Вега-2: Исследование Венеры и кометы Галлея

Soviet space probe

Vega 2 (along with Vega 1) was a Soviet space probe part of the Vega program to explore Halley's comet and Venus. The spacecraft was a development of the earlier Venera craft. The name VeGa (ВеГа) combines the first two letters Russian words for Venus (Венера: "Venera") and Halley (Галлея: "Galleya") They were designed by Babakin Space Centre and constructed as 5VK by Lavochkin at Khimki. The craft was powered by large twin solar panels. Instruments included an antenna dish, cameras, spectrometer, infrared sounder, magnetometers (MISCHA) and plasma probes. The craft was launched on top of a Proton 8K82K rocket from Baikonur Cosmodrome, Tyuratam, Kazakh SSR. Both Vega 1 and 2 were three axis stabilized spacecraft. The spacecraft were equipped with a dual bumper shield for dust protection from Halley's Comet.

The descent module arrived at Venus on 15 June 1985, two days after being released from the Vega 2 flyby probe. The module, a , diameter sphere, contained a surface lander and a balloon explorer. The flyby probe performed a gravitational assist maneuver using Venus, and continued its mission to intercept the comet.

The surface lander was identical to that of Vega 1 as well as the previous six Venera missions. The objective of the probe was the study of the atmosphere and the exposed surface of the planet. The scientific 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 of these scientific tools (the UV spectrometer, the mass spectrograph, and the devices to measure pressure and temperature) were developed in collaboration with French scientists.

The Vega 2 Lander/Balloon capsule entered the Venusian atmosphere ( altitude) at 02:06:04 UT (Earth received time; Moscow time 05:06:04) on 15 June 1985 at roughly At approximately 2:06:19 UT the parachute attached to the landing craft cap opened at an altitude of The cap and parachute were released 15 seconds later at altitude. The balloon package was pulled out of its compartment by parachute 40 seconds later at altitude, at 7.45 degrees S, 179.8 degrees east. A second parachute opened at an altitude of , 200 seconds after entry, extracting the furled balloon. The balloon was inflated 100 seconds later at and the parachute and inflation system were jettisoned. The ballast was jettisoned when the balloon reached roughly and the balloon floated back to a stable height between some 15 to 25 minutes after entry. The mean stable height was , with a pressure of and a temperature of in the middle, most active layer of the Venus three tiered cloud system. The balloon drifted westward in the zonal wind flow with an average speed of about at nearly constant latitude. The probe crossed the terminator from night to day at 9:10 UT on 16 June after traversing The probe continued to operate in the daytime until the final transmission was received at 00:38 UT on 17 June from 7.5 S, 76.3 E after a total traverse distance of It is not known how much further the balloon traveled after the final communication. Contact with Vega 2 was lost on 24 March 1987. Vega 1 had previously exhausted its attitude control propellant on 30 January 1987. Vega 2 is currently in heliocentric orbit, with perihelion of 0.70 AU, aphelion of 0.98 AU, eccentricity of 0.17, inclination of 2.3 degrees and orbital period of 281 days.