The prospect of a permanent lunar base has certainly excited astronaut Harrison Schmitt, a veteran of the Apollo 17 mission. Nowadays Schmitt is a geologist at the University of Wisconsin in Madison and chairman of Interlune Intermars which raises money to develop lunar mining.
President Bush鈥檚 announcement included references to the moon鈥檚 鈥渁bundant resources鈥�, but Schmitt and his co-prospectors are primarily interested in one: helium-3. Helium deposits are scarce on Earth, and the isotope helium-3 is even rarer. Nevertheless, it is valuable in medical diagnostics, and researchers developing nuclear fusion reactors as a future solution to terrestrial power generation will use helium-3 by the bucket load. Soil samples brought back from Apollo suggest that the lunar surface, or regolith, contains vast amounts of helium and hydrogen deposited by the solar wind.
Schmitt calculates he will need to excavate 14 million tonnes of helium-rich regolith a year in order to dig out 100 kilogrammes of helium-3 that would cover estimated annual operating costs of around $300 million. The setup will also need to heat excavated regolith to about 800 掳C to release the helium-3 from the rock it is bound to.
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For a power source, the mine could use hydrogen that comes out with the helium, reacting it with oxygen also available in minerals on the moon. Ideally, unmanned ships would carry the helium-3 back to Earth.
Schmitt is looking for investors, but this is certainly no guaranteed get-rich-quick scheme: investors can expect a wait of 10 to 25 years before any helium-laden ships start to come home. And even if they do start unloading helium-3 on Earth, who says there will be a huge market for it? The fusion technologies under development have yet to produce an economical fusion power station, and it might be rash to assume that the fusion dream will become reality.
Schmitt counters that helium-3 can also produce proton beams that could image or zap cancers, and make medically useful isotopes. These markets would start to produce a return for investors while the fusion market opens up for real.
