Venera 9(Russian:Венера-9,lit. 'Venus-9'), manufacturer's designation:4V-1 No. 660,[4]was aSovietuncrewed space missiontoVenus.It consisted of an orbiter and a lander. It was launched on June 8, 1975, at 02:38:00UTCand had a mass of 4,936 kilograms (10,882 lb).[5]The orbiter was the first spacecraft toorbit Venus,while the lander was the first to return images from the surface of another planet.[6]
 Model of Venera 9 lander | |
| Mission type | Venusorbiter / lander |
|---|---|
| Operator | Lavochkin |
| COSPAR ID | 1975-050A 1975-050D |
| SATCATno. | 7915 8411 |
| Mission duration | Orbiter: 158 days Lander: 53 minutes Launch to last contact: 292 days |
| Spacecraft properties | |
| Spacecraft | 4V-1No. 660 |
| Manufacturer | Lavochkin |
| Launch mass | 4,936 kg (10,882 lb)[1] |
| Landing mass | 1,560 kg (3,440 lb) |
| Payload mass | 660 kg (1,455 lb) |
| Start of mission | |
| Launch date | June 8, 1975, 02:38UTC[2] |
| Rocket | Proton-K/D[2] |
| Launch site | Baikonur81/24 |
| End of mission | |
| Last contact | Orbiter primary mission: March 22, 1976[3] Lander: October 22, 1975 |
| Orbital parameters | |
| Reference system | Cytherocentric |
| Eccentricity | 0.89002 |
| Pericytherion altitude | 7,625 km (4,738 mi) |
| Apocytherion altitude | 118,072 km (73,367 mi) |
| Inclination | 29.5 degrees |
| Period | 48.3 hours |
| Venusorbiter | |
| Spacecraft component | Orbiter |
| Orbital insertion | October 20, 1975 |
| Venuslander | |
| Spacecraft component | Lander |
| Landing date | October 22, 1975, 05:13 UTC |
| Landing site | 31°01′N291°38′E/ 31.01°N 291.64°E (nearBeta Regio) |
 Stamp of Venera 9 | |
Orbiter
editThis sectionneeds additional citations forverification.(October 2017) |
The orbiter entered Venus orbit on October 20, 1975. Its mission was to act as a communications relay for the lander and to explore cloud layers and atmospheric parameters with several instruments and experiments. It performed 17 survey missions from October 26, 1975, to December 25, 1975.
The orbiter consisted of a cylinder with twosolar panelwings and a high gain parabolic antenna attached to the curved surface. A bell-shaped unit holding propulsion systems was attached to the bottom of the cylinder, and mounted on top was a 2.4-metre (7.9 ft) sphere which held the lander.
Orbiter design
editThe instruments composing the orbiter included:[7]
- 1.6–2.8μmIRspectrometer
- 8–28 μm IR radiometer
- 352 nm UV photometer
- 2 photo-polarimeters(335–800 nm)
- 300–800 nm spectrometer
- Lyman-α ( Alpha ) H/D spectrometer
- Bistatic radar mapping
- CM, DM radio occultations
- TriaxialMagnetometer
- 345–380 nmUVcamera
- 355–445 nm camera
- 6 electrostatic analyzers
- 2 modulationion traps
- Low-energyproton/Alphadetector
- Low-energyelectrondetector
- 3semiconductorcounters
- 2 gas-discharge counters
- Cherenkov detector
Lander
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The lander was encased in a spherical shell before landing to help protect it from the heat of entry as it slowed from 10.7 kilometres per second (6.6 mi/s) to 150 metres per second (490 ft/s). This sphere was then separated with explosive bolts and a three-domed parachute was deployed which slowed the lander further to 50 metres per second (160 ft/s) at an altitude of 63 kilometres (39 mi) above the planet.[8]
The descent through the cloud layer took about 20 minutes, during which time the lander took measurements of the atmosphere and radioed the information to the orbiter.[8]To minimize lander damage in the hot atmosphere, the parachute was released at an altitude of 50 kilometres (31 mi), and the ring-shaped aerodynamic shield provided braking. The Venusian atmosphere is so dense near the surface that this shield provided a descent rate of 7 metres per second (23 ft/s) as the lander touched down.[8]The landing device, a hollow ring surrounding the lower part of the lander, was partly crushed upon touchdown to take up most of the landing impact.[8]
