Its primary mission satisfactorily completed, the NASA/ESA ISEE-3 (International Sun-Earth Explorer 3) satellite has a surplus of maneuvering fuel left over, and is given a new mission: it begins a series of over a dozen maneuvers utilizing both thrusters and gravity-assists, intended to push it out of its LaGrange point between Earth and the sun and toward a 1985 rendezvous with Comet Giacobinni-Zinner. Upon its final maneuver in 1983, ISEE-3 will be renamed ICE (International Cometary Explorer) and, after the complex series of course changes, will be perfectly targeted for its 1985 comet encounter.
