[extropy-chat] Re: MARS: Because it is hard

[Eugen Leitl]

On Thu, Apr 15, 2004 at 05:25:47AM -0700, Mike Lorrey wrote:

> Yes, but your dealing with a high power system that requires power
> storage for coil discharges all along the length of the rail, but the

I'm trying to remove the need for power storage (though high-voltage
capacitors can also be fabbed; high-voltage in vacuum is a problem due to
discharge, arcing, etc). The solenoids should live long, since being used 
semicontinuously. The design should have no movable parts, be made from
segments and utilize purely radiative cooling. This asks for small payloads,
launched at a rapid rate. Lunar rotation is too slow to give much assist, so
alignment doesn't need to be equatorial.

> goal of the discussion is to also use the rail to receive incoming
> payloads from Earth.

What for? The whole point of self-rep lunar industry is to establish a
massive presence in deep space, which translates into kT/s or MT/s
sustainable launch capacity. There's nothing there which can't be done via
Interplanet for control signals. Occasional visits can be done with chemical
rockets. There's nothing at all wrong with using chemical rockets to deorbit
and land softly. Using magnetic catchers to catch deorbiting manned modules
is silly -- people don't deccelerate very well, and there will be occasional
goofups, causing the crew to be deeply implanted into lunar surface, possibly
wrecking a very expensive (since very useful) launcher in the process.
 
> No ramp needed. The package will be in a trajectory the whole time it
> is going through the track, and so long as there are no mountains in
> the way when it exits the rail, does not need to be more than a few
> dozen meters above the regolith average elevation.

Average elevation on Luna means very little: there are lots of peaks there.
Initial orbit must be at least several km high, before you unfold, and start
to climb (photonically, or electrically).

If packets are dumb, it might make sense to catch and process them in an
orbital factory a bit higher up. With nanotechnology even very small smart
packets are not a problem.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a>
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