(CN) — Future lunar explorers could get water from glass beads.
Specifically, the impact glass beads scientists extracted from the soils that China's Chang’e 5, or CE5, lunar mission collected. The beads are “the quenched mixture of lunar surface material produced by meteorite or micrometeorite impact on the moon,” study author Sen Hu, professor at the Chinese Academy of Sciences, said via email.
Hu, along with Hejiu Hui of Nanjing University and their colleagues, reported their research in a Nature Geoscience study published Monday, which indicates that the impact glass beads have a solar wind origin.
The researchers said that the CE5 beads' precursor materials likely lost most of their original water content when the beads formed at high temperature. Then, at temperatures nearing 188 degrees Fahrenheit, the researchers' diffusion modeling indicates that the solar wind-derived water took between one to 15 years to diffuse into the impact glass beads.
One bead called CE5#33,036 caught the scientists' attention because it displayed "notable post-diffusion water loss at the very rim, suggesting that CE5 impact glass beads have the capacity of both incorporating solar wind-derived water and releasing it to the lunar exosphere if [temperature] increases," showing a connection to the lunar water cycle, according to the study.
The researchers also found that CE5 impact glass beads contained a higher bulk water abundance than CE5 mare basalts, or igneous rocks. Considering how the daily temperature of the moon’s surface – varying between -292.3 F and 301.7 F – is not high enough to drive the hydroxyl out of the mare basalts' apatite, the researchers said the impact glass beads are “probably the dominant reservoir involved in the lunar surface water cycle, except for the space-weathered rims and possibly water ice in polar regions.”
That said, the scientists believe a separate lunar water reservoir exists. Hu wrote that the “lunar surface water displays a spatio-temporal oscillation feature, indicating that there are some targets in lunar soils that are able to sustain the dynamic variation of water...detected on the lunar surface by many missions.”
Because major components in lunar soils such as basaltic samples and fine-grained soils cannot explain the lunar cycle, the researchers believe that there should be an unidentified reservoir “to sustain the lunar surface water cycle or the hypothesis of lunar surface water cycle may not be true.”
While the search for the unidentified lunar reservoir continues, Hu believes the impact glass beads could provide a means of attaining water for future lunar missions because they provide an alternative path for future in-situ water utilization as “some glass beads have released their entrapped water into space” and because they are a "common phase in lunar soils."
“We believe that impact glass beads in Apollo and Luna lunar soils have the same feature as what we find in CE5 lunar soils,” Hu wrote. “We hope other researchers can carry out parallel studies on those samples. The more detailed studies of how the impact glass beads buffer the lunar surface water cycle could shed light on better understanding the dynamics of the lunar water cycle.”
If successful, Hu says that future lunar explorers can collect the impact glass beads, heat them to more than 212 F, cool them to release vapor and have some water ready to go.
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