Vega 1 and 2
Twin spacecraft that dropped balloons into Venus's clouds, then took the first pictures of a comet's nucleus.
Key facts
- Agency
- Soviet Union, with European partners
- Type of mission
- Venus landers and balloons, then comet flybys
- Target
- Venus, then comet 1P/Halley
- Launched
- 15 and 21 December 1984
- Status
- Completed
The two Vega spacecraft had a double mission. Their name comes from the Russian words for Venus and Halley. In June 1985, as they flew past Venus, each released a lander that descended to the surface and a balloon that floated in the planet's clouds for about two days, sending back measurements of the winds.
Halley's Comet
The spacecraft then used Venus's gravity to swing on towards Halley's Comet. Vega 1 passed it on 6 March 1986 at about 8,900 kilometres, and Vega 2 on 9 March at about 8,000 kilometres. They took the first pictures of a comet's nucleus, showing a dark, irregular body roughly 15 kilometres long, wrapped in bright jets of gas and dust.
Their dust analysers found that many grains were made largely of the light elements carbon, hydrogen, oxygen and nitrogen, nicknamed CHON particles, alongside grains of rocky silicate. That revealed comets as a mixture of rock and organic matter.
Pathfinder
The Vega spacecraft's exact positions of the nucleus were passed to the European team running Giotto, which was to fly much closer. That international help let Giotto be aimed precisely. It became known as the Pathfinder project.
Why it matters to meteorites
The mixture of silicate and organic dust seen in Halley is also found in carbonaceous chondrites and in interplanetary dust particles collected in Earth's stratosphere.
Key dates
| Date | What happened |
|---|---|
| 15 December 1984 | Vega 1 launched. |
| 21 December 1984 | Vega 2 launched. |
| June 1985 | Both craft released landers and balloons at Venus. |
| 6 March 1986 | Vega 1 passed Halley's Comet at about 8,900 km. |
| 9 March 1986 | Vega 2 passed Halley's Comet at about 8,000 km. |
See where this mission fits among all the others in the mission timeline.
Did you know?
The Vega balloons were the first instruments to float in the atmosphere of another planet.
The nucleus of Halley turned out to be one of the darkest objects in the Solar System.
Related pages
Comets connected with this mission: Halley's Comet. See all comets.