美国太空探索技术公司三天内两次成功发射和回收火箭

摘要

US space firm SpaceX just capped off(圆满完成)two successful missions to space this weekend—the company’s quickest launch turnaround(周转期)yet.The first launch occurred on Friday(June 23,2017),when SpaceX’s second ever recycled(回收利用的)Falcon 9("猎鹰9"火箭)booster(助推器)was used