On October 20, 1975, the lander spacecraft separated from the orbiter, and landing was made with theSunnear zenith at 05:13 UTC on October 22.Venera 9landed within a 150 km (93 mi) radius of31°01′N291°38′E/ 31.01°N 291.64°E,nearBeta Regio,on a steep (20°) slope covered with boulders (suspected to be the slope of thetectonicriftvalley,Aikhylu Chasma). The entry sphere weighed 1,560 kg (3,440 lb) and the surface payload was 660 kg (1,455 lb).[9]
It was the first spacecraft to return an image from the surface of another planet. Many of the instruments began working immediately after touchdown and the cameras were operational 2 minutes later. These instruments revealed a smooth surface with numerous stones. The lander measured a light level of 14,000 lux, similar to that of Earth in full daylight but no direct sunshine.[8]
A system of circulating fluid was used to distribute the heat load. This system, plus pre-cooling prior to entry, permitted operation of the lander for 53 minutes after landing, at which time radio contact with the orbiter was lost as the orbiter moved out of radio range.[7]During descent, heat dissipation and deceleration were accomplished sequentially by protective hemispheric shells, three parachutes, a disc-shaped drag brake, and a compressible, metal, doughnut-shaped landing cushion. The landing was about 2,200 km (1,400 mi) from theVenera 10landing site.
Venera 9measured clouds that were 30–40 km (19–25 mi) thick with bases at 30–35 km (19–22 mi) altitude. It also measured atmospheric chemicals includinghydrochloric acid,hydrofluoric acid,bromineandiodine.Other measurements included surface pressure of about 9,100kilopascals(90atm), temperature of 485°C(905°F), and surface light levels comparable to those atEarthmid-latitudes on a cloudy summer day.Venera 9was the first probe to send back television pictures (black and white) from the Venusian surface, showing no shadows, no apparent dust in the air, and a variety of 30 to 40 cm (12 to 16 in) rocks which were not eroded. Planned 360-degree panoramic pictures could not be taken because one of two camera lens covers failed to come off, limiting pictures to 180 degrees. This failure recurred withVenera 10.
Lander payload
editThe lander payload was as follows:[7]
- Temperature and pressure sensors
- Accelerometer
- Visible / IRphotometer– IOV-75
- Backscatter and multi-anglenephelometers– MNV-75
- P-11mass spectrometer– MAV-75
- Panoramictelephotometers(2, with lamps)
- Anemometer– ISV-75
- Gamma-ray spectrometer– GS-12V
- Gamma-raydensitometer– RP-75
See also
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References
edit- ^Siddiqi, Asif (2018).Beyond Earth: A Chronicle of Deep Space Exploration, 1958–2016(PDF)(second ed.). NASA History Program Office.
- ^abMcDowell, Jonathan."Launch Log".Jonathan's Space Page.RetrievedApril 11,2013.
- ^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. 127–128.ISBN978-1-62683-042-4.LCCN2017059404.SP2018-4041.
- ^"History of the Venera 75 project".RussianSpaceWeb.
- ^"Venera 9".NASA Space Science Data Coordinated Archive.RetrievedApril 13,2013.
- ^"Solar System Exploration Multimedia Gallery: Venera 9".NASA.Archived fromthe originalon August 3, 2009.RetrievedAugust 7,2009.
- ^abcMitchell, Don P."First Pictures of the Surface of Venus".RetrievedApril 13,2013.
- ^abcdeKeldysh, M. V., 1977: "Venus Exploration with the Venera 9 and Venera 10 Spacecraft", Icarus,30:605-625.
- ^Interplanetary Spacecraft