地月平动点中继应用轨道维持

地月平动点中继应用轨道对于月球背面探测具有十分重要的应用价值,由于地月平动点的不稳定性,必须进行轨道维持。文章研究了真实力模型下月球平动点中继应用轨道的维持。首先,基于限制性三体问题下平动点轨道的运动特性,研究了平动点轨道维持的数学模型与维持策略,提出了平动点轨道维持的连续环绕控制方法,并给出了轨道维持的Halo和Lissajous两种控制方式;其次,充分考虑各天体和光压摄动下,采用数值手段研究了不同幅值的地月平动点周期中继应用轨道的维持间隔与速度增量等。研究结果表明:Lissajous控制方式适用于月球平动点中继应用轨道的维持,在给定测控精度条件下,维持间隔约7.4d,速度增量优于20m/s/a。该方法已经成功应用于我国"嫦娥2号"日地平动点任务和"嫦娥5T1"地月平动点任务并获得了良好的控制效果,还可直接应用于我国未来"嫦娥4号"等月球背面探测任务。

Maintenance of Relay Orbit About the Earth-Moon Collinear Libration Points

Relay orbits about the Earth-Moon collinear libration point shave significant valueon the exploration of the lunar farside, but have complex kinetic characteristics in the nature, thus the orbit maintenance has always been focused in the deep space navigation and control field. This paper explores orbit maintenance technology of the relay orbit about the collinear Earth-Moon libration points under the real dynamical conditions. First, based on the restricted three-body problem, the mathematic model of relay orbit station-keeping with the real dynamical model is analyzed. The continue-circling method is presented for the relay orbit maintenance with the two control styles, i.e., the Halo style and the Lissajous style. Second, with the third-body gravitation and the solar radiation pressure perturbations considered, the method is tested and analyzed by using the numerical simulations to achieve the control frequency and the corresponding velocity increment required by the relay orbits with different amplitudes. According to the simulations, the Lissajous style is suitable to the orbit maintenance with a control interval of 7.4 days and a velocity increment less than 20 m/s/a. Furthermore, the method has been successfully applied in Chang''e-2 and Chang''e-5T1 extended missions and can provide a beneficial reference for the future Chang''e-4 mission.