MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) is a low frequency, pulse-limited radar sounder and altimeter developed by the University of Rome La Sapienza and Alenia Spazio (today Thales Alenia Space Italy).[1] The Italian MARSIS instrument, which is operated by the European Space Agency, is operational and orbits Mars as an instrument for the ESA's Mars Express exploration mission.
The MARSIS Principal Investigator is Giovanni Picardi from the University of Rome "La Sapienza", Italy.[2] It features ground-penetrating radar capabilities, which uses synthetic aperture technique and a secondary receiving antenna to isolate subsurface reflections.[3] MARSIS identified buried basins on Mars.[4] MARSIS was funded by ASI (Italy) and NASA (USA).[5] The processor runs the real-time operating system EONIC Virtuoso.[6]
Due to severe limitations on the available mass, the antennas are of a novel design, each consisting of a folding composite tube that supports a pair of wires constituting the conductive element of the antenna. The antennas are deployed by pyrotechnic release mechanisms.