Satellite exploration of the moon began in October 1959, when the Soviet probe Luna 3 sent back the first photographs of the 41% that is invisible from earth. Although of very poor quality, they showed a surface more heavily cratered than the side that faces earth, and none of the large, basalt filled ‘seas’ (or maria) that characterise the near side. Subsequent explorations involved orbiting probes that undertook systematic surveys of the lunar surface. The main rationale seems to have been less for pure selenography (the lunar equivalent of geography) than for identifying potential landing sites for the projected American Apollo missions and manned Soviet missions. The American Lunar Orbiter programme, consisting of five separate probes launched between August 1966 and August 1967, surveyed some 95% of the surface of the satellite. The first two Orbiters concentrated on a band extending 5° north and south of the equator and 45° east and west of the prime meridian. This was considered to provide the best location for the first Apollo mission to land on the moon, Apollo 11 in July 1969.