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NASA made aviation history with the first and second successful flights of an X-43A scramjet-powered airplane at hypersonic speeds - speeds greater than Mach 5, or five times the speed of sound. Compared to a rocket-powered vehicle like the space shuttle, vehicles powered by scramjet (supersonic combustion ramjet) engines promise more airplane-like operations for increased affordability, flexibility and safety on ultra-high-speed flights within the atmosphere and into Earth orbit. Because they do not have to contain their own oxidizer, as rockets must, vehicles powered by air-breathing scramjets can be smaller and lighter - or be the same size but carry a larger payload. No vehicle powered by an air-breathing engine had ever flown at hypersonic speeds before the successful March 2004 X-43A flight that collected the first data from a scramjet engine in flight. In addition, the rocket boost and subsequent separation from the rocket to get to the scramjet test condition had complex components that had to work properly if the mission was to succeed. Careful analyses and design were applied to reduce risks to acceptable levels though some level of residual risk was inherent to the program. Three unpiloted X-43A research aircraft were built. Each of the 12-foot-long, 5-foot-wide vehicles was designed to fly once and not be recovered. They were identical in appearance, but engineered with differences relating to their designed Mach speed. The first and second vehicles were designed to fly at Mach 7 and the third at Mach 10. At these speeds, the shape of the vehicle forebody compresses the air entering the scramjet. Fuel is then injected for combustion. Gaseous hydrogen fueled the X-43A. After the first flight attempt, in June of 2001, failed when the booster rocket went out of control, the second and third attempts resulted in highly successful, record-breaking flights. Mach 6.8 was reached in March of 2004, and Mach 9.6 was reached in the final flight in November of 2004. Both flights began with the combined test vehicle/rocket "stack" being carried by a B-52B aircraft from Dryden to a predetermined point over the Pacific Ocean, 50 miles west of the Southern California coast. Release altitude from the B-52B was 40,000 feet for both successful flights. At that point, each stack was dropped from the B-52B, and the booster lifted each research vehicle to its test altitude and speed. Guinness World Records has recognized both the Mach 6.8 and Mach 9.6 accomplishments. Photo Description A modified Pegasus rocket ignites moments after release from the NB-52B, beginning the acceleration of the X-43A over the Pacific Ocean on March 27, 2004. NASA Photo by Jim Ross
Description
NASA made aviation history with the first and second successful flights of an X-43A scramjet-powered airplane at hypersonic speeds - speeds greater than Mach 5, or five times the speed of sound. Compared to a rocket-powered vehicle like the space shuttle, vehicles powered by scramjet (supersonic combustion ramjet) engines promise more airplane-like operations for increased affordability, flexibility and safety on ultra-high-speed flights within the atmosphere and into Earth orbit. Because they do not have to contain their own oxidizer, as rockets must, vehicles powered by air-breathing scramjets can be smaller and lighter - or be the same size but carry a larger payload. No vehicle powered by an air-breathing engine had ever flown at hypersonic speeds before the successful March 2004 X-43A flight that collected the first data from a scramjet engine in flight. In addition, the rocket boost and subsequent separation from the rocket to get to the scramjet test condition had complex components that had to work properly if the mission was to succeed. Careful analyses and design were applied to reduce risks to acceptable levels though some level of residual risk was inherent to the program. Three unpiloted X-43A research aircraft were built. Each of the 12-foot-long, 5-foot-wide vehicles was designed to fly once and not be recovered. They were identical in appearance, but engineered with differences relating to their designed Mach speed. The first and second vehicles were designed to fly at Mach 7 and the third at Mach 10. At these speeds, the shape of the vehicle forebody compresses the air entering the scramjet. Fuel is then injected for combustion. Gaseous hydrogen fueled the X-43A. After the first flight attempt, in June of 2001, failed when the booster rocket went out of control, the second and third attempts resulted in highly successful, record-breaking flights. Mach 6.8 was reached in March of 2004, and Mach 9.6 was reached in the final flight in November of 2004. Both flights began with the combined test vehicle/rocket "stack" being carried by a B-52B aircraft from Dryden to a predetermined point over the Pacific Ocean, 50 miles west of the Southern California coast. Release altitude from the B-52B was 40,000 feet for both successful flights. At that point, each stack was dropped from the B-52B, and the booster lifted each research vehicle to its test altitude and speed. Guinness World Records has recognized both the Mach 6.8 and Mach 9.6 accomplishments. Photo Description A modified Pegasus rocket ignites moments after release from the NB-52B, beginning the acceleration of the X-43A over the Pacific Ocean on March 27, 2004. NASA Photo by Jim Ross
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