U.S. military X-37B spaceplane prepares for eighth mission 

WASHINGTON — The U.S. Space Force announced a launch window for the next mission of the X-37B reusable spaceplane. The eighth flight of the Boeing-built plane, officially designated Orbital Test Vehicle-8 (OTV-8), is scheduled to lift off no earlier than August 21 from Kennedy Space Center, Florida, aboard a SpaceX Falcon 9 rocket.