1981年4月14日下午,航天飞机“哥伦比亚号”在完成了第一次轨道试验飞行任务之后,准确地着陆在加利福尼亚州爱德华兹空军基地的干湖床上。它的着陆点离预定的目标点仅相差1.69公里。在同年11月14日下午,“哥伦比亚号”在第二次试飞返航时又进行了一次更加漂亮的着陆动作。因为爱德华兹空军基地的干湖床极广阔,航天飞机在那里着陆误差1.69公里几乎是不会成为问题的。但是,到 On the afternoon of April 14, 1981, the space shuttle Columbia made an accurate landing at a dry lake bed at Edwards Air Force Base in California after completing its first orbital test mission. Its landing point is only 1.69 kilometers away from its intended target point. On the afternoon of November 14 of the same year, “Columbia” made a beautiful landing again on the second test flight. Because of the extremely large dry lake at Edwards Air Force Base, the spacecraft’s landing error of 1.69 km there is hardly a problem. But to