On this date in 1961, test pilot Major Robert M. White, USAF, flew the number two North American Aviation X-15 hypersonic research rocketplane to Mach 4.43 (2,905 mph) to 77,450 feet, becoming the first pilot to exceed Mach 4. The total duration of the flight, from the airdrop from the Boeing NB-52B Stratofortress to touchdown at Edwards Air Force Base, was 8 minutes, 34.1 seconds.
