 The US military's secret of X-37B robot spaceplane is poised for lift-off from Florida on December 11 on its seventh mission to orbit. The vehicle's first launch atop a SpaceX Falcon Heavy rocket capable of lofting it higher than ever before the Falcon Heavy, composed of three reusable rocket cores strapped together, was due for blast-off from NASA's Kennedy Space Center at Cape Canaveral during a 10-minute nighttime launch window starting at 8.14 pm EST, whether permitting the defense. Department has disclosed few details about the mission, conducted by the US Air Force and Space Force as part of the National Security Space Launch Program, the Boeing-built X-37B, roughly the size of a small bus and resembling a miniature space shuttle craft, is built to deploy various payloads and conduct technology experiments in long-duration orbital flights.