NASA X-43

The X-43 was an unmanned experimental hypersonic aircraft with multiple planned scale variations meant to test various aspects of hypersonic flight. It was part of the X-plane series and specifically of NASA's Hyper-X program. It set several airspeed records for jet-propelled aircraft. The X-43 is the fastest aircraft on record at approximately Mach 9.6 (7,310 mph) (11,850 km/h).

A winged booster rocket with the X-43 placed on top, called a "stack", was drop launched from a Boeing B-52 Stratofortress. After the booster rocket (a modified first stage of the Pegasus rocket) brought the stack to the target speed and altitude, it was discarded, and the X-43 flew free using its own engine, a scramjet.

The first plane in the series, the X-43A, was a single-use vehicle. Three of them were built. The first was destroyed after malfunctioning in flight; the other two have successfully flown, with the scramjet operating for approximately 10 seconds, followed by a 10-minute glide and intentional crash into the ocean.

The X-43 was part of NASA's Hyper-X program, involving the American space agency and contractors such as Boeing, Micro Craft Inc, Orbital Sciences Corporation and General Applied Science Laboratory (GASL). Micro Craft Inc. built the X-43A and GASL built its engine.

One of the primary goals of NASA's Aeronautics Enterprise, as delineated in the NASA Strategic Plan, specified the development and demonstration of technologies for air-breathing hypersonic flight. Following the cancelation of the National Aerospace Plane (NASP) program in November 1994, the United States lacked a cohesive hypersonic technology development program. As one of the "better, faster, cheaper" programs developed by NASA in the late 1990s, Hyper-X used National Aerospace Plane technology, and was to quickly move it forward to the next step, which was demonstration of hypersonic air breathing propulsion in flight.

...
Wikipedia