BOLT II Vehicle Design, Instrumentation, and Ground Test Comparisons to Flight

The Air Force Office of Scientific Research and the Air Force Research Laboratory (AFRL) funded the Boundary Layer Turbulence Flight Experiment in Memory of Mike Holden (BOLT II) to better understand and quantify natural and forced boundary-layer transition and turbulence in hypersonic flight regimes for a complex, three-dimensional geometry. Texas A&M University and CUBRC led the mission and vehicle design along with critical support from AFRL and NASA. The experimental flight launched from NASA Wallops on a two-stage suborbital sounding rocket on March 21st, 2022. A detailed overview of the vehicle design, over 400 instrumentation channels, and integration work is presented in this paper. Additionally, this is the first known time that a full-scale hypersonic flight vehicle has been tested in a wind tunnel before flight. The flight computers and key instruments worked and responded well during the short ground-test campaign and detailed results are reported here with comparisons to the flight data for both the natural transition experiment, side A, and the tripped experiment, side B.