For a factory where robots toil around the clock to build a rocket with almost no human labor, the sound of grunts echoing across the parking lot make for a jarring contrast.

“That’s Keanu Reeves’ stunt gym,” says Tim Ellis, the chief executive and cofounder of Relativity Space, a startup that wants to combine 3D printing and artificial intelligence to do for the rocket what Henry Ford did for the automobile. As we walk among the robots occupying Relativity’s factory, he points out the just-completed upper stage of the company’s rocket, which will soon be shipped to Mississippi for its first tests. Across the way, he says, gesturing to the outside world, is a recording studio run by Snoop Dogg.

Neither of those A-listers have paid a visit to Relativity’s rocket factory, but the presence of these unlikely neighbors seems to underscore the company’s main talking point: It can make rockets anywhere. In an ideal cosmos, though, its neighbors will be even more alien than Snoop Dogg. Relativity wants to not just build rockets, but to build them on Mars. How exactly? The answer, says Ellis, is robots—lots of them.

Roll up the loading bay doors at Relativity’s Los Angeles headquarters and you’ll find four of the largest metal 3D printers in the world, churning out rocket parts day and night. The latest model of the company’s proprietary printer, dubbed Stargate, stands 30 feet tall and has two massive robotic arms that protrude like tentacles from the machine. The Stargate printers will manufacture about 95 percent, by mass, of Relativity’s first rocket, named Terran-1. The only parts that won’t be printed are the electronics, cables, and a handful of moving parts and rubber gaskets.

Jordan Noone, Relativity's CTO and cofounder, stands beside the second version of the Stargate 3D printer at the company's headquarters. Photograph: Relativity

To make a rocket 3D-printable, Ellis’s team had to totally rethink the way rockets are designed. As a result, Terran-1 will have 100 times fewer parts than a comparable rocket. Its Aeon engine, for instance, consists of just 100 parts, whereas a typical liquid-fueled rocket would have thousands. By consolidating parts and optimizing them for 3D printing, Ellis says Relativity will be able to go from raw materials to the launch pad in just 60 days—in theory, anyway. Relativity hasn’t yet assembled a full Terran-1 and doesn’t expect the rocket to fly until 2021 at the earliest.

“A full-scale test will be the biggest milestone for them to prove this new technology,” says Shagun Sachdeva, a senior analyst at Northern Sky Research, a space consultancy. Then the company can start to address the other questions about its approach, such as whether there’s a need for a new rocket to pop into existence every 60 days.