The United States Air Force's (USAF) secretive X-37B spaceplan has now spent close to 500 days in orbit. The space plane has also broken its previous endurance record and is still going strong.

The X-37B is operated by the USAF and was built by Boeing in several facilities located in Southern California. The space plane was designed to be a reusable space vehicle to be used with long-term space objectives. The current X-37B is an unmanned orbital test vehicle and it may help bring about a new generation of American made space delivery vehicles.

Following NASA's "fallout" with Russia, the US is currently facing pressure to accelerate the development of its own human spaceflight program. Since the Space Shuttle program ended in 2011, the agency has been dependent on Russia for space transportation. The current tests conducted by the USAF with the X-37B may play a role in restoring the domestic space flight capabilities of the U.S.

Compared to the decommission space shuttles, the X-37B is a lot smaller being around a fourth of the size of a space shuttle. The size reduction was possible due to the fact that the current design was not made to accommodate manned missions. Without a crew on board, the space plane had no need for a cockpit, compartments for the crew or even windows and view ports. Moreover, the current X-37B has very little cargo space with a cargo hold roughly the same size as a pick-up truck's bed.

As of April 8, the X-37B has now spent over 484 days in orbit. However, little is known about what exactly the space plane is doing in space. The US Department of Defense has been rather secretive about the vehicle's mission details and no announcements have been made regarding the X-37B's return back to Earth.

The X-37B was sent up into space late 2012. When it was launched into orbit, the space plane was mounted on top of an Atlas-5 rocket. Since it arrived in Earth orbit, the vehicle has completed a few thousand orbits around the planet.

The USAF has been very secretive about the aircraft and aside from the details regarding its launch into space and a number of photos and videos, almost nothing is known about the spacecraft's capabilities. Experts are speculating that the vehicle is currently serving as a test bed for a number of new technologies that may be used in next generation spy satellites.