Artist's impression of the Comet Nucleus Tour (CONTOUR) spacecraft during an encounter with comet Schwassmann-Wachmann 3, scheduled for June 2006. The comet broke into at least three pieces after passing near the sun in the 1990s; when CONTOUR reaches SW3 mission scientists hope to see fresh, unaltered surfaces and evidence of the materials inside the comet. CREDIT: NASA/Johns Hopkins University Applied Physics Laboratory/Cornell University
