Editing UGM-27 Polaris (section)

{{Redirect|Polaris missile|the North Korean missile|Pukkuksong-1}}
{{Infobox weapon
|name            = UGM-27 Polaris
| image           = Polaris A3 (A3X-01) on pad LC-29A at CCSFS - 1962-08-07.jpg
|caption         = Polaris A-3 (A3X-01) on launch pad LC-29A before a test flight at [[Cape Canaveral Space Force Station|Cape Canaveral Air Force Station]], {{date|1962-08-07}}
|type            = [[Submarine-launched ballistic missile]]
<!-- Type selection -->
|service         = 1961–1996
|designer        =
|number          =
|spec_label      = Polaris A-3 (UGM-27C)
|length          =
|width           =
|height          = {{convert|32|ft|4|in|m|abbr=on}}
|diameter        = {{convert|4|ft|6|in|mm|abbr=on}}
<!-- Explosive specifications -->
| image_size      = 300
|origin          = United States
|is_missile      = yes
<!-- Service history -->
|used_by         = [[United States Navy]], [[Royal Navy]]
<!-- Production history -->
|design_date     = 1956–1960
|manufacturer    = [[Lockheed Corporation]]
|unit_cost       =
|production_date =
|variants        = A-1, A-2, A-3, [[Chevaline]]
<!-- General specifications -->
|weight          = {{convert|35700|lb|kg|abbr=on}}
|part_length     =
|filling         = 1 x [[W47]], 3 × [[W58]] [[thermonuclear weapon]]
|filling_weight  =
|detonation      =
|yield           = 3 × 200 kt
<!-- Vehicle/missile specifications -->
|engine          = First stage, [[Aerojet General]] [[Solid-fuel rocket]]
|engine_power    = Second stage, [[Hercules Inc.|Hercules]] rocket
|pw_ratio        =
|fuel_capacity   =
|vehicle_range   = {{convert|2500|nmi|km}}
|speed           = {{convert|8000|mph|km/h|abbr=on}}
|guidance        = [[Inertial navigation system|Inertial]]
|steering        = [[Thrust vectoring]]
<!-- Missiles only -->
|propellant      = [[Solid propellant]]
|ceiling         =
|altitude        =
|boost           =
|accuracy        = [[Circular error probable|CEP]] {{convert|3000|ft|m}}
|launch_platform = [[Ballistic missile submarine]]s
|transport       =
}}
The '''UGM-27 Polaris''' missile was a two-stage [[solid-fuel rocket|solid-fueled]] [[nuclear warhead|nuclear-armed]] [[submarine-launched ballistic missile]] (SLBM). As the [[United States Navy]]'s first SLBM, it served from 1961 to 1980.

In the mid-1950s the Navy was involved in the [[PGM-19 Jupiter|Jupiter missile]] project with the [[U.S. Army]], and had influenced the design by making it squat so it would fit in submarines. However, they had concerns about the use of [[liquid fuel rocket]]s on board ships, and some consideration was given to a [[solid fuel rocket|solid fuel]] version, Jupiter S. In 1956, during an anti-submarine study known as [[Project Nobska]], [[Edward Teller]] suggested that very small [[hydrogen bomb]] warheads were possible. A crash program to develop a missile suitable for carrying such warheads began as Polaris, launching its first shot less than four years later, in February 1960.<ref name="polarisa1">{{cite web|url=https://fas.org/nuke/guide/usa/slbm/a-1.htm|title=Polaris A1|access-date=26 November 2017}}</ref>

As the Polaris missile was fired underwater from a moving platform, it was essentially invulnerable to counterattack. This led the Navy to suggest, starting around 1959, that they be given the entire [[nuclear deterrent]] role. This led to new infighting between the Navy and the [[U.S. Air Force]], the latter responding by developing the [[counterforce]] concept that argued for the [[strategic bomber]] and [[ICBM]] as key elements in [[flexible response]]. Polaris formed the backbone of the U.S. Navy's nuclear force aboard a number of custom-designed submarines. In 1963, the [[Polaris Sales Agreement]] led to the [[Royal Navy]] taking over the [[United Kingdom]]'s nuclear role, and while some tests were carried out by the [[Italian Navy]], this did not lead to use.

The Polaris missile was gradually replaced on 31 of the 41 original [[Ballistic missile submarine|SSBNs]] in the U.S. Navy by the [[MIRV]]-capable [[UGM-73 Poseidon|Poseidon]] missile beginning in 1972. During the 1980s, these missiles were replaced on 12 of these submarines by the [[UGM-96 Trident I|Trident I]] missile. The 10 {{sclass|George Washington|submarine|5}}- and {{sclass|Ethan Allen|submarine|0}} SSBNs retained Polaris A-3 until 1980 because their missile tubes were not large enough to accommodate Poseidon. With {{USS|Ohio|SSBN-726|6}} beginning sea trials in 1980, these submarines were disarmed and redesignated as [[attack submarine]]s to avoid exceeding the [[SALT II]] strategic arms treaty limits.

The Polaris missile program's complexity led to the development of new project management techniques, including the [[Program Evaluation and Review Technique]] (PERT) to replace the simpler [[Gantt chart]] methodology.