Binary Asteroids: 1999 KW4

Abstract

Binary asteroids are estimated to constitute over 15 percent of the Near-Earth Asteroids and may be as prevalent in the Main Belt as well. There are many important issues of science that can be investigated by studying and sending probes to investigate these systems, and their study has been one of the main foci of asteroid science over the last decade. Thus, it is highly probable that a future space mission will visit a binary asteroid and need to carry out operations in its vicinity. The problem of trajectory design and navigation in these systems is complex and challenging, as it requires modeling of the dynamics of the asteroid system in addition to the motion of the spacecraft about the system. In the most general sense the problem of binary asteroids orbiters integrates four classical problems of astrodynamics: the Hill problem, the restricted three-body problem, the non-spherical orbiter problem and the full two-body problem [162], constituting a complex simulation problem. The general problem has been considered in detail in a number of analyses [165, 36, 38, 37, 35], all involving the solution of the full two-body problem for the gravitating components of the binary asteroid, a topic beyond the current book (Fig. 9.1 shows the general geometric description of this problem). Thus in this chapter we introduce the simplest model for a binary asteroid, which is still sufficient for initial mission design and analysis for many of the observed binary systems.