When astronauts go back to the moon for a long-term exploration mission, they may find abundant water resources already waiting for them beneath the lunar surface. A study published yesterday in Science Advances hints at the possibility that water ice could be trapped under the moon’s surface — and not just near the poles, as NASA’s Lunar Crater Observation and Sensing Satellite detected in 2009, but in widespread areas below the lunar crust.
The conclusion comes from researchers at Tohoku University in Japan, who analyzed a series of lunar meteorites discovered in northern Africa and found that one of them contained a special mineral which can only be formed in the presence of water.
The mineral, called moganite, is a silicon dioxide crystal similar to quartz and naturally forms on Earth in sediments that have rested in alkaline fluids.
According to study author Masahiro Kayama, from the university’s Department of Earth and Planetary Materials Science, this is the first time moganite has ever been uncovered in samples of lunar rock.
“For the first time, we can prove that there is water ice in the lunar material,” the study author told Space.com.
The lunar meteorite found to harbor the mineral is dubbed NWA 2727 and is the only one in a series of 14 ancient meteorites that was discovered to contain the moganite. These meteorites crashed on Earth around 17,000 years ago, landing in a desert in northern Africa, Phys.org reports, and are believed to have originated from Procellarum Terrane, a large province on the near side of the moon.
The team dismisses the possibility that the mineral could have formed on Earth after the meteorites fell in the desert. Instead, the researchers believe that the moganite was formed under the lunar surface following a comet crash or an impact by a water-bearing asteroid.
“Moganite formation as a result of terrestrial weathering can be excluded, because this scenario would imply a wide distribution of moganite in the sands of the hot desert where the meteorites were found,” the Japanese scientists wrote in their study.
Kayama points out that this discovery suggests the moon could hold hidden water caches deep under its surface.
“In a moganite, there is less water, because moganite forms from the evaporation of water. That’s the case on the surface of the moon. But in the subsurface, much water remains as ice, because it’s protected from the sunlight,” he explained.
By his estimates, the water content in the subsurface lunar soil could reach up to 0.6 percent. These water resources could come in handy to future moon pioneers, as they might be able to extract about 1.6 gallons of water per 36 cubic feet (six liters per cubic meter) of lunar rock.
If these calculations stand, it would mean that water is a “very abundant” resource on the moon, Kayama states. In fact, future lunar outposts might find “enough water to cover their need” under the moon’s surface and not need to bring water all the way back from Earth, he opines.