Lockheed Martin awarded Pratt & Whitney Rocketdyne a 10-month contract for preliminary design of the high-speed accelerator for a turbine-based combined-cycle (TBCC) propulsion system, which could support flight up to Mach 6. In Phase I of the TBCC Mode Transition Demonstrator Program, Pratt & Whitney Rocketdyne will develop preliminary designs for a dual-mode ramjet combustor with related control and fuel system components. Pratt & Whitney Rocketdyne will also define requirements for a test facility to perform TBCC propulsion system mode transition tests. The TBCC propulsion system consists of a turbojet engine, which can operate from takeoff to Mach 3, and a ramjet engine, which can operate from Mach 2.5 to Mach 6. Applications for the TBCC propulsion system could include reusable hypersonic cruise vehicles for strike and reconnaissance missions.