The Stardust spacecraft launches as part of NASA's
suite of low-cost, science-focused Discovery missions. It will fly
through comet Wild 2 in 2004 and uses a unique substance called
aerogel to collect cometary and interstellar dust particles for
analysis. In 2006, Stardust will be the first comet-sample-return
mission when it delivers its return capsule to the Air Force's Utah
Testing and Training Range.