Earth-Moon L1

With respect to your "First point", let us consider two scenarios:
1.) Keeping the solar cells at Earth-Moon L1, and landing rectenna
equipment at some point on the Moon.
2.) Landing solar cells at Malapert Mountain and using them directly.

I think your claim is that (1) has a big advantage over (2). I wonder.
With option (1), solar cells need to be launched from Earth, the same as
in option (2). With (1), additional rectenna equipment and the means to
deploy it must be launched from Earth and landed on the Moon. With (2),
solar cells need to landed on Luna.

How many square kilometers would the rectenna in option (1) cover? What
would the mass be of that area of rectenna? What kinds of machinery
would be required to deploy it over that area, and what would the mass be
of those robots? Do you still think that combined the it would be a lot
less mass than landing solar cells directly on the Moon?

The biggest delta-V hit is in getting things from the surface of the Earth
to L1 or lunar orbit. Getting them from L1 or lunar orbit to the surface
of Luna is a much smaller amount of delta-V.

Another point.... it is possible to conceive of a plan to start
bootstrapping at Malapert Mountain. Land the minimal amount of robotic
equipment necessary to begin manufacturing solar cells from lunar
materiel.

Ron

charles radley cfrjlr@...
12/13/02 04:29 PM

First point:

Continuous solar power at Malapert is not that
valuable.

The problem with solar power is that PV conversion
efficiency is only about 20% efficient, for rather
high priced PV cells. Plus PV cells are rather heavy
to ship from Earth and soft land on luna, rather
expensive to do.

A rectenna, on the other hand, is lightweight and has
a conversion efficiency of over 90%.

Soft landing hardware on to the Moon is very
expensive.

Let us assume a PV array is 10 times heavier per watt
than a rectenna.

That means we can get 5*10 = 50 times as much power
per kilogram for a rectenna than for a PV array.
That means a rectenna will be be at least 50 times
cheaper per watt of useful power than PV array at
Malapert. I say "at least" because the manufacturing
cost of a rectenna will be much cheaper than for PV
array.

=====

Second point:

I am not particularly interested in subsistence level
"living off the land" on luna or anywhere else.
I am interested in breaking open the vast resources of
the high frontier.

That means solar power satellites beaming power to
Earth as the primary economic power house for space
development.

That means an SPS demonstrator at L-1 is top priority.

==========

SPS makes lunar development cheaper, and it opens a
vast energy market for Earth.

A win-win scenario.