前言航天飞机的一个重要发展趋势是力求低成本、常规和低轨远程飞行。从1969年至1973年,在设计研制航天飞机的同时,曾对某些防热系统进行了评定。当时,考虑了金属防热屏、烧蚀材料、快速冷却系统和氧化硅陶瓷防热系统。以前的再入飞行器(包括阿波罗飞船)所用的烧蚀材料,都能在再入条件下防护航天飞 Preface An important development trend of the space shuttle is to strive for low cost, conventional and low-orbit long-range flight. From 1969 to 1973, some thermal protection systems were evaluated while designing and developing the space shuttle. At the time, metal heat shields, ablative materials, rapid cooling systems, and silica ceramic thermal systems were considered. Ablation materials used by previous reentry vehicles (including Apollo spacecraft) are capable of protecting spaceflight under re-entry conditions