MILTON O. THOMPSON

1926-1993

Milt Thompson holds the distinction of being the only X-15 pilot to have written a book on the X-15 program. Entitled At the Edge of Space: The X-15 Flight Program, it was published by Smithsonian Institution Press in 1992, a year before Thompson’s death. It is a highly recommended read for anybody interested in the inside story of the X-15 flight program. As the ninth test pilot to join the X-15 program, Thompson flew the airplane fourteen times, beginning on October 29, 1963. On November 27, 1963, the inertials failed at launch. On January 16, 1964, he reached Mach 4.92, but the speed brakes were extremely hard to open during the high aerodynamic heating phase. On February 19, at Mach 5.29, he had a premature burnout due to a clogged liquid oxygen line. His highest Mach number was 5.48, reached on January 13, 1965, during which he lost the pitch-and-roll damping mechanism during the pull-up/roll maneuver after burnout and temporarily lost control. His last flight in the X-15 was on August 25, 1965, when he achieved his highest altitude of 214,100 feet. The technical difficulties encountered by Thompson were typical of those encountered by all of the X-15 test pilots; there were very few totally “good flights” during the 199 flights of the airplane.

Milt Thompson was born on May 4, 1926, in Crookston, Minnesota. He became a naval aviator

at age nineteen and served in China and Japan during World War II. After six years of active duty, he left the Navy and entered the University of Washington, where he graduated with a bachelor’s degree in aeronautical engineering in 1953. Following graduation, like many Washington graduates, he joined the Boeing Aircraft Company as a structural-test and flight-test engineer. He is one of only two X-15 pilots (along with Scott Crossfield) to have worked in the aircraft industry. One of the projects to which Boeing assigned him was testing the new B-52. In March 1956, he seized the opportunity to go to work for the

A lifting body is a wingless aerodynamic configuration that generates its lift from the body at high angle of attack, somewhat like the Space Shuttle. In the period between the X-15 and the Space Shuttle, several “lifting bodies” were designed and flown to explore principally the subsonic characteristics of this hypersonic aerodynamic shape in order to provide data for the subsonic portion of the Space Shuttle flight.

NACA’s High Speed Flight Station at Edwards Air Force Base as a research pilot.

At the time, the NACA had only five pilots, including future X-15 pilots Joe Walker, Jack McKay, and Neil Armstrong. Thompson worked on the early X-airplanes. Of this experience, he admitted that he “watched apprehensively as these programs wound down and were terminated.” He felt that the glory days of the X-airplanes were over and that he had missed it all. “In the next few years,” he later wrote, “I realized that I was wrong. The golden years were still to come.”

For Thompson, those glory years began when he was selected by the Air Force to be the only civilian pilot on the X-20 Dyna-Soar winged hypersonic vehicle project. Although he again witnessed yet another cancelation when the Dyna-Soar project was prematurely stopped, his participation on lifting entry bodies continued.

He was the first person to fly such a lifting body, the lightweight M2-F1. He continued to fly this

aircraft a total of forty-seven times, after which he made the first five flights in the all-metal M2-F2. He took all this experience to the X-15 program.

Thompson finished his active flying career in 1967. Two years later, he became chief of Research Projects, and in 1975 he was appointed chief engineer, a position he held until his death on August 6, 1993.