Launch Rails..Was:Re: Orbital Towers.

From: Michael S. Lorrey (
Date: Fri Apr 14 2000 - 14:50:45 MDT

OK, new/old idea to talk about: mass drivers as launch system.

Thanks to my downloaded copy of the CIA World Factbook, I find that there are
several locations along the equator where there are islands with peaks of
2,000-3,000 meters or more.

Lets assume a launch acceleration of 4-6 g's within the rail, and that the
launch pod is built with either a scramjet capability or can utilize laser
propulsion beams aimed at it from the point at which it exits the linear drive
system for second stage propulsion.

The rail starts off at a sea floor station, follows the undersea terrain up to
the surface at the island coastline, to the peak, and have a 1,000-3,000 meter
tower/ramp extension above the peak This reduces tunnelling costs, and takes
advantage of sea transportation to allow tube sections to be assembled modularly
in an assembly line at a contractors location, then dropped into place.

Practical questions:
How long does the rail need to be to accelerate up to 2,000, 4,000, 6,000 and
8,000 mph respectively?
Given these estimated speeds at which the launch vehicle might exit the rail,
how does this affect the needed mass ratio of the vehicle for second stage
propulsion, and would laser propulsion be sufficient for this second stage

The launch vehicle I am thinking of is long and narrow, with ring lifting
surfaces around the vehicle, fore and aft, and the rear ring wing also acts in
concert with a scramjet/aerospike type assembly for propulsion. The rings
contain coils used in the mass driver stage for acceleration.

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