The SHAllow RADar instrument (SHARAD) is the sub-surface sounding radar provided by the Italian Space Agency (ASI) as one of six science instruments onboard NASA's 2005 Mars Reconnaissance Orbiter (MRO). SHARAD is a wideband radar sounder that operates on a 20 MHz central frequency with a 10 MHz bandwidth and transmits frequency-modulated radar pulses of about 85 microseconds in length.
SHARAD is designed to create subsurface profiles with approximately 10 to 20 m vertical resolution (15 m in free space), 300 to 1000 m along-track resolution, and 1500 to 8000 m across-track resolution, depending on spacecraft altitude and terrain roughness. Radar penetration depends on the dielectric properties of subsurface materials, and is estimated from several hundred meters up to 1 km for the range of dielectric properties of expected Martian rocks.