NASA designed a rocket engine injector using design features that employed a 3-D printer. 

The device is highly complex and sends propellant into the engine. The 3-D printer built each part by layering metal powder and fusing it together with a laser in a process known as selective laser printing. The new part was similar in size to those that power small engines but similar in design to those that power large ones. 

"We wanted to go a step beyond just testing an injector and demonstrate how 3-D 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."

Under traditional manufacturing methods 163 individual parts would need to be assembled, this new method required only two parts. 

Two rocket injectors were tested for five seconds each, producing 20,000 pounds of thrust. The designers allowed oxygen and hydrogen to swirl together before combusting at 1,400 pounds per square inch and temperatures of up to 6,000 degrees Fahrenheit. 

"One of our goals is to collaborate with a variety of companies and establish standards for this new manufacturing process," said Marshall 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."

The new method will allow researchers to test rocket equipement in a faster and smarter manner. 

"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 leading the testing. "This speeds up the whole design, development and testing process and allows us to try innovative designs with less risk and cost to projects."