The Case of the Missing Moon Water

On July 31, 1999, NASA's Lunar Prospector spacecraft dived into a permanently shadowed crater near the Moon's south pole. Scientists hoped that the crash might liberate up to 40 lb of water vapor along with a plume of dusty impact debris, proving once and for all that water exists on the moon. Hundreds of amateur and professional astronomers watched for signs of the impact using everything from home-built telescopes to the world's most powerful observatories. More...