[net.space] Electromagnetic catapult

kh (04/11/83)

     The main objection I've heard to using electromagnetic catapults for
assisting space launches is the high acceleration that you would experience
in one of a reasonable length. Well, build one of unreasonable length, I say!
Obviously, it would be hard to justify the expense of a 1000+ mile long
system for the use of NASA alone.  However, a transcontinental "subway" system
has already been proposed for ordinary transportation.  Using electromagnetic
suspension and propulsion in airless tunnels, near-orbital speeds can be
achieved with relative ease. (See a couple of RAND reports by a man named
"Salter".) So, if we open the end of a side tunnel (pointing east), we could
get a head start in launching vehicles into orbit.  Of course, there are
other problems, air friction being the foremost.  How fast can a shuttle-type
craft be launched without the atmosphere being like the proverbial brick wall?
(I can just see someone standing near the outlet of this tunnel hearing a
tremendous "boom" and looking up to see a huge shell being lobbed skyward.
"What was that?!" he asks.
"Oh, just the 5:30 express.")

Also, what angle would be the best to launch a spacecraft using this method?
Most of the velocity is needed parallel to the Earth's surface, but launching
straight up would reduce the air friction.  If anybody knows the answers to
any of these questions (or where I can find them), please mail me or post
an article to this newsgroup (or mailing-list).

					Kenny Hirsch
					duke!unc!kh
					kh.unc@UDel-Relay
					Chapel Hill, N.C.

P.S. These tunnels have other uses, too.  They provide a nice, safe place to
lay all those optic fiber cables and superconducting cables that we'll soon
need. Not to mention, they make a great bomb shelter. (Or a basing system
for the MX.)