Launched on August 5, 1973, the Mars 6 mission consisted of a flyby bus and a lander. On March 12, 1974, the lander separated and entered the atmosphere, transmitting in-situ data for the first time for 224 seconds. However, contact was abruptly lost at the moment of retrorocket activation, resulting in a high-speed impact, likely due to the degradation of electronic components.

Landing Failure

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SKP

Mars 5

Launched by the USSR in 1973, Mars 5 was the only spacecraft of that window (Mars 4, 5, 6, 7) to successfully enter Mars orbit on February 12, 1974. However, a depressurization of the instrument compartment, likely due to a micrometeoroid, caused its failure after only 22 orbits and 16 days of operation, though it managed to return 43 high-quality images and surface data.

Orbital Insertion

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Mars 4

Launched by the USSR in 1973 aiming to orbit Mars. Due to an onboard computer failure (chip degradation), the retrorockets failed to fire for orbital insertion. The spacecraft performed an unplanned flyby on February 10, 1974, at 1,844 km, returning images and detecting the night-side ionosphere of the planet for the first time.

Orbital Failure

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NASA

Mariner 9

NASA's Mariner 9 was the first probe to orbit another planet, arriving at Mars in November 1971. Although a global dust storm obscured the surface, the mission waited patiently. As the dust cleared, it revealed a new Mars: discovering Olympus Mons , Valles Marineris , and ancient riverbeds.

Mission Complete

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SKP

Mars 3 (Orbiter)

The USSR's Mars 3 mission (1971) was a historic partial success. Its orbiter functioned, but the lander, despite achieving the first-ever soft landing on Mars, only transmitted for 20 seconds. A massive global dust storm is believed to have caused the failure.

Mission Complete

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