Giotto

Europe's first deep-space mission flew within 600 kilometres of Halley's Comet.

Key facts

Agency

European Space Agency (ESA)

Type of mission

Comet flybys

Target

Comet 1P/Halley and comet 26P/Grigg–Skjellerup

Launched

2 July 1985

Status

Completed 1992

Giotto was named after the Italian painter Giotto di Bondone, who saw Halley's Comet in 1301 and painted a comet as the Star of Bethlehem in a fresco a few years later. It was the European Space Agency's first mission beyond Earth's orbit.

The encounter

Guided by positions from the Soviet Vega craft, Giotto passed the nucleus of Halley's Comet on the night of 13 to 14 March 1986 at about 600 kilometres, travelling at 68 kilometres per second relative to the comet. A shield at the front protected it from dust. Seconds before closest approach, a larger dust grain struck and set it wobbling, and some instruments, including the camera, were damaged.

Its pictures showed a peanut-shaped nucleus about 15 kilometres long, as black as velvet, with jets of gas and dust erupting from a few active patches on the sunlit side. Its mass spectrometers measured the dust grain by grain, finding both rocky silicate grains and CHON grains rich in carbon, hydrogen, oxygen and nitrogen.

A second comet

In 1990 Giotto returned past Earth, the first deep-space probe to use Earth's gravity to change course. On 10 July 1992 it flew past a second comet, 26P/Grigg–Skjellerup, at only about 200 kilometres.

Why it matters to meteorites

Giotto showed that comet dust is a mixture of minerals and organic matter much like the most primitive meteorites and micrometeorites. Halley's dust is what we see each year as the Orionid and Eta Aquariid meteors.

Key dates

See where this mission fits among all the others in the mission timeline.

Did you know?

Related pages

Comets connected with this mission: Halley's Comet, Comet Grigg–Skjellerup. See all comets.