What specialized material covered the Space Shuttle for its reusable heat protection?

Specialized tiles made of silica fiber material.

For vehicles requiring multiple uses, like the Space Shuttle, a different Thermal Protection System approach is necessary, focusing on radiating heat away rather than consuming material. The orbiter was covered in specialized tiles constructed from silica fiber material. These tiles possess the unique property of being incredibly lightweight while being poor conductors of heat, despite enduring extreme external temperatures that could cause the surface to glow incandescently white. Crucially, the inner surface of these tiles remained cool enough to touch shortly after exposure, demonstrating their exceptional insulating and radiating capabilities necessary for reusability.