Today is the first day of winter. For the Northern Hemisphere, that means it’s high time to get outside, head for the snow, and take in the frigid beauty of our planet’s rugged mountain landscapes.
But Earth isn’t the only planet offering such vistas. Thanks to a gorgeous image shared by the European Space Agency (ESA), we humans can also appreciate an icy formation on Mars. Created by piecing together five photograph strips taken by the Mars Express Orbiter, the stunningly high-resolution picture shows a vast body of frozen water contained in the Korolev crater.
Located in the Red Planet’s northern lowlands, just south of the northern Polar cap, Korolev is an exceptionally well-preserved impact crater about 51 miles (82 kilometers) wide and 1.2 miles (2 kilometers) deep, from rim to floor. The icy reservoir inside is estimated to be nearly 1.1 miles (1.8 kilometers) thick at its central point.

The ice stays frozen throughout the planet’s seasons due to a phenomenon known as a cold trap. When molecules in the atmosphere pass over the reservoir, they are chilled by contact with the ice, and thus condense and sink downward. Water has a very high specific heat capacity compared to most elements and other naturally occurring compounds, so the ice will cool the air more than the air will warm the ice. As a result, the crater is permanently covered with a cap of cold air, and because the gases within are poor heat conductors, even when the atmosphere around the cold trap warms significantly, the temperature of the area around the ice hardly fluctuates.
Korolev crater is named after famed Soviet rocket designer Sergei Korolev, who is considered to be the founder of the Soviet space program. Born in modern-day Ukraine in 1906, Korolev studied in Kiev and Moscow before helping form the Jet Propulsion Research Institute. After surviving imprisonment and torture under Stalin’s Great Purge, Korolev was commissioned into the army and, alongside a small group of other similarly trained engineers, tasked with recovering hardware and blueprints for German V-2 rockets from post-war occupied East Germany. The scientist and his colleagues then applied their findings and expertise to the Soviet missile program.
Korolev then led the development of the R-7 booster rocket and the Sputnik and Vostok mission spacecraft, including the 3KA capsule used in the first manned spaceflight in 1961. Variations of the R-7, which was based on Korolev’s design for the world’s first intercontinental missile, were used in nearly every Soviet space launch. The Soyuz rockets still in use by the Russian space agency also trace their lineage to the R-7.