Abstract: Aiming at the landing problem of a no propulsion or only weak maneuverability probe in a weak gravity binary asteroid system, a low energy landing orbit design method based on unstable manifold and Poincaré section method is proposed. By searching for periodic orbits near the collinear libration points, calculating the eigenvalues and eigenvectors of the monodromy matrix, and solving the unstable manifold of the periodic orbits, the fuel consumption during the landing process is greatly reduced. For a lander with weak maneuverability, an orbit design method based on connecting splicing unstable manifold and descent orbit set is proposed, which obtains a low energy landing orbit that satisfies the terminal constraints. Numerical simulation verifies compared with the method of calculating the double impulse landing trajectory by genetic algorithm, the method proposed in this paper can flexibly add terminal constraints and design the target landing point, and does not need to design penalty function and perform iterative calculation, with high computational efficiency.

Key words: binary asteroid system, ellipsoid ellipsoid model, poincaré section, low energy landing