Boeing’s new passenger spacecraft, the CST-100 Starliner, successfully docked itself to the International Space Station — demonstrating that the vehicle can potentially bring humans to the ISS in the future. It’s a crucial capability that Starliner has finally validated in space after years of delays and failures.

Starliner is in the midst of a key test flight for NASA called OFT-2, for Orbital Flight Test-2. The capsule, developed by Boeing for NASA’s Commercial Crew Program, was made to transport NASA’s astronauts to and from the space station. But before anyone climbs on board, NASA tasked Boeing with conducting an uncrewed flight demonstration of Starliner to show that the capsule can hit all of the major milestones it’ll need to hit when it is carrying passengers.

Boeing has struggled to showcase Starliner’s ability until now. This mission is called OFT-2 since it’s technically a do-over of a mission that Boeing attempted back in 2019, called OFT. During that flight, Starliner launched to space as planned, but a software glitch prevented the capsule from getting in the right orbit it needed to reach to rendezvous with the ISS. Boeing had to bring the vehicle home early, and the company never demonstrated Starliner’s ability to dock with the ISS.

Now, roughly two and a half years later, Starliner has finally shown what it was designed to do. Using a series of sensors, the capsule autonomously guided itself onto an open docking port on the space station. “Boeing Starliner spacecraft completes its historic first docking to the International Space Station opening a new avenue of access for crews to the orbiting laboratory,” Steve Siceloff, a communications representative for Boeing, said during the livestream of the docking. Docking occurred a little over an hour behind schedule, due to some issues with Starliner’s graphics and docking ring, which were resolved ahead of the docking.