The CaSSIS camera onboard the ExoMars Trace Gas Orbiter captured remnant frost deposits in a region near Sisyphi Tholus, in the high southern latitudes of Mars (74ºS/246ºE). This image was taken during the early morning of a midsummer day in the southern hemisphere. At these high latitudes, carbon dioxide ice and frost develop. Frost can be seen within polygonal cracks in the terrain, a feature that indicates the presence of water ice embedded in the soil. The black spots observed throughout the scene are due to dark soil being pushed through cracks in the carbon dioxide ice as it sublimates – turns directly from solid ice to vapour – in the summer months.

The scale is indicated on the image.

The ExoMars programme is a joint endeavour between ESA and Roscosmos.