Description: The Optimized and Repeatable Components in Additive-manufacturing (ORCA) project built upon the successful evolution of additive manufacturing (AM) core technology under the Low-Cost Upper Stage Propulsion (LCUSP)and Rapid Analysis and Manufacturing Propulsion Technology (RAMPT) projects for liquid rocket components and provided high payoff optimized performance technologies and enabling materials in AM for combustion chambers, injectors, nozzles, and turbomachinery. NASA has helped transform additive manufacturing and complex applications of the AM technology through process and material development and successful infusion into industry including a successful flight test and large-scale rocket engine testing of technology elements from RAMPT. Some fundamental enhancements required to allow the full infusion of AM to optimize performance for current and future missions are: 1) Advanced development of AM post-processing surface enhancement/polishing techniques for internal surfaces across multiple components are required to improve flow performance and ensure repeatable mechanical (fatigue) properties. 2) AM materials for large scale propulsion applications must sustain high performance under extreme oxygen-rich, high pressure, and high temperature environments 3) Advanced materials and process AM digital model twin development and validation will lead to efficient and repeatable part fabrication and the ability to predict residual stress as a function of process parameters and geometry. Two areas for alloy development were identified for rocket engine applications. The first was an extreme temperature alloy for applications such as injectors and turbopumps. NASA 's GRX-810 was identified as a candidate alloy for these applications. The other was oxygen compatible alloys for oxygen-rich staged combustion cycles. No commercial alloy has thus far shown sufficient oxygen compatibility and high strength in the extreme environment to meet this application and is an ongoing challenge in new engine development. Alloy development is required. ORCA addressed the longest lead times, highest costs, and high-risk components in the development, building, and testing of rocket engines. ORCA technology development is applicable to Lunar Lander Engine, Booster Engines, Upper Stage Engines, Commercial Space Engine Technology, and Nuclear Thermal Propulsion (NTP) technology. This project utilized public-private partnerships and cost sharing with specialty industry vendors, government partners, commercial crew providers, and infusion into commercial space companies and manufacturers.

Benefits: ORCA benefits include the following: 1) Modern evolved-additive alloys that will allow for significant improvements in performance and processing (ie. optimized for AM). 2) Improved surface finish to provide optimal performance. Surface finish is critical for flow and fatigue performance but has limited characterization and tailored options for aerospace alloys and internal flow passages, where AM is most often used (chambers, turbomachinery). 3) Improved success with long duration builds by eliminating build failures and reducing residual stresses. 4) Enable first time thru manufacturing by developing advanced materials and process modeling/validation. ORCA addressed the longest lead times, highest costs, and heaviest components in the development, build, and test of rocket engines. This maturation of AM will support the Space Technology Mission Directorate (STMD) Strategic Framework in all thrust areas of Go, Live and Explore and benefit NASA's science and exploration missions. This project specifically aligns with NASA's taxonomies TX01 Propulsion Systems; TX01.1 Chemical Space Propulsion; TX01.1.3 Cryogenic and TX12.1.4 Materials for Extreme Environments.