Mystery as US Air Force’s X-37B space plane looks set to return from top secret mission after two years in orbit

A TOP secret space plane is set to return after a two-year mission circling the planet.

The US Air Force's Boeing X-37B was launched on May 20 last year from Cape Canaveral, Florida in the fourth outing under the secretive program.

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According to Nasaspaceflight.com, "The historic Shuttle Landing Facility at the Florida spaceport is preparing to once again host an end of mission landing as the Air Force's X-37B mini spaceplane prepares to return from a near two year mission on orbit".

But Air Force officials claim this is simply a test exercise, and that the craft will continue its mysterious mission in space.

An Atlas V rocket was used to get the unmanned aviation vehicle into orbit back in 2015.

Neither the purpose of the mission nor the length of the space trip have been released to the public.

The US military has not revealed where the craft will land when it's flight comes to a close, however all previous OTV missions have landed at the Vandenberg Air Force Base in California

The secretive nature of the this trip has sparked a flurry of conspiracy theories about the mysterious space craft.

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One suggests that it could be a space weapon used to capture or destroy other satellites in orbit in a similar style to Blofeld's rocket in You Only Live Twice.

Another suspects the plane could be used for dropping high altitude bombs on unsuspecting countries.

Others believe it could be a straightforward surveillance craft or depositing lots of mini satellites in the sky.

One of the most outlandish theories suggests the X-37B could be operating as part of the High Frequency Active Auroral Research Programme (HAARP) and causing earthquakes and climate chaos.

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Some speculate the plane could be using HAARP technology to create seismic events and influence the weather,

The HAARP programme was commissioned to research the ionosphere layer of the earths atmosphere that is crammed with electrons.

No concrete evidence for any of these theories has been found.

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