Hypersonic flight

Flight at more than five times the speed of sound, where air heating and chemistry dominate vehicle design.

• Above Mach 5, air compressed ahead of the vehicle reaches well over 1,000 °C, and leading edges glow.
• Scramjets burn fuel in air that is still moving supersonically through the engine, which has no moving compressor.
• They produce no thrust at rest, so vehicles need a rocket or a separate jet engine to reach roughly Mach 4–5 first.
• It is mostly military today; materials must survive repeated heating, and ground facilities can recreate the conditions for only seconds.