SSTO vehicles

In a message dated 3/21/01 8:11:46 PM Eastern Standard Time, Ravenart@...
writes:

<< Tom,

What about using a mass driver on side of mountain to project SSTOs? I
remember Heinlein toyed with this idea in "The Moon is a Harsh Mistress"
even
though mass driver was an unknown concept then. That idea occurred to me
when I was reading O'Neil's mass driver on moon in "The High Frontier" that
it could be a cheap alternative to LHOX fuel for the first stage and then
fire up as it climb the higher attitudes. Later, I came across Savage's
same
idea except that it would be done in a tunnel to reduce air resistance. I
wonder why don't we at least try experiment with smaller rockets on mass
driver on a mountain? The moutains are close to many markets such as the
West Coast, China, India, etc.

Ravenart
>>

I've read Savage's book, his plan was to first build Sea Colonies by first
placing an OTEC plant in the middle of the ocean harnessing different water
temperatures at different depths to generate electricity. My Uncle is working
on an OTEC plant but of a different sort using ammonia boilers rather than
boiling water in a partial vaccum as Savage insists. From this OTEC plant you
would run chicken mesh on floats through the ocean and accrete minerals from
the ocean water to build a solid platform out of. truck in dirt plants and
housing and you have a floating artificial island. By creating these islands
you would use the municiple taxes to fund these electromagnetic launchers.
Last I heard they were building a seaside vacation resort in the Carribean, I
don't know what has become of them since. I think ocean colonies a a great
idea. One great use for them is to launch space shuttles from the equator. I
think they would make an excellent place to launch nuclear rockets from in
the deep ocean. Water makes an excellent barrier for radioactive
contamination. Lets compare different launch systems. We have Chemical SSTOs,
Nuclear SSTOs, Laser Launchers, Giant electromagnetic catapults.

Chemical SSTOs single disadvantage is that they require state of the art
materials science. 90% of its mass has to be rocket fuel while the remaining
10% has to be divided between structure and payload. Assuming we can devote
5% of the mass to structure, the other 5% would be payload so for every 100
tons of fully fueled launch vehicle, you can lift 5 tons into orbit. There is
little margin for error in engineering such a structure. This is equivalent
to building a bridge that can just barely support the traffic that crosses on
top of it with no consideration given to the wheather and the wind. A nuclear
SSTO can be built more robustly, it has twice the ISP and it is capable of
producing the same thrust as the Shuttle with further development. It
basically heats a gas in a nuclear reactor and expells it out a rocket
nozzle. The gas could be any gas including hydrogen or air. It seems that it
would be easier for a nuclear SSTO to take off from a runway sucking in air
from its intakes and superheating it to incandesence with a nuclear reactor,
at this point it is a nuclear jet, once it gains sufficient altitude and the
air thins out it switches to its onboard hydrogen tanks to achieve orbit, it
does this over the deepest part of uninhabited Pacific Ocean at a certain
altitude the nuclear byproducts are so diffuse as to be undetectable anyway.
Nuclear technology is of course a dangerous technology if mishandled, but it
is more energetic than chemical rockets and the reaction mass reserves +
nuclear fuel would take up less than half the weight of the fully fueled
vehicle.

A laser launcher requires SDI technology, the ability to track a target and
to hit it in the right spot. This launcher might possibly violate ABM
treaties since it might also be able to destroy an incoming nuclear warhead,
not that I care of course.

An electromanetic launcher launcher capable of accelreating an object in
excess of Mach 25 while making allowances for atmospheric drag must
accelerate an object with sufficient shielding so it can survive atmospheric
friction while having enough residual velocity left over so it can achieve
orbit with a small onboard rocket that is accelerated with the payload.

Savage's proposal is a combination of the last two. The nuclear SSTO is
closest to the launch technology we already have since it is a completely
self contained vehicle.

Tom Kalbfus