Venera 9
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| Venera 9 | |
 Venera 9 orbiter |
|
| Organization | USSR |
|---|---|
| Mission type | Orbiter and Lander |
| Satellite of | Venus |
| Orbital insertion date | October 20, 1975 |
| Launch date | June 8, 1975 |
| Launch vehicle | Proton Booster Plus Upper Stage and Escape Stages |
| Mission duration | June 8, 1975 to ~December 25, 1975? |
| NSSDC ID | 1975-050D |
| Mass | 2015 kg |
| Orbital elements | |
| Eccentricity | .89002 |
| Inclination | 29.5° |
| Orbital period | 48.3 h |
| Apoapsis | 19.51 RV |
| Periapsis | 1.26 RV |
Venera 9 (Russian: Венера-9) 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 weighed 4,936 kg (10,884 lb).
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[edit] Orbiter
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:
- 1.6-2.8 μm IR Spectrometer
- 8-28 μm IR Radiometer
- 352 nm UV Photometer
- 2 Photopolarimeters (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
[edit] 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 , 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).[1]
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 spacecraft for 53 minutes after landing. 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.
[edit] Image processing
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. This has produced much clearer pictures than were previously available, as is apparent from a comparison between the Venera 9 photo on Wikimedia Commons and the reconstructed version on Mitchell's website.[2]
[edit] References
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