Chinese scientists have developed a novel method to produce water on the moon, a resource that is scarce in the lunar environment, in support of eventual permanent human settlement.
The harsh, barren landscape of the moon is one of the greatest challenges to human activity on Earth’s closest celestial neighbor. Establishing a reliable source of water, which is essential for human life, marks a significant step toward colonization.
Water on the Moon
Initial analysis of samples brought back by the Apollo missions led scientists to believe that the moon was dry. However, subsequent lunar missions, such as Cassini and Deep Impact, revealed the presence of water on the moon. Lunar regolith contains minimal water concentrations, sometimes as low as ten parts per million. While scientists theorize that an unknown amount of water exists on the moon, locating, extracting, and purifying it into potable water remains a series of challenges that have yet to be overcome.
To bypass these complex extraction processes, a team led by Prof. Wang Junqiang explored the possibility of producing pure water by combining the moon’s existing hydrogen, implanted by solar winds, with oxygen already present in the regolith. The 2020 Chang’E-5 (CE-5) Chinese lunar mission, which landed in the Oceanus Procellarum basin—a high-altitude area of the moon rich in hydrogen—provided the perfect environment to test this hypothesis.
Making Water with Heat
The Chinese team discovered that the CE-5’s regolith samples contained significant amounts of both solar hydrogen and oxides. However, due to the relatively young age of the samples, there had not been enough time for significant hydrogen and oxygen reactions to occur, leaving the sample with a dry 283 ppm water content. The team then developed a method to induce an endogenous reaction to increase this moisture ratio. Prof. Wang stated, “We used lunar regolith samples brought back by the Chang’E-5 mission in our study, trying to find a way to produce water on the Moon.”
The regolith samples contained two iron oxides, FeO and Fe₂O₃, which held the oxygen. By heating the material to over 1200 K, the team generated water as iron separated from the iron oxides in the regolith, allowing oxygen to combine with hydrogen. This reaction produced crystallized iron dendrites and H₂O bubbles. The experiments yielded between 51 and 76 milligrams of water from 1 gram of regolith—approximately 10,000 times the original water content. FeTiO₃ was the most effective oxide for this process, as its particular lattice structure retains the most oxygen.
Producing Life’s Most Crucial Ingredient for the Future
Humanity views a permanent lunar installation as a stepping stone toward greater cosmic endeavors, such as landing a human on Mars. This new water production process brings that goal one step closer to reality. One ton of regolith can produce 50 kg of water, equivalent to 100 bottles, which can supply a day’s worth of water for 50 people.
However, drinking water is just one potential use. This water could also be used to irrigate crops, supporting a potential lunar food system. Furthermore, the water could be separated into its constituent elements—hydrogen and oxygen—providing oxygen for breathing and hydrogen for energy. Prof. Wang’s team may have laid the foundation for a completely sustainable lunar ecosystem.
The new paper “Massive Water Production from Lunar Ilmenite through Reaction with Endogenous Hydrogen” was published in The Innovation on August 22, 2024.
Ryan Whalen covers science and technology for The Debrief. He holds a BA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.