Optimal trajectories are obtained by using a direct adjoining approach (so called the D form Lagrangian)for the interception or the rendezvous of a target in low circular Earth orbit by a vehicle which is initially in a high orbit.

• 航天器从高轨道向位于低地球圆轨道的靶目标实施拦截或进行交会 ,并用间接求解的直接伴随方法 ,即用D型拉格朗日方法求解其优化问题。