NASA on Wednesday unveiled a futuristic aircraft designed to accelerate through the atmosphere at speeds up to 7,200 mph. NASA said the plane, which would be the world's fastest plane, would be designed to fly up to 10 times the speed of sound. Mach 1 is the speed of sound, which varies by altitude and is about 750 mph at sea level.
Conventional rockets carry both the hydrogen and oxidant.
Engineers will collect flight data needed to build future planes perhaps 200 feet in length. The first piloted prototypes may fly by 2025. Backers of the technology say air-breathing hypersonic propulsion could help space travel. None of the X-43As will be recovered from the ocean, officials said. Backers of the technology see air-breathing hypersonic propulsion as advantageous for improving access to space.