Craft Blasts Off on a Collision Course with Comet. NASA's Deep Impact spacecraft sets off on a 268-million-mile collision course with a comet. If all goes as planned, the craft will crash into Comet Tempel 1 on July 4, releasing particles that could provide a glimpse into the origins of the solar system. [NPR News: Health & Science] comments< 4:13:29 PM
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