The NASA Stardust mission was launched over seven years ago and has travelled several thousand millions of kilometres in deep space, chasing Comet Wild 2. In January 2004, the spacecraft encountered the comet to collect samples of particles ejected from its nucleus.
This was achieved with a sample canister containing cells filled with 'Aerogel', an extremely lightweight, porous material based on silicon technology, ideal for slowing down the fast-moving dust particles and collecting them. These particles are moving at 'hypervelocities', i.e. speeds of up to seven kilometres per second.
During the encounter with Wild 2, the canister was exposed to the cometary particles and then retracted inside the spacecraft and stored in its Sample Return Capsule. The spacecraft then began its two-year journey back to Earth to return carrying its precious cargo. Also a sample of interstellar dust was collected during the journey.
When we want to understand the origin and evolution of the Solar System, comets are among the most informative of its inhabitants. They formed four and a half thousand million years ago and have remained almost unchanged since then.
Studying them can provide important clues about the origin of the material out of which the Solar System formed, and could even help in understanding the origins of life on Earth.
"Missions like Stardust provide not only valuable data by the first-ever study in terrestrial laboratories of particles ejected from a known comet and collected in the very close vicinity to it," said Gerhard Schwehm, ESA's Rosetta Project Scientist.
"Results from such missions, which include ESA's Giotto spacecraft to Comet Halley in 1986, are also very important for the preparation and fine-tuning of
Contact: Michel van Baal
European Space Agency