booster stage

基本解释

The first-stage booster will parachute into the Atlantic Ocean where it will be recovered for inspection by engineers.
第一级助推器将借助降落伞掉入大西洋，然后由工程师对其回收并作检查。
The bombs were, first, the upper-stage booster of a probe called LCROSS (Lunar Crater Observation and SensingSatellite) and then, five minutes later, the LCROSS probe itself.
撞击先由LCROSS（月球陨石坑观察感应卫星）探测器的一级助推器完成，五分钟后LCROSS自身进行第二次撞击。
Tokyo said the first booster stage appeared to fall into the Sea of Japan, and the second into the Pacific Ocean – a marked improvement on a test of the Taepodong-2 missile three years ago.
日本方面表示第一节推助器好像掉入了日本海，第二节坠入了太平洋。这和三年之前试射的大浦洞2号导弹相比有明显改进。