A month ago, the U.S. Air Force launched an X-37B UOV (unmanned orbital vehicle). X-37B is a remotely controlled mini-Space Shuttle. The space vehicle has been spotted by amateur astronomers (who like to watch spy satellites as well), and the X-37B appears to be going through some tests. The X-37B is believed to have a payload of about 227-300 kg (500-660 pounds), and is capable of staying in orbit for 9 months. The payload bay is 2.1x1.4 meters (7x4 feet). When returned to earth, it will land by itself (after being ordered to use a specific landing area.) The X-37B weighs five tons, is nine meters (29 feet) long and has a wingspan of 4 meters (14 feet). The Space Shuttle is 56 meters long, weighs 2,000 tons and has a payload of 24 tons.
The X-37B is a classified project, so not many additional details are available. It's been in development for eleven years, but work was slowed down for a while because of lack of money. A second X-37B is now being built, and is to be launched next year.
What makes the X-37B so useful is that it is very maneuverable, contains some internal sensors (as well as communications gear), and can carry mini-satellites, or additional sensors, in the payload bay. Using a remotely controlled arm, the X-37B could refuel or repair other satellites. But X-37B is a classified project, with few details about its payload or mission (other than testing the system on its first mission), future missions will involve intelligence work, and perhaps servicing existing spy satellites (which use up their fuel to change their orbits.)