If it exists in three dimensions, chances are we'll be printing it some day. Take rocket engines. If we're ever going to take advantage of space and its unending bounty, making it cheaper to break orbit and blast around is an important step forward. Students at the University of California are doing their part, with a test-firing of their 3D printed metal rocket going fantastically well.
First of all, watch the video above. It'll easily fill your daily quota for cool things that spit fire.
While the engine, called "Tri-D" was funded mostly by NASA's Marshall Space Flight Center, it was the students that came up with the design. According to Gizmag's David Szondy, the Tri-D cost $US6800 to manufacture, which is apparently quite cheap for this sort of component.
A process called "Direct Metal Laser Sintering", which uses a laser to fuse layers of chromium-cobalt powder, is responsible for the final product -- a 17.7cm long, 4.5kg engine that can put out 200 pounds (90.7kg) of thrust.
Below is a less-exciting, but still interesting video of the rocket being tested with liquid nitrogen and water (probably a good thing to try before filling it with explosions).