The European Space Agency's Mars Express spacecraft has imaged Kasei Vallis, one of the largest outflow channels on Mars. The feature is believed to have been created by glaciers or the bursting of subterranean lakes dammed by them.

Image credit: ESA

The image was taken by the High Resolution Stereo Camera (HRSC) on board Mars Express during orbit 61 from an altitude of 272 km. The resolution is 12 metres per pixel. The image centre is located at 29.8° north and 309° east, the image width is 130 km, North is up.

The part of the outflow channel seen in this image has most probably been carved by glaciers or gigantic water-related outflows known from terrestrial subglacial lakes. The blackish-blue colour is related to sediments. The bright streaks oriented NE-SW are related to wind forces.

This image shows various details which give an insight into the erosional history of the outflow channel. The image also illustrates how difficult it is to achieve near-true colour in images of Mars when atmospheric dust and haze have a major disturbing influence on the scene.