science · 03 October 1967 · 57 years ago
In 1967, the X-15 rocket plane achieved a world record speed of Mach 6.7, which is 4,520 mph or over a mile per second, with U.S. Air Force pilot Pete Knight. It reached an altitude of 192,100 feet (58,552 m). Its internal structure of titanium was covered with a skin of Inconel X, a chrome-nickel alloy. To save fuel, the X-15 was air launched from a B-52 aircraft at about 45,000 ft. Test flights between 8 Jun 1959 and 24 Oct 1968 provided data on hypersonic air flow, aerodynamic heating, control and stability at hypersonic speeds and piloting techniques for reentry used in the development of the Mercury, Gemini, and Apollo spaceflight programs. The X-15 reached 354,200 feet (67 miles) on 22 Aug 1963.
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