翻译：空间飞行器在大气层外飞行受到地球引力作用与其构成二体模型。二体运动相对惯性空间的运动方程是二阶常微分方程17。具体到当前的二体问题若初始位置矢量和速度矢量已知可以通过二体运动方程计算空间飞行器相应时间的位置和速度。此问题称为初值问题。若初始时刻和终点的位置矢量已知则求得空间飞行器初始位置处的速度矢量。此问题称为两点边值问题。

A spacecraft flying in outer space is subject to the Earth's gravity, forming a two-body model. The relative inertial motion equation of the two-body motion is a second-order ordinary differential equation [17]. For the current two-body problem, if the initial position vector and velocity vector are known, the position and velocity of the spacecraft at the corresponding time can be calculated through the two-body motion equation. This problem is called the initial value problem. If the position vectors at the initial and final moments are known, the velocity vector of the spacecraft at the initial position can be obtained. This problem is called the two-point boundary value problem