The manned space shuttle, operated by NASA from 1981 to 2011, carried astronauts and sent various supplies or conducted experiments across Earth and space. The heat-resistant tiles used in these space shuttles required high performance and were said to have insulation that humans could touch with bare hands even when heated to an extremely high temperature of over 1200 degrees Celsius.
The space shuttle was originally developed as a manned spacecraft concept that can be reused repeatedly. Therefore, it was required to use the main body part, except for the disposable external fuel tank, after returning from space. Once the shuttle that has reached outer space returns to Earth, it must endure a re-entry into the atmosphere where the Earth enters the thick atmosphere from space close to vacuum. When the space shuttle re-enters the atmosphere, the heat is over 1600 degrees. However, the aluminum used for the main body deteriorates by about 200 degrees of heat, so the development of heat-resistant tiles to protect the main body from ultra-high temperatures was important in the development of the space shuttle.
So what was developed is insulation. Heat-resistant tile using silica glass fiber. Silica, which is made from quartz, boasts excellent thermal insulation performance, so covering the main body of the space shuttle with heat-resistant tiles could protect the basic aluminum when re-entering the atmosphere.
In the video, a person picks up a gray cube on a shelf. This is LI-900, a type of heat-resistant tile used in the space shuttle. LI-900 is a material obtained by adding 99.9% purity silica glass fiber to a sponge, and air occupies 94% of the volume.
The temperature inside the machine in the video reached 1204 degrees. The LI-900, heated to a very high temperature, glows orange, but you can touch it with your bare hands without wearing gloves. LI-900 exhibits such high thermal insulation performance because the silica glass fiber itself has high thermal insulation, but air, which occupies 94% of its volume, also has high thermal insulation. Related information can be found here .