SHARAD (Mars SHAllow RADar sounder) is a subsurface sounding radar embarked on the Mars Reconnaissance Orbiter probe. It complements the MARSIS instrument on Mars Express, providing lower penetration capabilities (some hundred meters) but much finer resolution (15 metres - untapered - in free space).SHARAD is developed under the responsibility of the Italian Space Agency (ASI, Agenzia Spaziale Italiana), and provided to JPL (Jet Propulsion Laboratory) for use on board the Mars Reconnaissance Orbiter Spacecraft in the frame of a NASA/ASI agreement which foresees exploitation of the data by a joint Italian/US team.