UGM-27 Polaris
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The Polaris missile was a submarine-launched, nuclear-tipped ballistic missile (SLBM) built during the Cold War by the United States Navy. It was designed to be used as part of the US Navy's contribution to the United States' nuclear deterrent, replacing the Regulus cruise missile.
Lockheed developed the solid-fuel Fleet Ballistic Missile (FBM), which first flew from Cape Canaveral on January 7, 1960.
The Polaris's first version, the A-1, weighed 28,800 lb (13.1 t), stood 28.5 ft (8.7 m) tall, had a diameter of 54 in (1.4 m), and had a range of 1,000 nautical miles (1850 km). A test launch from a submarine on July 20, 1960, was the first underwater guided-missile launch. The USS George Washington was the first fleet ballistic missile submarine (SSBN in US naval terminology) and carried 16 missiles. Forty more SSBNs were launched in 1960-66.
Work on its nuclear warhead began in 1957 at the facility now called the Lawrence Livermore National Laboratory by a team headed by Harold Brown. The Navy accepted delivery of the first 16 warheads in July 1960, and first launched one from a submarine on November 15.
On May 6, 1962, a Polaris missile with a live W47 warhead was tested in Operation Dominic I, in the Pacific Ocean the only U.S. test of a live offensive nuclear missile. (Surface-to-air and air-to-air missiles with nuclear warheads were also tested in the atmosphere, such as over Nevada.)
The later versions (the A-2, A-3, and B-3) were larger, weighed more, and had longer ranges. The range increase was most important: The A-2 could fly 1,500 nautical miles (2300 km), the A-3 2,500 nautical miles (4600 km), and the B-3 2,000 nautical miles (3700 km). The A-3 featured multiple re-entry vehicles (MRVs) which spread the warheads about a common target, and the B-3 was to have penetration aids to counter Soviet Anti-Ballistic Missile defenses. The B-3 missile evolved into the C-3 Poseidon missile, which abandoned the decoy concept in favour of using the C3's greater throw-weight for larger numbers (10-14) of a new hardened high-re-entry-speed R.V. that could overwhelm Soviet defences by sheer weight of numbers, and its high speed. The abandoned decoy system for the B-3 (Antelope) was passed to the UK where it evolved into Super Antelope and then Chevaline.
Polaris missiles had two stages, both steered by thrust vectoring. An inertial navigation system could guide the missile to about a 900 meter (3000 feet) circular error probability. This made them unsuitable for use against hardened targets. They were mostly useful for attacking dispersed surface targets, eg. airfields, radar sites; thus clearing a pathway for heavy bombers; and in the general public perception, they were a retaliatory weapon.
The missile began to be replaced by Poseidon beginning in 1972. In the 1980s both were replaced by the Trident I.
The UGM-27A Polaris A-1 missile was a medium-range, submarine-launched, solid propellant ballistic missile. It was originally developed from a plan to create a submarine-based Jupiter missile, which eventually evolved into the far smaller, solid-propellant Polaris. The Polaris program resulted in a series of three missiles, the A-1, A-2 and A-3. The Polaris A-1 was the first missile launched from a submerged submarine, the USS George Washington, as well as the first US missile to use a cold launch system.
Originally, the Navy favored cruise missile systems in a strategic role as deployed on the earlier USS Greyback, but it quickly became apparent that ballistic missile systems had advantages over cruise missiles in range and accuracy. The prime contractor for all three versions was Lockheed, now Lockheed-Martin.
The Polaris A-1 missile served as a strategic asset. The missile was developed to complement the limited number of medium-range systems deployed throughout Europe. As those systems lacked the range to attack major Russian targets, the Polaris was developed to increase the level of nuclear deterrence and calm concerned allies. During this time period, there was little threat of counterforce strikes, as few systems had the accuracy to destroy missile systems. Due to this, the primary advantage of missile submarines was the ability to move shorter ranged systems to within range. However, as the technology developed, the submarine-launched Polaris gained increased survivability over fixed systems. It had no capability to destroy hardened targets but would have been effective against dispersed surface targets, eg. airfields, radar and SAM missile sites, as well as population centers of strategic importance. The military authorities however regarded Polaris as but one of a team of players, each with its own function. The task alloted to Polaris of 'taking-out' or destroying the peripheral defences was well-suited to its characteristics.
The Polaris A-1 had a range of 2200 km (1,367 miles) on its single Mk 1 re-entry vehicle. It carried a W-47-Y1 600 kT nuclear warhead, which was guided by an inertial guidance system which provided an accuracy of 1800 m. The missile had a length of 8.53 m, a body diameter of 1.37 m and a launch weight of 12 700 kg. It used a two-stage solid propellant design.
