Giotto science highlights

Encounters with Comets Halley and Grigg-Skjellerup

Giotto was ESA's first deep-space mission. In 1986, it passed closest to the nucleus of a comet, Halley. Its images showed for the first time the shape of a comet nucleus and found the first evidences of organic material in a comet.

In 1992, after a long cruise through space, scientists directed Giotto to Comet Grigg-Skjellerup. It sent back a lot of information, passing just 200 kilometres from the nucleus.

• Giotto took the first ever close-up images of a comet nucleus.
• It was the first deep-space mission to change orbit by returning to Earth from an interplanetary trajectory for a gravity-assist.
• Giotto discovered the size and shape of Comet Halley's nucleus, found that its surface is very dark (the blackest object in the solar system) and that it emitted jets of gas and dust.
• Giotto made the closest comet fly-by to date by any spacecraft (about 200 kilometres from Comet Grigg-Skjellerup).