Test pilot Albert Scott Crossfield (1921-2006) was the first X-15 pilot and made a total of 14 flights. In 1953 Crossfield was the first pilot to exceed Mach 2 in the D-558-II Skyrocket. While an NACA research pilot, he made a total of 87 flights in the rocket-powered X-1 and D-558-II research aircraft.