When China’s Chang’E-5 probe visited the moon in December 2020, it didn’t just collect a sample of lunar material to return to Earth. While he was there, the mission made observations of the surrounding lunar rock – data vital to contextualizing the sample in future exploration.
These observations turned out to be a treasure. In spectroscopic images of the lunar regolith, scientists have found evidence of the existence of water on the moon.
According to measurements made with the Chang’E-5 lunar mineralogical spectrometer, water can be found in abundance up to 120 ppm in the Procellarum Northern Ocean, where the spacecraft has landed.
While we’ve seen evidence of water on the Moon before, it was either orbiting or passing spacecraft, or samples returned to Earth. This new evidence is the first to be obtained from on-site measurements.
The breakout confirms previous findings that the Moon may have relatively much water associated with minerals in the lunar regolith, the upper layer of dust and rubble on the Moon’s surface.
The abundance is incredibly dry by Earth standards, and extracting water will not be easy, so this does not mean that future missions to the Moon will have an available source of water.
But, interestingly, measurements of the Chang’E-5 boulder in its vicinity showed a higher water content – about 180 ppm.
This boulder is light and bubbly (pitted with many cavities), which is convincing evidence of its underground volcanic origin. In turn, this suggests that there may be an additional source of water in the bowels of the Moon.
“Compositional analysis and orbital remote sensing shows that rock can be extracted from an older basalt strata and ejected into the Chang’E-5 landing site,” explains geologist Honglei Lin of the Institute of Geology and Geophysics of the Chinese Academy of Sciences.
“Thus, the lower water content in the soil compared to the higher water content in the rock fragment may indicate degassing of the mantle reservoir under the ChangE-5 landing site.”
This interpretation is consistent with the history of the extensive volcanism of Oceanus Procellarum. This story was backed up by analysis of the Chang’E-5 sample returned to Earth, which showed that the region has been volcanically active for much longer than we previously thought.
In turn, this suggests that certain volcanic deposits may be necessary for human life support on long-term lunar bases in lower latitudes, where ice deposits are less likely to form.
Future studies of the rock’s water content will be required to determine if it is made up of water from the interior of the moon, the researchers said. They also hope that their results will be compared with future studies of the returned sample to learn more about water in the lunar regolith.
“It remains unclear whether the water we found is hydroxyl or molecular water,” they write in their article.
“Future research requires analysis of water and other volatiles, as well as the composition of hydroxyl and molecular water of lytic fragments of vesicular rocks in returned samples.”
The study was published in Scientific achievements…