Comparison of theory with atomic oxygen radiance data from a rocket flight

Results obtained from a state-of-the-art flow and radiation model are compared with vacuum-ultraviolet radiance data obtained from the recent Bow Shock 2 Flight Experiment. An extensive data set of atomic-oxygen resonance radiance measurements was obtained in flight for a re-entry speed of 5 km/s between the altitudes of approximately 65-85 km. A description of the NO photoionization cell used, the data, and the interpretation of the data will be presented. A new radiation model appropriate to the flight conditions of Bow Shock 2 is proposed. Comparison of theory with the data shows that at high altitudes the flow is optically thin. At altitudes lower than about 75 km the flow is optically thick and the disagreement between theory and experiment is attributed to the inadequate treatment of photon escape mechanisms from the shock layer.