In my #scifi books, Glory on Mars and Born on Mars, settlers have fancy 3D printers called fabricators, using lasers to sinter together almost anything. Giant robotic fabricators build their habitats while precision lab fabricators use metal foils to slowly construct any part they need. Lasers can even manipulate molecules or atoms, so they can make any crystal they want. But that’s science fiction.
One of MIT’s objections to the Mars-One plan for a permanent colony on the red planet is spare parts. As time goes on, spare parts for a growing colony would exceed the room in any plausible sized spacecraft.
Will 3D printing save the day?
NASA is working on this in the International Space Station – a way to make many different spare parts, as needed, from one source of material.
But we Earth-bound humans use a lot of different materials. My town’s recycling instructions list seven types of plastic, aluminum, steel, and glass. And what’s in the light bulbs and electronics I have to handle separately?
High-end industrial printers sinter parts from certain metal and plastic powders, but there are a lot of materials that can’t be printed. And 3D printers can’t easily mix materials in one print job. Printing a hammer is easy, but parts that will move must be printed separately and assembled. Also, the parts aren’t as strong because of weakness between the layers.
On the plus side, while 3D printing looks expensive compared to traditional manufacturing, it looks pretty good compared to sending spacecraft to Mars.
If you’re a colonist on Mars you’ll live in a bubble of earthly environment, and if that bubble pops you’re dead in five minutes. Spare parts will be life-and-death items. The technology I sent to Mars in my books is still in the real-world’s future.