| The secretive mission of a U.S. Air Force X-37B miniature space plane just winged past 500 days of flight.
The robotic drone is performing classified duties during the program’s fifth flight.
By Leonard David
X-37B missions are carried out under the auspices of the Air Force Rapid Capabilities Office, and mission control for OTV flights is handled by the 3rd Space Experimentation Squadron at Schriever Air Force Base in Colorado. This squadron oversees operations of the X-37B Orbital Test Vehicle.