UCSD (Uiversity of California, San Diego) have created a 3D-printed metal rocket engine using techniques previously only known to NASA, and successfully fired it at the Friends of Amateur Rocketry launch site in California’s Mojave Desert. Gizmag says that it is the “first such test of a printed liquid-fueled, metal rocket engine by any university in the world and the first designed and printed outside of NASA.”
The Tri-D rocket engine, as it’s called, was designed and built with the cooperation of NASA’s Marshall Space Flight Center as part of an effort to explore the feasibility of printed rocket components.
For purposes of the exercise, it was designed to power the third stage of a Nanosat launcher, that is, one capable of launching satellites that weigh less than 1.33 kg (2.93 lb).
Official Source: http://www.gizmag.com/3d-printed-rocket-seds/29306/