Last year’s big news story was the announcement of water on the Moon. This evidence came from five separate sources, and spanned over a decades’ worth of data. This climaxed with the October 9th impact of the LCROSS spacecraft in the quest for a moisture laden plume. Now, a reanalysis of lunar samples returned by Apollo astronauts have turned up evidence of microscopic water beads imbedded in volcanic glass. This leads scientist Alberto Saal to suggest that the lunar interior may contain water in the order of 745 parts per million, a tiny but measureable amount.
The first whiff of water in the form of clay hydroxyls came from the Clementine and Lunar Prospector orbiters in the mid 90’s. Cassini imaged the Moon in the infrared on its way out to Saturn, but the water signature detected at the time was suspected to be due to spacecraft contamination. More recently, lunar water got a boost from NASA’s spectrometer aboard the Indian orbiter Chandrayaan 1 and observations by the Deep Impact spacecraft in its role of simulated exoplanet hunter… keep in mind, the amount of water being discussed is tiny; were talking maybe a liter per ton of lunar regolith near the poles, and half that amount at the equator! With the cancellation of Constellation, it’s to be seen if any of the proposed unmanned rovers will take up the hunt for lunar water over the next few years.