Venera 12

Venera 12
Venera 12
Mission type Venus flyby / lander
Operator Soviet Academy of Sciences
COSPAR ID 1978-086A
1978-086C
SATCAT no. 11025
12028
Mission duration Travel: 3 months and 6 days
Lander: 110 minutes
Spacecraft properties
Spacecraft type 4V-1
Bus 4MV
Launch mass 4,940 kg (10,890 lb)
Dry mass 1,600 kg (3,500 lb)
Dimensions 2.3 m × 2.7 m × 5.7 m (7.5 ft × 8.9 ft × 18.7 ft)
Start of mission
Launch date 14 September 1978, 02:25:13 UTC
Rocket Proton-K/D-1 8K82K
Launch site Baikonur 81/23
Orbital parameters
Reference system Geocentric
Regime Low Earth
Semi-major axis 6,569 kilometres (4,082 mi)
Perigee 177 kilometres (110 mi)
Apogee 205 kilometres (127 mi)
Inclination 51.5°
Flyby of Venus
Spacecraft component Venera 12 flight platform
Closest approach 19 December 1978
Distance 35,000 km (22,000 mi)
Venus lander
Spacecraft component Venera 12 descent module
Landing date 21 December 1978, 03:30
Landing site 7°S 294°E / 7°S 294°E / -7; 294

The Venera 12 (Russian: Венера-12 meaning Venus 12) was a Soviet unmanned space mission to explore the planet Venus. Venera 12 was launched on 14 September 1978 at 02:25:13 UTC.[1]

Separating from its flight platform on December 19, 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 / 7°S 294°E / -7; 294. 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 January 5, 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 Ar36 / Ar40 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. ↑ "Venera 12".
  2. ↑ "Venera 12 – Detail".
  3. ↑ "Venera 12 (NASA NSS-DC)".
  4. 1 2 Mitchell, Don P. "Drilling into the Surface of Venus". Retrieved 13 April 2013.
  5. ↑ "Venera 12 Descent Craft".
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