Korolev crater is located in the northern lowlands of Mars, south of the large Olympia Undae dune field that partly surrounds Mars’ north polar cap. The crater is filled with water ice all year round.
Using an image mosaic made from single orbit observations from the High-Resolution Stereo Camera (HRSC) on Mars Express, ESA has created a movie showing the 82 km wide Korolev crater on Mars.
The mosaic combines data from the HRSC nadir and color channels; the nadir channel is aligned perpendicular to the surface of Mars as if looking straight down at the surface. The mosaic image was then combined with topography information from the stereo channels of HRSC to generate a three-dimensional landscape, which was later recorded from different perspectives, as with a movie camera, to render the flight shown in the video.
In Korolev crater, water is permanently stable as the profound part of this depression acts as a natural cold trap. The air above the ice cools and is thus heavier compared to the surrounding air: since air is a poor conductor of heat, the water ice mound is adequately shielded from heating and sublimation.
This ever-icy presence is due to an interesting phenomenon known as a ‘cold trap,’ which occurs as the name suggests. The crater’s floor is deep, lying some two kilometers vertically beneath its rim.