1970

Venera 7 Lands on Venus

Despite the failure of their lunar cosmonaut program in 1969, the Soviet Union continued to achieve remarkable successes with their robotic probes to the planets. The Venera 3–6 missions to Venus, undertaken from 1966 through 1969, did not survive to the surface, but still they provided enough new data on the planet’s atmosphere to enable mission controllers to design subsequent missions to withstand the harsh conditions. Success came with the flight of Venera 7, which on December 15, 1970, became the first human-made object to land and return data from the surface of another planet.

Venera 7 floated down through the atmosphere on a parachute for 35 minutes before landing, after which it continued to return data for another 23 minutes. During that time the lander relayed temperature data showing the surface to be at about 870°F (465°C), with a surface pressure inferred to be about 90 times Earth’s surface pressure. Under such scorching and crushing conditions, it’s a wonder the lander survived at all.

The success of Venera 7 set the stage for an incredible string of successful follow-on Soviet Venera landers, orbiters, and atmospheric probes between 1972 and 1985—the most ambitious long-term program of Venus robotic exploration ever conducted. Highlights included geochemical measurements of the planet’s surface composition (discovered to be similar at the landing sites to basaltic volcanic rock compositions found in places like Hawaii and Iceland); the first images of the rocky surface, dimly but adequately lit by sunlight filtering through the thick cloud layers; and the first large-scale maps of mountains, ridges, plains, and other tectonic and volcanic features, obtained using radar imaging from the Venera 15 and 16 orbiters.

An engineering test model of the Soviet Venera 7 landing capsule.

Besides the hellish surface conditions, the Venera probes also helped planetary scientists discover that the wind speeds in Venus’s middle and upper atmosphere exceed 220 miles (100 meters) per hour, which is much faster than the planet itself rotates (one Venus day is about 243 Earth days). The cause of this super rotation of the Venus atmosphere is unknown, and it is one focus of ongoing and planned future missions to study Earth’s so-called twin, Venus.

A reprocessed view of part of the Venus surface panorama obtained by the Soviet Venera 13 lander on March 1, 1982. A lander leg and piece of a jettisoned camera cover are in the foreground.