NASA has officially confirmed the presence of water on the light side of the Moon and is now working on mapping out just how much water is available and how to access it.
Using the Stratospheric Observatory for Infrared Astronomy (SOFIA), scientists detected water molecule wavelengths in a massive crater on the Moon’s southern hemisphere. Results published in the October 2020 issue of Nature Astronomy suggest that a cubic meter of lunar soil could be holding around 100-412 parts per million (approx. 12 ounces) of water.
“We had indications that H2O, the familiar water we know, might be present on the sunlit side of the Moon,” said Paul Hertz, Director of NASA’s Astrophysics Division in the Science Mission Directorate, in a press release. “Now we know it is there.”
But what do these findings mean for the future of space travel? Discovering water on the Moon is somewhat akin to discovering oil on Earth. A valuable and useable resource right there where we need it (without the need for transport from Earth) could cut the cost of space exploration significantly.
A water-coated Moon essentially becomes an orbital gas station. When water molecules are broken up into oxygen and hydrogen, cooled to liquid form, and funneled into a rocket together, an exothermic reaction generates extreme heat and energy for powerful propulsion.
In addition, a single astronaut needs around 100 gallons of water per day for drinking, cooking, and bathing. Currently, it costs around $8.35 million (around $10,000 per pound) for a rocket to carry 100 gallons of water from Earth into orbit – plus an additional amount to put it on the Moon.
NASA is working to cut the cost of transporting water to just $1,000 per pound, but it’s still a steep tab. Discovering water on the lunar surface itself is therefore incredibly valuable for Moon exploration and human habitation.
Interestingly, the observation that these molecules exist in sunlight is novel. Most observations of water-like molecules on the Moon are made along the poles and in shadowed areas that are never exposed to sunlight – areas that would be more difficult to mine. But SOFIA found water molecules in Clavius Crater on the sunlit side of the Moon.
Previously, scientists thought water would evaporate in sunlit areas that can reach 120oC during the day. But Casey Honniball, NASA Goddard Space Flight Center Postdoctoral Program Fellow and head author of the Nature Astronomy paper, suggests that the water molecules are stable here because they exist in a “trapped” state.
“Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space,” said Honniball. “Yet somehow we’re seeing it. Something is generating the water, and something must be trapping it there.”
“We believe the water is being stored inside the micro meteorite impact glass beads, and these would shelter the water from being lost to space or migrating to the lunar pole,” Honniball said. “And this would mean that without a lunar atmosphere the water could stay on the surface of the Moon.”
How did the water get there? Scientists suggest it may be the result of micrometeorites carrying water and impacting the lunar surface. In addition, oxygen in the lunar soil could be reacting with hydrogen from solar winds and radiation from micrometeorite collisions.
We still don’t know exactly how much water may be present on the Moon, where or how deep the water is, and how difficult it would be to extract. But the recent discovery has made lunar mining a hot topic among aerospace and drilling companies alike.
In preparation for the upcoming Artemis mission, NASA has chosen the Houston-based company Intuitive Machines to deliver a massive lunar drill to help harvest Moon ice. The Polar Resources Ice Mining Experiment (PRIME-1) drill is scheduled to arrive on the Moon by December 2022.
NASA plans to follow up by launching its Volatiles Investigating Polar Exploration Rover (VIPER) in late 2023 to create maps of Moon water resources and learn more about accessibility.
“The VIPER mission will give us surface-level detail of where the water is and how much is available for us to use, says NASA’s project overview. “This will bring us a significant step closer towards NASA’s ultimate goal of a sustainable, long-term presence on the Moon – making it possible to eventually explore Mars and beyond.”