August 28, 2013
3D Engine Component Produces Record Amount Of Thrust During Test
redOrbit Staff & Wire Reports - Your Universe Online
During the test, liquid oxygen and gaseous hydrogen passed through the component into a combustion chamber and wound up producing 10 times more thrust than an injector previously created through the use of additive manufacturing (another name for the 3D printing process).
In a statement, NASA called the test “a milestone for one of many important advances the agency is making to reduce the cost of space hardware,” and the 3D printing process would help “foster new and more cost-effective capabilities in the US space industry.”
Likewise, Chris Singer, director of the Engineering Directorate at the Marshall Space Flight Center, said the successful test “brings NASA significantly closer to proving this innovative technology can be used to reduce the cost of flight hardware.”
The injector was manufactured using a process known as selective laser melting. This method built up layers of nickel-chromium alloy powder in order to make the complex, subscale injector with 28 elements for channeling and mixing propellants, the agency explained.
The component was approximately the same size as the injectors used to power small rocket engines. It also reportedly shared many of the design elements of injectors for larger engines, such as the RS-25 unit that will be used to power the Space Launch System (SLS) rocket for deep space human missions.
The 3D printed injector only had two parts, while a normal injector tested earlier had a total of 115 parts. The successful test should make it possible to reduce the cost of rocket parts by using additive manufacturing to reduce the number of components needed for the injector, as well as the assembly required for the device.
“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."
“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,” added Brad Bullard, the propulsion engineer responsible for the injector’s 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 absolute and at almost 6,000 degrees Fahrenheit, and NASA reports the early results indicate the injector “worked flawlessly.” Engineers are expected to perform a series of inspections, including computer scans, within the next several days in order to complete a more in-depth analysis of the component.
In July, NASA reported it had successfully tested the first-ever 3D printed rocket component – an instrument they and Aerojet Rocketdyne were able to produce in less than four months with a 70 percent reduction in cost versus traditional injectors.
Later on that month, engineers at the Marshall Space Flight Center built a pair of subscale injectors with a specialized 3D printing machine and completed 11 main stage hot-fire tests. During those trials, NASA accumulated 46 seconds of total firing time at temperatures nearing 6,000 degrees Fahrenheit while burning liquid oxygen and gaseous hydrogen.
“Rocket engines are complex, with hundreds of individual components that many suppliers typically build and assemble, so testing an engine component built with a new process helps verify that it might be an affordable way to make future rockets,” Singer said following that test. “The additive manufacturing process has the potential to reduce the time and cost associated with making complex parts by an order of magnitude.”