The 4,450 kg ,Venera 11 USSR unmanned space mission was launched on 9 September 1978 at 3:25:39 UTC. Venera 11 was one of two identical probes (the other being Venera 12) that followed up on the highly successful Soviet missions to Venus in 1975. It’s mission, explore Venus.
The launch platform consisted of a Proton Booster Plus Upper Stage and Escape Stages. Venera 11 arrived at Venus after two course corrections on 16 September and 17 December 1978. The Venera 11 seperated from its flight platform on December 23, 1978 and the lander entered the Venus atmosphere two days later on Christmas day, December 25. The flight platform continued on to a heliocentric orbit where it acted as a relay for 95 minutes until it flew out of range.
During the descent, it employed aerodynamic braking, then parachute braking and ending with atmospheric braking. It touched down at 06:24 Moscow time on December 23rd after it descended for about an hour.
The Venera 11 flight platform scientific instruments included solar wind detectors, ionosphere electron instruments and two gamma ray burst detectors. The detectors were the Soviet KONUS and the French SIGNE 2.
A first ever event was cataloged by the Venera 11, detailed time profiles for 143 gamma-ray bursts. The last gamma-ray burst reported by Venera 11 occurred on January 27, 1980.
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
- 4 Semiconductor Counters
- 2 Gas-Discharge Counters
- 4 Scintillation Counters
- Hemispherical Proton Telescope
The lander carried instruments to study the temperature, atmospheric and soil chemical composition. A device called Groza detected lightning on Venus. The Venera 11 was equipped with two color cameras, Soviet literature does not mention them. Sadly, a design flaw did not eject the lens covers properly so no images were retrieved. The soil analyzer was also a failure, therefore no scientific readings from the analyzer were recovered.
The only success that the Venera had was a gas chromatograph , which measure the composition of the Venus atmosphere, as well as instruments to study scattered solar radiation. These instruments sent back an amazing detail though, Venus has evidence of lightning and thunder and also the discovery of carbon monoxide at low altitudes.
List of lander experiments and instruments:
- Backscatter Nephelometer
- Mass Spectrometer – MKh-6411
- Gas Chromatograph – Sigma
- X-Ray Fluorospectrometer
- 360° Scanning Photometer – IOAV
- Spectrometer (430-1170 nm)
- Low-Frequency Radio Sensor
- 4 Thermometers
- 3 Barometers
- Accelerometer – Bizon
- Penetrometer – PrOP-V
- Soil Analysis Device
- 2 Color Cameras
- Small solar batteries – MSB