NASA and contractors accelerate testing on 3D-printed rocket engine components
As NASA prepares the materials and machines to send humans to destinations far beyond the gravitational influence of Earth, the space agency is turning its attention on new game-changing technologies to help them in their efforts. The company’s that enable NASA to accomplish its objectives are also taking an active role in developing new methods to facilitate space exploration initiatives. One technology in particular, additive manufacturing, more commonly known as 3D printing, has come into its own and is being increasingly used to produce rocket engine components. NASA, Aerojet Rocketdyne, SpaceX and other firms have all been pushing this technology to new heights.
NASA recently announced that the space agency had tested the: “most complex rocket engine parts ever designed.” These components were put through their paces at Marshall Space Flight Center located in Huntsville, Alabama in order to assist NASA in developing their new heavy-lift booster – the Space Launch System or “SLS.”
A rocket engine injector, an important element of most launch vehicles, tasked with delivering fuel to the booster’s engine was recently developed using additive manufacturing processes. In a recently-issued press release, NASA described how the injector’s design was uploaded into the printer’s computer. With this data on hand, the printer then used metal powder fused together in layers in a process known as selective laser melting. Although this technology has only recently entered into the public’s consciousness – aerospace firms have been developing these methods for some time.
‘We had been doing this for over 10-12 years but not with the robust materials we have now. In early 2009 we began developing the fully dense materials these new machines have enabled,” said Jeffrey Haynes, Aerojet Rocketdyne’s Additive Manufacturing program manager.
Engineers working with this technology produced the injector through a series of 40 individual spray elements which were printed (as opposed to having the various parts printed individually and then assembled). If done via traditional means, NASA has stated that a similar injector would require 163 individual parts to be produced and then assembled. The 3D-printed system – only required two parts to be produced. With less individual components – the likelihood that something could go wrong should be dramatically diminished. Similarly, the expense of producing these parts and the time to produce them should also decrease.
“We wanted to go a step beyond just testing an injector and demonstrate how 3D printing could revolutionize rocket designs for increased system performance,” said Chris Singer, director of Marshall’s Engineering Directorate. “The parts performed exceptionally well during the tests.”
NASA worked with two companies to develop and build the injector. Solid Concepts based out of Valencia, California, and Directed Manufacturing located in Austin, Texas. Each company produced one injector.
Rather than go ahead and produce and test an injector that is used on either a medium or heavy-lift launch vehicle, the space agency opted to produce an injector designed for use on a small rocket engine. The injectors selected are similar in design to those used on larger engines, such as the Space Shuttle Main Engine’s (SSME ) RS-25. The RS-25 is planned to be used during the initial flights of the SLS and is tested at NASA’s Stennis Space Center located in Mississippi.
Four RS-25s will be used on SLS’ core stage providing some of the needed thrust to get the 200-foot-tall rocket off of the launch pad. The core stage measures some 27.6 feet (8 meters) in diameter and contains the cryogenic liquid hydrogen and liquid oxygen fuel that the RS-25s utilize. Developing a new heavy-lift booster – is no small feat. NASA is relying on a small army of engineers from an array of firms to produce these rockets.
“One of our goals is to collaborate with a variety of companies and establish standards for this new manufacturing process,” explained Marshall’s propulsion engineer Jason Turpin. “We are working with industry to learn how to take advantage of additive manufacturing in every stage of space hardware construction from design to operations in space. We are applying everything we learn about making rocket engine components to the Space Launch System and other space hardware.”
For this recent test, the two rocket injectors were each tested for approximately five seconds each. When tested, each of the engines produced an estimated 20,000 pounds of thrust. The injectors operated via complex geometric flow patterns where oxygen and hydrogen flowed together before they were ignited at some 1,400 pounds per square inch – at temperatures reaching some 6,000 degrees Fahrenheit. In terms of SLS, having the resources to develop and test these systems close at hand – has proven beneficial.
“Having an in-house additive manufacturing capability allows us to look at test data, modify parts or the test stand based on the data, implement changes quickly and get back to testing,” said Nicholas Case, a propulsion engineer who led the testing regimen for the injectors. “This speeds up the whole design, development and testing process and allows us to try innovative designs with less risk and cost to projects.”
NASA has expressed hope that, by using these systems at Marshall, 3D components can be produced and tested over at Stennis more quickly. NASA’s various teams and departments are collaborating so as to rapidly modify the parts so as to reduce the developmental process as well as components which are on the launch vehicles themselves.
The space agency has produced increasingly sophisticated 3D components in an effort to test the limits this technology can be used for spaceflight purposes. Besides injectors, rocket nozzles and other components have been created. NASA has stated that the overarching goal of the space agency’s efforts is to reduce the complexity, time and cost of building rocket engines.
Not to be left out of these efforts, Hawthorne, California-based SpaceX used a Main Oxidizer Valve (MOV) during the January 6, 2014 flight of a Falcon 9 v1.1 rocket with the Thaicom 6 commercial satellite. One of the booster’s nine Merlin 1D engines was outfitted with the 3D-printed MOV. The launch marked the first time that SpaceX has used a component constructed by additive manufacturing methods. The valve operated as advertised despite the vibration and extreme temperatures involved with launch.
Video Courtesy of NASA
Jason Rhian spent several years honing his skills with internships at NASA, the National Space Society and other organizations. He has provided content for outlets such as: Aviation Week & Space Technology, Space.com, The Mars Society and Universe Today.