Re: Launch Rails...

From: Michael S. Lorrey (
Date: Sat Apr 15 2000 - 14:57:28 MDT

Spike Jones wrote:
> > > Michael S. Lorrey wrote: 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?
> >
> > At 4 G, I get 13 miles, 51 miles, 115 miles and 204 miles respectively.
> >
> > At 6 G, I get 8 miles, 34 miles, 76 miles and 136 miles respectively.
> Doooh! I thought these numbers looked high. Missed em all
> by a factor of 2. The right answers are
> At 4 G, I get 6 miles, 25 miles, 57 miles and 102 miles respectively.
> At 6 G, I get 4 miles, 17 miles, 38 miles and 68 miles respectively.
> > And lets dispense with these english schminglish units. We
> > lose interplanetary probes that way... {8-[
> Thats it! Its all the fault of the UNITS! Not my fault at all.
> {8^D This shows to go ya, English units are very non-
> intuitive for space calcs.

OK, these seem reasonable. I'm not interested in building an HG Wells
Cannon that only solid materials can survive. I'm talking about a system
that you can use as a first stage to launch people and complex
assemblies into space with. I fully expect that such a system will be
unusable as a single stage to orbit type system, the vehicle will have
to have some upperstage and orbital insertion capability to it.

Would it be possible to make the laser propulsion type aerospike used in
current USAF research into a hybrid engine that can use laser
transmitted energy at low altitudes, then shift to a fuelled mode higher

68 miles at 6 gs seems reasonable to me. Remember, if we make this an
undersea tube, then this should be much less expensive than tunnelling,
right? This isn't an impossible structure, I mean we already have the
Prince Edward Island Link bridge as an example, we just need to build it
under water.

Now the question is: How much can we accelerate a vehicle using
electromagnets? If we augment the tube with pneumatic thrust as well,
what can we do? If we built a nuke plant down at the undersea end, and
used the nuclear pile to produce steam....

Mike Lorrey

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