Venera 10

Venera 10 (Венера-10 meaning Venus 10), or 4V-1 No. 661, was a Soviet uncrewed space mission to Venus. It consisted of an orbiter and a lander. It was launched on June 14, 1975, 03:00:31 UTC and had a mass of 5033 kg (11096 lb). When the mission launched, the Soviet Union only disclosed that the mission's objective was to explore Venus and the surrounding space. Western sources speculated that the spacecraft contained a lander. The orbiter entered Venus orbit on October 23, 1975. Its mission was to serve as a communications relay for the lander and to explore cloud layers and atmospheric parameters with several instruments and experiments: 1.6–2.8 μm IR Spectrometer 8–28 μm IR Radiometer 352 nm UV Photometer 2 Photopolarimeters (335–800 nm) 300–800 nm Spectrometer Lyman-α H/D Spectrometer Bistatic radar mapping CM, DM radio occultations Triaxial Magnetometer 345–380 nm UV Camera 355–445 nm Camera 6 Electrostatic analyzers 2 Modulation Ion Traps Low-Energy Proton / Alpha detector Low-Energy Electron detector 3 Semiconductor counters 2 Gas-Discharge counters Cherenkov detector The orbiter consisted of a cylinder with two solar panel wings and a high gain parabolic antenna attached to the curved surface. A bell-shaped unit holding propulsion systems was attached to the bottom of the cylinder, and mounted on top was a sphere which held the landers. To reach Venus, the spacecraft traveled in a heliocentric orbit from Earth to the planet with perihelion of 0.72 AU, apohelion of 1.02 AU, eccentricity of 0.17, inclination of 2.3 degrees and orbital period of 294 days. On October 23, 1975, the lander separated from the orbiter, and touched down with the sun near zenith, at 05:17 UT, on October 25. A system of circulating fluid was used to distribute the heat load. This system, plus precooling prior to entry, permitted operation of the spacecraft for 65 minutes after landing. During descent, heat dissipation and deceleration were accomplished sequentially by protective hemispheric shells, three parachutes, a disk-shaped drag brake, and a compressible, metal, doughnut-shaped, landing cushion.