#2 Heat Shield

**Aircraft-Some aircraft at high speed, such as the Concorde and SR-71 Blackbird, must be designed considering similar, but lower, overheating to what occurs in spacecraft . In the case of the Concorde the aluminum nose allowed to reach a maximum operating temperature of 127 °C (which is 180 °C higher than the ambient air outside which is below zero); the metallurgical consequences associated with the peak temperature were a significant factor in determining the maximum aircraft speed. **Spacecraft-Spacecraft that land on a planet with an atmosphere, such as Earth, Mars, and Venus, currently do so by entering the atmosphere at high speeds, depending on air resistance rather than rocket power to slow them down. A side effect of this method of atmospheric re-entry is aerodynamic heating, which can be highly destructive to the structure of an unprotected or faulty spacecraft. An aerodynamic heat shield consists of a protective layer of special materials to dissipate the heat.