On October 23, 2023, the Antarctic Bear learned that as part of the Fourth Industrial Revolution Reaction Additive Manufacturing (RAMFIRE) project, NASA has recently constructed and tested 3D printed aluminum rocket engine nozzles. NASA developers have stated that additive manufacturing nozzles are lighter than traditional nozzles and can carry higher payloads, laying the foundation for deep space flight of spacecraft.

According to the agency's announcement of collaboration opportunities, engineers at NASA Marshall Space Flight Center in Huntsville, Alabama, collaborated with Elementum 3D in Erie, Colorado to manufacture a weldable aluminum that has enough heat resistance to be used in rocket engines. Compared to other metals, aluminum has a lower density and can be used to manufacture high-strength and lightweight components.

△The RAMFIRE nozzle was subjected to thermal testing at booth 115 in the Marshall East testing area. The nozzle is made of a new aluminum alloy 6061-RAM2 and can withstand huge temperature gradients. When hot gas approaches 3300 degrees Celsius and burns, icicles form outside the engine nozzle. Source: NASA

However, due to its low resistance to extreme heat and susceptibility to cracking during welding, aluminum is currently difficult to use as an additive in the manufacturing of rocket engine parts.

The RAMFIRE project is funded by the NASA Space Technology Mission Directorate (STMD) and focuses on promoting aluminum rocket nozzles for lightweight, additive manufacturing. The nozzle design has a small internal channel to maintain sufficient low temperature to prevent melting.

Using traditional manufacturing methods, nozzles may require up to a thousand separately connected parts. The RAMFIRE nozzle adopts an integrated design, which greatly reduces the required adhesive amount and significantly shortens manufacturing time.

Paul Gradl, Chief Researcher at NASA Marshall RAMFIRE, said, "Industry collaboration with professional manufacturing suppliers helps advance the supply base and makes additive manufacturing easier to apply to NASA missions and the broader commercial and aerospace industries. We have reduced the steps involved in the manufacturing process, allowing us to manufacture large engine components as a single component within a few days

NASA's Moon to Mars target needs to be able to send more cargo to deep space destinations. This new alloy can play an important role in manufacturing lightweight rocket components that can withstand high structural loads.

John Vickers, Chief Technical Expert for Advanced Manufacturing at STMD, said, "Quality is crucial for NASA's future deep space missions. Projects such as mature additive manufacturing and advanced materials will help develop new propulsion systems, space manufacturing, and promote the smooth progress of NASA's space missions to the moon, Mars, and other areas.

Earlier this summer, two RAMFIRE nozzles completed multiple hot tests using liquid oxygen and liquid hydrogen, as well as liquid oxygen and liquid methane fuel configurations in the Marshall Eastern Pilot Zone. Due to the pressure chamber exceeding 825 pounds per square inch (psi) (exceeding the expected test pressure), the nozzle successfully accumulated 22 starts and a running time of 579 seconds (nearly 10 minutes). This event indicates that the nozzle can operate in the most demanding deep space environment.

This testing series marks an important milestone for the nozzle, and after a series of rigorous thermal tests, we have demonstrated that the nozzle can withstand the thermal, structural, and pressure loads of a lunar lander scale engine.

In addition to successfully constructing and testing rocket engine nozzles, the RAMFIRE project also uses RAMFIRE aluminum materials and additive manufacturing processes to construct other advanced large components for demonstration purposes. This includes a pneumatic plug nozzle with a diameter of 36 inches, a complex overall coolant channel, and a vacuum jacket tank for low-temperature fluid applications.

According to NASA, the agency and industry partners are working hard to share data and processes with business stakeholders and academia. Multiple aerospace companies are eva luating the manufacturing process of this new alloy and LP-DED additive, and looking for ways to use it for manufacturing satellites and other application components.