Boundary Layer Transition (BOLT) Post-Flight Research and BOLT II Flight Test Support

This report summarizes the three-year research effort by the Johns Hopkins University Applied Physics Laboratory (APL) under grant number FA9550-20-1-0043 from the Air Force Office of Scientific Research (AFOSR) to conduct postflight analysis of the BOLT flight experiment and to support the development, execution, and analysis of data from BOLT-2: The Holden Mission. Key accomplishments from this research included characterization of supersonic transition flight data received from the BOLT experiment, investigation and identification of the probably cause of unexpected flight behavior that occurred in the BOLT flight, significant independent analysis of theBOLT-2 flight during the pre- and postflight research phases, and new Spatial BiGlobal stability calculations of the BOLT geometry in support of the BOLT-2 flight analysis and a NATO STO-AVT-346 working group activities. The research resulted in seven conference papers with an eighth paper planned. The research led to advances in understanding of supersonic transition, flight dynamics, aeroelastic effects on aerodynamics, thermal analysis methodology for low-cost sounding rocket experiments, and advancements in the use of Spatial BiGlobal stability on the BOLT geometry. APL plans to continue research on many of these topics in a new grant from AFOSR, FA9550-22-1-0357, that will also support a re-flight attempt of the BOLT experiment called BOLT-1B.