Cool! But I still want a rocket printed in one piece.

That's fantastic.

Pretty cool, but also interesting to note that soon anyone with enough money will be able to launch anything from their own back yard, of it's been like this forever, but now the applications are so much more... real.

incredible! thanks for the read....

Blink ...and technology takes a giant step.

Very cool ,3D printing has so many possible ways to create new ,useful and less expensive things . It's just that sometimes they use it to make things that are more cost effective with conventional methods . " Like that ridiculous faux sandstone room ." Great to see the progress !

That video was too cool. I want one for my bicycle.

How was it hardened?
Is the technology available as open source? Especially the "regenerative cooling jacket".
Did they pay F.A.R.?
How does the private sector benefit from this research?

"students at the University of California, San Diego (UCSD) have built a metal rocket engine using a technique previously confined to NASA."
Well, ....no.
About 2-3 years ago Paul Breed, founder of "Unreasonable Rockets", a competitor in one of NASA's centennial challenges, designed and ordered a Hydrogen peroxide engine from a 3-d printing company that works in metals, and fired it successfully. IIRC, it cost him about $5,000 for the printing job.

Wunderbar, NOW DO ONE OF THESE, AND MAKE IT WORK: Put googie patents in google search field. Put 4689950 in google parent search field. No moving parts jet engine, NOT a pulse jet, NOT a ram jet. Probably tough to fabricate with fabrication methods at the time of it's invention, trivial with high strength high temp 3d printing. This guy is the second inventors name on the patent, the name may be familiar: http://en.m.wikipedia.org/wiki/Hans_von_Ohain