The Boeing-built X-37B space plane commissioned and operated by the U.S. Air Force has now broken its own record for time spent in space. Its latest mission has lasted 719 days as of today, which is one day longer than its last mission, which ended in 2017, as noted by Space.com. It’s not an overall record, as geocommunications satellites typically have life spans of five years or more, but it’s nonetheless an impressive milestone for this secretive Air Force vehicle, which is all about testing and developing U.S. technologies related to reusable spaceflight and more.

The X-37B began its current mission in September 2017, when it launched atop a SpaceX Falcon 9 rocket. The specific details of the spacecraft’s missions are classified, but in addition to apparently spending ever-increasing amounts of time up in space (each successive mission of the space plane has lasted longer), it’s also “operating experiments that can be returned to, and examined, on Earth.” These tests involve tech related to guidance, navigation, thermal protection, high-temperature materials and durability, flight and propulsion systems and more, which is basically not saying much, as that’s just about everything involved in space flight.

There’s no crew on board operating X-37B, but the vehicle can autonomously descend back through Earth’s atmosphere and land horizontally on a runway, just like the NASA Space Shuttle used to do when it was in operation.

NASA began the X-37 program in 1999; it was then transferred to DARPA and the U.S. Air Force in 2004. The X-37B has flown four times; in total, the first four missions have completed 2,085 days in space.