Power limited soft landing on an asteroid

This work is concerned with the final approach phase and vertical landing on a spherical asteroid with a power limited, electrically propelled spacecraft. With gravitational effects taken into account, a new solution to the fuel optimal vertical landing on an asteroid was obtained. In this particular solution the spacecraft commanded acceleration is colinear with the vehicle velocity, and the spacecraft trajectories are restricted to a plane. Based on qualitative methods of analysis, the guidance strategy and the resulting trajectories were studied. It is shown that these fuel optimal trajectories effectively assure a vertical soft landing on the asteroid. Results of numerical simulations for the vertical landing starting from an elliptic orbit are presented.