The Propulsion Systems Laboratory (PSL) was the National Advisory Committee for Aeronautics’ (NACA) most powerful facility for testing full-scale engines at simulated flight altitudes. The original PSL chambers, referred to as PSL No. 1 and 2, were a technological combination of the old static sea level test stands and the complex Altitude Wind Tunnel, which recreated actual flight conditions on a larger scale. PSL’s significance lies in the size and power of the engines it tested. When it became operational in 1952, PSL was the nation’s only facility that could run these large full-size engine systems in controlled altitude conditions. The ability to control the test environment was important in the advancement of the ever-increasing and complex turbojet systems.
The two 14-foot-diameter and 24-foot-long chambers were first used to study the increasingly powerful jet engines of the early 1950s and the ramjets for missile programs such as Navaho and Bomarc. With the advent of the space program in the late 1950s, the facility was used to study complex rocket engines, including the seminal Pratt & Whitney RL-10 that was used to power the Centaur rocket and Saturn I upper stages. In the mid-1960s, PSL returned its focus to jet engines, which continued to grow in size and performance. By 1972 two additional, more powerful test chambers were added to PSL to accommodate these new engines. The original chambers continued with jet engine research until being phased out in 1979. PSL No. 3 and 4 still maintains a busy schedule. It is NASA’s only facility for testing full-scale engine systems at flight altitudes.