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  • Dick writes about Earth and planetary science for Science magazine.
 

Accused Spy Was Hot on Trail of Lunar Ice

20 October 2009 3:22 pm
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Clementine.jpg

Before being arrested Monday and charged with trying to sell classified information to an FBI agent posing as an Israeli intelligence agent, planetary physicist Stewart Nozette was on a mission. Fifteen years earlier, he had gotten a whiff of ice hidden in the unbearably cold shadows of polar craters on the moon. Today, he heads one instrument team and co-leads another probing for lunar ice. Early signs of ice were promising.

Nozette, 52, got the lunar ice bug after running a jury-rigged experiment using the radio transmitter on the Clementine spacecraft orbiting the moon in 1994. Earth-based radar had strongly suggested subsurface ice in permanently shadowed—and therefore frigid—craters near the north pole of Mercury, of all places. So Nozette and his colleagues on Clementine—a joint technology demonstration mission between NASA and the Ballistic Missile Defense Organization—beamed a radio signal at the moon’s south polar region so that it penetrated a few meters before bouncing to Earth. Signs in the reflected, radar-like signal indicated subsurface ice, at least to Nozette and colleagues who reported their results in Science (29 November 1996, p. 1495).

Many researchers disputed the Clementine results, but the Lunar Prospector mission later added support for polar hydrogen and presumably ice. Then NASA was told to send astronauts to the moon, where water in a deep freeze would come in handy. So Nozette, who is currently associated with the Lunar and Planetary Institute (LPI) in Houston, Texas, became principal investigator of a bona fide radar instrument onboard the Lunar Reconnaissance Orbiter now orbiting the moon and co-PI of a similar radar on the now-defunct Chandrayaan-1 spacecraft orbited by India.

Early Chandrayaan-1 results reported at last March’s Lunar and Planetary Science Conference in Houston looked enticing, although co-PI Paul Spudis of LPI would not go so far as to make a claim for water. The LCROSS impact into one shadowed polar crater on 9 October failed to loft any obvious water into view, but that has not dampened the spirits of enthusiasts for the wider-ranging radars. Analysis of the radar data continues without one of their leaders; public announcements of results should come within the next few months.

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