On 16 November 2004, NASA’s (USA) unmanned Hyper-X (X-43A) scramjet aircraft reached Mach 9.68, nearly 7,000 mph or almost ten times the speed of sound. The X-43A was boosted to an altitude of 33,000 m (115,000 ft) by a Pegasus rocket launched from beneath a B52-B aircraft. The revolutionary aircraft then successfully burned its engine before plunging into the Pacific Ocean.