进行航天器轨道运算经常用到的函数，包括坐标转换，经纬度转换，二体运动，轨道要素计算-For spacecraft orbit operations frequently used functions, including coordinate conversion, latitude and longitude conversion, two-body movement, and so calculated orbital elements

用于地月轨道返回航天器轨道仿真，包括仿真主程序和大气模型-Back for the Earth-Moon orbit spacecraft orbit simulation, including the main program and the atmospheric model simulation

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