What cargo gets such royal reentry treatment? No less than rare samples collected from the sun--and the first extraterrestrial shipment brought to Earth since 1976. For the past three years NASA's robotic Genesis spacecraft has been in orbit 930,000 miles from Earth, catching billions of atoms and ions from solar wind. "The solar particles are in the same chemical proportions as the original solar nebula," says Genesis's principal investigator and geochemist, Don Burnett, referring to the primordial cloud of dust and gas that birthed the solar system some five billion years ago. Scientists say the particle samples will help them better grasp how planets and other celestial objects formed.