Full G on the Moon or other small bodies?

From: spacesettlers@yahoogroups.com
[mailto:spacesettlers@yahoogroups.com] On Behalf Of William

> > --in spacesettlers, "Combs, Mike" wrote:
> > We've eliminated the mass-driver and the L-2 mass-catcher.
>
> ????. Please elaborate.

Well, I thought your point was that anything built on the lunar surface
gets us around the problem of getting lunar resources away from the
moon. I was granting that we could begin massive construction on the
moon prior to building the lunar surface mass-driver and the
mass-catcher stationed at L-2.

> I was thinking about the ring not just being supported and resting on
> the ground but also on the tilted side too. That way the structural
> load of the sidewards 5/6 G on the ring would go to an outer track and
> not the ring itself. Admittedly, this means that an outer track would
> have to be built able to withstand this load. Perhaps a crater rim
> could be used.

Yeah, your thinking is pretty close to that of the guy I was debating on
Usenet. He mistakenly thought that the existence of this massive rock
outer track meant that he could talk in terms of his design not needing
any bearings. I was trying to get him to see that it merely meant the
bearings go in between the pressurized torus and the outer track.

But yeah, I agree that the massive rock outer ring would be a valued and
useful part of the design.

> An artificial structure in orbit capable of enclosing an entire
> Stanford Torus would have to be quite big. The radiation shield for an
> ST is 9 million tons, one for the facility to enclose an ST being
> built would have to be...?

Larger and more massive still. I'm just asking why assume it in the
lunar case, but not in the orbital case? I'd have to grant that such an
enclosing structure on the moon would avoid lunar lift costs associated
with an orbital equivalent, but neither structure is going to build
itself. In the longer term, I'm sure that even larger enclosing
structures will be built in orbital space (Island 3 being only one
example).

> It all depends on assumptions of how early in the settlement of space
> the above structures would be built. Early on in the settlement of
> space, having *any* kind of facility/settlement anywhere in space is
> going to be quite an accomplishment.

You're right. This is one thing I've had to look out for in my debates
with some on this topic. A lot of times their assumption that a certain
thing will be "easier" on the moon or Mars rather than in orbit is
because the scenario in their head is of a highly-developed and
functional lunar or Martian settlement, while orbital settlement is for
some reason assumed to be at square one.

> The moon, with its supply of materials already there and ready to be
> used, allows it to be settled in a much more incremental fashion than
> settlement(s) in orbit.

This may be a good point.

> Machine tools, for example, when flown to a
> moon base can be used to make more machine tools, because of the
> metals there. An enclosure flown to the moon can contain construction
> equipment to build more enclosures, and so on.

Yes, but Gerard O'Neill's point was that once you had a system in place
to economically deliver lunar material to High Earth Orbit, the same can
be said for that location as well.

> Because of this, the Moon will probably have the first large-scale
> settlement, capable of manufacturing its own items and being largely
> self-sufficient, and providing a reasonably secure place to have
> infrastructure in space, and to export this to other parts of space.

And the vast majority of space advocates are with you on that. I think
it can conceivably go that way, but I also think that the first
self-sufficient human settlement might be in HEO, simply because we
could get lunar resources into high orbits with a relatively modest
moonbase in place. Thus high orbit might beat the moon to large,
permanent settlements.

Regards,

Mike Combs