Splashdown On The Moon Kicks Up Water

When the ejected upper-stage rocket of NASA’s LCROSS spacecraft plunged to the moon’s surface last month, the impact kicked up about 100 kg of water—enough to fill a dozen or so 2-gal buckets, scientists reported at a press conference on Nov. 13. Instruments also detected possible signs of hydrocarbons, they said. LCROSS targeted the permanently shadowed crater Cabeus near the moon’s south pole, where scientists have suspected water ice might exist. Although the impact failed to generate a dramatic visible plume of debris, LCROSS found plenty of evidence of water: Shortly after the impact, the infrared spectrometer identified spectral dips unique to water, and the ultraviolet spectrometer displayed a sharp peak corresponding to the hydroxyl radical. “This is a really strong detection,” said Anthony Colaprete, LCROSS mission project scientist at NASA’s Ames Research Center, in Moffett Field, Calif. “What an exciting and extraordinary discovery this really is,” added Greg Delory, LCROSS mission team scientist at the University of California, Berkeley. “Equally important is what to do next: Where did the water come from? And how long has it been there?” Possible sources include comets or chemical reactions with solar wind, Delory said.