Analysis of transfer orbit deviation propagation mechanism and robust design for manned lunar landing

Earth-moon transfer orbit for manned lunar landing needs a long flight time, complex, nonlinear and variable coefficient dynamics model, and asks for a high reliability. Analysis of deviation propagation mechanism and robust design of transfer orbit are investigated in this paper. It is not only practical for projecting, but also significant for exploring the role of earth-moon space gravitational field upon transfer orbit deviation. This paper analyses firstly the boundary and the amplitude of the sun, earth, and moon central gravitation, the earth J2 perturbation that affect the transfer orbit deviation transmission. And then a method to analyse the deviation propagation mechanism based on nominal orbital data is obtained analytically. A robust indicator of transfer orbit based on deviation transition matrix is proposed,and a robust optimization design method that employs NSGA-II(nondominated sorting genetic algorithms) for earth-moon transfer orbit with robust indicator is proposed.Simulation shows that the analysis of transfer orbit deviation propagation mechanism can obtain earth-moon transfer orbit deviation propagation matrix quickly and precisely, and the deviation propagation matrix can be used to obtain the covariance matrix and mid-course correction delta V analytically and exactly. The quality of nominal transfer orbit is improved by optimizing with robust indicator.