The Venera program had a rocky start. The first three Venera missions, launched between 1961 and 1965, were unsuccessful. Radio contact with the first two probes was lost long before the craft reached Venus, and Venera 3 crash-landed on the surface of the planet. After that, though, the program began to succeed in gaining scientific results. Venera 4 reached Venus on October 18, 1967, and released its lander capsule successfully; it broadcast scientific data on the Venusian atmosphere for ninety-four minutes before it was crushed by the intense atmospheric pressure. Launched on August 17, 1970, Venera 7 successfully landed on the surface of Venus on December 15, the first successful soft landing of a spacecraft on another planet. This capsule was equipped with a cooling device that helped it survive for twenty-three minutes after landing. Venera 8 survived for fifty minutes. Venera 11,12, 13, and 14 all had successful landings, too. The various landers measured, among many other things, the amount of sunlight that reached the surface of Venus, the chemical composition of the atmosphere and surface rocks, and the presence of lightning in the planet’s atmosphere.

Venera 15 and 16 arrived at Venus in October 1983. Rather than drop probes to the surface, they remained in orbit and constructed detailed maps of the surface of Venus using Doppler radar systems. Over the next year, they mapped a large part of the northern hemisphere, including areas that were probably active with volcanoes in the distant past.