C-CAT, which has proven carbon-carbon fabrication capabilities, will investigate use of ACC-6 High Melt oxidation protective system on carbon-carbon for use on the Cryogenic and Non-Toxic Storable Propellant Space Engine nozzle and nozzle extensions. ACC-6 High Melt is a carbon-carbon coating application that embeds HfC,ZrB2 in the outer layers. This material system has been tested in Arc Jet environment at over 3000 degrees F, for more than 24 minutes with little to no erosion. ACC-6 High Melt has shown to be the best performing high temperature material system, and still retains the ease of manufacturing associated with carbon-carbon. ACC-6 High Melt has been manufactured in small scale leading edge experiments, but has yet to be demonstrated in large components. Manufacturability of large scale components remains as the main question to be answered for this material system. For Phase I, C-CAT proposes to build subsections of a nozzle extension representing the attach flange and the exit diameter of approximately 40" diameter. Success will be achieved by manufacturing the aforementioned subsection using ACC-6 High Melt with no voids or spalling of coating. This successful demonstration will provide the path for scale-up to a full size prototype nozzle extension for Phase II.