History of cometary missions
Here is an up-to-date summary of all previous and planned international cometary missions.
International Cometary Explorer (ICE)
Launched on 12 August 1978, ICE achieved the first-ever comet encounter. This NASA spacecraft was originally known as ISEE-3 (International Sun-Earth Explorer).
Having completed its original mission, it was reactivated and diverted to pass through the tail of Comet Giacobini-Zinner on 11 September 1985. It also observed Comet Halley from a distance of 28 million kilometres in March 1986.
Vega-1 and Vega-2
Launched on 15 and 20 December 1984, these two Russian probes each left a lander on the surface of Venus as they flew past it on the way to investigate and photograph Comet Halley.
Vega-1 made its closest approach to the comet on 6 March 1986 at a distance of 39 000 kilometres. Vega-2 flew in closer to the comet nucleus at a distance of 8030 kilometres on 9 March 1986.
Sakigake and Suisei
Launched 8 January 1985 and 19 August 1985, these twin spacecraft were Japan’s first deep-space missions.
Suisei approached to within 151 000 kilometres of Comet Halley on 8 March 1986 to observe its interactions with the solar wind. Sakigake approached to within seven million kilometres of the comet on 11 March 1986.
Giotto
Launched 2 July 1985, ESA’s Giotto obtained the closest pictures ever taken of a comet. This spacecraft flew past the nucleus of Comet Halley at a distance of less than 600 kilometres on 13 March 1986.
Images showed a black, potato-shaped object with active regions which were firing jets of gas and dust into space. Giotto then became the first spacecraft to visit two comets when it passed within 200 kilometres of Comet Grigg-Skjellerup on 10 July 1992.
Giotto was placed in hibernation on 23 July 1992, and the spacecraft has since been inactive. Giotto returned to the vicinity of the Earth on 1 July 1999. The distance of its closest approach was very uncertain, the estimate being about 220 000 kilometres, just over half the Earth-to-Moon distance. No communication with the spacecraft took place at this time.
Giotto will continue to orbit the Sun for the foreseeable future, completing six revolutions roughly every seven years.
Deep Space 1
This is the first spacecraft in NASA’s New Millennium programme. Launched 25 October 1998, its primary mission was to test 12 new advanced technologies. It approached within 26 kilometres of Asteroid 9969 Braille on 28 July 1999.
The few pictures returned showed that Braille's longest side is about 2.2 kilometres across and its shortest side appears to be one kilometre. In an extended mission, it encountered Comet Borrelly in September 2001 and returned the images and other science data. The spacecraft was retired on 18 December 2001.
Stardust
Launch 7 February 1999, this NASA mission travelled into the cloud of ice and dust that surround the nucleus of Comet Wild-2, coming to within 150 kilometres (100 miles) of the nucleus itself on 1 January 2004. There, it gathered comet dust particles and will deliver them back to Earth.
En route to the comet, Stardust attempted to capture interstellar particles that are believed to be blowing through our Solar System. The mission ends in January 2006, when the Stardust sample return capsule will return to Earth.
Contour (Comet Nucleus Tour)
Launched on 3 July 2002, Contour was a NASA mission to improve our understanding of comet nuclei. Encounters were planned with three comets. The spacecraft remained in Earth orbit until 15 August 2002, when it began the transit to Comet Encke. NASA controllers were not able to re-establish contact with the spacecraft following this manoeuvre and concluded the spacecraft was lost.
Deep Impact
This is a planned NASA mission to Comet Tempel 1, to be launched in December 2004. It will consist of two craft that will separate when the comet is reached. The main spacecraft will fly by the comet and record images and data. The second craft is the ‘impactor’, which will separate from the fly-by craft and be propelled into a target site of the comet in July 2005.
Last update: 16 July 2008
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