Giotto

A European Space Agency probe, which encountered Halley's Comet in March 1986. Up to two seconds before closest approach, a distance of 605 kilometres from the nucleus, all experiments worked perfectly. At that moment, a collision with a small particle caused the craft to wobble so that the communications antenna was not directed towards Earth. Communications were re-established after the encounter. The multicolour camera returned images, including close-ups of the nucleus, until the moment when contact was lost; it was subsequently destroyed by impacts. The other instruments on board included a dust impact detector and an ion mass spectrometer, which observed that the gas in the coma is 80 per cent water (by mass). When the dust and gas are considered together, the composition was found to be (by mass) 45 per cent water, 28 per cent stony material and 27 per cent organic material. ESA named the mission after the artist Giotto di Bondone, who is thought to have used the 1301 appearance of Halley's Comet as a model for the star of Bethlehem in his fresco, The Adoration of the Magi, painted in 1303 in the Scrovegni chapel in Padua. In 1992, Giotto was successfully reactivated after two years' dormancy and seven years in space for an encounter with Comet 26P/Grigg-Skjellerup, a project known as the Giotto Extended Mission (GEM).