The upper image of this composite is a 'radargram' from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) on board ESA's Mars Express. It shows data from the subsurface of Mars in the water-ice-rich layered deposits that surround the south pole of the planet. The lower image shows the position of the ground track of the spacecraft (indicated by a white line) on a topographic map of the area based on data from the MOLA laser altimeter on board NASA's Mars Global Surveyor. The images are 1250 kilometers wide.

NASA / JPL / ASI / ESA / Univ. of Rome / MOLA Science Team