Soviets were headed to Venus in 1972. The spacecraft is about to return.

A Cold War-era spacecraft is heading home after a half-century adrift. 

Back in the 1970s, the Soviet Union had its sights set on Venus, sometimes known as Earth's evil twin. A thick atmosphere traps heat in a runaway greenhouse effect, making it the hottest planet in the solar system, despite being farther than Mercury from the sun. 

But the Venera mission, which launched from Kazakhstan on March 31, 1972, failed long before the Soviets could attempt to touch down on the hellscape.