Not All Moon Water Alike, Says Scientist

This artist's rendering provided by NASA via Brown University shows the Centaur upper stage rocket separating from its shepherding spacecraft on a trajectory toward the moon. On Friday, Oct. 9, 2009, NASA will crash the Lunar Crater Observation and Sensing Satellite, or LCROSS, into a crater on the moon's south pole to search for evidence of water ice.
Following the discovery last year of trace amounts of water on the moon, scientists have been analyzing the data returned by probes mapping the lunar surface, and have determined that different forms of water compounds exist there.

This indication that water on the Moon comes from different sources - accounting for the varying organic compounds contained within - is reported in

Measurements from India's Chandrayaan-1 moon probe (which found frozen water in 40 craters) and from NASA's recent Lunar Crater Observation and Sensing Satellite (LCROSS) mission (which slammed into the moon last October to test soil content from the resulting impact plume and found additional water) suggest that three different varieties of lunar water have been identified.

Paul Spudis of Houston's Lunar and Planetary Institute told that in addition to nearly pure ice, there is also a "fluffy mix of ice crystals and dirt" found by LCROSS. Instruments on Chandrayaan-1 also detected a thin layer of water that "comes and goes" across the surface.

The initial impact of LCROSS released water and hydroxyl, with small bits of pure ice mixed in, from the surface layer. Beneath that, water from a deeper layer was released, likely from a much earlier time period.

That water, Spudis said, contains more water ice, in addition to a variety of molecular compounds - sulfur dioxide (SO2), methanol (CH3OH), and diacetylene (H2C4).
This layer, at least one-half-meter below the surface, "is probably older than the ice we're finding on the surface," he said.

While some surface water likely comes from bodies that have impacted the moon over the eons - comets, for example, which are primarily ice - Spudis told that some water might be formed on the moon.

"Protons in the solar wind can make small amounts of water continuously on the lunar surface by interacting with metal oxides in the rocks," he said.

For more info:
Mini-RF Overview - Mapping the Lunar Surface
Moon Mineralogy Mapper
Moon and Mars (