Felt reusable surface insulation (FRSI) was selected as the thermal protection material for the space shuttle orbiter. FRSI is a nylon material coated with silicone elastomer that is bonded to aluminum sheets with silicone adhesive. It was ranked first due to its high service temperature resistance, stiffness, low thermal expansion, and fracture toughness relative to its density. While ceramics also meet requirements, FRSI is lighter and can accommodate more temperature variation than ceramic tiles.