Cssini had a radar subsystem - To determine whether oceans exist on Titan, and, if so, to determine their distribution. - To investigate the geologic features and topography of the solid surface of Titan. RADAR's primary goal was to pierce Titan's thick veil of smog and aerosols to map its surface. The radar system peak operating power was 86 W, much more than a passive camera using the sunlight for illumination. Radar should provide its own illumination. See https://pds-imaging.jpl.nasa.gov/documentation/RADARUsersGuide2ndEdV2.pdf https://pds-imaging.jpl.nasa.gov/data/cassini/cassini_orbiter/CORADR_0284/DOCUMENT/BODPSIS.PDF