Venera 4V-2
Venera 4V-2 () was a series of two identical spacecraft sent to Venus by the Soviet Union, consisting of Venera 15 and Venera 16. Both uncrewed orbiters were to map the surface of Venus using high resolution imaging systems. The spacecraft were identical and based on modifications to the earlier Venera space probes. Mission profile Venera 15 was launched on June 2, 1983, at 02:38:39 UTC, and Venera 16 on June 7, 1983, at 02:32:00 UTC. Venera 15 and Venera 16 both reached Venus' orbit (on October 10, 1983, and October 14, 1983, respectively). The two spacecraft were inserted into Venus orbit a day apart with their orbital planes shifted by an angle of approximately 4° relative to one another. This made it possible to reimage an area if necessary. Each spacecraft was in a nearly polar orbit with a periapsis ~1000 km, at 62°N latitude, and apoapsis ~65000 km, with an inclination ~90°, the orbital period being ~24 hours. In June 1984, Venus was at superior conjunction and passed behind the Sun as seen from Earth. No transmissions were possible, so the orbit of Venera 16 was rotated back 20° at this time to map the areas missed during