US military's robot space plane due to land this week: The US military's mysterious robot space plane is expected to land this week after a 22-month orbit, officials said Tuesday, but the craft's mission remains shrouded in secrecy.
The unmanned X-37B, which looks like a miniature space shuttle, is due to glide back to Earth after having launched on December 11, 2012, on a mission that military officers say is strictly top secret.
"Preparations for the third landing of the X-37B are underway at Vandenberg Air Force Base" in California, said a US Air Force spokesman, Captain Chris Hoyler.
"The exact landing date and time will depend on technical and weather considerations," Hoyler said.
A defense official said that the space plane will likely touch down sometime this week and that future missions would seek to extend the vehicle's technical capabilities and time in orbit.