Application and analysis of an improved multiconic method in trajectory design of the lunar south pole return mission

The multiconic method is a fast and accurate method for trajectory propagation, which fills the gap between the patched conic and numerical integration. However, this method has been rarely applied in the Moon–Earth trajectory design, and Lunar oblateness perturbation is a necessary term that cannot be ignored. In Lunar exploration, the south polar region of the Moon has been highlighted as an attractive destination by European Space Agency and Russia because of technical and scientific factors. First, according to the illumination and communication conditions, this paper presents analysis of the trajectory injection window. An improved multiconic method that combines the Lunar oblateness correction in the propagation of Moon–Earth trajectories is then proposed. In additional, the elliptical B-plane parameters are introduced to improve the rate of convergence during the correction of initial values. Compared with the traditional multiconic method, significantly, the proposed methods improve the accuracy of propagation of the Moon–Earth trajectory