Advanced liquid rocket propulsion systems must achieve longer burn times without performance degradation to allow the lowest cost per kilogram access to space. Ablative thrust chambers have an extensive heritage and are the low cost approach to fabricating rocket thrust chambers. However, composite ablative chambers suffer from erosion that typically limits performance of the engine in terms of burn time and efficiency/performance of the combustion. In the last decade, there has been significant interest in utilizing fiber-reinforced ceramic composites such as carbon fiber-reinforced silicon carbide (C/SiC) composites. Such composites have demonstrated a low erosion rate in bi-propellant liquid rocket thrust chambers at temperatures approaching 4000F. However insertion of these materials have been limited by complexities associated with required system redesign to accommodate a radiatively-cooled chamber, attachment methods, and addressing chamber permeability issues. By incorporating a ceramic composite liner within an ablative thrust chamber in critical areas that are subjected to the highest temperatures, a low erosion, high performance chamber is obtained that eliminates costs and complexities that have limited the insertion of ceramic composite thrust chambers. The Phase I effort will produce a ceramic composite lined ablative thrust chamber, identify the degree of film cooling required and conduct a static hot fire test evaluation of the material to demonstrate the perfromance benefit of a CMC liner within an ablative thrust chamber.