Venera 7 became the first spacecraft to transmit data from the surface of Venus.
The Soviet probe landed on Venus on 15 December 1970 and transmitted measurements for about 23 minutes after reaching the surface. It was the first spacecraft to survive the descent and send data from another planet’s surface, a major achievement in the Space Race.
Venera 7 had to withstand temperatures near 475 °C and atmospheric pressure roughly 90 times that of Earth at sea level. Engineers strengthened the lander’s pressure vessel and designed it to operate briefly under conditions that had defeated earlier probes.
Venera 4 was the first probe to transmit atmospheric data while descending through Venus, but it did not return data from the surface. Venera 9 later returned the first photographs from the surface, so these milestones are often mixed up.