The Venera series probes were developed by the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

 between 1961 and 1984 to gather data from Venus

Venus

Venus is the second planet from the Sun, orbiting it every 224.7 Earth days. The planet is named after Venus, the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows...

, Venera being the Russian name for Venus. As with some of the Soviet Union's other planetary probes, the later versions were launched in pairs with a second vehicle being launched soon after the first of the pair.

Ten probes from the Venera series successfully landed on Venus and transmitted data from the surface, including the two Vega program and Venera-Halley probes.