The Phase I program will lead to improved C-C nozzle extension components for ETO propulsion systems via alternate fabrication methods coupled with proven design and analysis tools. The models developed here will allow various material candidates and involute configurations to be auditioned prior to fabrication and testing, reducing the cost of developing these higher-performance materials considerably. The technology developed here will also have a direct impact on the design and manufacturing of alternative C-C fabrication methods, and metal-to-composite nozzle joints for all future propulsion system designs by offering a domestically available alternative to the non-domestic state-of-the-art, such as the nozzle extension designed for RL 10B-2. Benefits include increased performance, and weight and cost savings, together with a larger supplier base for the fabrication of refractory composite nozzles and nozzle extensions for future heavy-lift launch propulsion systems. MR&D's core business is to provide design services to the aerospace materials community, so the methods developed here can be used to support other SBIR awardees, or transferred to other propulsion system designers. MR&D is involved in the development of C-C materials on several programs which will serve to establish standardized methods for the design and analysis of propulsion materials and structures for years to come.