Promontory Rocket Complex, Utah

Now owned by ATK, this is one of the nation's largest rocket development and manufacturing sites. NASA’s space shuttle rocket boosters were made at this isolated facility near the Promontory Mountains. Other defense and propulsions systems are developed and tested here by, part of which was once designated as “Air Force Plant 78.” Systems produced here include the solid fuel rocket motors for many of the ICBM vehicles still in use today, launchable from silos or submarines, as well as warheads and other missile components. Up to 3,000 people work in 450 buildings, clustered in the various industrial and test areas, scattered throughout the bare hills of the nearly 30 square mile complex. Operated for years by the Thiokol corporation, which was aquired by Alliant Tech Systems (ATK)'s Launch Systems Group in 2006. In addition to being a leader in solid-fuel rockets, ATK is the nation’s largest manufacturer of ammunition.