Friday 7 October 2011

Could we mine the moon for titanium?

This week scientists at the joint meeting of the European Planetary Science Congress and the American Astronomical Society's Division of Planetary Sciences in Nantes, revealed the discovery of extensive titanium reserves of the moon, with widespread deposits of the mineral ilmenite containing up to 10% titanium; ilmenite on Earth typically contains only 1% titanium. The research was presented by Mark Robinson of Arizona State University and Brett Denevi of Johns Hopkins University in Baltimore. It was based upon findings made by NASA's Lunar Reconnaissance Orbiter; which was able to make a spectrographic analysis of rocks on the lunar surface, by calibrating the spectral signal to rocks brought back from the surface by the Apollo 17 Astronauts and images made of the landing site by the Hubble Space Telescope.

A Lunar Reconnaissance Orbiter image of the moon.

This has lead to widespread speculation that we might mine titanium on the moon. Titanium is a valuable metal, lightweight, strong and corrosion resistant. It used in surgical implants, aircraft and high technology. The lunar reserves have been shown to be much richer than those on Earth, and in a form that is also rich in oxygen, something that any lunar colony would require.

However while titanium is valuable, this does not mean that it is automatically valuable enough to justify the expense of a lunar colony. Titanium is the ninth most abundant element on Earth, and the seventh most abundant metal. We extract about 90 000 tonnes of the metal from the Earth's surface, but there are thought to be workable reserves of about 600 000 000 tonnes; that is to say at current rates of extraction reserves will last for another 666 years, assuming no increase in recycling, nor any better replacement material being found. Resources that were valuable in 1345 are not necessarily the same ones considered valuable now; Europeans never hailed the discovery of America as a potential source of cheap thatch for their roofs. As such it is probable that any successful future lunar colony might choose to mine titanium for its own use, but highly unlikely that one would ever be established for the express purpose of titanium mining.