But this spaceplane, called the X-37B Orbital Test Vehicle, is very different. While it looks like a plane, is launched on a rocket, has a cargo bay and uses some of the same technology as the shuttle, such as thermal shielding to protect it during reentry, it is smaller and unmanned. It is designed to stay in orbit for months on end and can automatically land back on Earth. Perhaps more crucially, the Boeing-designed plane is operated by the US Air Force and its mission is a closely held secret, prompting a slew of speculation about its true purpose.
Since the first X-37B was launched in 2010, amateur satellite spotters have carefully followed the robotic spacecraft’s orbit, while those unconnected with the program have speculated that the plane could be anything from an anti-satellite weapon to so-called “on demand reconnaissance,” shorthand for a spy satellite that can be placed over any country in the world. Compounding the mystery was the launch of a second vehicle in 2011, which stayed in orbit for 469 days, long exceeding the Air Force’s stated maximum requirement of 270 days for the spaceplane.
