The polar night near Mars's South Pole has ended, and sunlight is once again illuminating the slopes of the high-latitude southern landscapes – the region known as Australe Scopuli. Situated between 83 and 86 degrees south, this area presents a typical late-winter scene, captured by the DLR High Resolution Stereo Camera (HRSC) from an altitude of approximately 350 kilometres, with a resolution of 15 metres per pixel. The polar landscape reveals alternating layers of light-coloured carbon dioxide and water ice interspersed with dark sands. At the end of winter, gas fountains pierce the CO₂ ice in many places, carrying dust to the surface, where it is deposited on the ice. The perspective view image is approximately 20 kilometres wide at its centre.
Australe Scopuli is a hilly polar landscape where deposits of water and carbon dioxide ice (CO₂) alternate with darker sand. Thin lines and circular formations clearly reveal the layered nature of these sediments. In the colour view captured by Mars Express, faint orange tones appear in the northern part of the image (right side; the north-south extent of the scene is approximately 330 kilometres). These tones are caused by reddish Martian dust blown on to the ice surface. In contrast, the left side of the image is dominated by numerous dark fan-shaped deposits, which appear here as small, thin spots. These fans are aligned with the prevailing winds and range in length from a few dozen metres to several hundred metres. The fan-shaped structures only emerge at the end of the austral winter in Australe Scopuli.
The polar landscape of Australe Scopuli, located between 83 and 86 degrees south, features alternating layers of light-coloured carbon dioxide and water ice interspersed with dark sands and dust. This image was captured at the end of the austral winter. As sunlight returns after the polar night and begins to warm the ice and the surfaces it covers, fountains of carbon dioxide gas break through the upper ice crust in many places, carrying dust to the surface. This dust is then deposited on the ice. Soon, only the permanent South Pole ice cap – located further south and spanning a diameter of 400 kilometres – will remain. The width of the image in the perspective view is approximately 25 kilometres at its centre.
New images from the German High Resolution Stereo Camera (HRSC) reveal Australe Scopuli in winter.
The region is characterised by layered deposits and remnants of gas plumes that have transported dark sand to the surface.
25 December 2024 will mark 21 years since the European Mars Express mission arrived at the Red Planet.
Focus: Spaceflight, Mars, HRSC stereo camera
Of all the times of the year when it could happen, it was Christmas Day when the European spacecraft Mars Express entered orbit around our neighbouring planet in 2003. Shortly afterwards, the High Resolution Stereo Camera (HRSC) began its work on board the orbiter. To date, the instrument, developed and operated by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), has captured countless spectacular images of the Martian surface. The latest release showcases a wintery scene in the southern polar region.
Fan-shaped structures of dark sand
Australe Scopuli is a hilly polar landscape where deposits of water and carbon dioxide (CO2) ice alternate with layers of darker sand. Thin lines and circular formations clearly reveal the layered nature of these sediments. In the true-colour view from above, faint orange tones appear in the northern part of the image (right side), originating from reddish Martian dust blown on to the ice surface. In contrast, the left side of the image is dominated by numerous dark, fan-shaped deposits, aligned with the prevailing winds. These features vary in length from a few dozen metres to several hundred metres.
Overview map of the Australe Scopuli region at the South Pole
The DLR High Resolution Stereo Camera (HRSC) on board ESA's Mars Express mission captured this image of part of the Australe Scopuli region during orbit number 23,324 (indicated by the large box). The specific images and landscape features presented here are located within the smaller box. Australe Scopuli lies at the outer edge of Mars's permanent southern ice cap, which spans a diameter of approximately 400 kilometres. During the six-month winter in Mars's southern hemisphere, the thin seasonal ice and frost cover extends as far as around 50 degrees latitude.
Credit:
NASA/PL (MOLA Science Team); FU Berlin (using GMT4)
The fan-shaped structures only appear at the end of winter in Australe Scopuli. They are formed by gas plumes that transport dark sand to the surface through the carbon dioxide ice layer that covers the landscape during the winter. This phenomenon occurs at the beginning of spring, when sunlight penetrates the transparent carbon dioxide ice and warms the deposits below it. The ice sublimates, causing pressure beneath the surface to increase until it breaks through in the form of jets, bringing dust to the surface along with gas. The resulting fan-like deposits are often compared to spiders and are known as araneiform formations. The extent of their activity is determined by the intensity of solar radiation.
More sun, more gas eruptions
Interestingly, the fans often appear to align with the layer boundaries of the interbedded polar deposits. These boundaries are likely to represent zones of weakness, where sand- and dust-laden carbon dioxide eruptions can more easily break through the seasonal ice sheet. Some areas are particularly dark due to the high concentration of fan deposits. Here, the seasonal carbon dioxide ice cover has almost completely vanished, revealing the dark material that lay beneath it across a large area.
(3D) Anaglyph image of the Australe Scopuli region
Anaglyph images are produced by combining data from the nadir channel – which looks vertically down onto the Martian surface – with data from one of the four stereo channels of the High Resolution Stereo Camera (HRSC), operated by DLR. When viewed with red-blue or red-green glasses, these images provide a three-dimensional perspective of the landscape, offering a spatial sense of elevation differences. Such images are particularly useful for examining subtle topographical features, as seen here in the Australe Scopuli region, located approximately five degrees north of the Martian South Pole. The Latin word scopuli means hill, slope, or even cliff – though this area is characterised by gentle terrain rather than steep features. The 3D view clearly highlights the layered structure of ice and dust that defines this polar landscape.
Appropriately for the current season on Earth, the 3D view is reminiscent of terrestrial ski resorts. However, hypothetical Martian skiers would need to dress far warmer than those in the Stubai Valley or at Lillehammer – during the Martian polar night, temperatures can plummet to minus 130 degrees Celsius. However you choose to spend the upcoming holidays, DLR wishes you a peaceful festive season and a happy new year! Meanwhile, on 25 December 2024, ESA's Mars Express orbiter and the DLR-operated HRSC will celebrate the 21st anniversary of their arrival in Mars's orbit.
Image processing
The images were taken by the HRSC during Mars Express Orbit 23,324. The ground resolution is approximately 15 metres per pixel, and the image is centred at 239 degrees east and 84 degrees south. The colour image was created using data from HSRC's nadir channel, whose field of view is perpendicular to the Martian surface, and colour channels. The oblique perspective view was created using a digital terrain model (DTM), HSRC's nadir channel and the colour channels. The anaglyph image, which conveys a three-dimensional impression of the landscape when viewed with red/blue or red/green glasses, was derived from the nadir channel and one stereo channel. The colour-coded view is based on a DTM of the region, from which the topography of the landscape can be derived. The reference unit for the HRSC-DTM is an equipotential surface of Mars (areoid).
Downloads
To download the released raw images and Digital Terrain Models (DTM) of the region in GIS-compatible formats, follow this link to the map server
The High Resolution Stereo (HRSC) was developed at the German Aerospace Center (DLR) and built in cooperation with industrial partners (EADS Astrium, Lewicki Microelectronic GmbH and Jena-Optronik GmbH). The science team, led by Principal Investigator (PI) Daniela Tirsch from the DLR Institute of Planetary Research, consists of 52 co-investigators from 34 institutions and 11 nations. The camera is operated by the DLR Institute of Planetary Research in Berlin-Adlershof.
