22. December 2022
Mission Mars Express

Mar­tian win­ter won­der­land – swirling snow in Ul­ti­mi Scop­uli

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Late winter landscape near the south pole of Mars
Late win­ter land­scape near the south pole of Mars
Image 1/6, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Late winter landscape near the south pole of Mars

While those of us in Cen­tral Eu­rope have to do with­out a snowy win­ter in many places al­most ev­ery year, on Mars we can re­ly on frosty, white pre­cip­i­ta­tion far in­to the tem­per­ate lat­i­tudes. In the mar­tian win­ter in the re­spec­tive hemi­sphere, the plan­et is cov­ered with car­bon diox­ide and wa­ter ice snow up to about the 50th par­al­lel in the di­rec­tion of the equa­tor. When the Sun shines on the land­scape again in spring, the snow cov­er evap­o­rates and the or­ange-brown Mar­tian sur­face reap­pears, as here in the Ul­ti­mi Scop­uli re­gion, where a ridge and large parts of a near­ly 40-kilo­me­tre crater are al­ready free of ice, al­low­ing this aes­thet­ic view, as if cre­at­ed by an artist.
Winter-white Mars: Ice and snow in the Ultimi Scopuli region.
Win­ter-white Mars: Ice and snow in the Ul­ti­mi Scop­uli re­gion.
Image 2/6, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Winter-white Mars: Ice and snow in the Ultimi Scopuli region.

At least in high­er north­ern and south­ern lat­i­tudes, Mars has a white Christ­mas ev­ery year. Like Earth, Mars, with its oblique ax­is of ro­ta­tion, goes through sea­sons dur­ing its two-year or­bit around the Sun. Then the po­lar re­gions are cov­ered with car­bon diox­ide and wa­ter ice and snow up to sev­er­al me­tres high. When they are ex­posed to so­lar ra­di­a­tion again at the be­gin­ning of spring and warm up, the ice and snow cov­er re­cedes to the per­ma­nent po­lar caps. This im­age shows a top view of Ul­ti­mi Scop­uli, Latin for the "last cliffs" (be­fore the South Pole) at 75 de­grees south lat­i­tude in ear­ly south­ern spring. It was tak­en by the DLR stereo cam­era HRSC at the end of May 2022.
Winter gives way to spring
Win­ter gives way to spring
Image 3/6, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Winter gives way to spring

This year, Christ­mas on Mars falls al­most ex­act­ly at the be­gin­ning of spring in the north­ern hemi­sphere. ‘The north of Mars will have a white Christ­mas in 2022. How­ev­er, the high­er lat­i­tudes of the north­ern hemi­sphere are now be­com­ing more and more ice-free af­ter the equinox - the ice is re­treat­ing to the per­ma­nent po­lar cap. This scene shows the Ul­ti­mi Scop­uli area near the South Pole a few weeks af­ter the be­gin­ning of spring in the south­ern hemi­sphere. The ice is re­ced­ing more and more, ex­pos­ing fine­ly lay­ered sed­i­ments at a crater al­most 40 kilo­me­tres in size.
Topographical image map of Ultimi Scopuli
To­po­graph­i­cal im­age map of Ul­ti­mi Scop­uli
Image 4/6, Credit: ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO

Topographical image map of Ultimi Scopuli

The DLR stereo cam­era HRSC on Mars Ex­press, with its nine sen­sors ar­ranged trans­verse­ly to the di­rec­tion of flight, records the sur­face of Mars at dif­fer­ent an­gles and with four colour chan­nels. From the two stereo chan­nels point­ing for­wards and the two stereo chan­nels point­ing back­wards at an an­gle to the sur­face and the nadir chan­nel point­ing per­pen­dic­u­lar­ly to Mars, teams of sci­en­tists at the DLR In­sti­tute of Plan­e­tary Re­search and the Freie Uni­ver­sität Berlin cal­cu­late dig­i­tal ter­rain mod­els that as­sign el­e­va­tion in­for­ma­tion to each pix­el. The al­ti­tude val­ues can be read from the leg­end at the top right of the im­age. From the low­est point of the ap­prox­i­mate­ly 70-kilo­me­tre im­pact crater in the right half of the im­age (light blue) to the south po­lar Mar­tian high­lands (yel­low-green or pur­ple on a high­er plateau), the dif­fer­ence in al­ti­tude is about 1000 to 1500 me­tres. The crater rims pro­trude an­oth­er 1000 me­tres from the plain.
The Ultimi Scopuli Region near the South Pole of Mars
The Ul­ti­mi Scop­uli Re­gion near the South Pole of Mars
Image 5/6, Credit: NASA/JPL/MOLA; FU Berlin

