MARSIS

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). The Italian MARSIS instrument is operational on the European Space Agency, Mars Express orbiter mission. 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). The Italian MARSIS instrument is operational on the European Space Agency, Mars Express orbiter mission. The MARSIS Principal Investigator is Giovanni Picardi from the University of Rome 'La Sapienza', Italy. It features ground-penetrating radar capabilities, which uses synthetic aperture techniques and a secondary receiving antenna to isolate subsurface reflections. MARSIS identified buried basins on Mars. MARSIS was funded by ASI (Italy) and NASA (USA). On May 4, 2005, Mars Express deployed the first of its two 20-metre-long radar booms for the MARSIS experiment. At first the boom didn't lock fully into place; however, exposing it to sunlight for a few minutes on May 10 fixed the glitch. The second 20 m boom was successfully deployed on June 14. Both 20 m booms were needed to create a 40 m dipole antenna for MARSIS to work; a less crucial 7-meter-long monopole antenna was deployed on June 17. The radar booms were originally scheduled to be deployed in April 2004, but this was delayed out of fear that the deployment could damage the spacecraft through a whiplash effect. Due to the delay it was decided to split the four-week commissioning phase in two parts, with two weeks running up to July 4 and another two weeks in December 2005.