Last year, in a flurry of “NASA Bombs Moon!” stories, the NASA LCROSS (Lunar Crater Observation and Sensing Satellite) project deliberately crashed into a deeply shadowed crater to kick up dust and test its contents – looking particularly for water. They found it. [SciTechStory: On the Moon or elsewhere follow the water] The quantities found were relatively small, but any water at all on the Moon was something of a breakthrough. At that point the stock of ‘Moon Base’ ideas went up, because water is such a versatile substance (like humans need it, and it can make rocket fuel). Now there’s more – more water that is, as confirmed by the Chandrayaan-1, India’s spacecraft that was sent to the Moon about the same time as LCROSS. Among other things, before it conked out, Chandrayaan-1 used its on-board Mini-SAR instrument (mini-Synthetic Aperture Radar, a piece of NASA equipment) to scan the Moon’s north pole craters for water.

Water was detected in 40 small craters ranging in size from 2-15 kilometers (1-9 miles) in diameter. Although the total amount of water (in the form of ice) depends on conditions in each crater, it is estimated there could be about 600 million metric tons (1.3 million pounds) of water ice. That’s roughly equivalent to a small pond (dimensions: 10x10x5 meters, 590,000 liters/156,000 gallons). This is not a big number, except if it were all potable (drinking water). Nevertheless, if there’s water in these 40 craters, there’s probably more in other craters. Collectively the Moon may not have enough water for industrial purposes, but it certainly looks like there’s enough for sustaining a human inhabited Moon base.

Of course, little is known about the conditions involved with extracting the water. “Conditions on the ground” have a way of disrupting neat calculations, which is why more test probes and other robotics will be needed to explore these craters.