20 December 2018
The image shows the 82-kilometre-diameter Korolev crater. It contains a 1800-metre-long glacier. It is extremely cold in Mars’ high northern latitudes – during the polar night, temperatures can fall well below minus 100 degrees Celsius. Some craters lying to the south of the permanent ice cap at the north pole become proper ‘cold traps’ that hold ice all year round, as the carbon dioxide atmosphere cools above the ice sheet, acting a little like an insulator. Frost and ice deposits have also formed along the two-kilometre-high crater rim, which sublimate over the course of the seasons, making the direct transition from solid to gas. The viewing direction is southeast to northwest.
ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO.
This image mosaic made up of images acquired by the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express spacecraft shows the well-preserved Korolev Crater on Mars, which is filled with water ice all year round. The crater was named after the renowned Russian rocket engineer and spacecraft designer Sergei Pavlovich Korolev. The HRSC camera on Mars Express is operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR). The systematic processing of the camera data took place at the DLR Institute for Planetary Research in Berlin-Adlershof. The working group of Planetary Science and Remote Sensing at Freie Universität Berlin used the data to create the image products shown here.
The 82-kilometre-diameter Korolev Crater was named after Sergei Pavlovich Korolev (1907–1966), the chief constructor and father of Russian space technology. Korolev developed the first Russian intercontinental rocket, R7, the precursor of the modern Soyuz rockets that are still used today. Korolev, who was known in his own country and in the West simply as the 'Chief Designer', anonymously oversaw the USSR's rocket programme, initially with the aim of developing intercontinental ballistic launchers for nuclear warheads, but with further applications for civil aviation. In 1957, Korolev put the first artificial satellite, Sputnik 1 (Russian for companion) in space via a Semyorka rocket during the International Geophysical Year, paving the way for the first manned space flight in 1961, with cosmonaut Yuri Gagarin on board the Vostok 1 space capsule. In the final years of his life, when he was already severely ill, Korolev devoted himself to developing the N1 launch vehicle, which allowed the Soviet Union to win the space race to the Moon ahead of the United States. His most famous saying was, "The simpler a design, the better. Anyone can build something complicated."
A year-round ice reservoir
Korolev impact crater is located in the northern lowlands of Mars, not far from the large dune field of Olympia Undae, which surrounds part of the north polar ice cap. The crater floor, which lies two kilometres beneath its rim, is covered in a 1.8-kilometre central mound of water ice all year round. This domed deposit forms a glacier comprising around 2200 cubic kilometres of non-polar ice on Mars. That is about 50 times the volume of Lake Constance and is comparable in size to the Canadian Great Bear Lake. This leads us to assume, however, that this quantity of ice is mixed with a certain amount of dust. Smaller amounts of water ice are distributed on and around the crater edge in the form of thin layers of frost.
At present, there is no liquid water on Mars, but there is a considerable quantity of ice. The planet's two polar caps consist of a mixture of carbon dioxide and water ice, which vary greatly in proportion to one another depending on the season. In winter, for instance, a one- to two-metre layer of carbon dioxide ice (dry ice) forms on the permanent ice cap at the north pole, but then sublimates again in summer, undergoing a direct transition from solid to gas. The changing expanses of the polar caps can be observed in detail using telescopes and satellite images. A considerable quantity of ground ice has also been detected in the Martian subsoil using radar measurements. The corresponding soil layer could be permeated by up to 50 percent frozen water. However, we do not have exact figures.
The water ice in Korolev Crater is permanently stable because the depression acts as a natural cold trap. The air above the ice cools down and is thus heavier than the warmer air around it. As air is a poor conductor of heat, it shields the ice from the environment. If it is immobile above the ice, little heating of the ice takes place via heat exchange, and the cold air protects the ice from warming and evaporation. Louth Crater, a similar crater with a smaller ice dome that is also located in the northern lowlands, was photographed by the HRSC back in February 2005. In this case, a layer of water ice formed against the dark dune field that lies on the crater floor. The dimensions are substantially smaller here: the ice cap of Louth Crater is 12 kilometres across, while the ice sheet in Korolev Crater can measure up to 60 kilometres.
The northern edge of Korolev Crater was also imaged by the CaSSIS camera on board the ESA ExoMars TGO probe on 15 April 2018 and was one of the first places on Mars to be photographed by the camera system, just days after the HRSC acquired images of the crater during orbit 18,042. ESA's ExoMars programme is devoted to searching for life on the Red Planet. It has two components: the ExoMars 2016 mission put the Trace Gas Orbiter (TGO) into Mars orbit, but fell short of the target of safely setting down the Schiaparelli landing demonstrator on the Martian surface. The second part of the ExoMars mission is planned for 2020, when a landing platform and a 2021 Rover are set to land in Oxia Planum on Mars’ highland-lowland border.
The mosaic consists of five orbit strips (18042, 5726, 5692, 5654, 1412) and covers a region 161.8 to 168.0 degrees East and 71.7 to 73.8 degrees North. Orbit 18,042 was captured on 4 April 2018. The resolution of the colour mosaic is approximately 21 metres per pixel. The colour mosaic was created using data from the nadir channels, the fields of view which are aligned perpendicular to the surface of Mars, and the colour channels of the HRSC. The oblique perspective view was generated from the digital terrain model, the nadir and colour channels of HRSC. The colour-coded topographic view is based on a digital terrain model (DTM) of the region, from which the topography of the landscape can be derived. The reference body for the HRSC DTM is a Martian sphere.
The High Resolution Stereo Camera was developed at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and built in collaboration with partners in industry (EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH). The science team, which is headed by Principal Investigator (PI) Ralf Jaumann, consists of 52 co-investigators from 34 institutions and 11 countries. The camera is operated by the DLR Institute of Planetary Research in Berlin-Adlershof.
Last modified:20/12/2018 11:20:16