Questions about technologies used to protect reentering space craft from the heat of friction from the atmosphere. May also refer to technologies used to block heat from solar radiation while in the vacuum of space.
The heat shield is used to protect spacecraft that reenter the atmosphere from the heat generated by the friction with the atmosphere.
Capsules generally use a material that either ablates (burns off, slowly) or else is able to withstand the heat load.
The term may also refer to spacecraft structures that are used to protect the spacecraft and manage thermal load while on-orbit in the vacuum of space. An example of this use would be the ceramic cloth heat shield on the MESSENGER Mercury orbiter.