The U.S. Air Force's secretive unmanned space plane will end a year-long mission in orbit sometime in the next few weeks, and there is no indication what that mission is.
The X-37B Orbital Test Vehicle 2 launched from Cape Canaveral, Fla., on March 5, 2011.
Its mission was scheduled to end in December but was extended for unknown reasons, reports Rob Waugh of the Daily Mail.
The 29-foot, solar-powered craft has been circling Earth at 17,000 miles per hour in a low-earth orbit between 110 and 500 miles above the Earth's surface (whereas the International Space Station orbits at about 220 miles).
Some analysts speculate that the mission was extended to take advantage of the technology on board because the office that developed the X-37B will be shut down under budget cuts for 2013 to 2017 proposed by the Obama administration.
Others have speculated that the Boeing-made craft is used for surveillance as last May amateur astronomers detected the orbital pattern of the first X-37B included flyovers of North Korea, Iraq, Iran, Pakistan and Afghanistan, according to Waugh.
Col. Nina Armagno, 30th Space Wing commander, told Leonard David of Space.com that the personnel at Vandenberg Air Force Base in California "are ready to execute safe landing operations anytime and at a moment’s notice."
The first version of the NASA-designed craft landed last December at Vandenberg after more than seven months in orbit.
Below is a layout of the X-37B (via Space.com):
Here is a video of the X-37 Approach and Landing Test Vehicle (the predecessor of the X-37B):
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