Thiokol builds the NASA space shuttle rocket motors at this sprawling isolated facility near the Promontory Mountains. Other defense and propulsions systems are developed, built, and tested here including ICBM rocket engines. The plant, once designated as "Air Force Plant 78" employs over three thousand people, who work in 450 buildings, clustered in the various industrial and test areas that are scattered throughout the bare hills of the 30 square mile complex. In 2001 Thiokol's propulsion divsion was acquired by Alliant Techsystems, a weapons and explosives manufacturer that operates a large plant outside Salt Lake City, the Bacchus Works. The Thiokol plant is expected to continue its current functions.