Dr. Westphal explains, “We hope to understand the grand cycle of matter in the Galaxy: how it’s formed in stars, ejected out into the interstellar medium, processed through shocks and bombardment by other particles, and incorporated again back into new solar systems. Stardust was the first spacecraft to return solid samples of extraterrestrial material from beyond the Moon. The spacecraft visited Comet Wild 2 (pronounced Vilt two), which has apparently been in the inner Solar System only since 1976. Before that, all the way back since the Solar System formed 4.5 billion years ago, it was in the outer Solar System in deep freeze.”
Capturing comet and stardust particles is no easy task. After many years of planning, Stardust launched in 1999 and spent 7 years in space, before returning its samples back to Earth for analysis. In addition to the technical challenges of rendezvousing with a comet and achieving a safe, soft landing for the spacecraft’s precious cargo, there was the difficulty of collecting the particles in the first place. The tiny particles move at tens of thousands of miles per hour, so just slowing them down enough to capture them without vaporizing them entirely is a huge challenge.