Joe Henry Engle (born August 26, 1932), (Maj Gen, USAF, Ret.), is an American pilot who served in the United States Air Force, test pilot for the North American X-15 program, aeronautical engineer, and a former NASA astronaut. As of 2015, he is the only surviving X-15 pilot.Engle test-flew the joint NASA-Air Force X-15 rocket airplane. During the course of testing, Engle earned his USAF Astronaut Wings, a Distinguished Flying Cross and other awards.