NASA's Mini-SAR instrument: Water on Earth and Moon Have Common Origin

NASA's Mini-SAR instrument, which flew aboard India's Chandrayaan-1 spacecraft, found more than 40 small craters with water ice. 

The craters range in size from 1 to 9 miles (2 to 15 km) in diameter. 

Although the total amount of ice depends on its thickness in each crater, it's estimated there could be at least 600 million metric tons of water ice. 

The red circles denote fresh craters; the green circle mark anomalous craters. 

Credit: NASA

The traces of water in ancient moon rocks may share a common source with water on Earth, scientists say.

If confirmed, the potential moon-Earth water link would add more support to the theory that the moon's material came from the proto-Earth, and that water in this material survived the aftermath of the giant impact thought to have formed Earth's large natural satellite, researchers explained earlier this month at the Lunar and Planetary Science Conference (LRSC) in Houston.

Until now, most studies of moon rocks have focused on assessing the water contents of the younger basalts and volcanic glasses, which are partially melted substances of the lunar mantle.

Researchers have access to the lunar rocks thanks to NASA's six Apollo moon landing missions and the three Russian robotic sample-return missions.

The Apollo missions returned to Earth with a huge load of 842 pounds (382 kilograms) of lunar rock and soil samples.

Backscatter electron image of a lunar melt inclusion from Apollo 17 sample 74220, enclosed within an olivine crystal. 

The inclusion is 30 μm in diameter. 

Skeletal crystals within the melt inclusion are a fine mixture of olivine and ilmenite. 

Dark area in the upper-left is an ion microprobe sputter crater. 

Credit: John Armstrong /Geophysical Laboratory, Carnegie Institution of Washington