Scientists already knew that there's water on the moon. For example, NASA's Lunar Crater Observation and Sensing Satellite detected the stuff in a shadowed crater near the moon's south pole. And India's probe Chandrayaan-1 recorded evidence of water in the thin atmosphere above the moon's surface.
But, according to Kayama, there has been no evidence so far of the presence of water in the subsurface at mid and lower latitudes.
"Many people think that remote-sensing spacecraft only found the evidence of water around the poles simply because
we can't see under the surface below a few millimeters," Kayama said. "This is the first insight into water in the subsurface zone."
The researchers estimate that the water content in the lunar soil under the surface could be up to 0.6 percent. If that's right, future moon pioneers could theoretically extract about 1.6 gallons of water per 36 cubic feet (6 liters per cubic meter) of lunar rock, Kayama said.
"This value means that water is very abundant," he said. "It would be enough for future astronauts and people that could perhaps live on the moon in the future to extract enough water to cover their needs."
Kayama said that the widespread presence of water ice under the surface of the moon in other areas than just the poles would mean future explorers would have easier access to the resource, which could also be used to make rocket fuel for missions to asteroids and other planets.
"We wouldn't need to bring all the water for drinking and the fuel to return to Earth or to travel to Mars, for example, with us from Earth," Kayama said. "If water is abundant in the lunar subsurface, we can easily use it."
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Kayama and his colleagues analyzed 14 lunar meteorites using sophisticated methods, including micro-Raman spectroscopy and electron microscopy. They found moganite in only one of those samples.
However, they said, concentrations of the mineral suggest that it was unlikely to have formed when the meteorite was already lying in the African desert, exposed to terrestrial weather.
"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 researchers wrote in the new study, which was published online May 2 in the journal Science Advances. "This case has not been reported. Moganite is readily and completely lost via water alteration at ambient pressure."
Kayama hopes that Japan's space agency JAXA will go ahead with plans to launch a lunar sample-return mission in the future, which would allow researchers to attempt to detect moganite in other lunar rocks.
Originally published on Space.com.
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