Mars 7

Mars 7 was the last of four Soviet missions launched toward Mars in 1973. Its design paired a flyby carrier with a descent module intended to investigate the atmosphere and surface. The carrier also carried magnetic-field, plasma, cosmic-ray and dust instruments for observations during the interplanetary flight and Mars encounter. On March 9, 1974, the descent module separated but failed to execute the maneuver needed to enter the Martian atmosphere. It missed the planet and continued into heliocentric orbit, so no landing or surface experiment was achieved. The carrier nevertheless returned encounter observations and remained in contact until March 25. Historical investigations associated the landing failure with onboard electronics problems, but the useful carrier measurements should be distinguished from the unsuccessful landing objective.