Venera 11
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| Venera 11 | |
|---|---|
 Venera 11 lander |
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| Organization: | USSR |
| Mission type: | Flyby and Lander |
| Flyby date: | December 25, 1978 |
| Satellite of: | Venus |
| Launch Date: | 9 September 1978 at 3:25:39 UTC |
| Launch Vehicle: | Proton Booster Plus Upper Stage and Escape Stages |
| NSSDC ID: | 1978-084D |
| Mass: | 4940 kg |
| Periapsis: | 6.62 RV (flight platform) |
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The Venera 11 (Russian: Венера-11) was an USSR unmanned space mission to explore the planet Venus. Venera 11 was launched on 9 September 1978 at 3:25:39 UTC.
Separating from its flight platform on December 23, 1978 the lander entered the Venus atmosphere two days later on December 25 at 11.2 km/s. During the descent, it employed aerodynamic braking followed by parachute braking and ending with atmospheric braking. It made a soft landing on the surface at 06:24 Moscow time on 25 December after a descent time of approximately 1 hour. The touchdown speed was 7 to 8 m/s. Landing coordinates are 14° S 299° E. Information was transmitted to the flight platform for retransmittal to earth until it moved out of range 95 minutes after touchdown.
[edit] Flight platform
After ejection of the lander probe, the flight platform continued on past Venus in a heliocentric orbit. Near encounter with Venus occurred on December 25, 1978, at approximately 34,000 km altitude. The flight platform acted as a data relay for the descent craft for 95 minutes until it flew out of range and returned its own measurements on interplanetary space.
Venera 11 flight platform carried solar wind detectors, ionosphere electron instruments and two gamma ray burst detectors - the Soviet-built KONUS and the French-built SIGNE 2. The SIGNE 2 detectors were simultaneously flown on Venera 12 and Prognoz 7 to allow triangulation of gamma ray sources.
List of flight platform instruments and experiments:
- 30-166 nm Extreme UV Spectrometer
- Compound Plasma Spectrometer
- KONUS Gamma-Ray Burst Detector
- SNEG Gamma-Ray Burst Detector
- Magnetometer
- 4 Semiconductor Counters
- 2 Gas-Discharge Counters
- 4 Scintillation Counters
- Hemispherical Proton Telescope
The mission ended in February, 1980.
[edit] Lander
The lander carried instruments to study the temperature and atmospheric and soil chemical composition. A device called Groza detected lightning on Venus. Both Venera 11 and Venera 12 had landers with two cameras, each designed for color imaging, though Soviet literature doesn't mention them. Each failed to return images when the lens covers did not separate after landing due to a design flaw. The soil analyzer also failed. A gas chromatograph was on board to measure the composition of the Venus atmosphere, as well as instruments to study scattered solar radiation. Results reported included evidence of lightning and thunder, a high Ar36/Ar40 ratio, and the discovery of carbon monoxide at low altitudes.
List of lander experiments and instruments:
- Backscatter Nephelometer
- Mass Spectrometer
- Gas Chromatograph
- X-Ray Fluorospectrometer
- 360° Scanning Photometer
- Spectrometer (430-1170 nm)
- Microphone/Anemometer
- Low-Frequency Radio Sensor
- 4 Thermometers
- 3 Barometer
- Accelerometer
- PROP-V Penetrometer
- Soil Analysis Device
- 2 Color Cameras
| Venera programme |
 |
|
1VA | Venera 1 | Sputnik 19 | Sputnik 20 | Sputnik 21 | Cosmos 21 | Venera 1964A | Venera 1964B | Cosmos 27 | Venera 2 | Venera 3 | Cosmos 96 | Venera 1965A | Venera 4 | Cosmos 167 | Venera 5 | Venera 6 | Venera 7 | Cosmos 359 | Venera 8 | Cosmos 482 | Venera 9 | Venera 10 | Venera 11 | Venera 12 | Venera 13 | Venera 14 | Venera 15 | Venera 16 |
| Flybys: Venera 1 · Mariner 2 · Zond 1 · Venera 2 · Mariner 5 · Mariner 10 · Venera 11 · Venera 12 · Galileo · Cassini-Huygens · MESSENGER | |
| Orbiters: Venera 9 · Venera 10 · Pioneer Venus Orbiter · Venera 15 · Venera 16 · Magellan probe · Venus Express | |
| Descent probes: Venera 3 · Venera 4 · Venera 5 · Venera 6 · Pioneer Venus Multiprobe | |
| Landers: Venera 7 · Venera 8 · Venera 9 · Venera 10 · Venera 11 · Venera 12 · Venera 13 · Venera 14 · Vega 1 · Vega 2 | |
| Balloon probes: Vega 1 · Vega 2 | |
| Future: PLANET-C · BepiColombo · Venera-D | |
| See also: Venus · Exploration of Venus | |
