Recent BOLT Discrete-Roughness Trip Results from the 20-Inch Mach 6 Tunnel

- Air Force Office of Scientific Research (AFOSR) primary sponsor of BOLT (for Boundary Layer Transition) sounding rocket flight project as continuation of previous HIFiRE flights (1 & 5)
- Sounding rockets provide cost-effective flight research tool
- Study hypersonic BoLT on increasingly complex geometries
- BOLT shape includes concave surfaces and swept leading edges
- Two missions, two flights:
- BOLT mission at Esrange, Sweden
- Johns Hopkins University Applied Physics Laboratory as lead
- Focus on transition onset measurements
- Flew June 2021 (staging anomaly)
- BOLT II mission at Wallops Flight Facility, Virginia
- Texas A&M and CUBRC provide primary leadership
- Focus on turbulence measurements
- Flew March 2022
- Flight named in memory of Mike Holden
- NASA’s support to both BOLT missions provided through the Hypersonic Technologies Project (HTP)