NASA X-43

X-43
Pegasus rocket booster accelerating NASA's X-43A (dark object mounted on nose) shortly after ignition during test flight (March 2, 2004)
Role	Experimental hypersonic UAV Type of aircraft
National origin	United States
Design group	NASA
Built by	Micro Craft (airframe) GASL (engine)
Primary user	NASA
Number built	3

The NASA X-43 was an experimental unmanned 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 developed in the late 1990s.^[1] It set several airspeed records for jet aircraft. The X-43 is the fastest jet-powered aircraft on record at approximately Mach 9.6.^[2]

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, of which three were built. The first X-43A was destroyed after malfunctioning in flight in 2001. Each of the other two flew successfully in 2004, setting speed records, with the scramjets operating for approximately 10 seconds followed by 10-minute glides and intentional crashes into the ocean. Plans for more planes in the X-43 series have been suspended or cancelled, and replaced by the USAF managed X-51 program.