From a Wall Street Journal story by Eric Niiler headlined Locked in Tiny Glass Beads”:
The moon’s surface contains a new source of water found embedded in microscopic glass beads, which might one day help future astronauts produce drinking water, breathable air and even rocket fuel, scientists say.
The findings come from a Chinese rover that spent two weeks on the moon in 2020. The Chang’e 5 rover drilled several feet into the lunar surface and returned 3.7 pounds of material, among which were the glass beads from an impact crater, according to a paper published Monday in the journal Nature Geoscience.
The moon’s surface is covered with tiny spherical beads of silicate glass, which range in size from a few tens of micrometers to a few millimeters. Some of the glass beads formed when asteroids slammed into the moon, others are the result of ancient volcanic activity on the lunar surface, both of which occurred millions of years ago.
In their Beijing laboratory, scientists from Chinese institutions examined a handful of the microscopic spheres using a special instrument called a secondary ion mass spectrometer that analyzes solid surfaces with a beam of ions, and discovered water embedded inside, according to the study.
The water is the result of a chemical reaction between oxygen in the beads and hydrogen atoms emitted from the sun that are transported to the moon’s surface by solar winds and deposited into the soil.
While the amount of water is tiny in each bead, there are a lot of beads on the moon—enough for an estimated 270 trillion kilograms of water, according to the study. That is the equivalent of 71 trillion gallons.
“Our direct measurements of this surface reservoir of lunar water show that impact glass beads can store substantial quantities of solar wind-derived water on the moon and suggest that impact glass may be water reservoirs on other airless bodies,” the authors wrote.
The researchers think other moons in the solar system might also have such a water reservoir.
“Maybe it is a common feature in our solar system and a way to understand other worlds,” said Sen Hu, a professor at the Institute of Geology and Geophysics at the Chinese Academy of Sciences in Beijing and an author on the paper.
The water found in tiny glass beads isn’t the only source of water on the moon. Water ice is also hidden in the permanently shadowed craters on the moon’s north and south poles. That is where both the National Aeronautics and Space Administration and China are planning to put future moon bases. In 2020, astronomers using an infrared telescope aboard a highflying NASA aircraft detected the presence of water locked inside lunar grit on a sunny section of the lunar surface.
To get the new source of water, future astronauts would have to figure out how to collect the beads that have water, and then heat them up to about 100 degrees Celsius, or about 212 degrees Fahrenheit, according to Dr. Hu.
Dr. Hu said impact beads brought back by the NASA Apollo missions had about 47 parts per million of water. However after examining beads returned in 2020 by the Chinese rover, the team found a higher water content, as much as 2,000 parts per million.
The researchers’ findings on the formation of water in the beads are accurate, according to Rhonda Stroud, director of the Buseck Center for Meteorite Studies and professor of earth and space exploration at Arizona State University. Dr. Stroud wasn’t involved in the study.
“I think their methods are good, they did their work carefully, so I think the measurements are pretty reliable,” said Dr. Stroud. “It definitely adds to our inventory of materials on the moon that we know contain water.”
A NASA spokeswoman said the agency doesn’t comment on scientific publications outside of the agency. Congress has prohibited NASA from working with China since 2011 because of past security concerns.
NASA hasn’t been to the moon’s surface since astronaut Gene Cernan left on Dec. 14, 1972. NASA’s Artemis program plans to orbit U.S. astronauts around the moon in 2024, and land them sometime afterward.
The missions of the Chang’e 5 rover consisted of four separate vehicles that allowed it to land on the moon, return a capsule from the rover to an orbiting spacecraft, return to Earth and then land the sample at a site in Mongolia.
The lander carried three scientific payloads, including cameras to check the landing site, ground-penetrating radar, and a spectrometer to analyze the minerals of the lunar surface, according to the Planetary Society, an Arizona-based scientific organization. The Chang’e 7 rover is scheduled to launch to the moon’s south polar region in 2026.
“They are certainly kicking our butts in robotic sample return at the moment,” Dr. Stroud said about the current Chinese lunar program. “But Artemis will bring back samples. It just takes longer when you do it with humans.”
Eric Niiler covers climate, ocean and Earth sciences for The Wall Street Journal. He is also following emerging applications of artificial intelligence in scientific and medical research. He joined the Journal from Wired, where he was a contributing science writer. His print and radio career has taken him from Iraq to Antarctica where he filed reports for National Geographic, the Washington Post and NPR.