The proposed project directly targets future launch and exploration vehicle propulsion systems as potential end-use applications. Of particular interest are large boost-scale nozzles and upper stage nozzle extensions, similar in scale to the J-2X nozzle extension or to the niobium alloy nozzles used on the SpaceX Merlin engine. More generally, the versatility of this concept makes it relevant to a variety of hot structures including combustion chambers, leading edges, thermal protection systems, airframe structures, and other propulsion components. The proposed integrated ceramic matrix composite and carbon/carbon material system would be directly applicable to a wide range of aerospace and defense applications that require low-cost material possessing, ultrahigh temperature oxidation stability, high strength, acceptable joinability, and low mass. These applications include propulsion components such as combustion chambers, rocket nozzles, hot gas generators, and hot gas valves, using both liquid and solid propellants. Defense applications include uses in the high temperature combustion environment of advanced gun barrels, where the use of C/C is desirable if survivability and joining issues can be solved. Non-defense-related uses may include components related to energy generation in which use temperature, environmental reactivity, and economy are increasingly demanding.