The Space Shuttle was an amazing piece of engineering. NASA had to solve hundreds of little problems no one had ever encountered before just to get the shuttles off the ground. However, getting them back down proved to be the most troublesome aspect of the shuttle design.
NASA worked with aerospace companies to develop completely new kinds of heat insulating materials for the Space Shuttle’s heat tiles, and one YouTube user has been kind enough to share a video of the tiles in action.
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.
These tiles were coated with either black or white insulation in order to regulate temperatures while the shuttle was in orbit. Additionally, the black tiles covered most of the bottom surface as they better dispersed the heat of reentry.
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.
Just one more piece of mind-bending tech developed for the space program.