NASA Successfully Tests 3D Printed Rocket Engine Parts

NASA‘s renewed efforts to return humans to the moon by 2024 has led to advances in new space technologies to improve processes, and reduce costs and development time. In early December 2020, we learned that engineers at the U.S. space agency’s Marshall Space Flight Center in Huntsville, Alabama successfully hot-fire tested 3D printed components for rocket engines. The copper alloy combustion chamber and nozzle were made of a high-strength, hydrogen-resistant alloy and could withstand the same extreme combustion environments that traditionally manufactured metal structures experience in flight. This huge milestone could pave the way for 3D printed parts aboard new rockets.

“This 3D printed technology is a game-changer when it comes to reducing total hardware manufacturing time and cost,” said Thomas Teasley, a test engineer at NASA’s Marshall Center. “These hot-fire tests are a critical step in preparing this hardware for use in future Moon and Mars missions.”

Teasley worked with a team of Marshall test engineers to prove how good these 3D printed parts are. For the task, they performed 23 hot-fire tests for a total duration of 280 seconds over 10 test days. Throughout the testing, engineers collected data, including pressure and temperature measurements in hardware coolant channels and the main chamber, and high-speed and high-resolution video of the exhaust plume and chamber throat. The team also calculated the chamber’s performance and how efficiently the engine used propellant overall.

Blown powder directed energy deposition can produce large structures – such as these engine nozzles – cheaper and quicker than traditional fabrication techniques. Image courtesy of NASA

The high-strength iron-nickel superalloy nozzle was printed using laser powder directed energy deposition (DED), one of NASA’s advanced manufacturing methods that will improve the performance and reduce the production costs of rocket thrust chamber assemblies, and was demonstrated in NASA’s Rapid and Analysis Manufacturing Propulsion Technology (RAMPT) project. NASA is currently developing lighter and more efficient liquid rocket engine parts for future missions to the Moon, Mars, and beyond. Furthermore, to cut down on highly complex and expensive rocket engine parts, RAMPT has become crucial for replacing some traditionally metal pieces on the thrust chamber with composite material, using advanced 3D printing methods to create the combustion chamber and nozzle, and employing innovative mechanical methods to fuse the two instead of relying on traditional metal joints.

In a statement, NASA hinted that future lunar landers might come equipped with 3D printed rocket engine parts to help bring down overall manufacturing costs and reduce production time. In fact, these 23 hot-fire tests were part of NASA’s Long-Life Additive Manufacturing Assembly (LLAMA) project, which aims to enable these 3D printed parts – along with other additively manufactured hardware – for use on future lunar landers. The Marshall team leads the LLAMA project for NASA’s Game Changing Development program, part of the agency’s Space Technology Mission Directorate, and is slated to perform additional hot-fire tests to further demonstrate and validate the durability of the engine components.

“These 3D printed rocket parts are good for the long haul,” stated NASA in a Twitter post announcing the 23 hot-fire tests, but they are not the only 3D printed parts tested by the U.S. space agency. Earlier in 2018, NASA broke ground in the world of additive manufacturing. Through its Low-Cost Upper Stage-Class Propulsion project, the agency successfully hot-fire tested a combustion chamber at Marshall, which was made using a combination of 3D printing techniques. Before that, the agency had successfully 3D printed the first, full-scale copper combustion chamber liner in 2015, also at Marshall, using a powdered copper alloy created by material scientists at the Glenn Research Center in Cleveland, Ohio.

illustration of Artemis astronauts on the Moon. Image courtesy of NASA

Moving forward with the final steps needed to land astronauts on the Moon by 2024 will take a lot of collaborative effort. Aside from testing its own 3D printed rocket parts at Marshall, NASA has also selected three U.S. companies to design and develop the human landing systems (HLS) for the agency’s Artemis program, one of which will land the first woman and next man on the lunar surface. According to NASA Administrator Jim Bridenstine, they are on track for sustainable human exploration of the Moon for the first time in history and have commercial and international partners to work with. Moreover, NASA’s lunar operations will provide the agency with the experience and knowledge necessary to enable a historic human mission to Mars.

Engineers at NASA’s Marshall Center have been using additive manufacturing since it first emerged in the 1990s. Today, the center has state-of-the-art 3D printers and unique expertise in leveraging new digital tools and applying them towards propulsion systems design and, in the future, for in-space manufacturing. Marshall is even helping develop the standards and qualifications “from art to part” for testing new advanced manufacturing processes and 3D printed parts. As NASA gets closer to establishing a lunar base, engineers at Marshall are helping the agency set new frontiers in human spaceflight, developing the foundations of an advanced manufacturing technology that could become the building blocks for the future of off-Earth exploration.