USNS Observation Island

The USNS Observation Island is a Missile Range Instrumentation Ship, used in the testing of U.S. missile systems, and to monitor other countries to ensure treaty compliance. It was originally launched in 1953 as the merchant ship Empire State Mariner and operated by the United States Lines for the Military Sea Transportation Service, before being transferred to the United States Navy for use in ballistic missile development in 1956 and renamed USS Observation Island, after an island in Florida's Lake Okeechobee. The Observation Island was the first naval ship to have a fully integrated Fleet Ballistic Missile System with the installation of the Polaris missile system in the late 1950s. Decommissioned by the U.S. Navy in 1972, the Observation Island was transferred to the Military Sealift Command in 1977 at the request of the United States Air Force Technical Applications Center for use as a tracking ship. Still owned by the U.S. Navy, its USNS prefix indicates that it is mostly crewed by civilians.