From: Anders Sandberg (asa@nada.kth.se)
Date: Fri Dec 14 2001 - 06:13:21 MST
On Fri, Dec 14, 2001 at 04:39:21AM -0800, Robert J. Bradbury wrote:
>
> On Thu, 13 Dec 2001, Olga Bourlin wrote:
>
> > Scientist proposes beaming electricity to Earth from the moon (and his
> > name's Criswell, no less, but NOT the Criswell who said "We are all
> > interested in the future, for that, my friend, is where you and I will
> > spend the rest of our lives." Heh ... heh.
>
> The paper author isn't just any "Criswell" -- he is *the* David Criswell of
> "star lifting" fame. Hmmm, lunar power systems after you propose how to
> lengthen the lifetime of a star. Kind of a let down if you ask me.
You have to start somewhere. His star lifting schemes all required
building huge solar collecor systems with beamed power anyway, so
this is a good start for getting experience with the technology,
setting up an industrial base, getting a few customers and so on.
Once that is proven, you can branch out.
Heute der Mond, morgen das Sonnensystem!
> In response to Damien's comments about whether you have the necessary
> materials. The material you need the most of if you don't care too
> much about efficiency is silicon and there is plenty of that up there.
> If you want high efficiency cells, then gallium arsenide is used to
> a greater degree. Since your ability to range all over the moon looking
> for deposits is likely to be limited, you are going to have to utilize
> trace element abundances. That most probably means you need elemental
> sorting capabilities. You can do that with current technology using mass
> spectrometers, but I suspect the throughput is pitiful. I don't think
> the idea is really going to fly until you have pretty robust nanotechnology.
What would the efficiency of simple moon made photovoltaics be, and
what about the energy requirements for mass sorters and robots? You
can afford taking things slowly at first, if you can get the system
to grow exponentially later.
Seems like a fun exercise to calculate the optimal rate of
construction of photovoltaics, mass sorters, utility robots and
assembly factories to get maximal growth rate. Since the
photovoltaics may be the rate limiting factor it would seem that you
should build them whenever you can, and use the rest of the
time/mass/energy to build the other systems.
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