The Moon may hold much more water than we think

https://www.sciencemag.org/news/2020/10/moon-may-hold-much-more-water-we-think

Source:  By Sid Perkins, Science Magazine. 

Excerpt: Scientists have long suspected the Moon holds sizable reserves of water, secreted as ice in the deep cold of permanently shadowed craters near the poles. Two new studies tell us more about the possible extent of those reserves. One suggests the shadowy polar caches may cover an area equivalent to the states of Connecticut and Massachusetts combined; the other reveals traces of water elsewhere on the Moon’s surface, trapped in rocks or between the grains of lunar soil. ...A 2008–09 orbital expedition detected the signature of water in shadowy lunar hollows. But how much is there? To find out, Paul Hayne, a planetary scientist at the University of Colorado, Boulder, and his colleagues estimated the number and size of permanently shadowed polar regions, where temperatures remain below –163°C. ...the team calculated that the Moon’s polar regions host about 40,000 square kilometers of permanently shadowed areas that could contain water, from kilometers-wide craters to shallow depressions in the meteorite-gouged terrain, they report today in Nature Astronomy. ...Just last week, NASA announced a $47 million commercial contract to send an ice-seeking drill to the Moon in 2023. A second study follows tantalizing evidence that there may be water elsewhere on the Moon. ...Casey Honniball, a lunar scientist at NASA’s Goddard Space Flight Center, and colleagues ...found that each kilogram of lunar soil along two narrow swaths of the Moon’s surface contains between 100 milligrams and 400 milligrams of water, or about one raindrop’s worth, the team reports today in Nature Astronomy. Almost all of that water, they note, would be locked in shadowed areas between grains of lunar soil, or trapped in glassy materials created when micrometeorites smacked the lunar surface....