What material primarily composed the High-Temperature Reusable Surface Insulation (HRSI) black tiles on the Space Shuttle?

Answer

Silica fiber

The black HRSI tiles, designed for the hottest areas covered by the tile system, were composed primarily of nearly pure silica fiber, making them exceptional insulators.

What material primarily composed the High-Temperature Reusable Surface Insulation (HRSI) black tiles on the Space Shuttle?
AerospaceMaterialspacecraftreentryheat shield