Korolev is an ice-filled impact crater in the Mare Boreum quadrangle of Mars, located at 73° north latitude and 165° east longitude. It is 81.4 kilometres (50.6 mi) in diameter and contains about 2,200 cubic kilometres (530 cu mi) of water ice, comparable in volume to Great Bear Lake in northern Canada. The crater was named after Sergei Korolev (1907–1966), the head Soviet rocket engineer and designer during the Space Race in the 1950s and 1960s.
Korolev crater is located on the Planum Boreum, the northern polar plain which surrounds the north polar ice cap, near the Olympia Undae dune field. The crater rim rises about 2 kilometres (1.2 mi) above the surrounding plains. The crater floor lies about 2 kilometres (1.2 mi) below the rim, and is covered by a 1.8 kilometres (1.1 mi) deep central mound of permanent water ice, up to 60 kilometres (37 mi) in diameter.
The ice is permanently stable because the crater acts as a natural cold trap. The thin Martian air above the crater ice is colder than air surrounding the crater; the colder local atmosphere is also heavier so it sinks to form a protective layer, insulating the ice, shielding it from melting and evaporation. Recent research indicates that the ice deposit formed in place within the crater and was not previously part of a once-larger polar ice sheet. The ice in the crater is part of the vast water resources at Mars poles.
See The Wikipedia article on Korolev.