jeudi 14 novembre 2013

Mars - Deep freeze












ESA - Mars Express Mission patch.

Nov. 14, 2013

Ismeniae Fossae

This scene shows a section of Ismeniae Fossae that straddles the southern highlands–northern lowlands of Mars. The 2 km-wide curvilinear trough that runs through this image contains numerous parallel grooves and ridges comprising material from the trough walls and material that has been dragged along the floor by ancient glaciers and ice-rich flows.

In the left portion of the scene the channel truncates a roughly 25 km-wide crater. Material in the crater walls has slumped down into the channel, smoothing over the grooved floor.

Around this crater, and elsewhere in Ismeniae Fossae, clusters of circular to elliptical, partially interconnected depressions are observed. These may be either secondary impact craters from debris flung out by larger impact craters, or collapse pits caused by the sublimation of subsurface ice.

The western portion of the 138 km-wide Moreux Crater is seen in the bottom right of the image. Numerous small dendritic valley systems west of the crater provide further evidence of water flowing in this region at some point in the Red Planet’s past, perhaps as water melting from the ice thought to have once covered this region.

The image was taken by the High Resolution Stereo Camera on ESA’s Mars Express on 16 June 2013 (orbit 11709), with a ground resolution of about 20 m per pixel. The image centre is at approximately 40°N / 42°E.

Ismeniae Fossae topography

This colour-coded topography map shows the heights and depths of features within Ismeniae Fossae. White and red show the highest terrains, while blue and purple show the deepest. The edge of Moreux crater is seen in the lower right as the deepest feature in this scene.

The region was imaged by the High Resolution Stereo Camera on ESA’s Mars Express on 16 June 2013 (orbit 11709), with a ground resolution.

Ismeniae Fossae perspective

Branches in the 2 km-wide trough of Ismeniae Fossae are seen in close-up detail in this scene. Material in the channels likely derived from the walls subsequently transported by glaciers or water flowing through the region. Smaller dendritic valley systems formed by water – possibly from melting ice – are seen at the bottom left and in the upper right portion of the image. The clusters of circular to elliptical depressions in the bottom left may be either secondary impact craters from debris flung out by larger impact craters, or collapse pits caused by the sublimation of subsurface ice.

This region was imaged by the High Resolution Stereo Camera on ESA’s Mars Express on 16 June 2013 (orbit 11709), with a ground resolution of about 20 m per pixel. The scene is located at approximately 40°N / 42°E.

Ismeniae Fossae 3D

Data from the nadir channel and one stereo channel of the High Resolution Stereo Camera on ESA’s Mars Express have been combined to produce this anaglyph 3D image of Ismeniae Fossae, which can be viewed using stereoscopic glasses with red–green or red–blue filters.

This region was imaged on 16 June 2013 (orbit 11709), with a ground resolution of about 20 m per pixel. The image centre is located at approximately 40°N / 42°E.

For more information about Mars Express Mission, visit: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

Images, Text, Credits: ESA / DLR / FU Berlin (G. Neukum).

Greetings, Orbiter.ch