NASA tests 3-D printed complex rocket parts

NASA has successfully tested the most complex rocket engine parts ever designed by the agency and created by 3-D printing, pushing the limits of the technology.
The advance at NASA's Marshall Space Flight Centre in Huntsville, Alabama shows just how the 3-D printing technology could potentially revolutionise how the agency makes use of additive manufacturing in rocket design.
NASA engineers pushed the limits of technology by designing a rocket engine injector - a highly complex part that sends propellant into the engine - with design features that took advantage of 3-D printing.
To make the parts, the design was entered into the 3-D printer's computer. The printer then built each part by layering metal powder and fusing it together with a laser, a process known as selective laser melting.

The additive manufacturing process allowed rocket designers to create an injector with 40 individual spray elements, all printed as a single component rather than manufactured individually.
The part was similar in size to injectors that power small rocket engines and similar in design to injectors for large engines, such as the RS-25 engine that will power NASA's Space Launch System (SLS) rocket, the heavy-lift, exploration class rocket under development to take humans beyond Earth orbit and to Mars.

"We wanted to go a step beyond just testing an injector and demonstrate how 3-D printing could revolutionise rocket designs for increased system performance," said Chris Singer, director of Marshall's Engineering Directorate.

"The parts performed exceptionally well during the tests," said Singer.
Using traditional manufacturing methods, 163 individual parts would be made and then assembled. But with 3-D printing technology, only two parts were required, saving time and money and allowing engineers to build parts that enhance rocket engine performance and are less prone to failure.
Two rocket injectors were tested for five seconds each, producing 20,000 pounds of thrust. Designers created complex geometric flow patterns that allowed oxygen and hydrogen to swirl together before combusting at 1,400 pounds per square inch and temperatures up to 3,315 degrees Celsius.
Additive manufacturing not only helped engineers build and test a rocket injector with a unique design, but it also enabled them to test faster and smarter, NASA said.