On the fortieth anniversary of the launch of the Vega interplanetary probes, which launched from the Baikonur Cosmodrome in December 1984, Roscosmos published several declassified documents related to these missions. A message about this appeared on the official website of the state corporation.
Model of Vega station / Image source: Wikipedia
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The Vega-1 and Vega-2 stations were completely identical in terms of the tasks they solved, flight patterns, design, as well as the composition of systems and scientific equipment. They consisted of two parts: the flyby vehicle and the descent vehicle. The launch of two identical stations was due to the need to increase the overall reliability of the expeditionary mission, as well as to conduct contact studies of the surface of Venus in two different regions of the planet and study Halley’s Comet at its different distances from the Sun.
The duration of the flight from Earth to Venus was 178 days for the Vega-1 station, and 176 days for the Vega-2 station. To guide the descent vehicles to the specified entry points into the planet’s atmosphere during the flight phase, two adjustments were made. For the first time in world cosmonautics, a balloon probe was used as a research tool. It flew at an altitude of 53-55 km from the surface of Venus and made meteorological measurements, and transmitted the received data to Earth at a wavelength of 18 cm. Two networks of radio telescopes were used to receive data.
After the flyby of Venus, the flight trajectory of the stations was adjusted to approach Halley’s Comet. “Vega-1” approached the comet’s nucleus at a distance of 8879 km, and “Vega-2” – at a distance of 8010 km. The flight speed reached 80 km/s. As a result of the study, it was possible to determine the structure and size of the nucleus, infrared temperature, etc. For the first time in history, it was possible to obtain images of the comet’s nucleus, a total of more than 1000 images.