I always think of that scene in Apollo 13: “We need to make this… fit into this… using this.” It’s a frustration that’s central to the whole film: how could we be able to send human beings all the way to the Moon and still be foiled by something as simple as the shape of a valve? More to the point, how could we send a rover all the way to Mars, and still worry about something as banal as a broken wheel or a bent rod? NASA has long struggled with this dissonance between the seemingly- and actually-difficult, and has recently looked to 3D printing to help close the gap; NASA wants to start printing replacement parts out of glue and Moon dust. Now that approach is being taken up by perhaps the only other organization that could hope to rival a space agency in terms of scale and grandeur: the US military.
For the rest of the story: http://www.extremetech.com/extreme/156773-us-navy-looks-to-3d-printing-to-turn-its-city-sized-aircraft-carriers-into-mobile-factories