Stardust was the first spacecraft ever to bring back to Earth extraterrestrial materials from beyond the Moon. It was two missions in one spacecraft. Stardust returned the first samples from a known primitive solar system body, the Jupiter-family comet Wild 2. Stardust also carried a separate collector that was exposed the interstellar dust stream for 200 days before the encounter with the comet. These tiny rocks — a trillion would fit into a teaspoon — were identified in the returned collector by a small army of more than 30,000 citizen scientists, through a project called Stardust@home.
