Bell X-1

Nasa's Experimental Aircraft (X-Planes) began in 1944 as a collaboration between the National Advisory Committee for Aeronautics (NACA, now NASA), the US Navy, and the US Army Air Forces. The purpose of the program was to build aircraft that would push the boundaries of aviation, including breaking speed & altitude barriers, and testing new technologies

The Bell X-1 was the first X-plane to fly and break the sound barrier on October 14, 1947,
Piloted by U.S. Air Force Capt. Charles E. "Chuck" Yeager, the X-1 reached a speed of 700 mph, Mach 1.06
It flew a total of 78 times, and on March 26, 1948, Yeager attained a speed of 957 mph, Mach 1.45, at an altitude of 71,900 feet
The airplane was named "Glamorous Glennis" by Yeager as a tribute to his wife

Douglas X-3 Stiletto

Designed to explore the challenges of supersonic flight, with its slender fuselage and needle-like nose

The X-3 flew 26 flights between 1952 and 1955.
Designed for Mach 2 but only reached Mach 1
The X-3 is now on display in the National Museum of the United States Air Force in Dayton, Ohio

Northrop X-4 Bantam

The X-4 was designed to test a semi-tailless wing configuration at transonic speeds

Northrop Aircraft Company wa commissioned on June 11, 1946, to build two X-4s
The aircraft was compact, with only 45mins of fuel supply
The first flight was on Dec. 15, 1948, with Northrop test pilot Charles Tucker
Testing & modifications through its 81st and final flight in 1953 determined that a swept-wing semi-tailless design was not suitable for speeds near Mach 1

North American X-15

Engineered to test piloted hypersonic flight within and outside the Earth’s atmosphere

First flown in 1959, the North American X-15 was the first winged aircraft to fly Mach 4, 5, & 6
The program saw 199 flights over 10 years and set the world’s unofficial speed and altitude records of 4,520 mph (Mach 6.7) and 354,200 feet
The success of the program contributed to the development of the Mercury, Gemini, Apollo and Space Shuttle piloted spaceflight programs
In 1967 the X-15 #3 had a technical issue with the adaptive flight control system, tragically resulting in the loss of the pilot

Grumman X-29 Polecat

Designed to explore the forward-swept wing concept, test improved lift qualities in extreme maneuvers, reduce aerodynamic drag, and fly more efficiently at cruise speeds

First flight of the No. 1 X-29 was Dec. 14, 1984, while the No. 2 aircraft first flew on May 23, 1989.
The X-29 did not demonstrate the overall reduction in aerodynamic drag
The program did demonstrate new uses of proven technologies including aeroelastic tailoring to control structural divergence and use of a relatively large, close-coupled canard for longitudinal control
With over 400 test flights the X-29 reached Mach 1.8

X-37B OTV

The X-37B is a small, robotic spaceplane built for long-duration, high-tech missions in low Earth orbit.

This secretive, unmanned spacecraft orbits the Earth, conducting experiments and gathering intelligence.
First Flight was April 22, 2010
The X-37B lands on runways like a regular plane, making it one of the few reusable spacecraft in operation today
After 908 days in orbit the 6th mission of X-37B was retrieved Nov 2022
Falcon Heavy launched the 7th mission on Dec 2023 from LC 39A, with an unknown return date

XB-70 Valkyrie

Designed to carry nuclear bombs and became a testbed for supersonic flight research.

The XB-70-Valkyrie was a prototype strategic bomber designed to fly at high altitudes and over Mach 3 (over 2000 mph)
The Valkyrie never entered production but was a technological marvel and influenced future aircraft designs
The aircraft featured a canard foreplane and folding wingtips to enhance stability and control at supersonic speeds.

We honor U.S. service members whose sacrifices fueled aviation and space exploration