基于轨道共面交会的月面上升器起飞参数计算方法

Method for calculation of takeoff parameters of lunar ascent module based on orbital coplanar rendezvous

针对上升器与轨道器以轨道共面实现控制量优化的月球轨道交会问题,提出了精确计算上升器起飞参数的方法.根据上升器月面起飞位置和轨道器环月轨道,利用环月轨道与起飞点共面的球面三角关系,给出了计算起飞方位角和起飞时刻初值的解析模型;基于上升器月面上升特征参数计算了上升器入轨轨道;采用四脉冲远程导引控制策略实现上升器交会轨道机动,建立了远程导引终点轨道平面偏差到入轨点轨道参数偏差的映射关系;推导了基于轨道倾角偏差和升交点赤经偏差修正起飞方位角和起飞时刻的解析算法;设计了精确月面起飞参数的迭代计算流程.仿真验证了上升器起飞参数初值方法和修正方法的正确性和快速收敛性,基于轨道共面交会获得的精确月面起飞参数有效消除了远程导引终点法向偏差,实现了无需轨道平面修正控制量的优化交会轨道控制,节省了推进剂消耗.可应用于从月球和其他地外天体起飞进行交会对接的起飞参数优化确定.

To solve the lunar orbit rendezvous problem, in which the ascent and orbital modules are coplanar to achieve fuel consumption optimization, a method that accurately determines the ascender’s takeoff parameters is proposed. Based on the lunar takeoff position of the ascent module and flight orbit of the orbital module, an analytical model for calculating the initial values of the takeoff azimuth and the takeoff time is presented using the spherical triangle relationship of the orbit plane passing through the takeoff site. The injection orbit of the ascent module is calculated based on its lunar ascending characteristic parameters. The four-pulse long-range guidance orbit maneuver strategy is adopted to realize the rendezvous orbit maneuvers of the ascent module. The mapping relationship between the orbital plane deviations of the long-range guidance terminal of the two-spacecraft rendezvous and the orbital parameter deviations of the injection orbit is established. The analytical algorithm for correcting takeoff azimuth and takeoff time based on orbit inclination deviation and the ascending node right ascension deviation is derived. Further, an iterative calculation process for precise lunar takeoff parameters is designed. Simulation results verify the correctness and rapid convergence of the initial value and correction methods for the lunar ascent module’s takeoff parameters. The long-range guidance terminal normal deviations are effectively eliminated by the precise lunar takeoff parameters obtained based on the orbital coplanar rendezvous. The optimized rendezvous orbit maneuver without orbital plane correction saves the ascent module’s propellant consumption. The method for calculating takeoff parameters can be used to optimize and determine the takeoff parameters for rendezvous and docking from the moon and other extraterrestrial bodies.