Read it in a german newspaper today (Süddeutsche Zeitung): The X-37 Project seems much further in its development than has been revealed. The unmanned X-37b Orbiter has returned after seven month (seven!) in orbit. Its mission objectives are kept a secret. Wether it carried a payload remains unknown. The orbiter is marked as Air Force, not NASA.
Russia is concerned over all the secrecy and made it clear, that if the US would use the project to carry weapons into space, it would trigger a new arms race.
I must wonder about all the secrecy: In the past projects like this have been heavilly advertised. Such secrecy did not surround the Space Shuttle Program, the ISS, the Space Lab, Hubble, Apollo nor Gemini. And its strange, that it is the US Air Force running the show, instead of NASA. Seems the US doesnt even bother anymore to hide the military aspects of their space program under the science-umbrella of NASA.
This is the best english speaking source I could find: