Sen— NASA has tested its largest 3-D printed rocket engine component during an engine firing that generated a record 20,000 pounds of thrust.
The component tested during the engine firing, an injector, delivers propellants to power an engine and provides the thrust necessary to send rockets to space. During the test, liquid oxygen and gaseous hydrogen passed through the injector into a combustion chamber and produced 10 times more thrust than any injector previously fabricated using 3-D printing.
"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, the director of the Engineering Directorate at NASA's Marshall Space Flight Center.
The component was manufactured using selective laser melting. This method built up layers of nickel-chromium alloy powder to make the injector with its 28 elements for channeling and mixing propellants. The was similar in design to injectors for large engines, such as the RS-25 engines that will be used to power NASA's new deep space rocket, the Space Launch System (SLS).
"This entire effort helped us learn what it takes to build larger 3-D parts, from design, to manufacturing, to testing," said Greg Barnett, the 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."
Propulsion systems engineer Greg Barnett prepares a rocket injector for a hot fire test at NASA's Marshall Space Flight Center. Image credit: NASA/MSFC/Emmett Given
One of the keys to reducing the cost of rocket parts is minimizing the number of components. This injector had only two parts, whereas a similar injector tested earlier had 115 parts. Fewer parts require less assembly effort, which means complex parts made with 3-D printing have the potential for significant cost savings.
"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 design of the injector. "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 injector was made by U.S. company Directed Manufacturing Inc., but NASA owns the injector design. NASA will make the test and materials data available to all U.S. companies through the Materials and Processes Information System database managed by Marshall's materials and processes laboratory.
Early data from the test, conducted at pressures up to 1,400 pounds per square inch absolute and at almost 6,000 degrees Fahrenheit, indicate the injector worked flawlessly. In the days to come, engineers will perform computer scans and other inspections to scrutinize the component more closely.
NASA seeks to advance technologies such as 3-D printing to make every aspect of space exploration more cost-effective. The agency is currently working to develop and test a 3-D printer that will soon print tools for the crew of the International Space Station, they are even exploring the possibility of printing food for long-duration space missions.