page_title: USNS Observation Island (T-AGM-23)
section_title: Military Sealift Command service
hierarchical_section_title: USNS Observation Island (T-AGM-23) / Military Sealift Command service
caption_attribution_description: English: A starboard quarter view of the missile range instrumentation ship USNS Observation Island (T-AGM-23) underway during exercise Cobra Judy, an exercise to test the ship's seaworthiness. Observation Island, which has been undergoing modifications, is now equipped with a phased-array radar turret on its stern.
context_page_description: USNS Observation Island (T-AGM-23) was built as the Mariner-class merchant ship Empire State Mariner for the United States Maritime Commission, launched 15 August 1953, and operated by United States Lines upon delivery on 24 February 1954, making voyages for the Military Sea Transportation Service until going into reserve at Mobile, Alabama on 9 November 1954. Title was transferred to the United States Navy on 10 September 1956 and, after conversion, the ship was renamed Observation Island. On commissioning the ship was classified as the "experimental miscellaneous auxiliary", USS Observation Island supporting fleet ballistic missile development. On 1 April 1968 Observation Island was redesignated as a miscellaneous auxiliary USS Observation Island. Observation Island was decommissioned and placed in reserve from 1972 until 1977 in the Suisun Bay Reserve Fleet until withdrawn and then returned in 1978. The ship was permanently withdrawn April 1979 and placed in service with MSTS successor, the Military Sealift Command.
  The ship was classified in 1979 as the missile range instrumentation ship USNS Observation Island (T-AGM-23).
context_section_description: 18 August 1977 Observation Island was transferred to the Military Sealift Command at the request of the United States Air Force for use as a tracking ship designated USNS Observation Island (T-AGM 23). The ship underwent a number of modifications including the installation of the AN/SPQ-11 Cobra Judy passive electronically scanned array radar which was used for verification of strategic arms treaties. In the 31 years that followed, the ship averaged 260 days a year at sea in support of this monitoring mission.
  In 2008, the USNS Observation Island was part of Operation Burnt Frost, the U.S. government program that used a RIM-161 Standard Missile 3 anti-ballistic missile to shoot down the satellite, USA-193.
caption: Aft view of the USNS Observation Island showing the location of the Cobra Judy array.
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