...with help from Chandrayaan-1

Using newly calibrated data taken from NASA’s Moon Mineralogy Mapper, which flew aboard India’s Chandrayaan-1 spacecraft, scientists have created the first global map of water in the Moon’s soil.

The study, published in the journal 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 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 in Providence, Rhode Island, US. “The amount of water increases toward the poles and does not show significant difference among distinct compositional terrains,” Li, now a postdoctoral researcher at University of Hawaii, added.

The water concentration reaches a maximum average of around 500 to 750 parts per million in the higher latitudes. That is not a lot — less than what is found in the sands of Earth’s driest deserts — but it is also not nothing.

“This is a roadmap to where water exists on the surface of the Moon,” study co-author Ralph Milliken, Associate Professor at Brown University said.

“Now that we have these quantitative maps showing where the water is and in what amounts, we can start thinking about whether or not it could be worthwhile to extract, either as drinking water for astronauts or to produce fuel,” Milliken said.

As useful as the new maps may be, they still leave plenty of unanswered questions about lunar water.

The Moon Mineralogy Mapper, which supplied the data for the research, measures light reflected off of the lunar surface. That means that it can’t look for water in places that are permanently shadowed from the sun’s rays.

Many scientists think these permanently shadowed regions, such as the floors on impact craters in the Moon’s polar regions, could hold large deposits of water ice.

“Those ice deposits may indeed be there, but because they are in shadowed areas it’s not something we can easily confirm using these data,” Milliken said.IANS

As useful as the new maps may be, they still leave plenty of unanswered questions about lunar water.