Moon Water
The moon is a lot wetter than we thought. That’s the conclusion of scientists who used data gathered by India’s first lunar mission to determine there may be widespread moisture locked in lunar soils.
The upper few millimeters of the moon’s surface contains molecules of water, or H2O, and hydroxyl (OH) -- an indication that water formation may be an ongoing process at the moon’s surface, the researchers said today in the journal Science.
“When we say ‘water on the moon,’ we are not talking about lakes, oceans or even puddles,” the study’s lead author, Carle Pieters, a planetary geologist at Rhode Island’s Brown University, said. “Water on the moon means molecules of water and hydroxyl that interact with molecules of rock and dust specifically in the top millimeters of the moon’s surface.”
The findings open the way for astronauts on lunar missions to harvest water from the moon’s surface, according to the paper. The National Aeronautics and Space Administration on June 18 launched two probes to search for frozen water on the moon.
Discovering the substance would be like finding a goldmine, the agency said at the time, putting the cost of transporting a bottle of water to the moon at $50,000.
“NASA wants to set up a permanent base on the moon, and they want to live off the land,” Colin Pillinger, professor of planetary science at the U.K.’s Open University in Milton Keynes said today in a phone interview. “To do that, they need water.”
Polar Ice
Pillinger, who this year co-wrote a study for NASA about extracting water and other compounds from the lunar surface, said that physical samples will be needed to prove the conclusions from today’s study, and that extracting water will be a challenge.
“Technically it’s easy, but logistically it’s awfully difficult because it takes a lot of energy,” Pillinger said. “If you want a long-term lunar base, then you go to the poles,” because no refrigerator will be necessary to condense water vapor that has been boiled out of the soil, he said.
Craters at the lunar poles haven’t been exposed to sunlight in billions of years and probably have temperatures of minus 328 degrees Fahrenheit (-200 degrees Celsius), according to NASA. That has led planetary scientists to theorize water ice may be present in those dark areas.
As many as 770 water molecules could be present in every million molecules in the thin top layer of the moon’s soil, according to today’s paper. Brown University said in a statement the proportion could be as high as 1,000 per million. The data was gathered by the Moon Mineralogy Mapper instrument aboard India’s Chandrayaan-1 craft.
Moon’s Topsoil
The researchers concluded the most likely origin of the water is as a result of the so-called solar wind, laden with charged hydrogen particles, impacting with the oxygen-rich lunar soil.
The mapper instrument, called M3, analyzed the way sunlight reflects off the lunar surface to determine the materials that constitute the soil, according to a statement from the University of Tennessee at Knoxville, which participated in the study.
Crashed Probe
NASA’s Lunar Prospector craft in 1998 detected hydrogen near the pole, prompting speculation that water was present. A year later, the agency deliberately crashed the craft into the moon’s surface, hoping to detect water vapor in the resulting dust plume, without success.
Trace amounts of water detected in rocks shipped back from the moon by Apollo missions 40 years ago were attributed to contamination from the Earth’s air because the boxes housing the samples had leaks, according to the University of Tennessee.
“The isotopes of oxygen that exist on the moon are the same as those that exist on Earth, so it was difficult if not impossible to tell the difference,” Larry Taylor, a co-author of today’s paper, said in the university’s statement. “Since the early soil samples only had trace amounts of water, it was easy to make the mistake of attributing it to contamination.”
Last year, researchers at Brown analyzed volcanic glasses recovered by the Apollo 15 mission, finding evidence of water, which they said must have had its origins deep inside the moon.
The Indian “moon craft” was designed to orbit the moon for two years at an altitude of 100 kilometers (62 miles). Scientists in the southern Indian city of Bangalore lost contact with it on Aug. 29 after 315 days in orbit.
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