UGM-27 Polaris

The UGM-27 Polaris missile was a two-stage <a href="/facts/Solid-fuel_rocket/RpgdYKIU">solid-fueled</a> <a href="/facts/Nuclear_warhead/QVdBcMdm">nuclear-armed</a> <a href="/facts/Submarine-launched_ballistic_missile/AypqGmQ9">submarine-launched ballistic missile</a> (SLBM). As the <a href="/facts/United_States_Navy/xYK0fUou">United States Navy</a>'s first SLBM, it served from 1961 to 1980.
In the mid-1950s the Navy was involved in the <a href="/facts/PGM-19_Jupiter/KD3QYXY0">Jupiter missile</a> project with the <a href="/facts/U.S._Army/WACWBEK9">U.S. Army</a>, and had influenced the design by making it squat so it would fit in submarines. However, they had concerns about the use of <a href="/facts/Liquid_fuel_rocket/TAonrVDn">liquid fuel rockets</a> on board ships, and some consideration was given to a <a href="/facts/Solid_fuel_rocket/RpgdYKIU">solid fuel</a> version, Jupiter S. In 1956, during an anti-submarine study known as <a href="/facts/Project_Nobska/8L71wIj6">Project Nobska</a>, <a href="/facts/Edward_Teller/9g3Mr9Mp">Edward Teller</a> suggested that very small <a href="/facts/Hydrogen_bomb/T9zFe3H0">hydrogen bomb</a> 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.
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 <a href="/facts/Nuclear_deterrent/osrg3g9G">nuclear deterrent</a> role. This led to new infighting between the Navy and the <a href="/facts/U.S._Air_Force/7MxWBYlc">U.S. Air Force</a>, the latter responding by developing the <a href="/facts/Counterforce/Tughk0mE">counterforce</a> concept that argued for the <a href="/facts/Strategic_bomber/g0PWamDC">strategic bomber</a> and <a href="/facts/ICBM/0vKnj2Y7">ICBM</a> as key elements in <a href="/facts/Flexible_response/Gl2xvHMz">flexible response</a>. Polaris formed the backbone of the U.S. Navy's nuclear force aboard a number of custom-designed submarines. In 1963, the <a href="/facts/Polaris_Sales_Agreement/SoN2lTPK">Polaris Sales Agreement</a> led to the <a href="/facts/Royal_Navy/Xdy8YCH7">Royal Navy</a> taking over the <a href="/facts/United_Kingdom/kuPAILt2">United Kingdom</a>'s nuclear role, and while some tests were carried out by the <a href="/facts/Italian_Navy/hFaazKk2">Italian Navy</a>, this did not lead to use.
The Polaris missile was gradually replaced on 31 of the 41 original <a href="/facts/Ballistic_missile_submarine/Alykksc1">SSBNs</a> in the U.S. Navy by the <a href="/facts/MIRV/cmzWwXxy">MIRV</a>-capable <a href="/facts/UGM-73_Poseidon/kWXDhFvI">Poseidon</a> missile beginning in 1972. During the 1980s, these missiles were replaced on 12 of these submarines by the <a href="/facts/UGM-96_Trident_I/1NFrTGYx">Trident I</a> missile. The 10 <a href="/facts/George_Washington-class_submarine/DCnzRn5J">George Washington</a>- and <a href="/facts/Ethan_Allen-class_submarine/trFpl74E">Ethan Allen-class</a> SSBNs retained Polaris A-3 until 1980 because their missile tubes were not large enough to accommodate Poseidon. With <a href="/facts/USS_Ohio_(SSGN-726)/sXskvu5v">USS Ohio</a> beginning sea trials in 1980, these submarines were disarmed and redesignated as <a href="/facts/Attack_submarine/8TsVhV80">attack submarines</a> to avoid exceeding the <a href="/facts/SALT_II/E1H7pIvA">SALT II</a> strategic arms treaty limits.
The Polaris missile program's complexity led to the development of new project management techniques, including the <a href="/facts/Program_Evaluation_and_Review_Technique/TVTWehCE">Program Evaluation and Review Technique</a> (PERT) to replace the simpler <a href="/facts/Gantt_chart/HooQgCvs">Gantt chart</a> methodology.

UGM-27 Polaris open-in-new

UGM-27 Polaris