The Poles of the Moon

The lunar poles feature a microenvironment that is almost entirely unknown to planetary science. Because of the very small tilt of the Moon’s axis with respect to the Sun, craters and other depressions near the poles are permanently shaded from direct sunlight. As a consequence, these surfaces should have maintained extremely low temperatures, well under 100 K, for billions of years. There is some evidence that these surfaces act as cold traps, capturing and sequestering volatiles from the Moon and elsewhere. Most popular attention has focused on the possible presence of water ice that might be used by astronauts in the future, but the poles may offer a unique scientific resource. Possible sources for volatiles at the lunar poles range from the Sun to interstellar clouds, and if present, such volatile deposits may provide unique information about many aspects of planetary science.