The closure of Ramey Air Force Base began in 1971 as part of a SAC-wide reduction in bombardment wings and lasted until 1973. Following its closure, it was converted into a joint civilian-military airport with the United States Coast Guard comprising the remaining military aviation activities at the airport as Coast Guard Air Station Borinquen and Puerto Rico Air National Guard, Army National Guard and the United States Army Reserve maintaining non-aviation units. Antilles Air Command, 1 March-25 August 1946 As: Antilles Air Division, 12 January 1948 – 22 January 1949 24th Composite Wing, 25 August 1946 – 28 June 1948 55th Strategic Reconnaissance Wing, 1 November 1950 – 1953 72nd Strategic Reconnaissance Wing, 1953 – 1959 (RB-36 Peacemaker) 72nd Bombardment Wing, 1959 – 30 June 1971 (B-52 Stratofortress) U.S. Naval Facility Ramey/Punta Borinquen Success with a test array and then a full scale 40-element operational array at Eleuthera, Bahamas 1951-1952 led the Navy in 1952 to order six (quickly expanded to nine) undersea surveillance systems under the classified name of Sound Surveillance System (SOSUS) to be installed under the unclassified name Project Caesar. The shore terminals were described as supporting "oceanographic research" and given the generic and ambiguous name "Naval Facility" with the actual submarine detection purpose classified on a strict need-to-know basis. The first of the systems was to terminate at a Naval Facility (NAVFAC) on a beach under the cliff of the Air Force Base (). Construction began in 1953 with Naval Facility Ramey commissioned on 18 September 1954. In 1985 with mobile, towed arrays entering the system, SOSUS became the Integrated Undersea Surveillance System (IUSS). SOSUS/IUSS mark their beginnings with the commissioning of Naval Facility Ramey. The facility, unlike NAVFAC Grand Turk and NAVFAC San Salvador completed later that year and not close to a military base, got support for all functions except its classified operations from the base. When the Air Force Base closed 1 January 1974 the facility became Naval Facility Punta Borinquen and self supporting until it was decommissioned 30 April 1976. Remaining military presence In 1971, as a result of the closing of Naval Air Station Isla Grande, the United States Coast Guard relocated its aviation activities to Ramey. The Coast Guard took possession of an outstanding hangar, a part of the Air Force housing area and the DoDEA Ramey Unit School for the newly formed Coast Guard Air Station Borinquen. The