secondary propulsion system

例句：

1. 1. Thenew spacecraft uses a secondary propulsion system to reach its destination.
   新型宇宙飞船使用辅助推进系统到达目的地。
2. 2. Therocket's secondary propulsionsystem is responsible for maintaining altitude during theascent.
   火箭的辅助推进系统负责在上升过程中保持高度。
3. 3. Thesecondary propulsion systemis designed to provide additional thrustwhen the main engine fails.
   辅助推进系统设计用来在主引擎失效时提供额外的推力。