Encounter with comet Halley
Date: 07 September 2011
Copyright: ESA
Twenty-five years ago, ESA's Giotto probe swept within 600 km of Comet Halley, obtaining the first close-up images of a comet. It revealed the first evidence of organic material in a comet and, still today, much of what we know about comets comes from the pioneering mission.
Launched on 2 July 1985 by Ariane 1, Giotto was ESA's first deep-space mission, part of an ambitious international effort to solve the mysteries surrounding Comet Halley. It was also the first deep-space mission to return from an interplanetary trajectory and use Earth's gravitational field to change orbit.
After a cruise of eight months, Giotto arrived at its destination and revealed the size and shape of Halley's nucleus. It found that the comet's surface is very dark (one of the blackest object in the Solar System) and that it emitted jets of gas and dust.
Giotto's camera recorded many images that gave scientists a rare opportunity – the comet will not return to the inner Solar System again until 2061 – to study Halley intensively. It was particularly important to determine the comet's composition through the readings made by Giotto as it passed through Halley's tail.
After completing its Halley mission, Giotto went into hibernation before being woken up in the summer of 1990 for tests, and then hibernating again until early 1992.
Although a few of the instruments had been damaged during the Halley encounter, the spacecraft had survived the battering by cometary dust and was able to conduct a second flyby, this time of Comet 26P/Grigg-Skjellerup, in July 1992.
This video is a new compilation of Giotto's historic images acquired by the Halley Multicolour Camera (HMC). It shows the comet as seen by the probe as it approached from about 900 000 km, coming to within 596 km.
The images were processed by the HMC team led by Uwe Keller at the Max Planck Institute for Solar System Research (MPS/Lindau). Together with B. Grieger from the Rosetta team at ESA/ESAC, they produced this video in 2011 to mark the 25th anniversary of Giotto's flyby.
Images and video credit/copyright: © MPS 1986–2011