A series of US space probes intended to crash onto the lunar surface while transmitting photographs up to the moment of impact. The first attempted launching was on 23 August 1961, but the series was dogged by failure. Successful completion of mission was achieved with Rangers 7, 8 and 9 (the last of the series, Ranger 9, being launched on 17 February 1965) which, between them, returned over 17000 photographs with resolution better than 10 centimetres in some cases.
