This article was originally published at The Conversation. The publication contributed the article to Space.com’s Expert Voices: Op-Ed & Insights.

The entire Apollo 11 mission to the moon took just eight days. If we ever want to build permanent bases on the moon, or perhaps even Mars or beyond, then future astronauts will have to spend many more days, months and maybe even years in space without a constant lifeline to Earth. The question is how would they get hold of everything they needed. Using rockets to send all the equipment and supplies for building and maintaining long-term settlements on the moon would be hugely expensive.

This is where 3D printing could come in, allowing astronauts to construct whatever their lunar colony needed from raw materials. Much of the excitement around 3D printing in space has focused on using it to construct buildings from lunar rock. But my research suggests it may actually be more practical to use this moondust to supply lunar manufacturing labs turning out replacement components for all sorts of equipment.