NASA’s Stardust mission marked a major first in space exploration by bringing solid material from a comet back to Earth. During a flyby of comet 81P/Wild 2 on 2 January 2004, the spacecraft passed through the cloud of dust around the comet at about 6.1 kilometres per second.
To collect the particles, Stardust used a tray filled with silica aerogel, an extremely light material designed to slow incoming grains without destroying them. That approach allowed the probe to trap fragile comet dust that would otherwise have been damaged at such high speed.
After gathering the material, the spacecraft carried the samples across roughly 4.6 billion kilometres of space and eventually released them in a return capsule that landed in the Utah desert. The mission became the first to deliver solid pieces of a comet to Earth for direct study.
The returned dust gave scientists a rare chance to examine ancient material left over from the early solar system. By studying those grains in laboratories on Earth, researchers were able to investigate the composition of comet matter in far greater detail than remote observations alone could provide.
