Gravity. More than the name of a killer movie, it’s likely something we take for granted every single day. After all, nearly everything we do is reliant on the idea that stuff stays in place when we stop holding it. Astronauts don’t have that luxury, however, and when even simple tasks take a ton of effort, something relatively complex like using a 3D printer is even harder. Why would astronauts need one of those? Well, because stuff breaks in space, and replacing a busted part isn’t as simple as hitting Home Depot.

Tomorrow, weather permitting, NASA will launch a 3D printer into space for the first time. Carried aboard a SpaceX Dragon capsule, the printer will be installed in the International Space Station, where astronauts will test the technology that NASA hopes will one day transform space exploration, eventually playing a vital role in travel to the moon, asteroids, and Mars. For consumers, the hype surrounding 3D printing has generally far overshot clear uses for it, but space exploration is one case where the technology could actually be revolutionary. “Right now if something breaks, we’re completely dependent on launching a replacement from the ground,” says Niki Werkheiser, the project manager for the printer experiment, a process that can take months and cost thousands of dollars per pound sent into orbit. “Imagine launching everything you might ever need for mission to Mars or an asteroid, it would be challenging or impossible.”