The Arlington Heights Army Air Defense Site was a Project Nike Missile Master installation started in late 1959 after the United States Army had purchased 44 acres (18 ha).† Adjacent to the Arlington Heights Air Force Station, the Arlington Heights Army Installation opened on October 28, 1960, as the 8th of 10 Army Air Defense Command Posts (AADCP) to have a Martin AN/FSG-1 Antiaircraft Defense System installed for Nike-Hercules command and control. In addition to the Army's 2 AN/FPS-6 radars, the radars of the co-located USAF station provided AADCP data for the 45th Artillery Brigade's control of the Chicago-Gary Defense Area (10 missile batteries and their Integrated Fire Control sites). The vacuum tube AN/FSG-1 was replaced c. October 1967* with a solid-state Hughes AN/TSQ-51 Air Defens