The Ultimi Scopuli Region near the South Pole of Mars

This colour-cod­ed to­po­graph­i­cal map shows the Ul­ti­mi Scop­uli re­gion on Mars, which stretch­es along the 180th merid­i­an and is about 15 de­grees of lat­i­tude north of the South Pole. ESA's Mars Ex­press or­biter flew over the area on 19 May 2022 dur­ing the space­craft's Mars or­bit 23,219, a few weeks af­ter the start of spring in the south­ern hemi­sphere. DLR’s HRSC record­ed the elon­gat­ed im­age strip. The scenes pre­sent­ed here are from the small­er trape­zoidal square, which cov­ers an area of 215 by 65 kilo­me­tres.
(3D) anaglyph image of the Ultimi Scopuli region
(3D) anaglyph im­age of the Ul­ti­mi Scop­uli re­gion
Image 6/6, Credit: ESA/DLR/FU Berlin, CC-BY SA 3.0 IGO

(3D) anaglyph image of the Ultimi Scopuli region

So-called anaglyph im­ages can be gen­er­at­ed from the nadir chan­nel of the DLR-op­er­at­ed HRSC cam­era sys­tem on board ESA's Mars Ex­press space­craft, which is di­rect­ed per­pen­dic­u­lar­ly to the sur­face of Mars, and one of the four oblique stereo chan­nels. When used with red-blue or red-green glass­es, they al­low a three-di­men­sion­al view of the land­scape and give the view­er a spa­tial idea of the dif­fer­ences in al­ti­tude. The two craters to the left and right of the cen­tre of the im­age have di­am­e­ters of 40 and 70 kilo­me­tres re­spec­tive­ly and depths of up to 1500 me­tres.

• Image data from the High Resolution Stereo Camera (HRSC) on board the Mars Express mission reveal layered deposits, frost, ice and dark dunes near the martian South Pole.
• The scenery resembles an abstract work of art with strongly contrasting shades of colour.
• HRSC is a camera experiment developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) that has been relaying images of the martian surface to Earth since January 2004.
• Focus: Spaceflight

Christmas and winter spirit – also on Mars. Impact craters connected by a striped, coloured ribbon can be seen in the final and very wintry HRSC Mars image of this year. We wish all readers of our martian image series, published together with the European Space Agency (ESA) and Freie Universität Berlin, happy holidays!

Image data from the High Resolution Stereo Camera (HRSC) on board ESA's Mars Express mission reveal an exciting landscape of layered deposits, frost, ice, and dark dunes near the south polar region of Mars, known as Ultimi Scopuli (from the Latin for ‘the final cliffs’). The High Resolution Stereo Camera (HRSC) was developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) and has been sending images of the Martian surface to Earth since January 2004.

This amazing image shows a section of the landscape measuring approximately 215 by 65 kilometres and located 14 degrees north of the south pole. Many interesting landforms are visible – typical of regions that are permanently frozen but not covered by ice. Together with formations carved by the wind, known as aeolian landforms, and seasonal frost clouds, they complete the scenery.

The scenery appears very abstract with the strongly contrasting colour shades from the orange tones of the Martian soil and the white of water and carbon dioxide ice. Together with the curved landscape forms, it is not an easy landscape to make sense of at first glance. Nature seems to have acted as an expressionist artist on Mars too, giving the HRSC science team an aesthetic element to their processing of the colour stereo image data during the Christmas and New Year period.

These image data were acquired in the southern spring – the time when the ice retreats southward, leaving only a small ice cap at the south pole during summer in the southern hemisphere. During the seasonal cycle on Mars, carbon dioxide ice is deposited at the poles in winter. The amount of atmospheric gases trapped as ice at each pole in winter and then evaporating in spring is enormous, comprising over 10 percent of the atmosphere. This process leads to strong pressure changes in the martian gas envelope and, as a result, to very high wind speeds. These occur primarily in the autumn and are caused by this difference in atmospheric pressure in the hemispheres.

