Issue Date: October 21, 2010 Moon Crater's Icy Character For the
first time, scientists have directly examined the contents of an
icy lunar crater, showing that the surface contains a remarkably
high percentage of water, much of which is in the form of pure
ice crystals, possibly deposited by a comet. The debris kicked
up from a lunar crater bombarded by the upper-stage rocket of
NASA's LCROSS spacecraft last year was loaded with water and
other volatile chemical species, which represent 10–20% of the
total material, the scientists announced on Oct. 21. The water,
which alone made up a "remarkable" 5% of the ejected material,
was largely in the form of pure ice grains, rather than mixed,
"dirty" grains, says Anthony Colaprete, LCROSS mission project
scientist at NASA's Ames Research Center, in Moffett Field,
Calif. "That's really exciting," he says, because he and his
colleagues didn't expect lunar ice to be so pure. The team also
detected a plethora of other species in the ejected material,
including methane