Vega 2
Soviet probe that studied Venus and Halley's Comet.
Vega 2 was a Soviet space probe developed as part of the Vega program to explore Halley's Comet and Venus. It was built by Lavochkin as a 5VK design from the Babakin Space Centre, based on earlier Venera craft. The spacecraft carried instruments including cameras, a spectrometer, magnetometers and plasma probes, and was protected against cometary dust by a dual bumper shield.
Quick Facts
- Names list
- Venera–Halley 2
- Operator
- Soviet space program
- Satcat
- 15449; 15856; 15857
- Mission duration
- Lander: 56 minutes
- Balloon: 15 Jun 1985, 17 Jun 1985
- Flyby: 21 Dec 1984, 24 Mar 1987
- Spacecraft
- 5VK No. 902
- Manufacturer
- NPO Lavochkin
- Launch mass
- 4,840 kg / 10,670 lb
- Landing mass
- 1,520 kg / 3,351 lb
Facts from the source article.
Venus mission
The descent module reached Venus on 15 June 1985, two days after its release from the Vega 2 flyby probe. The 1,500 kg, 240 cm sphere held a surface lander and a balloon explorer. The flyby probe used Venus for a gravity assist and continued toward the comet. The lander, identical to Vega 1's and to six earlier Venera landers, studied the atmosphere and surface. Its payload included a UV spectrometer, temperature and pressure sensors, a water concentration meter, a gas-phase chromatograph, an X-ray spectrometer, a mass spectrometer, and a surface sampling device. Several instruments were developed with French scientists. Because the landing occurred at night, no images were taken. The lander touched down at 03:00:50 UT on 15 June 1985 in Rusalka Planitia, northern Aphrodite Terra, at an altitude 0.1 km above the planetary mean radius. Pressure at the site was 91 atm and temperature 736 K. The surface sample was an anorthosite–troctolite rock, rare on Earth but present in lunar highlands, suggesting the area was the oldest explored by any Venera vehicle. Data was transmitted for 56 minutes. The lander/balloon capsule entered the atmosphere at 125 km altitude at 02:06:04 UT on 15 June 1985 at about 11 km/s. At 02:06:19 UT the parachute on the landing craft cap opened at 64 km; the cap and parachute were released 15 seconds later at 63 km. The balloon package was pulled out by parachute 40 seconds later at 61 km altitude at 7.45°S, 179.8°E. A second parachute opened at 55 km, 200 seconds after entry, extracting the furled balloon.
Halley mission
After Venus, the mothership was redirected by the planet's gravity to intercept Halley's Comet. The encounter began on 7 March 1986 with 100 photos taken from 14,000,000 km. Closest approach occurred at 07:20 UT on 9 March 1986 at 8,030 km. The intensive examination covered the three hours around closest approach, measuring the nucleus's physical parameters, coma structure and dynamics, gas composition near the nucleus, dust properties, and cometary-solar wind interaction. Vega 2 took 700 images with better resolution than Vega 1 due to less dust outside the coma, but recorded an 80% power loss during encounter. Further imaging sessions occurred on 10 and 11 March 1986, after which the primary mission ended.
Post Halley
The Vega 2 probe lacked the fuel to adjust its course for a planned 6 million kilometer flyby of the asteroid 2101 Adonis. Instead, it measured dust while crossing the orbital paths of three comets: 72P/Denning–Fujikawa, Biela's Comet, and 289P/Blanpain. Mission controllers lost contact with Vega 2 on March 24, 1987. The spacecraft now orbits the Sun with a perihelion of 0.70 AU, aphelion of 0.98 AU, an eccentricity of 0.17, an inclination of 2.3 degrees, and an orbital period of 281 days.
More in Space Probes of ESA, Japan, China, India and the USSR
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