Geoscience: Water on the Moon stored in beads of impact glass

Glass beads formed from the cooling of melted material ejected by impacts and found strewn across the Moon could store substantial quantities of water, according to a study published in Nature Geoscience. These findings, as a result of analyses of samples from China’s Chang’e-5 mission, suggest that lunar soils contain a higher amount of solar wind-derived water than previously thought.

Although the Moon was once thought to be dry, analyses of samples collected during the Apollo missions revealed water trapped within minerals from the lunar interior and orbiters have detected the presence of water across the lunar surface. It is thought that the interaction of the solar wind with surface materials could produce water and sustain a water cycle on the Moon’s surface. However, a reservoir of lunar surface water has yet to be identified.

Sen Hu, Hejiu Hui and colleagues analysed the water content within glass beads produced by impact events, extracted from Chang’e-5 lunar soil samples. They identify water stored within the impact glass that is consistent with a solar wind origin. Furthermore, the distribution of water within individual beads indicates that water can rapidly accumulate in glass beads by diffusion, over timescales of only a few years, and be rapidly released. The authors suggest this presents an efficient recharge mechanism to drive an active water cycle on the lunar surface.

The authors suggest that the water trapped in impact glass beads could represent a potential water resource for future lunar exploration that is relatively easy to extract. They conclude that impact glass may host similar water reservoirs on other airless bodies.