Normally, rockets are made of a whole bunch of small parts that are intricately attached to each other to form the body that can actually fly into space. If you could build complex geometrical parts out of a single piece of material, however, things would get much easier. That's where metal powder and lasers come in.
The process is called selective laser melting, and for all intents and purposes, it's like a more badass version of typical 3D printing. Instead of putting down layers of plastic, the system works with a pile of metal powder which is then welded into the appropriate form by being shot by lasers. When you brush the excess metal away, you've got exactly the piece you need all in one part.
In addition to reducing the places where a rocket could critically fail, the process of selective laser melting also makes it easy to churn out custom-built pieces way faster than any competing method. Some selective laser melted parts are due to be tested in hot-fire tests of a J-2X engine later this year. The hope is they can be tested in actual test flight by 2017. No matter how those tests may turn out, you can't deny the method is pretty righteous. [NASA via Engadget]