The US military’s secretive X-37B robot spaceplane blasted off from Florida on its seventh mission atop a SpaceX Falcon Heavy rocket on December 28. The rocket lifted off from NASA’s Kennedy Space Center in Florida more than two weeks late due to poor weather and technical issues. This launch marked the first time the space plane hitched a ride on a SpaceX Falcon Heavy, one of the most powerful operational rockets in the world. Watch the video to find out more about X-37B.