OPTIMIZATION OF ORBIT DESIGN FOR LUNAR SATELLITE

Orbit design of lunar satellite is optimized by using zonal harmonics J₂ and J₃. First, the effects of perturbation factors are analyzed. The result shows that the primary perturbation on a low-altitude lunar satellite orbit is the moon’s nonspher-ical gravity field. Second, the formula of frozen orbit are derived in response to J₂ and J₃ and verified by direct integration of differential equation including only lunar gravity model. In this analysis, all other perturbations （third body perturbation, solar radiation pressure, etc.） are neglected. Finally, polar orbit design is optimized by proper selection of e_o and ω_o, and simulated. As a numerical result, initial val-ues of 213.49° for argument of perigee and approximately 0.0109 for eccentricity （80×120 km orbit） can limit excursions beyond the ±20 km range within about 70 d on the orbit of α=1838 km. It shows that the optimization method is very useful.