Goals: Like its twin, Venera 9, the Venera 10 mission called for an orbiter and a lander to explore Venus. The orbiter was to act as a communications relay and study Venus from above while the lander descended via parachute to study and photograph the planet's surface.
Accomplishments: Venera 10 arrived at Venus three days after its twin. Though 2,200 km (1,367 miles) closer to the equator than Venera 9, the Venera 10 lander measured a temperature only 5 degrees C (9 degrees F) hotter. Atmospheric pressure at the surface was found to be 92 times that of Earth at sea level. As in the Venera 9 mission, the orbiter served as a communications relay for the lander while imaging the atmosphere in ultraviolet light and conducting other experiments. The lander transmitted data for a then record 65 minutes, including a panoramic picture of Venus' surface. Gamma ray readings suggested a basaltic surface in agreement with measurements by Venera 9, though the landscape appeared to be older than that of Venera 9's landing site.