Alliant Techsystems (ATK) has demonstrated a simplified hypersonic engine that could enable near-term development of a high-speed strike weapon. Tests included ground runs of a flight-weight, actively fuel-cooled engine at Mach 5. It is an engine design using existing materials, established manufacturing processes and conventional JP10 hydrocarbon fuel. It is tuned to run at a specific mach number. Since it only can run at one mach number it does not need to be reconfigurable. It is smaller than the existing demonstrator engines, so it leaves room for a recovery parachute.
Ground testing of the new engine
The TTRJ (thermally throated ramjet) is scalable to higher Mach numbers, with supersonic combustion, different inlets and advanced materials.
Further reading on hypersonic research and development:
A hypersonic development study
A Mach 10 test vehicle is planned for 2008