Shackleton is an
impact crater that lies at the
south pole of the
Moon. The peaks along the crater's rim are exposed to almost continual sunlight, while the interior is perpetually in shadow (a
Crater of eternal darkness). The low-temperature interior of this crater functions as a cold trap that may capture and freeze
volatiles shed during
comet impacts on the Moon. Measurements by the
Lunar Prospector spacecraft showed higher than normal amounts of
hydrogen within the crater, which may indicate the presence of water ice. The crater is named after
Antarctic explorer
Ernest Shackleton.