Autonomous Rendezvous Architecture Design for Lunar Lander

A precise and convenient targeting architecture for accomplishing the rendezvous of a lunar lander with an orbiter in a near-circular lunar parking orbit is proposed in this paper. This procedure enables a systematic design and refinement of the number of thrust impulses, their application times, and the mission duration. The simplicity and accuracy of this targeting procedure makes it well suited for onboard use during real-time control and strategy reconstruction operations. A concise and revealing form of the linearized rendezvous equations is derived based on the Clohessy–Wiltshire model, as adopted to generate feasible initial solutions to satisfy the demands of rapid mission analysis and design. A three-step iterative procedure is adopted to determine the minimum-impulse control strategies for autonomous rendezvous, involving the progress of the solution from a linear model to a nonlinear, two-body model and finally to a high-fidelity model. The two-body model is introduced as an intermediary to enable a smooth transition from the linear to the high-fidelity lunar gravitational model. Numerical simulations are undertaken to verify the control strategies calculated and to illustrate the efficiency and convergence of the proposed iteration algorithm.