The Air Force is known to possess two X-37B vehicles, each of which was built by Boeing. The 29-foot-long space planes launch vertically and land horizontally, just like the space shuttle used to do.

The US X-37B and China's Shenlong are competing unmanned space planes whose covert missions are getting more complex. See how the spacecraft compare.

The US X-37B and China's Shenlong are competing unmanned space planes whose covert missions are getting more complex. See how the spacecraft compare.

Boeing's X-37B, an unmanned and highly advanced space plane, just completed a nearly-two-long year Air Force mission whose purpose is still not currently known. Whatever its mission, the plane ...

Classified duties. The X-37B has winged past 666 days of flight on this latest mission, which is called OTV-5 because it's the fifth flight for the program.. OTV-5 began on Sept. 7, 2017, with a ...

The U.S. Air Force's unmanned X-37B space plane has now circled Earth for more than 400 days on a hush-hush mission that is creeping closer and closer to the vehicle's orbital longevity record.

The X-37 Orbital Test Vehicle (OTV) began life under the umbrella of NASA, but was passed to the US military, which created the X-37B variant. That model first flew in orbit in 2010 and the two ...

X-37B’s seventh mission could be its last, according to comments from General B. Chance Saltzman, chief of space operations for the Space Force, in 2020. That could be consequential given ...