关键词: 冻结轨道, 太阳同步, 测控回归, 轨道设计, 中继卫星

Abstract:

To satisfy the relay communication requirements of the Chang’E-6 lunar far side sample and return mission， a new type of frozen lunar orbit under the Sun-synchronous repeating tracking condition and the corresponding design method are proposed. By using the von Zeipel canonical transformation method， the mean motion equations of high elliptical lunar orbits are obtained， taking into account the first and second order terms of the Earth’s three-body perturbation and the J₂ terms of the Moon. Based on the mean motion equations， the frozen orbit conditions and corresponding constraint equations are established. Using the frozen condition， the conditions of the Sun-synchronous frozen orbit are further proposed， and the unique advantages of this type of orbit for the lunar far-side sample and return mission are revealed. The matching problem of the relay satellite orbit with the Chang’E-6 multi-launch windows is resolved. Based on the concept of nodal period of low Earth orbit， the concept of repeating tracking condition for lunar orbit is proposed， and the corresponding constraint equation is established. The repeated periodic resonance of the mission orbit period with tracking conditions is realized， and stable tracking conditions are maintained for a long period. The detailed design process and results of Chang’E-6 lunar high elliptical relay orbit satisfying the frozen conditions， Sun-synchronous and repeating tracking are given. The high-fidelity perturbation model is used to verify the orbit design results. The simulation results show that the relay orbit elements are frozen stable and well synchronized with the Sun， and the accuracy of the repeating tracking condition is high， satisfying the requirements of the Chang’E-6 lunar far side sample return mission.

Key words: frozen orbit, sun-synchronous, repeating tracking condition, orbit design, relay communication satellite