Helium-3—a variation of the helium used in balloons—can reduce temperatures to nearly absolute zero, provide non-radioactive medical lung imaging, and detect neutrons emanating from smuggled nuclear devices. It may even be an element of a clean energy source. For decades, this non-toxic and non-corrosive gas has been in adequate supply, but now that supply is dwindling just as demand is rising dramatically.
On a quest to locate water and other volatile minerals in the Moon’s soil, the LCROSS experiment—Lunar Crater Observation and Sensing Satellite—hurtled a spent Centaur rocket into a dark crater at the lunar South Pole last year. The crater, known as Cabeus, is one of the permanently shadowed regions of the Moon, and researchers believe it is also one of the coldest.