A technician prepares to unlatch the door built into the guide vanes of the 16-foot transonic wind tunnel at NASA Langley Research Center in Hampton, Virginia, in March of 2010. The tunnel, one of dozens of research facilities at Langley, was built in 1939 and operated until 2004, when it was retired as part of a national initiative to optimize government-owned wind tunnels. Operating "transonically" or across the speed of sound, the air in the test section traveled from about 150 to 1,000 miles per hour. The guide vanes, which formed an ellipse 58 feet high and 82 feet wide, cut across each cylindrical tube at a 45-degree angle. Similar sets of vanes at the three other corners of the wind tunnel turned the air uniformly as it rushed through the 1,000-foot race track-like enclosed tube. If guide vanes were omitted, the air would have piled up in dense masses along the outside curves, like water rounding a bend in a fast brook. #

The air intake for NACA tunnel number one. In 1920, the National Advisory Committee for Aeronautics (NACA) completed its first wind-tunnel facility, a copy of an existing British tunnel. The honeycombed open-circuit air intake ensured a steady, non-turbulent flow of air. #

The eight-foot-high speed tunnel, located in Building 641 of NASA's Langley Research Center in Hampton, Virginia, seen from the water in 1936. The reinforced concrete structure contained generated winds up to Mach 1. #

Construction of the 40 foot by 80 foot wind tunnel at Ames Research Center in July of 1943. Construction began in late 1941, with the mammoth construction task sorely taxing the resources of the new center. Two and a half years later, in June of 1944, the full-scale tunnel went into operation. #

A 1/40th-scale model of the navy airship U.S.S. Akron being prepared for aerodynamic testing on a ground board at zero degrees of yaw in the full-scale tunnel in 1935. #

The Langley engineer Charles Zimmerman developed what some called a "flying pancake," better known as the Zimmer Skimmer or V-173 Flying Wing. The concept was designed for the U.S. Navy as a potential vertical takeoff and landing aircraft for use onboard ships. A view of the prototype, on which the XF5U was based, photographed during wind-tunnel testing on November 28, 1941. #

Construction view from inside the contraction framing of the 40 foot by 80 foot wind tunnel at Ames Research Center with a blimp flying in the background, in July of 1943. #

Six 40-foot-diameter fans stand in the Ames 40 foot by 80 foot wind tunnel, each powered by a 6,000-horsepower electric motor, capable of maintaining airflow up to 230 miles per hour. Photographed on June 9, 1944. #

Two men on top of the altitude wind tunnel at the NACA Aircraft Engine Research Laboratory, circa 1945. The tunnel was a massive rectangular structure, which for years provided one of the highest vantage points of the laboratory. The tunnel was 263 feet long on the north and south legs and 121 feet long on the east and west sides. The larger west end of the tunnel, seen here, was 51 feet in diameter. #

Langley full-scale tunnel exit cone and tunnel-drive fans, photographed on January 18, 1946. Each fan is 35.5 feet in diameter and is powered by a 4,000-horsepower electric motor. #

At lower left, evidence of a mishap during testing in the full-scale tunnel at Langley Research Center in 1948. A helicopter rotor that had been attached to the apparatus at right tore loose and crashed into the structure. #

A technician on a ladder examines a Mercury capsule before it is tested in Langley's 30 foot by 60 foot wind tunnel. Much of the early work on the Mercury program was performed at Langley. #

Rear view of the Avrocar with tail, mounted on variable height struts in the NASA Ames 40 foot by 80 foot wind tunnel on March 3, 1961. The Avrocar was a secret experimental vertical-take-off-and-landing craft developed by Avro Canada and the U.S. Military. #

Following the crash of a sister lunar landing training vehicle at Ellington Field in Houston, Texas, the Bell LLTV was sent from Houston to Langley for tests in the 30 foot by 60 foot full-scale tunnel on January 16, 1969. #

A wind-tunnel model of a supersonic transport undergoing testing at NASA Langley Research Center on January 17, 1975. The 30 foot by 60 foot tunnel was used in the mid 1970s to test the model at low speeds. #

Mary Jackson began her career at the NACA Langley Memorial Aeronautical Laboratory’s segregated west area computing section in 1951, reporting to the group’s supervisor Dorothy Vaughan. After two years in the computing pool, Mary Jackson received an offer to work for the engineer Kazimierz Czarnecki in the 4 foot by 4 foot Supersonic Pressure Tunnel. Czarnecki offered Mary hands-on experience conducting experiments in the facility, and eventually suggested that she enter a training program that would allow her to earn a promotion from mathematician to engineer. Trainees had to take graduate-level math and physics in after-work courses managed by the University of Virginia. Because the classes were held at then-segregated Hampton High School, however, Mary needed special permission from the City of Hampton to join her white peers in the classroom. Mary completed the courses, earned the promotion, and in 1958 became NASA’s first black female engineer. #

A Space Shuttle model is magnetically suspended in the transparent hexagonal test section of the MIT/NASA Langley 6-inch magnetic suspension and balance system on June 11, 1991. The low-speed (Mach 0.5) wind tunnel was handcrafted from mahogany. Aerodynamic forces on the test model are measured by the proportional electrical current used to hold the model in place. The system was built by MIT in the late sixties, and was relocated to Langley in the mid-eighties. #

A researcher examines the ice build-up on a turboprop engine nacelle in the icing research tunnel in 1983. The nacelle was mounted on its side to center its inlet in the optimum cloud field. The curved exhaust duct draws air into the inlet to ensure the proper flow into and around it. #

Researchers at NASA's Langley Research Center use all sorts of tools and techniques to learn more during the development of aircraft and spacecraft designs. In this photo, engineers led by the researcher Greg Gatlin sprayed fluorescent oil on a 5.8 percent-scale model of a hybrid-wing body during tests in the 14 foot by 22 foot subsonic wind tunnel. The oil helps researchers "see" the flow patterns when air passes over and around the model. Those patterns are important in determining crucial aircraft characteristics such as lift and drag. #