Venera 9

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Venera 9
Venera 9 orbiter.jpg
Venera 9 orbiter
Mission type Venus orbiter/lander
COSPAR ID Orbiter: 1975-050A
Lander: 1975-050D
SATCAT № Orbiter: 7915
Lander: 8411
Mission duration 200 days
Spacecraft properties
Spacecraft 4V-1 No.660
Launch mass 2,015 kilograms (4,442 lb)
Start of mission
Launch date June 8, 1975, 02:38:00 (1975-06-08UTC02:38Z) UTC[1]
Rocket Proton-K/D[1]
Launch site Baikonur 81/24
End of mission
Last contact Lander: October 22, 1975
Orbiter: 25 December 1975 (1975-12-26)
Orbital parameters
Reference system Cytherocentric
Eccentricity 0.89002
Pericytherion 7,625 kilometres (4,738 mi)
Apocytherion 118,072 kilometres (73,367 mi)
Inclination 29.5 degrees
Period 48.3 hours
Venus orbiter
Spacecraft component Orbiter
Orbital insertion October 20, 1975
Venus lander
Spacecraft component Lander
Landing date October 22, 1975, 05:13 UTC
Landing site 31°01′N 291°38′E / 31.01°N 291.64°E / 31.01; 291.64

Venera 9 (Russian: Венера-9 meaning Venus 9), manufacturer's designation: 4V-1 No. 660,[2] was a USSR unmanned space mission to Venus. It consisted of an orbiter and a lander. It was launched on June 8, 1975 02:38:00 UTC and had a mass of 4,936 kg (10,884 lb).[3] The orbiter was the first spacecraft to orbit Venus, while the lander was the first to return images from the surface of another planet.[4]

Orbiter[edit]

The orbiter consisted of a cylinder with two solar panel wings 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 meter sphere which held the lander.

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.

List of orbiter instruments and experiments[edit]

180-degree panorama taken by Venera 9 of the surface of Venus

[5]

  • 1.6-2.8 μm IR Spectrometer
  • 8-28 μm IR Radiometer
  • 352 nm UV Photometer
  • 2 Photo-polarimeters (335-800 nm)
  • 300-800 nm Spectrometer
  • . Lyman-α H/D Spectrometer
  • Bistatic Radar Mapping
  • CM, DM Radio Occultations
  • Triaxial Magnetometer
  • 345-380 nm UV Camera
  • 355-445 nm Camera
  • 6 Electrostatic Analyzers
  • 2 Modulation Ion Traps
  • Low-Energy Proton / Alpha detector
  • Low-Energy Electron detector
  • 3 Semiconductor Counters
  • 2 Gas-Discharge Counters
  • Cherenkov Detector

Lander[edit]

Venera 9 lander

On October 20, 1975, the lander spacecraft was separated from the orbiter, and landing was made with the Sun near zenith at 05:13 UTC on October 22. Venera 9 landed within a 150 km radius of 31°01′N 291°38′E / 31.01°N 291.64°E / 31.01; 291.64, near Beta Regio, on a steep (20°) slope covered with boulders (suspected to be the slope of the tectonic rift valley, Aikhulu Chasma). The entry sphere weighed 1,560 kg (3,440 lb) and the surface payload 660 kg (1,455 lb).[6]

It was the first spacecraft to return an image from the surface of another planet. The Soviet space program had far more success with Venus landers than Mars landers, possibly because the mechanics of landing on Venus involve fewer steps than Mars due to the much thicker atmosphere.

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.[5] 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 from the Venera 10 landing site.

Venera 9 measured clouds that were 30–40 km thick with bases at 30–35 km altitude. It also measured atmospheric chemicals including hydrochloric acid, hydrofluoric acid, bromine, and iodine. Other measurements included surface pressure of about 90 atmospheres (9 MPa), temperature of 485 °C, and surface light levels comparable to those at Earth mid-latitudes on a cloudy summer day. Venera 9 was the first probe to send back black and white television pictures from the Venusian surface showing shadows, no apparent dust in the air, and a variety of 30 to 40 cm 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 with Venera 10.

Lander payload[5][edit]

Image processing[edit]

Don P. Mitchell recently came across the original Venera imaging data while researching the Soviet Venus program, and reconstructed the images using modern image processing software.

References[edit]

  1. ^ a b McDowell, Jonathan. "Launch Log". Jonathan's Space Page. Retrieved 11 April 2013. 
  2. ^ [1] RussianSpaceWeb.com
  3. ^ "NSSDC Master Catalog - Venera 9". NASA National Science Data Center. Retrieved 13 April 2013. 
  4. ^ Solar System Exploration Multimedia Gallery: Venera 9, NASA website, accessed August 7, 2009.
  5. ^ a b c Mitchell, Don P. "First Pictures of the Surface of Venus". Retrieved 13 April 2013. 
  6. ^ Interplanetary Spacecraft