If 3D printing were as popular on earth as it seems to be off world, we'd be surrounded by 3D printed parts already. From these Michelin 3D printed rover wheels to NASA's Moon to Mars Planetary Autonomous Construction Technology (i.e. 3D printing with planet soil) to the new 3D printed rocket thrusters from X-Bow Systems that will get us there — in space tech, 3D printing is the method of choice.