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From: knudsen@ihnss.UUCP
Newsgroups: net.space
Subject: Re: Electromagnetic mass drivers
Message-ID: <2298@ihnss.UUCP>
Date: Thu, 8-Nov-84 19:06:35 EST
Article-I.D.: ihnss.2298
Posted: Thu Nov  8 19:06:35 1984
Date-Received: Sat, 10-Nov-84 07:32:04 EST
Organization: AT&T Bell Labs, Naperville, IL
Lines: 21



Subject: Re: Sixty Cents a Pound?
References: <1062@inuxc.UUCP>

The main restrictions on electromagnetic mass drivers are:
(1) the object must contain quite a bit of iron (of course)
(2) you really should launch above/outside/without an atmosphere.
On Earth, the projectile would have to survive 3+ miles of our air, much more
if not launched straight up, and EXIT our air at escape velocity,
meaning a tremendous initial velocity.  Aside from the ablative heat shielding
required (which you have to accelerate along with the rest of the load, even
tho it never leaves our planet), the G forces of DEceleration encountered
after leaving the electro-gun would be almost as bad as the acceleration
inside the launcher.  Of course, if the object is all iron, the parts are
accelerated evenly and little stress occurs during acceleration.

Anyway, most advocates of mass drivers are talking about installations
on the Moon, asteroids, L5 space colonies, etc.
A GOOD possibility: a mass driver in low earth orbit, to shoot things up
to geo-synch, to moon, Mars, ....    mike k