This coming Sunday, if all goes well, the Stardust probe will land in the Utah desert carrying microscopic dust gathered from Comet Wild 2 and interstellar space. This was a seven-year, 2.88 billion mile, 200 million dollar mission. You can follow the exciting progress at the official NASA link. The comet and interstellar dust is captured in an aerogel array mounted on the spacecraft.
It is expected that a few thousand cometary dust grains and just 45 interstellar submicroscopic grains will be captured by the collector. The grains will be embedded at high speed into the gel and create tracks like subatomic particles in a bubble chamber. Digital images will be taken and must be analyzed by hand. It is expected that 30,000 person hours will be required to examine 1.5 million images. NASA is asking for volunteers to take part through a Seti@home-like project called Stardust@home. Each volunteer must first pass a test where they must find a few tracks on a sample image. If two of four volunteers for a given image finds a track it will then be subjected to the scrutiny of 100 more volunteers. If it still passes muster it will then be examined by a crack team of Berkeley undergraduates. The dust grains will then be extracted by a specially designed microtweeser which wasn’t even developed until after Stardust was launched. I’m dying to find out what sorts of things they’ll find. Who knows, maybe they’ll be some organic molecules and life on earth really was seeded from space.