地球大气层外的浩瀚宇宙里有丰富的空间资源,隐藏着无穷的奥秘。近半个世纪以来,人类不断开发宇宙,探索太空并取得了举世瞩目的成就。21世纪航空航天技术将会取得更大的发展,其发展方向将主要集中在航天运输、人造卫星、空间站、考察月球火星和深空探测等方面。一次性使用的多? There are abundant space resources in the vast universe outside the Earth’s atmosphere, hiding endless mysteries. For nearly half a century, mankind has continuously developed the universe, explored space and made remarkable achievements. In the 21st century, there will be more development in aerospace technology. Its development will mainly focus on space transportation, artificial satellites, space stations, lunar Mars exploration and deep space exploration. One-time use of more?