NASA Integrates Post-Processing for Flight-Ready Rocket Parts

At NASA's Marshall Space Flight Center, engineers are treating metal additive manufacturing (AM) for aerospace as a unified sequence of design, build, and post-processing steps. This approach aims to mitigate risks associated with undetected flaws in components like combustion chambers or nozzles, which could cause significant delays. Dr. Paul Gradl, a principal engineer at the center, highlighted this perspective during the Additive Manufacturing Advantage: Aerospace, Space and Defense 2025 event.

Gradl explained that the success of metal AM in aerospace hinges on a thorough understanding of post-processing. This phase includes crucial steps such as powder removal, heat treatment, support and build plate removal, and inspection. He noted that NASA has experienced part rejections due to overlooked aspects in post-processing. The entire manufacturing sequence is iterative, often requiring multiple cycles of design, build, and post-processing before a method is finalized.

NASA maintains a process-agnostic stance, utilizing various AM technologies like powder bed fusion, directed energy deposition (DED), and additive friction stir deposition, selecting the most suitable method for specific applications. This flexibility allows for the creation of complex internal geometries with powder bed fusion, as well as large-scale DED parts measuring up to two to three meters in diameter and height, capabilities that were not feasible just five years ago.

Additive manufacturing has enabled NASA to work with novel materials that were previously difficult or impossible to form into useful shapes. Alloys like GRCop-42, a high-conductivity, high-temperature copper alloy, can now be directly formed into combustion chamber geometries. Similarly, NASA HR-1, a hydrogen-resistant alloy, has become practical for high-pressure hydrogen applications, and GRX-810, an oxide dispersion strengthened alloy, offers significantly improved creep life at extreme temperatures compared to traditional superalloys.

Integrated computational materials engineering tools have accelerated development, allowing for rapid prototyping of new materials. Furthermore, multi-material and multi-process AM techniques enable the combination of different alloys and manufacturing methods within a single component, such as combustion chambers integrating GRCop-42 and NASA HR-1 using both powder bed fusion and DED to achieve specific properties in different zones. NASA is also conducting extensive material characterization, collecting data on approximately 50 AM materials across thousands of samples to build comprehensive databases and establish standards for human spaceflight.