Water, Water Everywhere—Even On The Moon

When the National Aeronautics and Space Administration's LCROSS spacecraft plunged to the moon's surface last month, the impact kicked up about 100 kg of water in the camera's field of view—enough to fill a dozen or so two gallon buckets, scientists reported today at a press conference.

The spacecraft targeted the permanently shadowed crater Cabeus near the moon's south pole, where scientists have suspected water ice might be able to exist. Although the impact failed to generate a dramatic visible plume of debris, LCROSS's instruments found plenty of evidence for water from two key areas of the spectrum: infrared and ultraviolet. Shortly after the impact, the infrared spectrometer identified spectral dips unique to water, and the ultraviolet spectrum showed a sharp peak corresponding to the hydroxyl radical, which is also associated with water. "This is a really strong detection," said Anthony Colaprete, LCROSS mission project scientist at NASA Ames Research Center in Moffett Field, Calif.

"What an exciting and extraordinary discovery this really is," said 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.