orbit from the Earth's surface.  An
orbit is always an ellipse, a closed curve.  The projectile would try
to return to its starting point -- from underneath!
  You could, I think, cause the projectile to fly by the Moon in such
a way as to go into a very high Earth orbit.  But this probably
wouldn't be stable since it would eventually get close to the Moon
again.  Besides, that's really too high to be useful (for the near
term).
  A more interesting possibilty is for the projectile to be 'caught'
and decelerated by a railgun in Earth orbit.  This railgun in space
need not really be in orbit.  It could be relatively stationary over
one point (a low altitude 'geosynchronous' 'sattelite') since it would
be getting frequent boosts from catching the projectiles.  It would
use the energy gained by decelerating the projectiles to boost them
horizontally, into orbit (equal numbers in each direction, to prevent
the railgun from drifting horizontally).
								...Keith