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1957年10月4日,前苏联发射第一颗人造地球卫星,标志着第一太空时代的到来,这一时代将随着航天飞机在2010年完成最后一次飞行而宣告结束。第二太空时代始于
On October 4, 1957, the launch of the first man-made earth satellite by the former Soviet Union marked the arrival of the first space age, which will come to an end as the space shuttle completes its last flight by 2010. The Second Space Age began