Why 2200°F space shuttle heat tiles won’t burn your bare hands
In the video you’ll see a giant industrial oven at Kennedy Space Center baking blocks of the material used in the shuttle’s thermal tiles. The small white cubes are LI-900, a type of low-density surface insulation composed almost entirely of silica glass fibers. They are basically pure quartz sand that are 94% air by volume.
LI-900 can be heated to 2200°F, which is exactly what the blocks in the video are heated to. Even after being subjected to that temperature for so long, they can be picked up almost immediately after being taken out of the oven.
Air and silica glass are both extremely poor conductors of heat, and thus great insulators. That’s why you can touch them after coming out of a super-hot oven. On the Space Shuttle, they protected the aluminum hull from the heat of reentry. The tiles were not mechanically attached to the craft, but were instead glued so they could be easily repaired.
Many of the tiles were replaced after each flight, especially after a damaged heat shield led to the loss of the Space Shuttle Columbia in 2003.
