Approaching Small Bodies

This paper presents analysis of when and how well, on the approach to previously unvisited small bodies, the trajectory-design relevant physical parameters are determined. Quick acquisition of the knowledge of these parameters is required so that the orbital phase of a mission can be designed. We give the modeling assumptions and show covariance analysis results for a variety of conditions on the approach to four classes of small bodies ranging in diameter from 1 to 500 km. Time histories of the knowledge of mass, rotation characteristics, and comet outgassing are given for a variety of approach trajectories.