This proposed Small Business Innovative Research (SBIR) Phase I addresses the development of advanced gel propellants and determination of their suitability for selected applications. Currently, propellant gels consist of fuel (or oxidizer) combined with a polymeric gellant such as a cellulose derivative and suspended aluminum (or silica) particles. However, higher specific impulse and density specific impulse, more efficient (i.e., finer) spray formation, and reduced pumping requirements are desired so that formulations incorporating combustible particulate species (solid additive and particulate gellant, which, ideally would be the same) are sought. Phase I will consider a matrix of formulations drawn from various highly combustible solid nanoparticulate species and additives. Properties (density and Isp) of various formulations will be calculated. Formulations with the desired calculated Isp will be prepared and measurements of surface tension between various system components performed. Rheological properties of the resulting gels will be measured and the flow and spray characteristics of candidate formulations evaluated. Finally, initial testing of preferred gel systems arising from Phase I will be conducted. Phase II will consist of extensive testing of preferred propellant formulations and determination of their suitability for various applications.