Exploring comets and asteroids



Two upcoming NASA Discovery missions will have close encounters with comets and asteroids.

Scheduled for launch on 1 July 2002, the Comet Nucleus Tour (CONTOUR) mission will photograph, map, and analyze at least two comets at a distance of about 160 kilometers from their nuclei. Comet Encke, which CONTOUR will encounter in November 2003, circles the Sun in 3.2 years and has the shortest orbital period of any known comet. Comet Schwassmann-Wachmann 3 presents an opportunity for CONTOUR in June 2006 to possibly examine subsurface material that was exposed when a large piece split from the comet in 1996.