NASA is preparing to test a futuristic aircraft designed to accelerate through the atmosphere at speeds up to 7,200 mph, making it the world's fastest plane. NASA said the plane is designed to fly seven to 10 times faster than the speed of sound. Mach 1 is the speed of sound, which is about 750 mph at sea level. If successful, the planes will smash the speed record of Mach 6.7, set by an X-15 in October 1967. It carries hydrogen for fuel but must scoop oxygen out of the atmosphere to burn it.
Conventional rockets carry fuel and an oxidant.
Engineers will collect flight data needed to build future planes perhaps 200 feet in length. The first piloted prototypes might fly by 2025. Backers of the technology say air-breathing hypersonic propulsion could help space travel. Eliminating the need to carry oxygen could cut the weight of a plane in half. The X-43A, however, requires a big boost to get going.