Newt Gingrich has been the target of a lot of mockery for his space policy speech yesterday, during which he pledged to establish a permanent U.S. lunar base by the end of his second term. The idea may seem a bit out of place in a campaign that has been overwhelmingly focused on the more terrestrial concerns of a struggling U.S. economy, but it isn't actually that novel a concept. NASA had plans for the construction of a moon base during the George W. Bush presidency which have since been scrapped. China, Japan, and Russia all have moon base plans at various stages of development. 

But beyond nationalist bravado, pure scientific research, or the fun of space tourism, is there any reason for people to be on the moon? Is there anything we want there? Gingrich himself proposed one idea in a recent presidential debate. Moon mining:

"If you take all the money we've spent at NASA since we landed on the moon and you had applied that money for incentives to the private sector, we would today probably have a permanent station on the moon, three or four permanent stations in space, a new generation of lift vehicles."

Are there really lunar riches waiting to be scooped up? Well, perhaps. But not as many as you might think. 

The prospect of lunar mining has been a tantalizing one since the Apollo 12 mission brought back a type of rock known as KREEP -- an acronym the chemical symbol of potassium, rare earth metalsm and phosphorous. With recent concerns over the supply of rare earth metals, used in various energy-saving technologies, and particularly China's near-monopoly over their supply, some have proposed the moon as an alternative source for these minerals. 

But while the KREEP-rich samples brought back by the Apollo astronauts led researchers to believe that rare earth metals were abundant through the moon, recent gamma-ray spectrometer analysis has indicated that there's far less rare-earth material on the moon than previously though, and that's it's concentrated in specific areas. In other words, prospective moon miners should pick their landing site carefully. 

Others, notably former Apollo 17 astronaut Harrison Schmidt, have suggested mining the moon for Helium-3, an isotope that's relatively common on the lunar surface but extremely rare on earth. Helium is used for a variety of current purposes, including radiation detection and MRIs, but some believe it could also be used for nuclear fusion power. India and Russia have both discussed plans to mine the moon for Helium-3.

Unfortunately, mining HE-3 is not so easy. According to an analysis by the Wisconsin Center for Space Automation and Robotics, obtaining just one gram of He-3 from the lunar surface would require excavating 150 tons of lunar regolith. The moon also has large amounts of titanium, but this would need to be seperated from a compound also containing iron and oxygen.   

In other words, the upfront costs of lunar mining would be pretty massive and perhaps only ultimately worth it if nuclear fusion using He-3 pans out, which is still a big if. This isn't even getting into the legal difficulties -- the Outer Space Treaty prohibits countries from establishing territorial sovereignty on the moon and there's not mechanism for land titles -- or the environmental concerns. (Yes, it is possible to pollute the moon.)

So while it certainly might be possible to set up a manned lunar facility of some kind -- and recent water discoveries have raised hopes for the feasibility of permanent colonization --  it's probably going to be a while before anyone makes money there.