Attitude dynamics of satellites orbiting an asteroid

Attitude motion of satellites orbiting an asteroid is examined. The highly irregular shape of the asteroids along with their rotational states can lead to very interesting attitude dynamics. As a start, the case of uniform rotation of the asteroid is examined and attention is focused on planar attitude motion (pitch). Four asteroids, Vesta, Eros, Gaspra, and Castalia, are considered. For the case of circular equatorial orbits, the radius for which resonant pitch oscillations are excited, is determined. It is noticed that for slowly rotating large asteroids such as Vesta, more than one resonant region can exist. Stability of pitch motion is significantly affected by the rotational state as well as the shape of the small body. General threedimensional attitude motion is considered next. Orbits corresponding to large 3D motion are identified.