Abstract:

Based on a specified Moon-to-Earth return trajectory in the demonstration of the third step of lunar exploration program of China, the error factors resulting in the position error of the separation point where the return vehicle separates from the orbiter are analyzed. Then the corresponding error covariance propagation model is constructed. The impact of the different time of the last midcourse correction on the orbit error is discussed by simulation, giving the relationship between the position error of the separation point and the orbit error after the last correction. The relation between the time of the last midcourse correction and the choice of the separation height is preliminarily analyzed. The results show that properly delaying the time of the last midcourse maintenance or properly advancing the separation can help to control the position error of the separation point.