Layered deposits of water ice and fine duste

The two most eye-catching features of this image are two large impact craters that appear to be connected by a striped band. The band and craters exhibit an intense reddish-brown hue that contrasts with the grey and white of the surrounding landscape. In addition, alternating layers can be seen in the crater rims and band – especially when you zoom in. These layers are successive layers of dust and sand that have been deposited continuously and approximately horizontally on the terrain features. They consist primarily of water ice and approximately 10 percent of fine sediments.

The individual layers differ from each other in their albedo (the reflectivity of sunlight), their colour, thickness and their degree of weathering. These deposits are formed by dust and water ice dissolving from the atmosphere and sinking to the surface, and by direct frost condensation on the ground. The orange regions in the image clearly show the layered nature of these deposits.

Some regions in the image appear hazy. Clouds have formed over the scene and can be detected, particularly in the centre, above the band. Clouds in the south polar region contain not only water droplets frozen into ice crystals, but often needles of carbon dioxide ice given the extremely low temperatures of well below minus 100 degrees Celsius. Their trajectory as they sink to the ground is partly influenced by the landforms on the surface. In some regions of the image, extensive evaporation structures can be seen, making the surface appear levelled and resembling the water level of terrestrial lakes.

Mysterious dark material

Dark dunes and dune fields can be identified in numerous places, often covered by a thin layer of frost. Where they have been strung into thin lines by the wind, they resemble a formation of elongated rock ridges and wind alleys pointing in the same direction, known as yardangs. From their orientation one can read the prevailing wind direction, which can vary greatly on a local scale and is strongly influenced by the terrain formations.

There are still open questions about the origin of the dark material on Mars. It is assumed that it originates from old, buried layers of volcanic ash as well as from weathered lava. Deposits of this type are found in almost every region on Mars. While the dark dunes on the innumerable crater floors often unite to form large complex dune fields, the dunes at the north and south poles are often still present in their individual form, as can be seen here in the innumerable black dots. Presumably, in the polar regions, the frost covering prevents the material transport, which is already a rare phenomenon on Mars, and thus the mobility and ‘unification’ of the dunes.

In addition, the image presented here also shows individual, small dark spots from which narrow lines that resemble spider legs emerge in different directions. These may be indicative of another distribution process of dark material typical of polar latitudes on Mars: carbon dioxide jets formed by heating dark material under an ice sheet, leading to a direct transition of ice from the solid to the gaseous state, which is then ejected at high pressure in fountains mixed with dark sand. Continuous observation of these phenomena help us to understand processes that are constantly changing the surface appearance in the polar regions on Mars.

Image processing

The images were acquired by the High Resolution Stereo Camera (HRSC) on 19 May 2022, during Mars Express orbit 23 219. The ground resolution is approximately 18 meters per pixel. The image is centred at approximately 185 degrees East and 76 degrees South.

This colour image was created from data from the nadir channel, the field of view oriented perpendicular to the surface of Mars, and the HRSC colour channels.

HRSC is a camera experiment developed and operated by the German Aerospace Center (DLR). The systematic processing of the camera data was carried out at the DLR Institute of Planetary Research. Personnel in the Department of Planetary Sciences and Remote Sensing at the Freie Universität Berlin used these data to create the image products shown here.

The HRSC experiment on Mars Express

The High Resolution Stereo Camera (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) Dr Thomas Roatsch of 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.

These high-resolution images and more images acquired by HRSC can be found in the Mars Express image gallery on flickr.

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  • Michael Müller
    Ed­i­tor
    Ger­man Aerospace Cen­ter (DLR)
    Cor­po­rate Com­mu­ni­ca­tions
    Telephone: +49 2203 601-3717
    Fax: +49 2203 601-3249

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  • Thomas Roatsch
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Rutherfordstraße 2
    12489 Berlin
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  • Ulrich Köhler
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
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    12489 Berlin
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  • Daniela Tirsch
    Ger­man Aerospace Cen­ter (DLR)
    In­sti­tute of Plan­e­tary Re­search
    Rutherfordstraße 2
    12489 Berlin
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