The military gets the lion’s share of wacky conspiracy theories, but it’s things like this latest announcement from the U.S. Air Force that add fuel to the fire: An unmanned, reusable “space plane” called the X-37B is set to land today Vandenberg Air Force Base in California.

The aircraft reportedly went up for the last time in December of 2012, where it’s been orbiting Earth ever since. If that’s news to you, you’re not alone – when the aircraft launched, the Air Force gave very little explanation as to its intentions or capabilities.

In talking to sources, The Daily Beast reported in April that the spaceship was likely a reconnaissance tool, armed with a payload of high-tech sensors and cameras similar to those found on spy satellites. The fact that X-37B’s orbit took it over countries like North Korea, China and Afghanistan lend credence to the theory.

“I think it is primarily an ISR (Intelligence, Surveillance and Reconnaissance) platform for testing new sensor technologies or validating new technologies.” Brian Weeden, a former officer with the U.S. Air Force’s Space Command told The Daily Beast in April. “The current [vehicle] on orbit has basically been in the same orbit since launch, with only the occasional maneuver to maintain that orbit. That’s consistent with a remote sensing/ISR mission.”

One explanation for the X-37B is that it’s actually more flexible than a satellite performing a similar function. Not only can it be guided more like an aircraft, but it’s reusable where satellites typically aren’t. Of course, that hasn’t stopped some from cooking up more interesting theories as to the true nature of the mission – everything from scooping up enemy satellites to bombing enemies from outer space.

“Team Vandenberg stands ready to implement safe landing operations for the X-37B Orbital Test Vehicle, the third time for this unique mission” said Col. Keith Baits, 30th Space Wing commander.