Rapid Optimization of Hovering Point for Integrated Mission of Asteroid Hovering and Landing

An asteroid landing mission usually includes 2 stages: the observation stage at a hovering point and the landing stage starting from the hovering point. To reduce the total fuel consumption of the 2-stage integrated mission, a rapid optimization method for the hovering point is developed. The optimization problem of the hovering point is established with the hovering position as the optimization variables and the total fuel consumption of the 2 stages as the performance index. To improve the efficiency of the optimization, the fuel consumption for the hovering stage is expressed as an analytical term in the performance index. Furthermore, to overcome the nonlinear problem of the analytical term caused by gravitational acceleration, a pseudo-gravitational acceleration is introduced as an augmented state. The optimization problem is solved using the sequential convex optimization method, with the landing trajectory starting from the equilibrium point as the initial value of the iteration. Finally, the optimization method for the hovering point is simulated in a hovering–landing integrated mission of the asteroid 433 Eros. Simulation results indicate that the proposed method has high efficiency in calculating the optimal hovering point.