VISIBLE SPECTRA OF THRUSTER PLUMES FROM THE SPACE-SHUTTLE PRIMARY REACTION CONTROL-SYSTEM

In situ measurements of plume spectra from high-altitude, 870-lb, liqu id propellent engine plumes have been obtained from observations of th e Space Shuttle's primary reaction control system engines. Spectra wer e taken in the wavelength range of 350-800 nm with a spectral resoluti on of 3 nm and a spatial resolution of 10 cm. These spectra show numer ous emissions from molecular and atomic species. There is significant variation in the spatial distribution of the emitting species. A surve y of the auroral photography experiment (APE) thruster emission data w ill be given. The data will be compared to a chemical kinetic multizon e flowfield model. This model was developed to analyze data from vacuu m chamber tests. It incorporates 149 separate reactions and 53 distinc t ground and excited state species, but this model is only valid aroun d the exit plane of the thruster. A simplified exhaust plume model, va lid for the first few meters of the plume, was then applied to the exi t-plane conditions and the results are consistent with all of the majo r features of the data.