Water, Water Everywhere

From the American Geophysical Union meeting in San Francisco: Wednesday the talk was about water on the Moon. In 1999, as the Cassini spacecraft passed the Moon on the way to Saturn, the Visual Infared Mapping Spectrometer (VIMS) found the 3-micron signature of water molecules and hydroxyl. Though found 10 years ago, this discovery was not published until this September.

This year the finding was confirmed by the Moon Mineralogy Mapper (M3) aboard India's Chandrayaan orbiter. Further confirmation was found from the Epoxi spacecraft which passed the Moon in June 2009 on its way to encounter a comet. Corroborating evidence from 3 missions show water and/or hydroxyl on the Moon. Today the Moon, once thought drier than a bone, is known to contain water.

As seen in this slide from yesterday afternoon, the two major 'water relations' on the Moon are temperature and composition. Cold terrain, such as near the poles contains more water. Mare contain less water than the lunar highlands. For these reasons, polar highlands are considered to be likely locations for settlement.

In response to this writer's question, another speaker noted that 10^21 kg asteroid Ceres could be composed of nearly 30% fresh water. While Earth contains about 10^21 kg water, not all of it is fresh. Ceres could potentially contain more fresh water than Earth! The asteroids are also potential sites for human mining. With possible changes in NASA's visions for the Moon and beyond, humans could venture to an asteroid in the near future.