Chang’E-5 samples reveal high water content in lunar minerals

Abstract

The formation and distribution of lunar surficial water remains ambiguous. Here, we show the prominence of water (OH/H2O) attributed to solar wind implantation on the uppermost surface of olivine, plagioclase, and pyroxene grains from Chang’E-5 samples. The results of spectral and microstructural analyses indicate that solar wind-derived water is affected by exposure time, crystal structure, and mineral composition. Our estimate of a minimum of 170 ppm water content in lunar soils in the Chang’E-5 region is consistent with that reported by the Moon Minerology Mapper and Chang’E-5 lander. By comparing with remote sensing data and through lunar soil maturity analysis, the amount of water in Chang’E-5 provides a reference for the distribution of surficial water in middle latitude of the Moon. We conclude that minerals in lunar soils are important reservoirs of water, and formation and retention of water originating from solar wind occurs on airless bodies.

A solar wind-derived water reservoir on the Moon hosted by impact glass beads

“…However, finding this water reservoir has remained elusive, despite several studies having investigated the water inventory of fine mineral grains in lunar soils (for example, refs. 34,35 ), impact-produced agglutinates 27 , volcanic rocks (for example, ref. 26 ) and pyroclastic glass beads 21,36 .…”

“…Importantly, this estimate provides a minimum quantity of water available at the lunar subsurface as it does not take into account the water contribution from permanently shadowed regions [4][5][6]11 , indigenous lunar rocks (for example, ref. 26 ), delivery by meteoritic impacts 13,27 and solar wind-derived water preserved in the space-weathered rims of lunar soils 34,35 . These findings indicate that the lunar soils contain a much higher amount of solar wind-derived water than previously thought, which could be a water reservoir for in situ utilization in future lunar exploration.…”

Dependences of Energetic Neutral Atoms Energy on the Solar Wind Energy and Solar Zenith Angle Observed by the Chang’E-4 Rover

“…In such an interaction, about 0.1%-1% of solar wind protons are directly scattered as protons (Saito et al 2008), and around 10%-20% of solar wind protons are scattered as energetic neutral atoms (ENAs) as they capture an electron during their interaction with the surface (McComas et al 2009;Wieser et al 2009). The left part of solar wind protons are implanted into the lunar regolith, providing an important source for the formation of OH/H 2 O on the lunar surface (Xu et al 2022;Zhou et al 2022), which shows diurnal variations with higher concentrations near the polar regions (Watson et al 1961a(Watson et al , 1961bSunshine et al 2009;McCord et al 2011;Li & Milliken 2017). Additionally, some lunar surface components can be released from the surface by solar wind sputtering, contributing to the tenuous lunar exosphere (Wurz et al 2007;Sarantos et al 2012;Vorburger et al 2014).…”

Rapid detection and identification of rocks and minerals by laser‐induced breakdown spectroscopy

“…The study of rocks plays an important role in the exploration of terrestrial planets 1,2 . At present, the plan of extraterrestrial exploration will include sample collection and returning to earth 3 . The exploration of rock samples of rocky planets outside the Earth costs a lot of resources.…”

“…1,2 At present, the plan of extraterrestrial exploration will include sample collection and returning to earth. 3 The exploration of rock samples of rocky planets outside the Earth costs a lot of resources. At present, the methods of rock sample analysis include the analysis of rock cleavage commonly used in geological exploration and the chemical analysis used in the laboratory.…”