Generating 5-km/s low density hypersonic test flows in an expansion tube for studying ultraviolet radiation

New flight paths are becoming important with the development of scramjet staged access-to-space systems. These new flight regimes may produce significant convective heating loads on final stage vehicles due to surface catalytic formation of nitric oxide during hypervelocity high altitude flight. To quantify the radiative emission produced during these new flight paths low density hypersonic test ows of 4.5 and 4.6-km/s are generated in the X2 expansion tube using a Fixed volume cold helium driver. Pitot pressure traces have been made demonstrating steady test time of 250 μs with results suggesting accurate simulation of Mach 9.5 and 11 test flows with 10.6 and 10.34 MJ/kg total enthalpy respectively. This paper documents the development and preliminary results associated with this new operating capability