自从三十多年前苏联第一颗人造地球卫星发射以来,空间运载系统已取得巨大进步。美国航天飞机“挑战者”号发生事故后,航天运载系统的发展发生了许多新的变化。目前美国、苏联、西欧及日本都面临发展新一代及下下一代航天运载工具的问题。 Space launch systems have made great strides since the launch of the Soviet Union’s first man-made earth satellite more than three decades ago. After the accident on the US space shuttle Challenger, many new changes have taken place in the development of the space transportation system. At present, the United States, the Soviet Union, Western Europe and Japan are all facing the issue of developing new-generation and next-generation aerospace vehicles.