直接再入大气的月地转移轨道设计

针对从月球停泊轨道出发直接再入大气的月地转移轨道设计问题，提出了一种数值求解算法。该算法由初值设计和精确解求解两部分组成。首先，根据轨道设计的相应约束，采用伪状态理论，通过简单迭代求解高精度的初值。然后，考虑精确的动力学模型，通过数值积分计算真实轨道和状态转移矩阵，并利用微分修正方法搜索精确解。该算法通过设计高精度的初值，降低了月地转移轨道的设计难度。数值仿真表明:该算法求解效率高，具有良好的鲁棒性。 

Design of Moon-to-Earth transfer orbit with direct atmospheric reentry

A new solution algorithm for the design of Moon-to-Earth transfer orbit which leaves from the Moon parking orbit with direct atmospheric reentry and single impulse is presented in this paper. The algorithm is divided into two steps, designing the initial solution and searching the exact solution. First, according to the constraint conditions, the high-precision initial solution is generated by simple iteration using pseudostate theory. Then, the real orbit and state transition matrix are calculated by numerical integration in the real dynamic model, and the exact solution is found by the differential correction method. Because the initial solution with high accuracy is used, the difficulty of finding the solution for the design of Moon-to-Earth transfer orbit is greatly reduced. Numerical simulations indicate that the algorithm is of high efficiency and good robustness.