Charleston Air Force Station Charleston Air Force Station is a defunct Air Force Station that opened in 1952 and closed in 1980 . It was located in Charleston , Maine and is the site of a radar station and other buildings . After closure , it was redeveloped into a jail for the state of Maine . History . In late 1950 , construction began on Charleston Air Force Station . Known as Bull Hill for its location in the town , the station was one of twenty - eight stations built as part of the second segment of the permanent Air Defense Command national radar network . Prompted by the start of the Korean War , on July 11 , 1950 , the Secretary of the Air Force asked the Secretary of Defense for approval to expedite construction of the second segment of the permanent network . Receiving the Defense Secretary ’ s approval on July 21 , the Air Force directed the Corps of Engineers to proceed with construction . Completed in early 1951 , and fully manned and operational when the 765th Aircraft Control and Warning Squadron brought Charleston AFS to life in April 1952 and assumed coverage that had been provided by a temporary Lashup Radar Network site at Dow AFB ( L - l ) . The site initially had AN / FPS - 3 and AN / FPS - 5 radars , and initially the station functioned as an aircraft control and warning station . In 1957 an AN / FPS - 6 replaced the AN / FPS - 5 height - finder radar . Another height - finder radar came in 1958 along with an AN / FPS - 20 search radar that replaced the AN / FPS - 3 . During 1959 Charleston AFS joined the Semi Automatic Ground Environment ( SAGE ) system , feeding data to DC - 05 at Topsham AFS , Maine . After joining , the squadron was redesignated as the 765th Radar Squadron ( SAGE ) on 1 October 1959 . The radar squadron provided information 24 / 7 the SAGE Direction Center where it was analyzed to determine range , direction , altitude , speed , and whether or not aircraft were friendly or hostile . In 1963 the site became the first in the nation to receive an AN / FPS - 27 radar and on 31 July 1963 , the site was redesignated as NORAD ID Z - 65 . This radar subsequently was upgraded to become an AN / FPS - 27A . The AN / FPS - 26A was then converted into an AN / FSS - 7 submarine - launched ballistic missile radar in 1966 for Detachment 6 , 14th Missile Warning Squadron ( MWS ) to monitor for Ballistic Missile launches by submarines . In addition to the main facility , Charleston operated two unmanned Gap Filler sites : Topsfield was equipped with an AN / FPS - 18 ; Control of Sedgwick was transferred to Charleston AFS after Brunswick AFS ( Z - 13 ) closed in 1965 and was equipped with the AN / FPS - 14 . Over the years , the equipment at the station was upgraded or modified to improve the efficiency and accuracy of the information gathered by the radars . The 765th Radar Sq was inactivated and replaced by the 765th Air Defense Group in March 1970 . The upgrade to group status was done because of Charleston AFS ' status as a Backup Interceptor Control ( BUIC ) site . BUIC sites were alternate control sites in the event that SAGE Direction Centers became disabled and unable to control interceptor aircraft . The group was inactivated and replaced by the 765th Radar Squadron . as defenses against manned bombers were reduced . The group was disbanded in 1984 . The 765th Radar Squadron was inactivated on 29 June 1979 as part of a general draw down of air defense forces by Aerospace Defense Command and the transfer of the mission to Tactical Air Command . The 14th MWS detachment was inactivated a year later . After the base closed , the radar site was abandoned , with several radar towers still standing . The station area was transformed into the Charleston Correctional Facility , which opened in 1980 . The family - housing area has been entirely demolished . Air Force units and assignments . Units . Commanders . 765th Air Defense Group Assignments . 765th Squadron 765th Group