The X-37B, which looks like a small space shuttle, took off to a clandestine mission over undisclosed nations, from Cape Canaveral in Florida on December 11, 2012.

It is believed that the X-37B operates like a spying satellite but with a large fuel tank for maneuvering that lets it switch orbits and escape detection from ground.

The Vandenberg Air Force Base in California released a notice to aviators on the Federal Aviation Administration's website and announced that airspace around the Southern California base would remain closed from morning to afternoon on Tuesday.

"Team Vandenberg stands ready to implement safe landing operations for the X-37B Orbital Test Vehicle, MORE @ http://www.presstv.ir/detail/2014/10/14/382200/secret-us-air-force-space-plane-lands/