Venera 12

The Venera 12 (Russian: Венера-12 meaning Venus 12) was a Soviet uncrewed space mission to explore the planet Venus. Venera 12 was launched on 14 September 1978 at 02:25:13 UTC.[2]

Venera 12
Venera 12
Mission typeVenus flyby / lander
OperatorSoviet Academy of Sciences
COSPAR ID1978-086A
1978-086C
SATCAT no.11025
12028
Mission durationTravel: 3 months and 6 days
Lander: 110 minutes
Spacecraft properties
Spacecraft type4V-1
Bus4MV
Launch mass4,940 kg (10,890 lb)
Dry mass1,600 kg (3,500 lb)
Dimensions2.3 m × 2.7 m × 5.7 m (7.5 ft × 8.9 ft × 18.7 ft)
Start of mission
Launch date14 September 1978, 02:25:13 UTC
RocketProton-K/D-1 8K82K
Launch siteBaikonur 81/23
End of mission
Last contact18 April 1980[1]
Orbital parameters
Reference systemGeocentric
RegimeLow Earth
Semi-major axis6,569 kilometres (4,082 mi)
Perigee altitude177 kilometres (110 mi)
Apogee altitude205 kilometres (127 mi)
Inclination51.5°
Flyby of Venus
Spacecraft componentVenera 12 flight platform
Closest approach19 December 1978
Distance35,000 km (22,000 mi)
Venus lander
Spacecraft componentVenera 12 descent module
Landing date21 December 1978, 03:30
Landing site7°S 294°E
 

Separating from its flight platform on 19 December 1978, the lander entered the Venus atmosphere two days later 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 06:30 Moscow time (0330 UT) on 21 December after a descent time of approximately 1 hour. The touchdown speed was 7–8 m/s. Landing coordinates are 7°S 294°E. It transmitted data to the flight platform for 110 minutes after touchdown until the flight platform moved out of range while remaining in a heliocentric orbit. Identical instruments were carried on Venera 11 and 12.[2]

Flight platform

Venera 12 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. Before and after Venus flyby, Venera 11 and Venera 12 yielded detailed time-profiles for 143 gamma-ray bursts, resulting in the first ever catalog of such events. The last gamma-ray burst reported by Venera 12 occurred on 5 January 1980. Venera 12 used its ultraviolet spectrometer to study comet Bradfield (C/1979 Y1) on 13 February 1980, and reported spectrophotometric data until 19 March 1980.[3]

List of flight platform instruments and experiments:[4]

  • 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 active phase of the science mission for the flight platform ended in April 1980. Venera 12 is currently in heliocentric orbit, with perihelion of 0.69 AU, aphelion of 1.01 AU, eccentricity of 0.19, inclination of 2.3 degrees and orbital period of 284 days.

Lander

The Venera 12 descent craft carried instruments designed to study the detailed chemical composition of the atmosphere, the nature of the clouds, and the thermal balance of the atmosphere. Among the instruments on board was a gas chromatograph to measure the composition of the Venus atmosphere, instruments to study scattered solar radiation and soil composition, and a device named Groza which was designed to measure atmospheric electrical discharges. Results reported included evidence of lightning and thunder, a high 36Ar/40Ar ratio, and the discovery of carbon monoxide at low altitudes.

Both Venera 11 and Venera 12 had landers with two cameras, each designed for color imaging. Each failed to return images when the lens covers did not separate after landing due to a design flaw.[5]

List of lander experiments and instruments:[4]

See also

References
  1. Siddiqi, Asif A. (2018). Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016 (PDF). The NASA history series (second ed.). Washington, DC: NASA History Program Office. pp. 152–153. ISBN 978-1-62683-042-4. LCCN 2017059404. SP2018-4041.
  2. "Venera 12". NASA.
  3. "Venera 12". NASA Space Science Data Coordinated Archive.
  4. Mitchell, Don P. "Drilling into the Surface of Venus". Retrieved 13 April 2013.
  5. "Venera 12 Descent Craft". NASA Space Science Data Coordinated Archive.
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