Artist's impression of MARSIS Boom 1 deployed

This is an impression of how the first stage of deployment looks for the Mars Express MARSIS experiment. The 13 segments of the first 20-metre boom have sprung out and locked into place.

The MARSIS experiment will map the Martian sub-surface structure to a depth of a few kilometres. The instrument's 40-metre long antenna booms will send low frequency radio waves towards the planet, which will be reflected from any surface they encounter.