Spaceflight
In spacecraft design, ablation is used to both cool and protect mechanical parts and/or payloads that would otherwise be damaged by extremely high temperatures. Two principal applications are heat shields for spacecraft entering a planetary atmosphere from space and cooling of rocket engine nozzles. Examples include the Apollo Command Module that protected astronauts from the heat of atmospheric reentry and the Kestrel second stage rocket engine designed for exclusive use in an environment of space vacuum since no heat convection is possible.
In a basic sense, ablative material is designed to slowly burn away in a controlled manner, so that heat can be carried away from the spacecraft by the gases generated by the ablative process; while the remaining solid material insulates the craft from superheated gases. There is an entire branch of spaceflight research involving the search for new fireproofing materials to achieve the best ablative performance; this function is critical to protect the spacecraft occupants and payload from otherwise excessive heat loading. The same technology is used in some passive fire protection applications, in some cases by the same vendors, who offer different versions of these fireproofing products, some for aerospace and some for structural fire protection.
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