With several smaller, successful tests completed using the technology, NASA conducted another test firing of an engine that had a fuel injector produced by 3-D printing. The process, known as additive manufacturing, has made the news recently as other tests have successfully been conducted. The Aug. 22 test firing generated an estimated 20,000 pounds of thrust.
This test is a milestone for both NASA and the 3-D printing industry in that the technology could result in both lowered costs and essential components being fabricated more conveniently in fewer parts. This injector, for example, was fabricated from two pieces, versus 115 in a similar, conventionally manufactured injector. This method requires less assembly and, potentially, monetary savings for the space agency.
“This successful test of a 3-D-printed rocket injector brings NASA significantly closer to proving this innovative technology can be used to reduce the cost of flight hardware,” said Chris Singer, director of the Engineering Directorate at NASA’s Marshall Space Flight Center in Huntsville, Ala.
“This entire effort helped us learn what it takes to build larger 3-D parts—from design, to manufacturing, to testing,” said Greg Barnett, lead engineer for the project. “This technology can be applied to any of SLS’s engines, or to rocket components being built by private industry.”
3-D printing is being touted as a more cost-effective alternative to conventional manufacturing. A few recent AmericaSpace articles touched on the use of this relatively new technology. Aerojet Rocketdyne tested a 3-D-printed rocket engine component with successful results. Jeff Haynes, an Aerojet project manager, recently spoke with us about the significance of that test.
The component tested was an injector, which delivers propellants to rocket engines, in turn sending rockets into space. During this test, liquid oxygen and hydrogen gas were passed though the component. Ten times more thrust was produced during this test than in previous tests of 3-D-printed components. The injector was manufactured in a process called selective laser melting, in which layers of nickel-chromium alloy powder were fashioned into a complex injector with 28 channels. It is similar in size to small rocket injectors and has a similar design to the Space Launch System’s (SLS) injectors.
“We took the design of an existing injector that we already tested and modified the design so the injector could be made with a 3-D printer,” explained Brad Bullard, the propulsion engineer responsible for the injector design. “We will be able to directly compare test data for both the traditionally assembled injector and the 3-D-printed injector to see if there’s any difference in performance.”
The test was conducted at pressures up to 1,400 pounds per square inch in a vacuum and temperatures up to nearly 6,000 degrees Fahrenheit. Word is that the injector performed “flawlessly.” Engineers will analyze the effects of the test on the injector more thoroughly in coming days using computer scans and other means.
While NASA owns the injector design, the injector itself was fabricated by Directed Manufacturing, Inc., of Austin, Texas. NASA will make the test and materials data available to all vendors through the Materials and Processes Information System database, which is controlled by Marshall’s materials and processes lab.
NASA intends to build upon the previous knowledge it has gleaned about 3-D-printed components through further tests, such as this one. Hot fire tests were previously completed at Marshall and NASA’s Glenn Research Center. In addition, engineers at Marshall recently finished tests with Made in Space, a company in Moffett Field, Calif., which is working with NASA to develop a 3-D printer to be sent to the International Space Station. The idea of 3-D-printed food is also being explored for future manned missions.
NASA is also a leading partner with the National Network for Manufacturing Innovation and the Advanced Manufacturing Initiative, working together to develop this technology and materials to reduce spaceflight costs.