作为可重复使用的航天器,航天飞机曾让美国在太空探索事业上大放异彩。近十几年来,美届航天飞机在执行任务的过程中频繁出现“意外状况”,尤其是2005年6月,“发现”号的惊险之旅更加让美国意识到了研制新型航天器的必要性。另一个航天大国俄罗斯也在积极地酝酿自己的新一代航天器。随着航天事业的不断发展,他们迫切需要新的航天器来帮助完成新的探索任务,请看—— As a reusable spacecraft, the space shuttle used to make the United States shine in space exploration. In the past decade or so, the U.S. space shuttle frequently encountered “unexpected situations” during its mission. In particular, in June 2005, Discovery’s thrilling journey made the United States realize the necessity of developing new spacecraft. Russia, another big space country, is also actively preparing its own new generation of spacecraft. As the aerospace industry continues to evolve, they urgently need new spacecraft to help them with new exploration missions. See -