Mars 3 lands, transmits for 20 seconds, and stops
Mars 2's lander crashed and became the first human object on the surface. Mars 3 touched down intact, sent 20 seconds of signal, and went silent for good.
The Mars 2 descent module separated from its orbiter on 27 November 1971, about four and a half hours before arrival. Something in the entry sequence went wrong — the accepted explanation is an entry angle that was too steep — and the parachute never deployed. The capsule hit the surface at speed near 4°N, 47°W, carrying a pennant with the Soviet coat of arms. It was the first object built by humans to reach the ground on another planet, and it arrived as wreckage.
Five days later its sister tried again. The Mars 3 descent module touched down at around 13:50:35 UT on 2 December 1971, near 45°S, 158°W, and it worked: braking cone, parachute, retro-rockets, and foam packed round the capsule to absorb what was left of the impact. Ninety seconds after landing it began transmitting to the orbiter overhead. Twenty seconds after that, at 13:52:25, the signal stopped and was never heard again. What came back in those twenty seconds was a fragment of a panoramic image showing no detail at all, at an illumination of about 50 lux — dusk.
The dust matters here. Mars 3 landed into the same planet-wide storm that had just blinded Mariner 9, which explains the dim, featureless picture and may also explain the silence: the leading suspicion is a coronal discharge induced by the charged, dust-laden air, which would have destroyed the communications system outright. Nobody knows. The Soviet planners had committed to a fixed arrival date years in advance and could not wait out the weather the way an orbiter could, so both landers descended into the worst atmospheric conditions Mars had shown in decades.
The rest of the 1971 Soviet effort had already gone badly. Cosmos 419, launched on 10 May, never left Earth orbit: the ignition timer on its escape stage had been programmed for 1.5 years instead of 1.5 hours, so the burn for Mars never came and the spacecraft reentered two days later. The Mars 2 and Mars 3 orbiters both worked and returned data into August 1972, but their imaging sequences had been loaded on Earth before launch and ran on schedule regardless of what the cameras were pointed at, which during the storm was a featureless brown ceiling.
So the first soft landing on Mars is genuinely a Soviet achievement, and it is also a footnote: twenty seconds of carrier and half a grey frame. No usable science came off the martian surface for another four and a half years. What Mars 3 actually proved is that the descent could be survived at all, which in 1971 was not obvious.