This NASA sponsored STTR project will investigate methods for close-out of large, liquid rocket engine, nickel or stainless steel nozzle, coolant channels utilizing robotic laser and pulsed-arc additive manufacturing (AM)methods. Structural jacket to coolant channel land area interface strength will be quantified and metallurgical characterization completed. Process optimizations will be conducted to select best deposition parameters and starting feed stock for the AM processes based on article pressure drop and pressure testing. Sub-scale and intermediate size nozzles will be fabricated using the hybrid Metal Digital Direct Manufacturing (MDDM) processes and delivered to the NASA-MSFC for hot fire testing. Value stream analysis and process cost modeling methods will be used to estimate nozzle should costs and to identify relative economic risk of each nozzle AM operation.