![]() Two basic types of aerodynamic heat shield have been used: An aerodynamic heat shield consists of a protective layer of special materials to dissipate the heat. 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. ![]() 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. Thermal soak aerodynamic heat shield used on the Space Shuttle. The European Commission funded a research project, C3HARME, under the NMP-19-2015 call of Framework Programmes for Research and Technological Development in 2016 (still ongoing) for the design, development, production and testing of a new class of ultra-refractory ceramic matrix composites reinforced with silicon carbide fibers and carbon fibers suitable for applications in severe aerospace environments. NASA funded (and subsequently discontinued) a research and development program in 2001 for testing this protection system through the University of Montana. They are also structurally more resistant than RCC, so they do not require additional reinforcements, and are very efficient in re-irradiating the absorbed heat. The materials used have thermal protection characteristics in a temperature range from 0 ☌ to + 2000 ☌, with melting point at over 3500 ☌. The thermal protection system based on these materials would allow to reach a speed of Mach number 7 at sea level, Mach 11 at 35000 meters and significant improvements for vehicles designed for hypersonic speed. The prototype SHARP ( Slender Hypervelocity Aerothermodynamic Research Probe) is based on ultra-high-temperature ceramics such as zirconium diboride (ZrB 2) and hafnium diboride (HfB 2). Recently new materials have been developed that could be superior to RCC. In the case of the Concorde the aluminum nose can reach a maximum operating temperature of 127 ☌ (which is 180 ☌ 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. 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. With the help of proper thermal analysis and use of heat shields, the engine mount vents can be optimised for the best performances. When a vehicle is at higher speed there is enough ram air to cool the under hood engine compartment, but when the vehicle is moving at lower speeds or climbing a gradient there is a need of insulating the engine heat to get transferred to other parts around it, e.g. Heat shields are also used to cool engine mount vents.
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