The U.S. Air Force has an un-manned mini-shuttle, and although no one admits to knowing what it is used for exactly, it apparently is very good at its mission. From an article from earlier this week at the military blog Strategy Page:
A U.S. Air Force X-37B UOV (unmanned orbital vehicle) landed October 17th under software control after 675 days in orbit. Previously an X-37B landed on June 16th 2012 after 469 days in orbit. The first mission ended on December 3rd 2010 after 224 days in orbit. The air force reports few details about the X-37B but has said it plans to launch another one in 2015.
The official endurance of the X-37B was originally about 280 days. The real endurance appears to be nearly three times that. The long endurance is largely because the X-37B carries a large solar panel, which is deployed from the cargo bay, unfolded and produces enough power to keep the X-37B up there for a long time. The air force has not reported what the X-37B has been doing up there all this time. The air force has revealed that it is designing an X-37C, which would be twice the size of the X-37B and able to carry up to six passengers. Think of it as Space Shuttle Lite, but robotic and run by the military, not NASA.
The X-37B is a remotely controlled mini-Space Shuttle. The space vehicle, according to amateur astronomers (who like to watch spy satellites as well), appears to be going through some tests. The X-37B is believed to have a payload of about 227-300 kg (500-660 pounds). The payload bay is 2.1×1.4 meters (7×4 feet). As it returned to earth, it landed 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). In contrast the Space Shuttle was 56 meters long, weighed 2,000 tons and had a payload of 24 tons.
The X-37B is a classified project, so not many additional details are available. It’s been in development since 2000 but work was slowed down for a while because of lack of money. Whatever the X-37B is now doing up there has been convincing enough to get Congress to spend over a billion dollars on it. 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 little confirmed information 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.) The X-37B is believed capable of serving as a platform for attacks on enemy satellites in wartime. It is believed that recent missions may have also involved testing new spy satellite components in space, where the harsh environment, especially the radiation, can have unpredictable effects on microelectronics.
The “blue yonder” gets wilder every year.