Orbital evolution of two near-earth asteroids: Nereus and 1989 ML Original Research Article

In 2002, the Institute of Space and Astronautical Science (ISAS) of Japan will send the MUSES-C spacecraft to an asteroid to get the surface material of the asteroid, and return them to the Earth in 2006. The target asteroid is (4660) Nereus, and the backup target is 1989 ML. In this paper, we studied the orbital evolution of these asteroids. We found that both of these asteroids show chaotic motions. In particular the motion of Nereus is quite chaotic, so we cannot determine its orbital evolution for more than 200 years. However, we also found that these asteroids have been moving around the Sun in asteroid-like orbits for at least 5,000 years.