Boundary Layer Transition Protuberance Tests at NASA JSC Arc-Jet Facility

§§ A series of tests with protuberances on Space Shuttle thermal protection tiles were conducted at the NASA JSC arc-jet test facility. The tests provided temperature data for the protuberances and surrounding smooth tile surfaces, as wel l as the tile bondline. The tests demonstrated that a protruding tile material can survive th e exposure to the high enthalpy flows characteristic of the Space Shuttle Orbiter re-e ntry environments. In addition, the levels of heating needed to exceed the protuberance mat erial temperature limit were also achieved, and the protuberance failure mode was demonstrated.