Space Shuttle Tile Replica (HRSI)

A replica of two models of the Space Shuttle Tile used as High-temperature reusable surface insulation (HRSI)

The black HRSI tiles provided protection against temperatures up to 1,260 °C (2,300 °F). There were 20,548 HRSI tiles which covered the landing gear doors, external tank umbilical connection doors, and the rest of the orbiter's under surfaces. They were also used in areas on the upper forward fuselage, parts of the orbital maneuvering system pods, vertical stabilizer leading edge, elevon trailing edges, and upper body flap surface. They varied in thickness from 1 to 5 inches (2.5 to 12.7 cm), depending upon the heat load encountered during reentry. Except for closeout areas, these tiles were normally 6 by 6 inches (15 by 15 cm) square. The HRSI tile was composed of high purity silica fibers. Ninety percent of the volume of the tile was empty space, giving it a very low density (9 lb/cu ft or 140 kg/m3) making it light enough for spaceflight.[1] The uncoated tiles were bright white in appearance and looked more like a solid ceramic than the foam-like material that they were.