The greatest speed ever reached by a manned aircraft that is not a spacecraft is 7,270 km/h (4,520 mph) (Mach 6.7) by USAF Major William J. Knight in the experimental North American Aviation X-15A-2 on 3 October 1967 over the Mojave Desert, California, USA. It was released from its NB-52 mother plane at 10,600 m (35,000 ft) and set an unofficial absolute human speed record which stood unbroken until exceeded by the Space Shuttle. The X-15A-2 was encased in a full scale pink ablative coat and then a white sealant coat to protect the craft from the extreme temperatures of supersonic flight. The title of this record refers to the fact that it is neither a production aircraft nor a space rocket/ship.