The X-43 Hyper-X program demonstrated integrated hypersonic scramjet technologies from 2001-2004. Three unmanned aircraft were built and two were successfully flown at record-breaking speeds up to Mach 9.6. The X-43A was launched from a B-52 and then propelled by a Pegasus rocket to high altitude as the scramjet’s air intake opened and the engine ignited. The aircraft fell into the Pacific Ocean at the end of the test flights.