| X-15 | |
|---|---|
 The X-15 pulling away from its drop launch plane | |
| General information | |
| Type | Experimental high-speed rocket-powered research aircraft |
| Manufacturer | North American Aviation |
| Primary users | United States Air Force |
| Number built | 3 |
| History | |
| Introduction date | 17 September 1959 |
| First flight | 8 June 1959 [1] |
| Retired | December 1968 [1] |
The North American X-15 is a hypersonic rocket-powered aircraft operated by the United States Air Force and the National Aeronautics and Space Administration (NASA) as part of the X-plane series of experimental aircraft. The X-15 set speed and altitude records in the 1960s, crossing the edge of outer space and returning with valuable data used in aircraft and spacecraft design. The X-15's highest speed, 4,520 miles per hour (7,274 km/h; 2,021 m/s),[1] was achieved on 3 October 1967,[2] when William J. Knight flew at Mach 6.7 at an altitude of 102,100 feet (31,120 m), or 19.34 miles. This set the official world record for the highest speed ever recorded by a crewed, powered aircraft, which remains unbroken.[3][4]
During the X-15 program, 12 pilots flew a combined 199 flights.[1] Of these, 8 pilots flew a combined 13 flights which met the Air Force spaceflight criterion by exceeding the altitude of 50 miles (80 km), thus qualifying these pilots as being astronauts; of those 13 flights, two (flown by the same civilian pilot) met the FAI definition (100 kilometres (62 mi)) of outer space. The 5 Air Force pilots qualified for military astronaut wings immediately, while the 3 civilian pilots were eventually awarded NASA astronaut wings in 2005, 35 years after the last X-15 flight.[5][6]
- ^ a b c d Gibbs, Yvonne, ed. (28 February 2014). "NASA Armstrong Fact Sheet: X-15 Hypersonic Research Program". NASA. Retrieved 4 October 2015.
4,520 mph (Mach 6.7 on Oct. 3, 1967,
- ^ Haskins, Caroline; Anderson, Brian; Koebler, Jason (6 October 2017). "Why the Piloted Flight Speed Record Hasn't Been Broken in 50 Years". Retrieved 5 February 2019.
- ^ "North American X-15 High-Speed Research Aircraft". Aerospaceweb.org. 2010. Retrieved 24 November 2008.
- ^ Jacopo Prisco (28 July 2020). "X-15: The fastest manned rocket plane ever". CNN. Retrieved 12 November 2020.
- ^ Jenkins 2001, p. 10.
- ^ Thompson, Elvia H.; Johnsen, Frederick A. (23 August 2005). "NASA Honors High Flying Space Pioneers" (Press release). NASA. Release 05-233. Archived from the original on 13 April 2018. Retrieved 15 September 2007.