Abstract: A new guidance algorithm for midcorrection of translunar trajectory was presented. The algorithm was divided into two steps, i.e.,designing the initial solution and searching for the exact solution. First, the initial solution was generated using the pseudostate theory, and the Vinti prediction was adopted to improve the accuracy of the initial solution by eliminating the earth oblateness effect. Then, while searching for the exact solution, the state transition matrix was calculated by an analytical method based on the pseudostate theory. Because the initial solution with high accuracy is used, the difficulty of finding the solution for midcorrection of translunar trajectory is greatly reduced. Moreover, the calculation of the state transition matrix by using traditional numerical methods is omitted. Numerical simulations indicate that the algorithm is of high efficiency.

Key words: translunar trajectory, midcorrection, pseudostate theory, Vinti prediction, state transition matrix