发射体

例句：

1. 1. The rocket is designed tolaunch satellites into space.
   火箭设计用来将卫星送入太空。
2. 2. The scientist used anew propellant to make therocket go faster.
   科学家使用了一种新推进剂使火箭飞得更快。
3. 3. Therocket's engine was the most powerfulin the world at that time.
   当时，这枚火箭的发动机是世界上最强大的。