The Bell X-2 was built to break barriers and reach the edge of space—but pushing the limits came at a devastating cost. This Mach 3 rocket plane marked a turning point in aviation history ...

Main image: Bell XS-1 The first X-plane ... Power: Reaction Motors XLR-11-RM-3 rocket, 6,000 lbs. static thrust. A derivative aircraft, the X-1A, reached Mach 2.43 in December 1953.