The find has attracted much attention due to its potential for in situ resource utilization in future lunar exploration missions and other space missions.

A research group led by Professor HU Sen of the Chinese Academy of Sciences (CAS) Institute of Geology and Geophysics (IGG) has discovered that impact glass beads from lunar soils of the Chang’e-5 (CE5) contain some wateras published in the journal ‘Nature Geoscience’.

Lunar surface water has attracted much attention due to its potential for utilization of in situ resources in future missions lunar exploration and other space missions.

Now, detailed studies show that these glass beads are probably a new water reservoir on the Moon, which records the dynamic input and output of water derived from the solar wind and acts as a buffer for the water cycle on the lunar surface.

Less water than on earth

Numerous lunar missions have confirmed the presence of structural water or water ice on the Moon and there is no longer any doubt that most of the lunar surface contains water, although the amount is much less than on Earth.

The surface water of the Moon shows diurnal cycles and losses to spaceindicating that a hydrated layer or reservoir should exist deep in lunar soils to maintain the retention, release, and replenishment of water on the Moon’s surface.

However, previous inventory studies of water in fine mineral grains of lunar soils, impact clumping, volcanic rocks, and pyroclastic glass beads have failed to explain the retention, release, and replenishment of water on the Moon’s surface (i.e., the water cycle on the Moon). lunar surface).

Therefore, there must be a water tank not yet identified in lunar soils having the ability to buffer the lunar surface water cycle.

Reason for further investigation

PhD student HE Huicun, under the direction of Professor HU Sen, considered impact glass beads, a ubiquitous component in amorphous lunar soils, to be a potential candidate for layer research or unidentified hydrated deposit in lunar soils.

He systematically characterized the petrography, the composition of the main elements, the abundance of water and the isotopic composition of hydrogen of the impact glass beads returned from CE5 missionwith the aim of identifying and characterizing the water reservoir that was missing on the lunar surface.

CE5 mission impact glass beads have Homogeneous chemical compositions and smooth exposed surfaces. They are characterized by an abundance of water up to about 2,000 micrograms.g-1, with extreme deuterium depletion characteristics. The negative agreement between the abundance of water and the isotopic composition of hydrogen reflects the fact that the water in the CE5 impact glass beads comes from the solar winds.

The researchers also look at the water abundance along six transects on five glass beads, showing the hydration profiles of water derived from solar winds. Some glass beads were overlaid by a subsequent outgassing event.

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impact glass beads acted like a sponge to buffer the water cycle on the lunar surface. The researchers estimate that the amount of water contributed by impact glass beads to lunar soils varies between 3.0*1011 kg and 2.7*1014 kg.

«These findings indicate that impact glasses from the surface of the Moon and other airless bodies in the solar system are capable of water deposits derived from the solar wind and release it into space,» says Professor HU.