Reconfigurable Guidance for Energy Management of Hypersonic Vehicles

The flight envelope for X-34 ranges from subsonic to hypersonic with altitudes up to 50 miles. Designing a guidance law that performs across this broad flight envelope presents several challenges. Robustness to uncertain aerodynamics is of paramount importance because of the sparse amount of wind tunnel and flight test data that exists for reusable launch vehicles at hypersonic Mach numbers. The need to compensate for potential control surface failures imposes additional guidance requirements. Barron Associates, Inc. (BAI) has teamed with Orbital Sciences Corporation to develop control and guidance systems that can reconfigure in real time to significantly increase the reliability of reusable launch vehicles. An innovative modular architecture, presently under development, will be used to reshape trajectories on-line. We believe that leveraging this concurrent effort is a main strength of the proposal. The approach autonomously identifies the closed-inner-loop dynamics and adapts the guidance for off-nominal performance. In Phase I, a modification of the existing X-34 energy management approach will be investigated. A more formal optimization technique developed and matured by BAI will also be considered. Studies will focus on aerodynamic uncertainties and control failures that primarily affect lateral-directional maneuvering capabilities, which are critical in managing vehicle energy for unpowered descent.