地月系统中，探月航天器运动的简单的数学模型，月球绕地运动近似为匀速圆周运动，程序中各天体坐标可以在JPL的星历表中查询修改。(In the Earth Moon system, the simple mathematical model of lunar exploration spacecraft motion is similar to the uniform motion around the moon. The coordinates of celestial bodies can be querying in the ephemeris of JPL.)