Artificial Biospheres In Space

From: babbler36 [mailto:babbler36@...]

> That why the moon is terrable for settlement: you cannot grow food
> there (maybe at the poles...), because of the radition and month long
> sol.

Maybe, maybe not. I'm certainly of the opinion that the moon is not as
well-suited for agriculture as orbital settlements well outside of the
shadow of any planet. But agriculture on the moon may just be possible.

It all turns on one idea. The notion has been put forth that if one were to
allow a lunar greenhouse to chill during the 2-week long night (and indeed
it would take a deliberate effort to keep it from chilling), the plants
might "hibernate" and revive after the sun rises. We'll just have to
experiment.

> Mars is ten times better than the moon and space settlement (or space
> habitat or whatever) better so.

I think you'll find considerable disagreement here on that assertion. For a
list of reasons why orbital settlements are superior to Mars (or indeed any
other planetary location), please read Gerard O'Neill's "The High Frontier"
(http://www.space-frontier.org/HighFrontier/). Or, if you want something
shorter than a book, try this FAQ entry
http://members.aol.com/oscarcombs/spacsetl.htm#advantages or
http://members.aol.com/oscarcombs/case_spc.htm.

Sorry, but it sounds like you might have bought into Zubrin's assertion that
Mars is the only place off the Earth where one can do agriculture. But
Zubrin's insistence on this point stems from his casual dismissal of the
concept of large-yet-flimsy space mirrors the size of croplands, when
there's no detailed reason offered for being skeptical about our abilities
to engineer such things in 0-G. On the other hand, the solar intensity at
Mars' distance from the sun is only about half of what Earthly crop plants
are used to, and even Zubrin confesses that crop energetics relate to
insolation. Orbital habitats may be placed further from the sun if we make
the mirrors bigger and concentrating. But this is a solution which would
not work for Mars, due to gravity and weather.

If you're thinking about those Martian greenhouses made from thin plastic
films, you'd better go back and read the fine print. That's after an
assumed many-decades-long terraforming effort has increased the density of
the air many times over its present value. It might be the 22nd century
before we could see greenhouses of that variety. For the foreseeable
future, a Martian greenhouse would require just as thick glass as an orbital
one.

Regards,

Mike Combs