一、引言 国际空间站计划最初于1984年由美国提出,经与欧洲空间局成员国、加拿大和日本协调,到1988年9月正式签署了国际空间站政府合作协定。此后开始了以美国为主的“自由号”国际空间站的研究开发和设计,由有关合作单位参加。由于预算过于庞大,1992年美国会提出质疑并压缩国际空间站预算开支,导致1993年对“自由号”空间站计划进行了重新修改。随 I. INTRODUCTION The ISS project was first proposed by the United States in 1984 and was officially signed by the United States in September 1988 in coordination with the members of the European Space Agency, Canada and Japan. Since then, the United States-based “Liberty” International Space Station has started its research and development and design with the participation of relevant cooperative units. Due to the huge budget, the United States raised its doubts in 1992 and reduced the budget expenditures of the ISS. As a result, the “Liberty” space station plan was revised in 1993. With