its 31st flight. The X-15 was attached to its mothership the Boeing NB-52B Stratofortress 53-008, nicknamed Balls 8. McKay's mission was to reach an altitude of at Mach 5.5 and to fly the aircraft without the lower part of its ventral fin. Further, the mission was to determine the flight response and stability of the aircraft and the characteristics of its flight boundary layer. The X-15 was released from the Stratofortress on schedule at over Mud Lake, Nevada at 10:23:07.0 local time with a launch speed of 450 knots. Upon release, McKay was unable to attain the full power of the rocket engine which became stuck at 30% power and unresponsive to throttle control. Due to the lack of throttle response it was decided to make a forced landing at Mud Lake instead of landing at Edwards Air Force Base due to concerns about the reliability of the engine. McKay was at an altitude of having attained a speed of Mach 1.49 when he started his descent for landing at Mud Lake. The motor was kept operating for 70.5 seconds to burn excess fuel and to reduce weight. The flaps failed to activate during landing and the aircraft speed at touchdown was higher than normal. Due to the excess speed and weight the aircraft experienced failures because of the increased dynamic loading which eventually led to its overturning. The X-15 airframe rolled and struck the lakebed while inverted. While McKay appeared to suffer no permanent disabilities as a result of the crash, evidence was later found that he had sustained brain damage. Also, while he returned to piloting duties with NASA, recurring severe pain caused by the crash forced his early retirement. Death McKay died on April 27, 1975, in Lancaster, California at the age of 52. Injuries suffered by McKay in the X-15 crash and subsequent permanent pain were a major factor in his premature death. He also suffered from diabetes and turned to alcohol to numb the pain of his accident injuries. Liver disease was a contributing factor to his death. In 1996, he was inducted into the Aerospace Walk of Honor, and in 2005 he was posthumously awarded Astronaut Wings. Awards and honors Air Medal (two clusters) Presidential Unit Citation John J. Montgomery Award National Society of Aerospace Professionals Award for Achievement, National Aeronautics Association Virginia Polytechnic Institute's Hall of Fame Aerospace Walk of Honor (1996) References