In 1971 the Soviet Union sent probes "Mars 2" and "Mars 3", each carrying a lander, as part of the Mars probe program M-71. The Mars 2 lander failed to land and impacted Mars. The Mars 3 lander became the first probe to successfully soft-land on Mars, but its data-gathering had less success. The lander began transmitting to the Mars 3 orbiter 90 seconds after landing, but after 14.5 seconds, transmission ceased for unknown reasons. The cause of the failure may have been related to the extremely powerful Martian dust storm taking place at the time. These space probes each contained a Mars rover although they were never deployed.