NASA has produced rocket parts on a 3D printer, successfully test-firing a pair of injectors. This test engine contained the most advanced rocket parts ever manufactured by the space agency utilizing 3D printing technology.

Rocket injectors are complex components designed to feed fuel to the engine, combining liquid hydrogen and oxygen, which erupts in a vigorous explosion. Injectors tested in this run burned at 6,000 degrees Fahrenheit at a pressure of 1,400 pounds per square inch, producing over 20,000 pounds of thrust. The experiment tested the parts during five seconds of live ignition, known as a hot fire test.

Rocket engine parts were designed to take advantage of 3D printing. In a process called selective laser melting, the printer sprinkled metal powder, according to a virtual pattern. After each layer was laid down, a laser fused the powder together, creating the injectors. These devices contained 40 individual spray elements, constructed in a single piece.

Injectors were specially-designed to create complex flow patterns, which stirred the reactants before they were ignited, increasing efficiency.

The Space Launch System (SLS) booster is scheduled to be NASA's workhorse spacecraft in a few years. The vehicle will be used to bring a human crew to Mars sometime in the 2030's, as per NASA's current schedule. Injectors tested in this experiment are similar to those that will be used in the new rocket boosters.

Without additive manufacturing, a total of 163 individual parts needed to be assembled to create a similar injector. Using 3D technology, the injectors were constructed from just two parts. This could save designers significant time and money over using traditional construction techniques.

Solid Concepts in Valencia, California and Directed Manufacturing in Austin, Texas each built a single injector for the test.

"One of our goals is to collaborate with a variety of companies and establish standards for this new manufacturing process. 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," Jason Turpin, propulsion engineer for the Marshall Space Flight Center, said.

The capability to produce 3D printed directly at the test center in Huntsville, Alabama allowed engineers and designers to tweak designs as research progressed. Tests showed 3D printed parts were capable of performing within operating specifications for the engines.

"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," Nicholas Case, propulsion engineer on the program, told the press.

Additive manufacturing is being utilized to create increasing-complex parts for future space travel.

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