This picture of Ganymede, Jupiter's largest satellite was taken on the afternoon of March 5, 1979 from a range 145,000 km (87,000 mi). The width of the picture represents about 580 km (548 mi.) on the surface of Ganymede, and the smallest visible features are about 3 km (1.7 mi) across. The picture shows complex patterns of ridges and grooves which are probably the results of deformations of Ganymede's thick icy crust. Some systems of grooves and ridges are superposed on the ridge and groove systems indicating they are younger. A more degraded crater near the left center of the picture is crossed by ridges indicated that it predates the period of crystal deformation. JPL manages and controls the Voyager Project of NASA's Office of Space Science.