Mars 2

Key facts

Mission & specifications

Mission

Mars 2 was the first of two identical orbiter-and-lander spacecraft the Soviet Union sent to Mars in May 1971. Each weighed about 4,650 kg: an orbiter built around a large fuel tank, with a 1,210 kg descent module on top holding a spherical lander, a pennant bearing the Soviet coat of arms, and a small walking robot, PROP-M, meant to shuffle across the ground on skis at the end of a 15-metre cable. On 27 November 1971 the lander separated 4.5 hours before arrival. Its final course correction had been so accurate that the pre-programmed sequence, which assumed an error to correct, turned the lander the wrong way. It entered the atmosphere too steeply, its parachute never opened, and it crashed. It was the first human-made object to reach the surface of Mars. The records do not agree on where: NSSDCA's orbiter record gives 45° S, 313° W — 47° E, on the edge of the Hellas basin, where the map shows it — while its lander record and NASA's history Beyond Earth give 4° N, 47° W. The orbiter entered an 18-hour orbit the same day, and with Mars 3's orbiter it returned 60 pictures, most of the data arriving between December 1971 and March 1972. The data revealed mountains up to 22 km high, surface temperatures from −110 °C to +13 °C, pressures of 5.5 to 6 millibars and far less water vapour than Earth's air. The Soviet Union announced on 22 August 1972 that both missions were complete, after 362 orbits by Mars 2.

1. 1971Mars 2 launches toward Mars on a Proton rocketLaunch

   An orbiter carrying a lander and a small walking robot sets out.

2. 1971The first human-made object on MarsImpactor

   The lander enters too steeply; its parachute never opens and it crashes.

3. 1971Enters orbit around MarsArrival

   An 18-hour orbit, inclined 48.9°.

4. 1972Mission completeMission end

   Announced after 362 orbits; with Mars 3 it returned 60 pictures.

Images

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