Hybrid propulsion lacks the research flight heritage of solid rocket motors and liquid rocket engines leading. This often leads to hybrids being beat out in trade studies by liquids and solids and keeps hybrids under developed and at low technical readiness levels. With increasing diversity of space exploration missions the performance requirements are also becoming more diverse leading to the need for alternative propulsion systems such as hybrids. This creates a need to increase the understanding of hybrid performance. One area that is not well understood is combustion instabilities. Combustion instability is a problem that plagues nearly all propulsion systems and is particularly apparent in the development of new propulsion systems such as hybrids. The Auburn Combustion Physics Lab is developing an optically accessible hybrid rocket engine to use as a test bed for analyzing combustion instabilities in hybrids. The goal is to compare fuel types, find the conditions that instabilities occur, and measure those instabilities.
