A NASA radar aboard India's lunar orbiter has detected ice deposits, astronomers reported Monday, in the moon's north pole craters. More than 40 small craters -- ranging from 1 to 9 miles across -- containing water ice turned up in the search by the NASA "Mini-SAR" radar aboard India's Chandrayaan-1 spacecraft.

"Although the total amount of ice depends on its thickness in each crater, it's estimated there could be at least 1.3 trillion pounds of water ice," says NASA statement. The finding confirms ice indications from NASA's Lunar Prospector mission, and comes after November's impact-blast test that successfully detected ice in south pole lunar craters by NASA's $79 million LCROSS mission.

"The emerging picture from the multiple measurements and resulting data of the instruments on lunar missions indicates that water creation, migration, deposition and retention are occurring on the moon," said Mini-SAR investigator Paul Spudis, of Lunar and Planetary Institute in Houston, in a statement.

Because polar craters on the moon have been shaded from sunlight for billions of years, planetary scientists suspect ice can remain frozen in the shadows, chilled to temperatures below -300 degrees Fahrenheit. The Mini-SAR results show surface roughness inside the craters suggestive of ice mixed with lunar dirt.

Chandrayaan-1 was launched in 2006, aimed at exploring the moon from a 60-mile high lunar-pole-circling orbit.

By Dan Vergano