| Kosmos 359 | |
| Mission Type: | Venus lander[1] |
| Operator: | Lavochkin |
| Cospar Id: | 1970-065A |
| Satcat: | 04501 |
| Mission Duration: | Launch failure |
| Spacecraft Type: | 3MV |
| Manufacturer: | Lavochkin |
| Launch Mass: | 1180kg (2,600lb) |
| Launch Date: | UTC |
| Launch Rocket: | Molniya-M 8K78M |
| Launch Site: | Baikonur 31/6 |
| Orbit Reference: | Geocentric |
| Orbit Regime: | Low Earth |
| Orbit Eccentricity: | 0.05041 |
| Orbit Periapsis: | 210km (130miles) |
| Orbit Apoapsis: | 910km (570miles) |
| Orbit Inclination: | 51.5 degrees |
| Orbit Period: | 95.70 minutes |
| Apsis: | gee |
| Programme: | Venera |
| Previous Mission: | Venera 7 |
| Next Mission: | Venera 8 |
Kosmos 359 was an unmanned Soviet probe launched on 22 August 1970.[2] The probe's intended purpose was to explore Venus, but an error caused the final-stage rocket to malfunction. This left the craft trapped in an elliptical orbit around Earth for 410 days before orbital decay and atmospheric entry.[3] Kosmos 359 was launched five days after Venera 7 and had an identical design; had the craft not suffered a mission-ending failure, it would have landed on Venus shortly after Venera 7.[4] To publicly acknowledge the failure of the attempted Venus lander would be a public relations disaster for the Soviet space program; after the mission failed, the Venera spacecraft was renamed Kosmos 359 in order to conceal the mishap from the public.[5]
The lander was designed to be able to survive atmospheric pressures of up to and temperatures of . This was significantly greater than what was expected to be encountered, but significant uncertainties as to the surface temperatures and pressure of Venus resulted in the designers opting for a large margin of error. The degree of hardening added mass to the probe, which limited the amount of mass available for scientific instruments on the probe and the interplanetary bus.[6]
After reaching orbit, the main upper stage engine ignited late and shut down early after running for only twenty-five seconds. The error was ultimately attributed to an error in the DC transformer of the power supply system.
Kosmos 359 carried a limited set of scientific instruments, including a solar wind detector, cosmic-ray detector, resistance thermometer, and aneroid barometer.