Kosmos 419

Launch date: 10 May 1971
Nation: USSR
Outcome: failure

Wikipedia - "In 1971, Mars was at its closest to Earth since 1956 and in May of that year both the Soviet Union and the United States made new attempts to reach the Red Planet. Kosmos 419 was intended to overtake the United States probes, Mariner 8 and Mariner 9, in the aim of becoming the first Mars orbiter. As it was, Mariner 8 was lost in a launch failure two days before Kosmos 419 was launched, and Mariner 9 went on to become the first spacecraft to orbit Mars."