Leonard David's INSIDE OUTER SPACE

A new map reveals quantities of water trapped in the lunar soil. The amounts increase toward the poles, suggesting that much of the water was implanted by the solar wind (yellow dots mark Apollo landing sites).
Credit: Milliken Lab/Brown University

Water as a resource in future lunar exploration has been deemed critical. Now there’s a map to help determine whether or not water could be worthwhile to extract, either as drinking water for astronauts or to produce fuel.

The study, published in Science Advances, builds on the initial discovery in 2009 of water and a related molecule — hydroxyl, which consists of one atom each of hydrogen and oxygen — in the lunar soil.

“The signature of water is present nearly everywhere on the lunar surface, not limited to the polar regions as previously reported,” said the study’s lead author, Shuai Li, who performed the work while a Ph.D. student at Brown University and is now a postdoctoral researcher at the University of Hawaii.

Roadmap for resources

“This is a roadmap to where water exists on the surface of the Moon,” says Ralph Milliken, an associate professor at Brown and Li’s co-author.

The process of water formation in the lunar soil “is active and happening today,” Milliken adds. “This raises the possibility that water may re-accumulate after extraction, but we need to better understand the physics of why and how this happens to understand the timescale over which water may be renewed.”

Furthermore, the researchers note that they are only sensing the upper millimeter or so of soil, and they can’t say for sure what the water content is like underneath that. “The distribution of water with depth could make a big difference in terms of how much water is actually there,” Milliken says.

Credit: Milliken Lab/Brown University

Good starting point

Nevertheless, the researchers say the study provides a good starting point for thinking about how lunar water resources might be utilized in the future.

“It remains to be seen whether extraction could be feasible,” Milliken concludes. “But these results show us what the range of water availability across the surface is so we can start thinking about where we might want to go to get it and whether it makes economic sense to do so.”

The research was funded by the NASA Lunar Advanced Science and Exploration Research Program (NNX12AO63G).

For a copy of their research, “Water on the surface of the Moon as seen by the Moon Mineralogy Mapper: Distribution, abundance, and origins,” go to:

http://advances.sciencemag.org/content/3/9/e1701471.full