Water on the Moon likely accumulated gradually over billions of years rather than arriving in a single large event, according to a new study by an international team of planetary scientists. The research, which involved Paul Hayne, a planetary scientist at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado Boulder, points to specific regions near the lunar poles as the most probable locations where water ice is preserved today.
The study highlights that permanently shadowed regions (PSRs) — craters and other areas near the Moon's poles that never receive direct sunlight — are the most likely reservoirs for water ice. These cold traps can maintain temperatures low enough to preserve ice for billions of years, making them prime targets for future lunar exploration missions.
The researchers modeled how water molecules migrate across the lunar surface after being delivered by sources such as comets, asteroids, and the solar wind. Their findings suggest that water gradually accumulates in these cold polar traps over geological timescales, rather than being deposited all at once by a single large impactor or volcanic event.
The findings carry significant implications for upcoming crewed lunar missions, including NASA's Artemis program, which aims to establish a sustained human presence near the Moon's south pole. Accessible water ice could be used for drinking water, oxygen production, and rocket propellant, making it a critical resource for long-term lunar exploration. Scientists caution, however, that the exact quantity and accessibility of lunar water ice remain uncertain and will require direct surface investigation to confirm.
