X-37B was launched into space via SpaceX’s Falcon Heavy rocket for its seventh mission (OTV-7) in December 2023. Since then, it has been orbiting Earth in an extremely elliptical path with a perigee (the closest point of an orbit) of 620 miles and an apogee of more than 22,210 miles, per Live Science’s Rory Bathgate—though it has been spotted as close as 185 miles above Earth.
But exactly what it’s doing on that orbit is unclear. “Since December 28, 2023, the United States Space Force, supported by the Air Force Rapid Capabilities Office, has conducted radiation effect experiments and has been testing Space Domain Awareness technologies in a Highly Elliptical Orbit,” is all the agency said of the spaceplane’s overall mission in the recent statement.