The Air Force says that the almost one-of-a-kind spacecraft "conducted on-orbit experiments" in the the longest-ever mission for the X-37B program.
But what it's doing up there or for how long -- well, you might glean more from talking to the wall than asking the Air Force about its hush-hush mission.
An Atlas V rocket carrying the unmanned craft, which looks like a miniature space shuttle, has the green light for a planned liftoff Tuesday. Just don't ask what it's up to.
The unmanned spacecraft has been in orbit for more than a year. The Air Force won't say much about its mission, but surely it's more than just a test drive.
Resembling a shrunk-down space shuttle, the Air Force's X-37B returns to Earth from its debut test flight, pointing the way toward cheaper, adaptable--and perhaps military--missions.
The unmanned X-37B Orbital Test Vehicle heads into space on its first mission, as the Air Force scopes out how it might eventually serve "warfighters' needs."
The X-37B -- undertaking its fourth mission -- shared its rocket ride back to space with an experimental LightSail spacecraft provided by the Bill Nye-backed Planetary Society.
Second Boeing-built, unmanned X-37B heads into orbit, after the first craft returned safely to Earth late last year amid speculation of potential military uses.
San Antonio Spurs' Mani Ginobili turns to Facebook to say he saw something strange in the skies. He thought it might be the X-37B secret space plane. But it turns out it wasn't.
On April 19, the Air Force is to launch a new robotic spacecraft called the X-37B that's designed to carry out military missions and land autonomously.