Ceramic Composites for Rocket Engine Turbines

Use of ceramic materials in the hot sectionof the fuel turbopump of advanced reusablerocket engines promises increased performanceand payload capability, improved component lifeand economics, and greater design flexibility.Severe thermal transients present duringoperation of the Space Shuttle Main Engine(SSME) push metallic components to the limit oftheir capabilities. Future engine requirementsmay be even more severe. In Phase I of thistwo Phase program, performance benefits havebeen quantified and continuous fiber reinforcedceramic matrix composite (FRCMC) components havedemonstrated a potential to survive the hostileenvironment of an advanced rocket engine turbo-pump.INTRODUCTIONReusable rocket engines for future missionsof earth-to-orbit and beyond must operate lon-ger, withstand more duty cycles, and be moreefficient than present generation engines.Today the most advanced reusable rocket engineof this type is the Space Shuttle Main Engine(SSME). Metal turbopump blades, stator vanesand other hot gas flow path components of thishydrogen/oxygen burning engine have limiteddurability. For improved efficiency, futureAdvanced Launch Systems (ALS) such as the SpaceTransport Booster Engine (STBE) and SpaceTransport Main Engine (STME) will requirematerials with greater temperature capability.Materials with potential to significantlyoutperform the currently used superalloysinclude ceramics, synthetic alloys such asintermetallics, and carbon/carbon. These mate-rials have a lower density and can operate athigher temperatures than superalloys (Fig. 1).Of the candidate materials, ceramics exhibitbetter potential for overall tolerance to theaggressive rocket engine environment. The loadcarrying capability of monolithic ceramics is,