It's been quietly buzzing over our heads, round and round the earth for a year, and it's coming back down soon.

A highly classified robotic 'spaceplane' has been circling the earth for over a year,  but what it's been doing is still not known.   The Boeing XB-37 is slated to return to earth in a few days, wrapping up what scientists are calling a very successful mission.   What people wonder is, what mission?   The XB-37, the second one to fly around the earth,  is highly shrouded in secrecy, although most believe it is militarily related to spying and surveillance. 

 The 29 foot long aircraft, dwarfed in size by the Space Shuttle, was launched last March, and Air Force officials said it was to test a variety of current and future space technology.   It was originally designed to return last December, but due to the success of the flight (at about 110 miles above the earth) it was kept up for many more months.   The future of the highly secret aircraft is in doubt, as budget cuts announced between 2013 and 2017 by the Obama Administration indicate the office that oversees the project will be shut down.   Another XB-37 was launched in June, and returned to Vandenberg Air Force Base in California after a 7 month orbit.

  The true complete purpose of the plane's missions has never been fully explained by the Air Force.