The current need for high-fidelity modeling to aid with solid rocket motor design requires new, more advanced characterization technologies to be developed. In this project, I propose to develop the technique of phosphor thermometry within the combustion environment of a burning composite propellant. When excited by a laser source, thermographic phosphors fluoresce. This fluorescence is temperature dependent and can therefore be exploited for thermometry. My goal is to perform in-situ 2D temperature measurements of the surface and near-surface flame structure of an AP/HTPB composite propellant. These measurements within this environment would be the first of their kind. I will use two different methods to determine temperature of these burning composite propellants, known as the lifetime and intensity ratio methods. These will be compared for their efficacy of obtaining high frequency temperature measurements within this combustion environment. The development of this characterization technique when applied to composite propellants will help achieve the goals of TA 1: Launch Propulsion Systems by providing empirical data of propulsion environments for the development of new models, in turn reducing time and costs of solid rocket motor development.