The last hurrah of NASA's highly successful Lunar Prospector spacecraft - a controlled crash last July on to the surface of the Moon - did not unfortunately deliver the hoped for telltale signs of water ice. It was thought that the powerful impact might allow observers using spectrometers to spot hydroxyl molecules (O-H), a sign of ice trapped in the lunar surface.
There was no "water signature" detected, but that does not mean there was definitely no ice, the experts pointed out. They still believe that there might be six billion metric tonnes of water ice in the soils at the moon's south and north poles.