Reaction Cured Borosilicate Glass Coating for Low-Density Fibrous Silica Insulation
The Space Shuttle Orbiter, shown in Fig. 1 will be the world’s first reusable space vehicle. Basic to the development of such a vehicle is the requirement for a heat shield that can survive multiple reentries into the earth’s atmosphere at temperatures up to 1400°C. For the majority of the orbiter’s surface, a material was required that had good insulative properties, could survive temperatures up to 1260°C, and would be extremely light weight. It would also be required to survive large temperature gradients (>1000°C/cm) and severe thermal shock resulting from the entry environment (Fig. 2). The convective heating environment which occurs during the vehicle’s entry is unique in that it can result in chemical interactions between the high-temperature gases and the solid surface. These interactions cause an abnormally high vaporization rate to occur among the less refractory compounds present in a heat-shield surface (1). Therefore, the stability of the heat shield in this type of environment is critical to the success of the vehicle.
KeywordsBorosilicate Glass Boron Oxide Silica Substrate Heat Shield Corning Glass Work
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