Water on the Moon

Abstract Samples returned from the Moon during the Apollo era contain only trace amounts of hydrogen; they are extremely “dry” and, more generally, depleted of volatiles. However, in permanently shadowed craters near the Moon’s rotational poles, temperatures are so low that the sublimation rate of water ice into space becomes negligible. It is in these regions that ice could have accumulated and remained preserved over geologic timescales. Molecular water, especially in concentrated form as ice, is of interest to scientific exploration as well as a resource for sustained human presence on the Moon.