The DARPA/AF Falcon Program: The Hypersonic Technology Vehicle #2 (HTV-2) Flight Demonstration Phase

[Abstract] The DARPA/Air Force Falcon Technology program is developing and validating, in-flight, hypersonic technologies to enable prompt global reach missions. The far-term vision of the hypersonics program is a reusable, aircraft-like hypersonic cruise vehicle that can take-off and land at today's runways and reach anywhere in the world in 2 hours or less. Key enabling technologies for such a vehicle include efficient aerodynamic shaping for high lift to drag, lightweight and durable high temperature materials, thermal management techniques including trajectory shaping, navigation and autonomous flight control, as well as a turbine-based combined cycle (TBCC) propulsion system. A series of hypersonic technology vehicles will be flown to demonstrate these key technologies for a future reusable system. The program will design three different Hypersonic Technology Vehicles (HTVs) to fly these technologies. The program will also investigate and validate current state of the art modeling of the aero and thermal environments for extended hypersonic flight through the upper atmosphere. It is currently impossible to validate models for certain regimes in ground test facilities due to their physical limitations.