NASA has selected Allied Aerospace Industries of Tullahoma, Tennessee, to provide three hypersonic, flight-ready experimental demonstrator vehicles that will travel at approximately 5,000 miles per hour. The contract for the project, dubbed X-43C, is valued at nearly $150 million over 66 months.
NASA’s Langley Research Center (LaRC) is leading a combined US Air Force and industry team in the design and development of the X-43C demonstrator vehicle and its propulsion system, which will be capable of accelerating from Mach 5 to Mach 7. The engine, which will be provided by the US Air Force, will be a dual-mode scramjet capable of running as a ramjet or scramjet.
A ramjet has no moving parts and achieves compression of intake air by the forward speed of the air vehicle. Air entering the intake of a supersonic aircraft is slowed by aerodynamic diffusion created by the inlet and diffuser to velocities comparable to those in a turbojet augmentor. The expansion of hot gases after fuel injection and combustion accelerates the exhaust air to a velocity higher than that at the inlet and creates positive push. A Scramjet (Supersonic Combustion Ramjet) differs from the ramjet in that combustion takes place at supersonic air velocities through the engine.
According to NASA, future air-breathing space access vehicles offer advantages over conventional rocket-powered vehicles that must carry an oxidiser needed to burn their fuel. By minimising the need to carry oxidiser, smaller and more efficient vehicles can be designed for space missions.
‘When fully developed, these advanced propulsion systems will offer increased safety, payload capacity and economy of operation for future, reusable space access vehicles,’ said Paul Moses, manager of the X-43C project. ‘The X-43C project will validate advanced technologies, design tools and test techniques that will enable design of such vehicles in the future,’ he said.
For the three demonstration flights, a Pegasus-derived rocket booster will be air-launched by a carrier aircraft to boost the X-43C demonstrator vehicles to Mach 5 at approximately 80,000 feet. The X-43C will separate from the booster and continue to accelerate to Mach 7 under its own power and autonomous control.