had been taken aloft by a carrier, whether resulting in a free flight or not. For example, the X-15-1 was first taken aloft on scheduled captive test flight 1-C-1, next performed three aborted missions (1-A-2, 1-A-3, and 1-A-4), and then performed its first successful free flight on its fifth time taken aloft (1-1-5). On 9 November 1962, flight 74 (2-31-52), the X-15-2 suffered a landing accident which damaged the craft and also injured its pilot, John McKay, who suffered crushed vertebrae and later returned to active flight status. This presented North American with an opportunity not only to repair the plane, but to modify it—an idea which the Air Force and NASA were uninterested in while all three spaceplanes were in operational service, but agreed to once repairs were made necessary. The result was a new, distinct airframe known as the X-15A-2 which returned to flight in June 1964, first on a scheduled captive check-out flight (15 June, 2-C-53) and an abort (23 June, 2-A-54) before finally making its return free flight on 25 June (flight 109, 2-32-55), all piloted by Robert Rushworth. The flight numbering conventions made no distinction between the original craft and its modified iteration; it continued to be designated "2". Neither convention accounted for which of the two NB-52 carriers took an X-15 aloft, given in a separate column below. On free flights, the NB-52A carried the X-15 aloft 93 times, while the NB-52B carried it aloft 106 times. List of flights See also List of human spaceflights, 1961–1970 List of Space Shuttle missions SpaceShipOne SpaceShipTwo Notes References Further reading Flight lists