Topographic image map of the Caralis Chaos region
Topographic image map of the Caralis Chaos region
DLR's HRSC stereo camera on Mars Express uses its nine sensors to record the surface of Mars from various perspectives, at right angles to the direction of flight. Teams of scientists at the DLR Institute of Planetary Research and Freie Universität Berlin create digital terrain models, which assign height information to each pixel, from two stereo channels directed obliquely forwards and backwards on to the surface, together with the nadir channel directed vertically on Mars. The colour scale at the top-right of the image shows the altitude values in relation to the areoid – an imaginary surface on Mars with the same gravitational pull. This clearly shows how the edge of the approximately 30-kilometre-wide crater in the centre of the image towers over its surroundings by some two kilometres. At the same time, it can also be seen that in the northeast (bottom-right of the image) there is a depression a thousand metres lower down, where a lake called Eridania was probably located in the early days of Mars.
