A satellite built by the German startup Orbital Matter satellite 3D printed a half-meter long beam out of a custom plastic material, in what executives called a first for a free-flying spacecraft in orbit, and a step toward constructing large structures in space.

The company’s small satellite, Replicator-2, was launched on a SpaceX rideshare mission this summer, with four of the company’s 3D printers onboard. Each printer can create a rigid, cylindrical beam by extruding coils of resin that are cured by an ultraviolet light, which the company analogizes to cement and water.

This technology matters because future spacecraft will need to generate a lot more electrical power and radiate a lot more heat into the vacuum of space, particularly if they’re going to serve as orbital data centers. They’ll also still need to fit into the tight confines of the fairing on top of the rocket that carries them into orbit. If spacecraft are able to construct their equipment in orbit, the power and heat-dissipation challenges may get a lot easier to solve.

“Replicator 2 is the first proof that we can simply build the array in space, at whatever size the mission demands,” said Jakub Stojek, CEO and co-founder of Orbital Matter. The company is partnering with the European Space Agency and Thales Alenia, a leading European satellite builder, which it collborated with on Replicator 2.

Today’s large structures in space are origami projects—large solar arrays or telescope mirrors are folded up and then deployed on orbit. That’s a tricky engineering project, and so the idea of making and assembling those structures in space is appealing. NASA has funded some efforts at the idea, notably a mission with the company Redwire that 3D-printed structural beams in a vacuum chamber in 2023 but never got off the ground.

Two of Orbital Matter’s printers are designed to deploy a flexible solar array, but an anomaly led one of the printers to fail. Still, the boom that was created successfully deployed the solar array, and is an important proof of concept. Previous 3D-printing efforts in microgravity were limited to the pressurized environment onboard the International Space Station.

“That’s why we put so many printers on this single satellite. We preferred to learn in orbit and adapt the software as needed rather than waste years testing every possibility on the ground,” Orbital Matters CTO Robert Ihnatisin told TechCrunch.

The boom’s length is limited by the amount of resin carried onboard the satellite, and the company’s engineers believe that 100 meter booms are feasible. For comparison, SpaceX’s Starlink V2 Mini satellites — among the most powerful mass-produced satellites in orbit — uses solar arrays that are 20 meters long.

Orbital Matter was co-founded in 2022 by Ihnatsin, who previously worked at 3D printing company FormLabs, and Stojek, and raised a $3 million seed round.

Now, Orbital Matter is working on another demonstration mission, scheduled for launch in 2028, that will test a larger version of its printer on a bigger satellite that the company hopes will deploy a solar array that can generate 5 kw of power. That will be a “stepping stone” toward larger deployments of 100+ KW per wing by 2030.

The company is also collaborating with satellite builders that are considering incorporating its PADS (printer-assisted deployment system) into their spacecraft to extend solar panels, antennas, or other components.