Flight dynamics in the gravitational fields of irregular asteroids

Asteroid exploration is one of the main topics of deep space exploration, and has great scientific significance. Due to the irregular gravitational field of most asteroids, dynamical behaviors of spacecraft close to them are very complicated. Affected by the central gravity, the perturbing forces from the fast spin of the irregular shapes of asteroids, the solar radiation pressure force, etc., the spacecraft easily collide with the asteroids or escape from them. In this article, an overview of the status of asteroid research and the irregular gravitational field modeling methods is given. Particularly, this article focuses on the dynamic characteristics of irregular gravitational fields, including equilibrium points, local manifolds, natural periodic orbits and body-fixed hovering flights, and tries to propose new research directions.