The Polaris program started development in 1956, with its first flight test in 1959. In 1962, the USS Ethan Allen successfully fired a Polaris A-1 missile equipped with a W-47 nuclear warhead against a test target. The missile entered service onboard the USS George Washington, the first US missile submarine, in 1960. The Polaris A-2 was essentially an upgraded A-1 and entered service in late 1961. The A-2 was fitted on a total of 13 submarines and served until June 1974.(1). The Polaris A-3 was the final model, replacing the earlier A-1 and A-2 in the U.S.Navy and equipping the British Polaris force. The A-3 had a range extended to 4'600 km (2'500 nautical miles) and a new weapon bay housing three Mk 2 re-entry vehicles (ReB or Re-Entry Body in U.S.Navy and British usage); and a new warhead the W-58 of 200 kT yield. This arrangement was originally described as a 'cluster warhead' but was replaced with the term Multiple-Re-Entry-Vehicle. The three warheads were spread about a common target and were not independently targeted. Later A-3 missiles (but not the ReBs) were also given limited hardening to protect the missile electronics against electromagnetic pulse effects while in the boost phase. This was known as the A-3T (T for Topsy) and was the final production model.
British Polaris
The British became interested in Polaris after the cancellations of the Blue Streak and Skybolt missiles in the 1950s. Under the Nassau agreement that emerged from the 1962 Nassau Conference between Harold Macmillan and John F. Kennedy, the United States would supply Britain with Polaris missiles, launch tubes, ReBs and the fire control system. Britain would make the warheads and submarines. In return, America was given certain assurances by Britain regarding the use of the missile. The Polaris Sales Agreement was signed on April 6, 1963.The British Polaris submarines were the Resolution-class ballistic missile submarines. The UK Polaris was updated with an 'Improved-Front-End' (IFE) added to replace the unhardened warheads and ReBs of the original that were vulnerable to ABM defences sited to defend Moscow. The original U.S.Navy Polaris had not been designed to penetrate ABM defences, the American strategy being to 'drench' or 'swamp' the defences of 64-100 ABMs with large quantities of warheads. The British, with only four submarines, and with often only one on station, had to ensure that their small force could penetrate the ABM screen around Moscow. The result was a programme called Chevaline that reduced the number of new super-hardened warheads and ReBs to two, and added multiple decoys, chaff, and other defensive countermeasures. Although Chevaline was concieved and designed in Britain it was heavily dependent on U.S. assistance from government and U.S. industry. Approx half the programme costs were spent in the U.S. The British deployed four-boatloads of missiles and warheads plus spares of the original A-3T model. Only three boatloads of the Chevaline IFE type were deployed, with one of the four submarines being in permanent refit.
Although planning for a successor-system to Chevaline began by 1974, possibly earlier, the British rationale for pursuing the expensive Chevaline programme was part-based on the expected lifetime of the submarine hulls. When the decision was taken around 1975 to opt for Chevaline the hulls were only fifteen years old, with an expected life of thirty years. The improvements to Polaris extended the missile life to match the life of the submarines, while meeting the essential requirement of the military planners; that Chevaline could penetrate the Moscow defences.
The British upgraded to the Trident missile after much political wrangling within the Callaghan Labour government over the cost and necessity. Unusually, after a General Election, and in the interests of national security, the outgoing Prime Minister Callaghan made his government's papers on Trident available to the incoming Conservative government of Margaret Thatcher who promptly took the decision to acquire Trident C4. A later decision to upgrade to the larger, longer-ranged Trident D5 was probably taken to ensure that there was commonality between the United States Navy and the Royal Navy; especially important when they were to use common repair and maintenance facilities at King's Bay, Georgia. A recurring problem with the U.K. Polaris force had been that the U.K. equipment was in use long after Polaris was retired by the U.S.Navy, and many spare parts and repair facilities in the U.S. ceased to be available to the British who then had to have production lines re-opened at considerable extra cost, eg. to life-extend the solid fuel propellant motors. The British naval planners were anxious not to perpetuate that lack of commonality in a successor system that had been a strongly argued part of the U.K. naval preference for choosing the Poseidon system as an alternative to the earlier decision to choose Chevaline. In hindsight, it is now recognised that Poseidon would have been a less costly successor than Chevaline. Commonality of the Trident D5 missiles means that a missile can be issued by King's Bay to either a British or a U.S. SSBN. Only the warheads (added later) are different.
See also: Program Evaluation and Review Technique, List of missiles
Fiction
- The Spy Who Loved Me (1977), tenth Bond movie
- For Your Eyes Only (1981), twelfth Bond movie
External links
- [Federation of American Scientists history of A-1 Polaris; see also "a-2.htm," "a-3.htm," and "b-3.htm".]
- [U.S. Nuclear Missiles: History and Guide to Resources]
- http://www.mcis.soton.ac.uk/Site_Files/pdf/nuclear_history/glossary.pdf University of Southampton, 2005.
- Dr R.Moore. A Glossary of British Nuclear Weapons. Prospero/Journal of BROHP. 2004.
- Dr F.Panton. The Unveiling of Chevaline. Prospero/Journal of BROHP. 2004.
- Dr F.Panton. Polaris Improvements and the Chevaline System. Prospero/Journal of BROHP. 2004.
- Dr Peter Jones Director, AWE (Ret). Chevaline Technical Programme. Prospero. 2005.
- Various authors - Proceedings, Royal Aeronautical Society. 2004. ISBN 1-185768-109-6. Abridged version is available as an email download from Brian Burnell. Contact via Talk Page.
- The National Archives, London. Various declassified public-domain documents.
- Chuck Hansen. Swords of Armageddon. 1995.
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