The corner of the nose-gear door can be seen at the lower left. Purpose Ī closer view of the tiles under the forward fuselage and the front end of the left wing. Fragile The only known technology in the early 1970s with the required thermal and weight characteristics was also so fragile, due to the very low density, that one could easily crush a TPS tile by hand.
The winged shuttle had much more surface area than previous spacecraft, so a lightweight TPS was crucial. For example, the ablative heat shield on the Apollo Command Module comprised about 15% of the vehicle weight. Lightweight Previous ablative heat shields were very heavy. By contrast, the reusable shuttle required a reusable thermal protection system. This insulation was robust and reliable, and the single-use nature was appropriate for a single-use vehicle. Reusable Previous spacecraft generally used ablative heat shields which burned off during reentry and so could not be reused. The shuttle TPS had three key characteristics that distinguished it from the TPS used on previous spacecraft: Used where temperatures stayed below 371 ☌ (700 ☏).Įach type of TPS had specific heat protection, impact resistance, and weight characteristics, which determined the locations where it was used and the amount used. White Nomex felt blankets on the upper payload bay doors, portions of the mid fuselage and aft fuselage sides, portions of the upper wing surface and a portion of the OMS/RCS pods. Felt reusable surface insulation (FRSI).Toughened unipiece fibrous insulation (TUFI) tiles, a stronger, tougher tile which came into use in 1996.Used in temperature ranges roughly similar to FIB. Low-temperature Reusable Surface Insulation (LRSI) tiles, formerly used on the upper fuselage, but were mostly replaced by FIB.Used where reentry temperature was below 649 ☌ (1,200 ☏). Flexible Insulation Blankets (FIB), a quilted, flexible blanket-like surface insulation.Some HRSI tiles were replaced by this type. Fibrous refractory composite insulation (FRCI) tiles, used to provide improved strength, durability, resistance to coating cracking and weight reduction.Used where reentry temperature was below 1,260 ☌. High-temperature reusable surface insulation (HRSI) tiles, used on the orbiter underside.Used where reentry temperature exceeded 1,260 ☌ (2,300 ☏). Reinforced carbon–carbon (RCC), used in the nose cap, the chin area between the nose cap and nose landing gear doors, the arrowhead aft of the nose landing gear door, and the wing leading edges.The TPS covered essentially the entire orbiter surface, and consisted of seven different materials in varying locations based on amount of required heat protection: Endeavour in the California Science Center museum, showing tiles near door