Comparison of theory with experiment for the bow shock ultraviolet rocket flight

Comparison is made between the results obtained from a state-of-the-art thermo-chemical nonequilibrium flowfield and radiation code and data obtained from a recent experiment. The experiment obtained the first measurements of ultraviolet radiation from the shock-heated gas in the nose region of a 0.1016 m nose radius vehicle traveling at about 3.5 km/sec at altitudes between 40 to 70 km. The pre-flight computations agree at low altitudes, but under predict the data at high altitudes. Postflight flowfield and radiation sensitivity studies suggests improvements for the models at high altitudes. Specifically, excitation mechanisms that contribute to production of NO gamma band emission need to be revised. Altitude dependence of the radiation observed from the OH radical can be understood in terms of nonequilibrium chemistry in the flow.