Adaptive Structures for Optimized Performance of Overland Low Boom Supersonic Vehicles

To enable the return of overland civil supersonic flight, aircraft designs must evolve beyond traditional static configurations and point-design performance metrics. Changes in a supersonic vehicle's Mach number, angle of attack, and the atmospheric profile between the aircraft and the ground are known to significantly affect perceived sonic boom loudness. Texas A&M recently completed a 5-year project, sponsored by NASA's University Leadership Initiative program (ULI), demonstrating that modifications to a vehicle's outer mold line (OML) can effectively maintain a low sonic boom signature across various vehicle configurations and atmospheres. The ULI project successfully developed several technologies and tools for adaptive structural design, including efficient CFD and optimization tools, advanced high-temperature shape memory alloys (HTSMAs) for lightweight actuation, and adaptive structural designs for aircraft integration. Building on the success of the ULI project, NASA is sponsoring a feasibility study for a potential adaptive structures supersonic flight test to validate the recently developed tools and technologies. In addition to evaluating the OML geometries aimed at minimizing the sonic boom, this new study will assess any adverse effects the shape changes may have on other aerodynamic performance parameters, such as drag, efficiency, and emissions. The flight test will demonstrate that adaptive structures can modify a supersonic vehicle's OML in real-time, striking a balance between the need for acceptable noise levels and other performance metrics, such as drag. This paper will describe the tools and technologies developed during the ULI project and provide an update on the status of the flight test feasibility study.