Giotto
The Giotto space probe, launched in 1985 on an Ariane 1 V14 launcher, brushed past the hidden nucleus of Halley's comet in 1986. Its camera recorded many images that gave scientists an unique opportunity (the comet will not pass close to the Earth again until 2061) to increase their knowledge of comets.
Though damaged by the multiple impacts, Giotto carried on with its mission. After a period of hibernation, it was reactived in 1990 for a fresh task - flying by comet Grigg-Skjellerup on 10 July 1992. Giotto was the first probe to study two comets.
