Mars program

The Mars program was a series of uncrewed spacecraft launched by the Soviet Union between 1960 and 1973. The spacecraft were intended to explore Mars, and included flyby probes, landers and orbiters.

Early Mars spacecraft were small, and launched by Molniya rockets. Starting with two failures in 1969, the heavier Proton-K rocket was used to launch larger 5 tonne spacecraft, consisting of an orbiter and a lander to Mars. The orbiter bus design was likely somewhat rushed into service and immature,^{[citation needed]} considering that it performed very unreliably in the Venera variant after 1975. This reliability problem was common to much Soviet space hardware from the late 1960s and early 1970s and was largely corrected with a deliberate policy, implemented in the mid-1970s, of consolidating (or "debugging") existing designs rather than introducing new ones. The names of the "Mars" missions do not need to be translated, as the word "Mars" is spelled and pronounced approximately the same way in English and Russian.

In addition to the Mars program, the Soviet Union also sent a probe to Mars as part of the Zond program; Zond 2, however it failed en route. Two more spacecraft were sent during the Phobos program; both failed. In 1996, Russia launched Mars 96, its first interplanetary mission since the dissolution of the Soviet Union, however it failed to depart Earth orbit.