As we know it, 3D printing is usually confined to small-scale projects like headphones. NASA is ever so slightly more ambitious. It's using a closely related technique from Concept Laser, selective laser melting, to build elements of its Space Launch System on a pace that wouldn't be feasible with traditional methods. By firing brief, exact laser pulses at metal powder, Concept Laser's CAD system creates solid metal parts that are geometrically complex but don't need to be welded together. The technique saves the money and time that would normally be spent on building many smaller pieces, but it could be even more vital for safety: having monolithic components reduces the points of failure that could bring the rocket down. We'll have a first inkling of how well laser melting works for NASA when the SLS' upper-stage J-2X engine goes through testing before the end of 2012, and the printed parts should receive their ultimate seal of approval with a first flight in 2017.