The performance liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure and reducing engine weight. State of the art Bi-propellant engines are metallic; the highest temperature combustion chambers are made of iridium/rhenium metals. Utilizing carbon-carbon composites for thrust chamber structures can reduce component weight by as much as 90%. Unfortunately carbon composites suffer from unacceptably high oxidation rates. Lining carbon-carbon chambers with a thin layer of iridium or iridium/rhenium is an innovative way to provide the oxidation barrier necessary to enable the use of carbon-carbon composites. This proposal evaluates using metal-lined carbon-carbon to produce high pressure, light weight thrust chambers.