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Halley's comet fly by space mission

Giotto was a European robotic spacecraft mission from the European Space Agency. The spacecraft flew by and studied Halley's Comet and in doing so became the first spacecraft to make close up observations of a comet. On 13 March 1986, the spacecraft succeeded in approaching Halley's nucleus at a distance of 596 kilometers. It was named after the Early Italian Renaissance painter Giotto di Bondone. He had observed Halley's Comet in 1301 and was inspired to depict it as the star of Bethlehem in his painting Adoration of the Magi in the Scrovegni Chapel.

Originally a United States partner probe was planned that would accompany Giotto, but this fell through due to budget cuts at NASA. There were plans to have observation equipment on board a Space Shuttle in low Earth orbit around the time of Giottos fly by, but they in turn fell through with the Challenger disaster. The plan then became a cooperative armada of five space probes including Giotto, two from the Soviet Union's Vega program and two from Japan: the Sakigake and Suisei probes. The idea was for Japanese probes and the pre existing American probe International Cometary Explorer to make long distance measurements, followed by the Russian Vegas which would locate the nucleus, and the resulting information sent back would allow Giotto to precisely target very close to the nucleus. Because Giotto would pass so very close to the nucleus ESA was mostly convinced it would not survive the encounter due to the spacecraft colliding at very high speed with the many dust particles from the comet. The coordinated group of probes became known as the Halley Armada.

The Soviet Vega 1 started returning images of Halley on 4 March 1986, and the first ever of its nucleus, and made its flyby on 6 March, followed by Vega 2 making its flyby on 9 March. Vega 1's closest approach to Halley was
8 889 km. Giotto passed Halley successfully on 14 March 1986 at 596 km distance, and surprisingly survived despite being hit by some small particles. One impact sent it spinning off its stabilized spin axis so that its antenna no longer always pointed at the Earth, and its dust shield no longer protected its instruments. After 32 minutes Giotto re stabilized itself and continued gathering science data. Another impact destroyed the Halley Multicolor Camera, but not before it took photographs of the nucleus at closest approach.

Giottos trajectory was adjusted for an Earth flyby and its science instruments were turned off on 15 March 1986 at 02:00 UTC.

Giotto was commanded to wake up on 2 July 1990 when it flew by Earth in order to sling shot to its next cometary encounter. The probe then flew by the Comet Grigg–Skjellerup on 10 July 1992 which it approached to a distance of about 200 km. Afterwards, Giotto was again switched off on 23 July 1992.

In 1999 Giotto made another Earth flyby but was not reactivated.