Arnold Engineering Development Complex (AEDC) operates more than 68 aerodynamic and propulsion wind tunnels, rocket and turbine engine test cells, space environmental chambers, arc heaters, ballistic ranges and other specialized units located in eight states. Many of the complex's test units have capabilities unmatched elsewhere in the United States; some are unique in the world. AEDC is one of three installations which are part of the Air Force Test Center (AFTC), one of six subordinate commands of the Air Force Materiel Command organization and an important national resource.