Editing Trident (missile) (section)

==Development==
In 1971, the US Navy began studies of an advanced Undersea Long-range Missile System (ULMS). A Decision Coordinating Paper (DCP) for the ULMS was approved on 14 September 1971. ULMS program outlined a long-term modernization plan, which proposed the development of a longer-range missile termed ULMS II, which was to achieve twice the range of the existing Poseidon (ULMS I) missile. In addition to a longer-range missile, a larger submarine was proposed to replace the {{sclass|Lafayette|submarine|5}}, {{sclass|James Madison|submarine|5}} and {{sclass|Benjamin Franklin|submarine|5}}-class SSBNs in 1978. The ULMS II missile system was designed to be retrofitted to the existing SSBNs, while also being fitted to the proposed {{sclass|Ohio|submarine|1}}.

In May 1972, the term ULMS II was replaced with Trident. The Trident was to be a larger, higher-performance missile with a range capacity greater than {{convert|6000|mi}}. The first test of the Trident was on 18 January 1977 when an unarmed missile was launched from [[Cape Canaveral]] in [[Florida]] and traveled almost its full range of {{convert|4600|mi}}, to a point in the South Atlantic Ocean near [[Ascension Island]].<ref>"The World", ''Los Angeles Times'', 19 January 1977, p.I-2</ref>

Trident I (designated as ''C4'') was deployed in 1979 and retired in 2005.<ref>{{cite web |url=http://www.navy.mil/search/display.asp?story_id=20913 |title=USS Alabama Offloads Last of C4 Trident Missiles |publisher=US Navy |work=navy.mil |date=5 November 2005 |access-date=2012-05-16 |last=Popejoy |first=Mary |url-status=dead |archive-url=https://web.archive.org/web/20070912180153/https://www.navy.mil/search/display.asp?story_id=20913 |archive-date=12 September 2007}}</ref> Its objective was to achieve performance similar to Poseidon (C3) but at extended range. Trident II (designated ''D5'') had the objective of improved [[circular error probable]] (CEP), or accuracy, and was first deployed in 1990, and was planned to be in service for the thirty-year life of the submarines, until 2027.

Trident missiles are provided to the United Kingdom under the terms of the 1963 [[Polaris Sales Agreement]] which was modified in 1982 for Trident.<ref>Suzanne Doyle, "The United States Sale of Trident to Britain, 1977–1982: Deal Making in the Anglo-American Relationship." ''Diplomacy and Statecraft'', 28:3 (2017), 477–493.</ref> British Prime Minister [[Margaret Thatcher]] wrote to [[Jimmy Carter|President Carter]] on 10 July 1980, to request that he approve supply of Trident I missiles. However, in 1982 Thatcher wrote to [[Ronald Reagan|President Reagan]] to request the United Kingdom be allowed to procure the Trident II system, the procurement of which had been accelerated by the US Navy. This was agreed upon in March 1982.<ref>
{{cite web
 |url         = http://www.reagan.utexas.edu/archives/speeches/1982/31182b.htm
 |title       = Letter to Prime Minister Margaret Thatcher of the United Kingdom Confirming the Sale of the Trident II Missile System to Her Country
 |date        = 11 March 1982
 |access-date  = 2012-11-23
 |url-status     = live
 |archive-url  = https://web.archive.org/web/20100913055759/http://www.reagan.utexas.edu/archives/speeches/1982/31182b.htm
 |archive-date = 13 September 2010}}</ref> Under the agreement, the United Kingdom paid an additional 5% of their total procurement cost of $2.5 billion to the US government as a research and development contribution.<ref name=NAO-1987>{{cite book |title=Ministry of Defence and Property Services Agency: Control and Management of the Trident Programme |publisher=[[National Audit Office (United Kingdom)|National Audit Office]] |date=29 June 1987 |pages=Part 4 |isbn=0-10-202788-9 |no-pp=true}}</ref>

The total cost of the Trident program thus far came to $39.546 billion in 2011, with a cost of $70 million per missile.<ref>{{cite web
 |url         = http://costofwar.com/en/publications/2011/analysis-fiscal-year-2012-pentagon-spending-request/
 |title       = Analysis of the Fiscal Year 2012 Pentagon Spending Request
 |publisher   = [[Cost of War]]
 |date        = 15 February 2011
 |access-date  = 2012-11-23
 |url-status  = dead
 |archive-url  = https://web.archive.org/web/20110805235044/http://costofwar.com/en/publications/2011/analysis-fiscal-year-2012-pentagon-spending-request/
 |archive-date = 5 August 2011
}}</ref>

In 2009, the United States upgraded the warheads carried by American D5 missiles with an arming, fuzing and firing (AF&F) system called the "super-fuze" that allows them to time their detonation to target silos and bunkers more accurately, greatly increasing their effectiveness against hardened targets.<ref>{{cite journal |last1=Kristensen |first1=Hans M. |last2=McKinzie |first2=Matthew |last3=Postol |first3=Theodore A. |date=1 March 2017 |title=How US nuclear force modernization is undermining strategic stability: The burst-height compensating super-fuze |url=https://thebulletin.org/2017/03/how-us-nuclear-force-modernization-is-undermining-strategic-stability-the-burst-height-compensating-super-fuze/ |url-status=live |journal=Bulletin of the Atomic Scientists |archive-url=https://web.archive.org/web/20170305115022/http://thebulletin.org/how-us-nuclear-force-modernization-undermining-strategic-stability-burst-height-compensating-super10578 |archive-date=5 March 2017}}</ref>