Joseph A. Walker
Joseph Albert Walker (20 February 1921 - 8 June 1966) was an American military test pilot; in 1963, he made two X-15 flights past the 100 kilometer edge of space, the only spaceplane flights past that threshold made until SpaceShipOne in 2004.
Born in Washington, Pennsylvania, Walker earned a degree in physics from Washington and Jefferson College before entering the United States Army Air Force. He flew P-38 aircraft in World War II.
After World War II, Walker spent 21 years working as a test pilot. In 1960, he made the first test flight of the X-15 aircraft; Walker would go on to fly the X-15 24 times, including the only two flights of the X-15 to exceed 100 kilometers in altitude, Flight 90(19 July, 1963; 106 km) and Flight 91 (22 August, 1963; 108 km).
One of the first Fellows of the Society of Experimental Test Pilots, Walker was killed on June 8, 1966, in a collision between his F-104 aircraft and an XB-70 chase plane. Walker was married and had four children.
