These rockets were built at a time when space technology was in its infancy.这些火箭是在航天技术仍处于初级阶段的时候制造的。Of all nations, the U.S. is the front-runner in space technology.在所有国家之中，美国是太空科技的先驱者。That country is way ahead in most important aspects of space technology.那个国家的空间技术在大部分重要的领域里是遥遥领先的。