Mars 3 achieved the first soft landing on Mars on 2 December 1971.
The Soviet Mars 3 mission consisted of an orbiter and a lander launched in May 1971. The lander entered the Martian atmosphere, deployed a parachute, and used retrorockets to reach the surface safely in the region of Terra Sirenum.
Mars 3 began transmitting after landing, but communication stopped after about 20 seconds. The cause has never been established with certainty; possibilities discussed by researchers include a powerful electrical discharge associated with the planet-wide dust storm then affecting Mars.
Mars 2 reached Mars shortly before Mars 3 but crashed during its descent, so it did not accomplish a soft landing. Later missions, including Viking 1 and Viking 2, achieved long-lasting surface operations.