Lunascaping and Zubrin

> That was my take on it too. To see what I have to say on this subject, go
> to http://members.aol.com/oscarcombs/spacsetl.htm#zubrin

"When Zubrin factors in lack of cloudy atmosphere, and the ability to track
the sun, together with conversion efficiencies, he calculates an orbital solar
array would outperform a land-based one by a factor of 3. If the surface array
is designed with sun-tracking panels, however, he estimates this factor would
shrink to 1.5,"

Was it 1.5? I seem to recall a 50%, but thought that was saying SPS would be
twice as efficient as tracking ground-based, instead of 3 times as efficient
as non-tracking. Numbers seemed low compared to O'Neill saying 33 W/m^2 for
ground... but maybe that was including actual efficiency of conversion (PV?)
in which case my idea of 1300 W/m^2 in space wouldn't be accurate, since you
wouldn't get the whole thing. (Although you would for heat.)

"Launch costs 1/10,000th current prices certainly sounds like a generous
assumption. But is there in fact any basis for comparison between rocketry and
launch via electromagnetic forces? One M.I.T. study concluded that a lunar
mass-driver could launch ore into orbit for a cost of around 10
cents/kilogram."

For a different datapoint, the Wikipedia page on the Orion Drive has a claim
of a small city being launchable for 5 1950 cents a pound. Call it 50 cents a
pound today, perhaps. I thought it was insane until I remember relative
nuclear and chemical energy densities, after which 50 cents seems 500 times
too expensive. :)

Chemical rockets off planets suck. :)

> I also pick on Zubrin a little here:
> http://members.aol.com/oscarcombs/case_spc.htm#Robert_Zubrin

I think Martian or Lunar advocates could claim a point, especially for
incremental increase of living space, if they dropped terraforming (easy
enough for any Lunars) and simply pointed out the ease of already having
surface area. I don't know if it'd be a valid point -- numbers! -- but
certainly intuition suggests it'd be cheaper to build new domes or tunnels on
an existing surface rather than spining or blowing new surface de novo,
whether O'Neill style or Savage style.

One might argue by analogy to life, which hits a surface and breaks it up and
builds off of it. The effective way might be to land directly on an asteroid
and tunnel it, or dome over. Like the primary phase or succession in ecology
-- I forget the proper terms, but the initial lichens. Then you end up mining
and crumbling the asteroid, both digging deeper and throwing stuff out to spin
with, but without committing to large structures up front.

Of course this would lose the artificial gravity. I think O'Neill definitely
led the *humanization* of space (suburbanization?). Dyson wants extreme
biological engineering, Savage wants adaptation to zero-gee bubbles, and as an
AI researcher part of me thinks all the monkeys-in-tin-cans scenarios are just
a backup plan anyway. :)

-xx- Damien X-)