Researchers are hoping that water found in glass bead samples collected by a Chinese lunar lander means that a reservoir is trapped deep beneath the surface of the Moon.
Impact glass beads, which formed millions of years ago after asteroids crashed on the Moon, were collected by the Chang’e-5 lander and were found to contain water.
A study was led by Prof Hu Sen from the Institute of Geology and Geophysics, with findings published in the Nature Geoscience journal on Monday.
“These findings indicate that the impact glasses on the surface of the Moon and other airless bodies in the solar system are capable of storing solar wind-derived water and releasing it into space,” said Prof Hu.
The Chang'e-5 mission was China's first lunar sample return mission. It touched down on the surface on December 1, 2020, and returned to Earth with samples two weeks later.
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Scientists have been trying to discover liquid water on the Moon for decades.
While it would allow them to learn more about the formation of the solar system, it would also help astronauts who travel to the Moon for long-duration missions.
Water is too heavy to transport to space, so they would have to use resources already available to them.
Previous lunar missions have revealed structural water and ice water, including by studying fine mineral grains in lunar soils and volcanic rocks.
But these have not been able to explain the retention, release and replenishment of water on the surface of the Moon.
After studying the samples found in the impact glass beads, scientists behind the research believe that there has to be an as yet unidentified water reservoir that is bringing water up to the surface.
This is not the first time samples collected by the Chinese lander have hinted at water on the Moon.
A previous study showed that lunar dust and rocks collected by Chang'e-5 had water in the form of hydroxyl, a minor but important element of what makes up the liquid.