Vega 1 and 2 Spacecraft
Vega 1 and Vega 2 (contraction of Venus and Halley in Russian) were two identical spacecraft designed by the USSR in cooperation with European countries to investigate Venus and Comet Halley. Launched from Baikonur by Proton rockets, respectively, on 15 and 21 December 1984, they released modules into Venus’s atmosphere and then flew through Halley’s coma on 6 and 9 March 1986, at 8,900 and 8,000 km nucleocentric distance, playing the role of pathfinders for the Giotto spacecraft. The dust mass spectrometers (PUMA) discovered the presence of a large amount of organic molecules within cometary dust particles. Their elemental composition is therefore called CHON. This acronym stands for the most abundant elements: carbon, hydrogen, oxygen, and nitrogen.
The navigation data of the two Vega spacecraft were used also to help the close flyby of the nucleus of the comet by the European spacecraft named Giotto.