This stunning image swath was taken by ESA’s Mars Express during camera calibration as the spacecraft flew over the north pole (bottom) towards the equator (top).
The images were taken by the high-resolution stereo camera’s nine channels (one nadir, four colour and four stereo), which were panned over the surface to record a large area at uniform illumination conditions. At the same time the camera was shifted to the horizon, instead of just pointing to the surface as in routine imaging.
The images were taken on 19 June 2017 during Mars Express orbit 17 050. The ground resolution in the centre of the image is about 1 km/pixel and the images are centred at 249ºE / 65°N.