HUNTSVILLE, Alabama – NASA engineers at Alabama’s Marshall Space Flight Center have produced the first full-scale, copper rocket part using additive manufacturing – a milestone for aerospace 3-D printing.
The part is a combustion chamber liner that must operate at extreme conditions during flight. In fact, temperatures on the inside of the paper-thin copper liner wall can reach 5,000 degrees Fahrenheit. It’s kept from melting by recirculating gases on the outside cooled to less than 100 degrees above absolute zero, the theoretical limit of cold.
“To circulate the gas, the combustion chamber liner has more than 200 intricate channels built between the inner and outer liner wall,” said Chris Singer, director of the Engineering Directorate at NASA’s Alabama hub. “Making these tiny passages with complex internal geometries challenged our additive manufacturing team.”
NASA says only a handful of cooper rocket parts have been made with additive manufacturing, so Marshall’s engineers are breaking new technological ground based on the specifications of the combustion chamber. A selective laser melting machine in Marshall’s Materials and Processing Laboratory fused 8,255 layers of copper powder to make the chamber in 10 days and 18 hours.
“Copper is extremely good at conducting heat,” said Zach Jones, the materials engineer who led the manufacturing at Huntsville’s Marshall. “That’s why copper is an ideal material for lining an engine combustion chamber and for other parts as well, but this property makes the additive manufacturing of copper challenging because the laser has difficulty continuously melting the copper powder.”
NASA says additive manufacturing has the potential to reduce the time and cost of making rocket parts like the copper liner.
“Our goal is to build rocket engine parts up to 10 times faster and reduce cost by more than 50 percent,” said Chris Protz, the Marshall propulsion engineer leading the project. “We are not trying to just make and test one part. We are developing a repeatable process that industry can adopt to manufacture engine parts with advanced designs. The ultimate goal is to make building rocket engines more affordable for everyone.”
The next stop for the copper liner is NASA’s Langley Research Center in Hampton, Virginia, where an electron beam freedom fabrication facility will direct deposit a nickel super-alloy structural jacket onto the outside of the liner. Later this summer, the engine component will be hot-fire tested at Marshall to determine how the engine performs.
The 3-D printing lab at Marshall in Alabama has become the hub of NASA’s additive manufacturing initiative. Last year, Marshall engineers tested a 3-D printer bound for use on the International Space Station. (Astronauts this year printed a wrench, the first tool built in space.) In 2013, Marshall tested a 3-D printed rocket injector.
“Additive manufacturing is one of many technologies we are embracing to help us continue our journey to Mars and even sustain explorers living on the Red Planet,” said Steve Jurczyk, associate administrator for the Space Technology Mission Directorate at NASA Headquarters in Washington.