New Threat Upgrade
New Threat Upgrade (NTU) was a United States Navy program to improve and modernize the capability of existing cruisers and destroyers equipped with Terrier and Tartar anti-aircraft systems, keeping them in service longer. It was a key component of then-President Ronald Reagan's 600-ship Navy plan. The Program. was selected to install and test the Terrier New Threat Upgrade (NTU) Combat System with the improved Standard Missile Two Block II (Extended Range). Testing lasted from October 1981- March 1985. New Threat Upgrade allowed the full use of newer Standard missiles (SM-2ER BlkII w/Mk80  booster) and improved the interoperability of the radar, computer, tracking and engagement systems aboard the ships. The system allows the ships to which it was fitted to time share illumination radars for multiple missile interceptions in a manner similar the Aegis Combat System. History. The New Threat Upgrade to the "Leahy" class included massive remodeling of the ship from food service space rehabilitation to a main propulsion system overhaul. Entire systems were removed and replaced, for example the AN/SPS-40 air-search radar was replaced with the AN/SPS-49 air-search radar. In 1988–90, the "Kidd"-class destroyers received the New  Threat Upgrade, including a new superstructure and heavier mainmast cooperative engagement with Aegis "Ticonderoga"-class cruisers, which could control the Kidds’ surface-to-air missiles while they remained electronically silent. The "Spruance" class, the predecessor to and close relative of the "Kidd"-class, did not receive the NTU.. End of NTU. The Cold War ended shortly after the New Threat Upgrade was initiated. The lower levels of funding available to the United States Navy after the Cold War meant that the NTU upgrade was never applied to all of the intended vessels. The NTU upgrade itself was expensive. Many of these ships  were retired in the 1990s whether they received the full NTU modification or not; most of these warships built in the 1960s-1970s had high operational costs and manpower requirements (especially those which were nuclear-powered), compared to newer Aegis warships. The USS Texas (CGN-39) was decommissioned during the upgrade, in the midst of her reactor refueling. USS "Gridley" (CG-21) received NTU in 1991 at a cost of $55 million but was decommissioned in early 1994. Overall, all US Navy ships that received the NTU upgrades were decommissioned within six years of their upgrade, as the Navy chose instead to  order new ships with the Aegis weapon system. The Navy also accelerated the retirement of the "Spruance" and "Kidd" classes, despite their recent modifications, due to the arrival of the Aegis-equipped "Arleigh Burke"-class destroyers, which were more effective and cost-efficient. The four "Kidd" destroyers were later transferred to Taiwan (Republic of China) where they remain in service, while some members of the "Spruance" class remained in service until 2005. NTU ships. These classes had some of their units modified with the New Threat Upgrade. KDX-II Class. The Navy of the Republic of Korea uses a NTU derived  system for its Chungmugong Yi Sunshin class destroyers.