The Stardust mission collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for study. Preliminary analysis shows that the nonvolatile portion of the comet contains an unequilibrated mix of materials with both presolar and solar system origins. The comet contains abundant silicate grains larger than predicted by interstellar grain models, many of which are high-temperature minerals formed in the inner solar nebula. Their presence in a comet indicates that the solar system's formation involved large-scale mixing. Stardust was the first mission to return solid samples from a comet other than the Moon. The samples, collected from a comet believed to have formed in the outer solar nebula, provide new insights into the solar system's formation. The samples offer unprecedented opportunities to compare preserved building blocks from the edge of the solar system with data from asteroids and other bodies. The comet's samples are the first primitive materials from a known body and provide context for all primitive meteoritic samples. The Stardust spacecraft collected over 10,000 particles during its 2004 flyby of comet Wild 2. These particles, which range in size from 1 to 300 micrometers, were returned to Earth in 2006. The particles were collected in silica aerogel and aluminum, and their impact features reveal information about the comet's composition and structure. The aerogel collected particles that were not altered by internal processes, indicating that the comet's surface was not significantly modified by heating or aqueous alteration. The Stardust mission's samples include a variety of materials, including silicate minerals, sulfides, and organic compounds. These samples provide insights into the formation of comets, the origin of crystalline silicates around stars, and large-scale mixing in the solar nebula. The samples also show that the comet contains materials that may have formed in the inner solar nebula and were transported outward, indicating that the solar nebula was not well mixed. The Stardust mission's findings suggest that the solar nebula had significant radial transport of solids, and that comets may have formed in the outer solar system. The samples also indicate that the comet contains materials that may have formed in the inner solar nebula and were transported outward, indicating that the solar nebula was not well mixed. The Stardust mission's findings provide important insights into the origin of the solar system and the formation of planetary bodies.The Stardust mission collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for study. Preliminary analysis shows that the nonvolatile portion of the comet contains an unequilibrated mix of materials with both presolar and solar system origins. The comet contains abundant silicate grains larger than predicted by interstellar grain models, many of which are high-temperature minerals formed in the inner solar nebula. Their presence in a comet indicates that the solar system's formation involved large-scale mixing. Stardust was the first mission to return solid samples from a comet other than the Moon. The samples, collected from a comet believed to have formed in the outer solar nebula, provide new insights into the solar system's formation. The samples offer unprecedented opportunities to compare preserved building blocks from the edge of the solar system with data from asteroids and other bodies. The comet's samples are the first primitive materials from a known body and provide context for all primitive meteoritic samples. The Stardust spacecraft collected over 10,000 particles during its 2004 flyby of comet Wild 2. These particles, which range in size from 1 to 300 micrometers, were returned to Earth in 2006. The particles were collected in silica aerogel and aluminum, and their impact features reveal information about the comet's composition and structure. The aerogel collected particles that were not altered by internal processes, indicating that the comet's surface was not significantly modified by heating or aqueous alteration. The Stardust mission's samples include a variety of materials, including silicate minerals, sulfides, and organic compounds. These samples provide insights into the formation of comets, the origin of crystalline silicates around stars, and large-scale mixing in the solar nebula. The samples also show that the comet contains materials that may have formed in the inner solar nebula and were transported outward, indicating that the solar nebula was not well mixed. The Stardust mission's findings suggest that the solar nebula had significant radial transport of solids, and that comets may have formed in the outer solar system. The samples also indicate that the comet contains materials that may have formed in the inner solar nebula and were transported outward, indicating that the solar nebula was not well mixed. The Stardust mission's findings provide important insights into the origin of the solar system and the formation of planetary bodies.