The notion of a permanent return to the Moon appears to be in the air. The June 2009 issue of Analog had an article about the possibility of building a base in Shackleton Crater near the lunar south pole and the METRO, of all things, had an item in its Wednesday 27 issue.
Such a venture would cost billions – likely hundreds of billions. As I have remarked elsewhere under another name although I am in favour of human expansion into space, realistically I have to admit that it will not happen unless someone can turn a profit from so doing.
Many SF stories have used the concept of minerals being mined on the Moon and sent to Earth. In fact this would be far more expensive than mining low-grade ores – or even old scrap-yards and waste dumps on Earth itself so this will not finance the return.
A possible economic support for settling the Moon turned up in the METRO article referred to above which discussed the possibility of mining helium-3 (He-3) from the lunar regolith for use in fusion reactors.
He-3 is a helium nucleus that has only one neutron instead of the usual two, has a higher energy ground-state than He-4 and has an ‘affinity’ for an extra neutron in a manner slightly analogous to the affinity atoms of electronegative elements such as chlorine and fluorine have for electrons. Fusion of He-3 and deuterium would thus produce He-4 and protons.
The usual proposals for fusion reactors would have them employing the deuterium -tritium reaction which would produce He-4 and neutrons. The neutrons, being uncharged, would be unconfined by the magnetic fields confining the super-hot plasma and thus would fly out and strike the reactor walls, eventually making it radioactive.
The protons of the deuterium-Helium -3 reaction would also be confined by the fields so the problem of induced radiactivity would not arise. Furthermore, given the affinity of He-3 for an extra neutron, the reaction would require lower temperatures and pressures to initiate and sustain, thus requiring less energy to run and thus be more capable of producing energy over and above that needed to sustain the reaction than would a D-T reactor.
The drawback of the D-He3 reaction is that helium – 3 is extremely rare on Earth. There are however quantities of it in the solar wind – and the particles in the solar wind become trapped in the regolith when they strike the lunar surface. Over the millenia this has built up until each tonne of regolith contains a gramme of He3.
Rick Stroud, author of The Book of the Moon, is concerned that if we strip mine the Moon for this fuel (valued at $5billion per ton) we will lose “a record of five billion years of our universe’s history. Mining will fundementally change the Moon’s atmosphere and destroy its surface.” He does have a point about the loss of data but how rapidly would we mine the Moon?
It is estimated that one tonne of He3 would supply New York’s energy needs for a year. Four hundred tonnes per year would thus give the entire world the energy availability (and thus potentially the living standards) currently enjoyed by New Yorkers. This would require the processing of four hundred million tonnes of regolith. In volume this would be about 0.13 cubic kilometers. Assuming the He3 is found no deeper than 10 centimetres, this would require 1300 square kilometers to be strip mined. The Moon has an area of about 38 million square kilometers so it would take almost 30,000 years to strip mine its entire surface. This is short on the cosmic scale but five times longer than any kind of civilisation has existed on Earth – plenty of time for scientific research.
As for the notion that this would destroy the Lunar environment and “fundementally change [its] atmosphere”, the Moon has no life of any kind and its atmosphere is so tenuous that the exhaust fumes from the Apollo missions have already fundementally altered it.
He also says: “It’s a proirity to get clean water to everbody on Earth, at a fraction of the cost of winging off to the Moon. And to not just make tons [sic] of electricity to run central heating systems and car plants.”
I do not argue about the need for clean water but this could paid for if various African and Asian dictators were to stop spending their GDPs on military toys or feathering their own nests. Abandoning space exploration and handing the money over to crooked politicians and generals will not produce a single drop of clean water.
As for running central heating systems, I entirely fail to see what is wrong with this. It still gets cold in the winter and the energy has to come from somewhere. Nor do I see anything wrong with producing consumer goods. Judging by what I have seen in Africa, few Africans have a problem with it either.
Returning to the Moon could not only provide a bonanza of scientific data but it could supply our energy needs and improve everybody’s standard of living as well. What’s not to like?
Alternaties Corporation 
Leave a Reply