Extended-mission opportunities for a Discovery-class asteroid rendezvous mission

The nominal target for NASA's proposed Near-Earth Asteroid Rendezvous (NEAR) mission is a small object called 4660 Nereus (formerly known as 1982 DB). A Delta-7925 rocket will be used to launch the NEAR spacecraft towards this body in January 1998. On its way to Nereus, NEAR will perform a flyby of the main-belt asteroid, 2019 Van Albada. The rendezvous phase at Nereus will begin in January 2000. It is planned to initiate an extended-mission phase on September 12, 2000. On this date, a small propulsive maneuver will be used to retarget NEAR for an Earth encounter in February 2002. Different combinations of Earth-swingby and propulsive maneuvers can then be used to redirect the NEAR spacecraft to a variety of asteroids and comets. Possible targets include Encke's comet, the large near-Earth asteroids, 433 Eros and 1036 Ganymed, a prominent main-belt asteroid, 4 Vesta, and a defunct comet nucleus, 4015 (1979 VA). The majority of the extended-mission scenarios presented here contain multiple-encounter sequences. In one plan, called the Small-Body Grand Tour, flybys of two comets and two asteroids are achieved over a 10-year period.