With the prospect of hydrocarbon-fueled rocket engines, such as Rocket Propellant 1 (RP-1) or methane (CH4) fueled engines being considered for use in future space flight systems, the contributions of intermediate or final combustion products resulting from these hydrocarbon fuels are of great interest. The effect of several diatomic molecular radicals, such as Carbon Monoxide, Molecular Carbon, Methylene Radical, Cyanide or Cyano Radical, Hydroxyl, and Nitric Oxide, needs to be identified and the effects of their band systems on the spectral region from 300 nm to 850 nm determined. This work shows the effect of different engine operating parameters, oxidizer-to-fuel ratio and chamber pressure, and different optical alignments, different lines-of-sight and fields-ofview, on the spectral signature of the engine exhaust plume of a small hydrocarbonfueled test engine. Computational results, along with experimental results of an extensive test program are presented
