An unmanned, solar-powered military plane has now spent more than 719 days in orbit around Earth. This space plane is the US Air Force X-37B, on its fifth mission (Orbital Test Vehicle 5). The nature of its mission remains classified, and the US Air Force uses very general terms when they talk about the space plane. ScienceAlert detailed what is known about this mysterious space plane:
Some things we do know - X-37B looks a little like a smaller version of NASA's old space shuttle, and the US Air Force has at least two of the solar-powered aircraft, which were built by Boeing.
According to the Air Force, the X-37B's primary objectives are to research reusable spacecraft technologies for America's future in space, and to conduct experiments that can be returned to, and examined, on Earth.
Beyond that, officials haven't given up much actual dirt on the specifics of its orbital experiments.
Regardless of what the plane's mission is, it was initially only designed for an orbit window of 270 days, so the fact that it's been able to more than double that time is a pretty big win for solar-powered aircraft.
image credit: Boeing via ScienceAlert