[ExI] The Moon's Cold Embrace

[Rafal Smigrodzki]

On Tue, Aug 11, 2020 at 4:57 PM Keith Henson via extropy-chat <
extropy-chat at lists.extropy.org> wrote:

>
> Farming is a particularly difficult problem on the moon.  It takes
> around 25 kW of light on a farming area to support a person.  Where
> does it come from?  You also have to get rid of 25 kW per person.  How
> is that done?
>

### Greenhouses on the Moon would need relatively small openings at the
top, with diffusers and UV filters, to provide for plant growth. That
should be easy. Of course you would also need energy storage for the lunar
nights, but the area of solar cells needed to harvest this energy (at 1.36
kW/sq.m) would not be insanely large. Yes, maintaining greenhouse
illumination at night would warm up the greenhouse but active radiative
cooling at night would be pretty effective.

Being surrounded by a large mass and having access to practically unlimited
amounts of mass to construct a settlement on the Moon is a big advantage
over orbital habitats. If you need to radiate heat, you just build a bigger
radiator farm on the surface and run it all night long. It's much more
difficult to build large radiators if you need to launch the building
materials and machines from somewhere far away.
 --------------------

>
> Free space O"Neill type colonies are a lot less difficult with respect
> to energy (light) for plants and heat sinks.
>

### How so? The solar constant is the same on the Moon and in orbit. Heat
sinks are heavy, brittle, it should be easy to plonk down on the lunar
ground rather than lug it all in space.

OTOH, a lunar beanstalk is feasible using existing materials, so delivery
from the Moon would be actually pretty cheap.

I don't know of any major showstoppers to either lunar settlements or
habitats but I think at least at small scale the Moon would be easier.

Maybe you could mention the problems that don't have recognized solutions.

Rafal
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