Before Check Yeager could make his historic first supersonic flight in 1947 in the rocket-powered X-1, a lot of testing was done to understand how jet engines would perform at extreme speeds and high altitudes. Some of that testing was done at the National Advisory Committee on Aeronautics (NACA) Airplane Engine Research Laboratory (AERL) Icing Research Tunnel. (NACA was a precursor to NASA.)
In this 1944 photo from the U.S. space agency, the Altitude Tunnel is in the center background, the propeller motor drive housing in the right background, and the Air Dryer and Cooling Tower in the left background.
Each weekday, SPACE.com looks back at the history of spaceflight through photos (archive).