orbit maintenance

例句：

1. 1.The spacecraft orbits the Earth at a constant altitude.
   宇宙飞船以恒定的高度绕地球飞行。
2. 2.The satellite orbits the earth in a circular path.
   卫星以圆形路径绕地球运行。
3. 3. The orbit maintenance crew is responsible for ensuring the spacecraft's safety and stability.
   轨道维护团队负责确保航天器的安全和稳定。