Top secret American spy plane returns to Earth after seven months... but U.S. still won't say what it was doing in space



The U.S.'s first unmanned re-entry spacecraft landed at an airfield today, seven months after it was launched.

The X-37B's exact purpose remained shrouded in secrecy when it touched-down at at Vandenberg Air Force Base on the California coast 130 miles north west of Los Angeles.



It was launched by an Atlas 5 rocket from Cape Canaveral, Florida, on April 22, with a maximum mission duration of 270 days and is suspected of being an advanced spy plane.



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Inspection: Scientists approach the unmanned X-37B after it touched down at Vandenberg Air Force Base in California

Lift off: The X-37B sits on top of an Atlas V rocket as it's launched at Cape Canaveral Air Force Station in Florida in 2010

This undated image released by the U.S. Air Force shows the X-37B spacecraft. Its mission and cost are shrouded in secrecy

Also known as the Orbital Test Vehicle, the Boeing-built spacecraft was originally a NASA project before being taken over by the military.



Jeremy Eggers, a spokesman for Vandenberg Air Force Base, described the successful landing as 'very exciting' and said the X-37B was due to return to space next year.



He said would not say whether it carried anything in its cargo bay, but insists the primary purpose of the mission was to test the craft itself.



Theories have abounded following the secretive launch, with some experts suggesting the spacecraft is America's attempt at gaining the military dominance of space.



'We are very pleased that the program completed all the on-orbit objectives for the first mission,' programme manager Lt. Col. Troy Giese said in a statement.



Mystery: Scientists work on a prototype for the rocket prior to its launch



A computer graphic shows what the X-37B will look like operating in space. The craft took a decade to develop and is operated by the U.S. Air Force

This computer image shows the space plane re-entering Earth. Although it resembles a small space shuttle it is not designed to carry humans. It's wingspan is a mere 4.5m with a length of 8.9m. It is powered by batteries and solar cells

Officials have only released a general description of the mission objectives including the testing of guidance, navigation, control, thermal protection and autonomous operation in orbit, re-entry and landing.



The voyage culminated the project's long and expensive journey from NASA to the Pentagon's research and development arm and then on to the secretive Air Force Rapid Capabilities Office.



Hundreds of millions of dollars have been spent on the X-37 program, but the current total hasn't been released.

While the massive space shuttles have been likened to cargo-hauling trucks, the X-37B is more like a sports car, with the equivalent trunk capacity.



Built by Boeing Co.'s Phantom Works, the 11,000-pound craft is 9.5 feet tall and just over 29 feet long, with a wingspan of less than 15 feet. It has two angled tail fins rather than a single vertical stabiliser.



Unlike the shuttle, it was designed for launch like a satellite, housed in a fairing on top the expendable Atlas V rocket, and capable of deploying solar panels to provide electrical power in orbit.

Speaking after the launch, Air Force deputy under-secretary for space systems Gary Payton, admitted it was impossible to hide a space launch but was cagey about the what exactly the X-37B would do.

'On this flight the main thing we want to emphasise is the vehicle itself, not really, what's going on in the on-orbit phase because the vehicle itself is the piece of news here,' he said.

He refuted claims that the craft was a step towards military dominance in space.



'I don't know how this could be called weaponisation of space,' he said. 'It's just an updated version of the Space Shuttle type of activities in space.

'We, the Air Force, have a suite of military missions in space and this new vehicle could potentially help us do those missions better.'

Closer look: The spacecraft is subjected to scrutiny

Ready for launch: The X-37B rocket in Florida before it blasted off into space