TheVenera 12(Russian:Венера-12meaning Venus 12) was anuncrewedSovietspace mission designed to explore the planetVenus.Venera 12 was launched on 14 September 1978 at 02:25:13UTC.[3]
 Venera 12 model | |
| Operator | Soviet Academy of Sciences |
|---|---|
| COSPAR ID | 1978-086A 1978-086C |
| SATCATno. | 11025 12028 |
| Mission duration | Travel: 3 months and 6 days Lander: 110 minutes |
| Spacecraft properties | |
| Spacecraft type | 4V-1 |
| Bus | 4MV |
| Launch mass | 4,457.9 kg (9,828 lb)[1] |
| 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[1] |
| Rocket | Proton-K/D-1 8K82K |
| Launch site | Baikonur81/23 |
| End of mission | |
| Last contact | 18 April 1980[2] |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Low Earth |
| Semi-major axis | 6,569 kilometres (4,082 mi) |
| Perigee altitude | 177 kilometres (110 mi) |
| Apogee altitude | 205 kilometres (127 mi) |
| Inclination | 51.5° |
| Flyby ofVenus | |
| Spacecraft component | Venera 12 flight platform |
| Closest approach | 19 December 1978 |
| Distance | ~35,000 kilometers (22,000 mi) |
| Venuslander | |
| Spacecraft component | Venera 12 descent craft |
| Landing date | 21 December 1978, 03:30 |
| Landing site | 7°S294°E/ 7°S 294°E |
After separating from its flight platform on 19 December 1978, the Venera 12 lander entered the Venus atmosphere two days later at 11.2 kilometres per second (7.0 mi/s). During its descent, the lander employedaerodynamic brakingfollowed byparachute braking,ending with atmospheric braking. After a nearly one-hour descent, a soft landing was made at 06:30Moscow time(0330 UT) on 21 December. Touchdown speed was 7–8 metres per second (23–26 ft/s); landing coordinates are7°S294°E/ 7°S 294°E.Continuing for about 110 minutes after touchdown, the lander transmitted data to the flight platform for about 110 minutes until the flight platform, which remained in aheliocentric orbit,moved out of range. Venera 11 and 12 carried identical instruments.[3]
Flight platform
editThe Venera 12 flight platform carried solar wind detectors, ionosphere electron instruments, and twogamma ray burstdetectors – the Soviet-built KONUS and theFrench-built SIGNE 2. The SIGNE 2 detectors were simultaneously flown on Venera 12 andPrognoz 7to allow for triangulation of gamma ray sources. Before and after the 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.[4]
The list of flight platform instruments and experiments are:[5]
- 30–166nmExtremeUVspectrometer
- Compound plasma spectrometer
- KONUSGamma-rayburst 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, withperihelionof 0.69AU,aphelionof 1.01 AU,eccentricityof 0.19,inclinationof 2.3 degrees andorbital periodof 284 days.
Lander
editThe 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. These instruments included agas chromatographto 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 high36Ar/40Arratio, and the discovery ofcarbon monoxideat low altitudes.
Each of the Venera 11 and Venera 12 included landers with a pair of cameras, each of which was designed for color imaging. A design flaw prevented the lens caps from separating, resulting in all cameras failing to capture and return images.[6]
The list of lander experiments and instruments are:[5]
- Backscatternephelometer
- Mass spectrometer– MKh-6411
- Gaschromatograph– Sigma
- X-rayfluorospectrometer
- 360° scanning photometer – IOAV
- Spectrometer (430–1170 nm)
- Microphone/anemometer
- Low-Frequency radio sensor
- 4Thermometers
- 3Barometers
- Accelerometer– Bizon
- Penetrometer– PrOP-V
- Soil Analysis Device
- 2 Color Cameras
- Small solar batteries – MSB
See also
edit
References
edit- ^abSiddiqi, Asif (2018).Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016(PDF)(second ed.). NASA History Program Office.
- ^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.ISBN978-1-62683-042-4.LCCN2017059404.SP2018-4041.
- ^ab"Venera 12".NASA.
- ^"Venera 12".NASA Space Science Data Coordinated Archive.
- ^abMitchell, Don P."Drilling into the Surface of Venus".Retrieved13 April2013.
- ^"Venera 12 Descent Craft".NASA Space Science Data Coordinated Archive.