(Photo: US Air Force)

An Air Force Orbital Test Vehicle (OTV) broke its previous record for continuous flight, floating above Earth for 719 days, two days longer than its previous voyage.

As Space.com reports, the X-37B OTV launched on the back of a SpaceX rocket in 2017 and has been used for nearly a decade, though the X-37 program has existed for twice as long. Private companies have toyed with reusable spacecraft in the last decade, too, but while reuse is an important part of the Air Force vehicle's purpose, it's not what makes it unique.

"The X-37B is the first vehicle since NASA's Shuttle Orbiter with the ability to return experiments to Earth for further inspection and analysis, but with an on-orbit time of 270 days or greater, the X-37B can stay in space for much longer," an Air Force fact sheet says.

At 11,000 pounds, the Boeing-built plane looks like a real-world Quinjet (minus the folding wings) and a mix of solar cells and lithium-ion batteries propel the 23-foot-long, unmanned rocket into orbit. But besides its appearance and a handful of superficial stats, little is known about the X-37B.

The Air Force provides a broad overview of the plane's missions: test reusable spacecrafts and conduct secret experiments on guidance, navigation, and thermal protection systems as well as experimental flight and propulsion technology. But the nature of those projects remains under wraps.