The European Space Agency’s (ESA) Mars Express beamed back images of the Red Planet’s Korolev crater covered with what appears to be a large patch of fresh, untrodden snow.
Several stunning photographs, which the agency labelled “a winter wonderland on Mars”, depict the crater, located 82 km across and found in the northern lowlands of the planet.
It is an especially well-preserved example of a martian crater, according to ESA and its snowy contents is actually a mound of water ice at least 1.8 km thick, which lies in the crater all year round.
The icy mass is due to a phenomenon called a “cold trap”. This crater’s floor lies as far as 2 km below its rim and the very deepest parts of Korolev crater, which contain ice, act as a natural cold trap.
Air moving over the deposit of ice cools down and sinks, creating a layer of cold air that sits directly above the ice itself, according to ESA.
Acting as a shield, this layer helps the ice remain stable and stops it from heating up and disappearing.
Air is a poor conductor of heat, which exacerbates this effect and keeps Korolev crater in a permanently icy state, the space agency added.
These snowy photographs are not the only link between ESA’s Mars Express mission and Christmas — the satellite fired its main engine and entered orbit around the Red Planet on December 25.
This month marks the 15-year anniversary of the spacecraft’s orbit insertion and the beginning of its science programme.
The ESA called the photographs a “celebration” of this milestone. Taken with the Mars Express High-Resolution Stereo Camera (HRSC), the main picture of Korolev crater comprises five different ‘strips’ that have been combined to form a single image, with each strip gathered over a different orbit.