At the Edge of Space

March 30, 1992
Initiated in the 1950s, the X-15 program tested a unique rocket-powered aircraft at supersonic speeds in the atmosphere's outer limits. The stubby-winged, needle-nosed craft achieved speeds of 4000 mph, could fly at altitudes of well over 200,000 feet and yielded data crucial to NASA's space missions. Thomson, one of the test pilots, traces the technical developments of the program, emphasizing the viewpoint of the men who (barely) controlled the unpredictable plane in the air. He demonstrates through a series of vivid anecdotes the effect of g forces, extreme vertigo and other mental and physical problems associated with supersonic flight. Thompson includes accounts of hair-raising emergency rescues and a somber description of the death of one of his colleagues during a 1967 test flight. Retired in 1968 along with the program itself, the X-15 now hangs in the Smithsonian's National Air and Space Museum. Surprisingly, it is still the world's fastest airplane. Thompson's well-written history of the program captures the technical challenges, the camaraderie and, most of all, the high adventure of X-15 flight. Highly recommended. Photos.