UGM-27 Polaris

The Polaris missile replaced an earlier plan to create a submarine-based missile force based on a derivative of the US Army Jupiter Intermediate-range ballistic missile. Chief of Naval Operations Admiral Arleigh Burke appointed Rear Admiral W. F. "Red" Raborn as head of a Special Project Office to develop Jupiter for the Navy in late 1955. The Jupiter missile's large diameter was a product of the need to keep the length short enough to fit in a reasonably-sized submarine. At the seminal Project Nobska conference in 1956, with Admiral Burke present, nuclear physicist Edward Teller stated that a physically small one-megaton warhead could be produced for Polaris within a few years, and this prompted Burke to leave the Jupiter program and concentrate on Polaris in December of that year. Polaris was spearheaded by the Special Project Office's Missile Branch under Rear Admiral Roderick Osgood Middleton, and is still under the Special Project Office. Admiral Burke later was instrumental in determining the size of the Polaris submarine force, suggesting that 40–45 submarines with 16 missiles each would be sufficient. Eventually, the number of Polaris submarines was fixed at 41. The was the first submarine capable of deploying US developed submarine-launched ballistic missiles (SLBM). The responsibility of the development of SLBMs was given to the Navy and the Army. The Air Force was charged with developing a land-based intermediate range ballistic missile (IRBM), while an IRBM which could be launched by land or by sea was tasked to the Navy and Army. The Navy Special Projects (SP) office was at the head of the project. It was led by Rear Admiral William Raborn. The first IRBM had a liquid-fueled design. Liquid fuel is easier to integrate with land-based missile, which are fixed in location and easier to service. Solid fuels, on the other hand, make logistics and storage simpler and are safer. In the summer of 1956, the navy sponsored a study by the National Academy of Sciences on anti-submarine warfare at Nobska Point in Woods Hole, Massachusetts, known as Project NOBSKA. The navy's intention was to have a new missile developed that would be lighter than existing missiles and cover a range up to fifteen hundred miles. A problem that needed to be solved was that this design would not be able to carry the desired one-megaton thermonuclear warhead. This study brought Edward Teller from the recently formed nuclear weapons laboratory at Livermore and J. Carson Mark, representing the Los Alamos nuclear weapons laboratory. Teller was already known as a nuclear salesman, but this became the first instance where there was a big betting battle where he outbid his Los Alamos counterpart. The two knew each other well: Mark was named head of the theoretical division of Los Alamos in 1947, a job that was originally offered for Teller. Mark was a cautious physicist and no match for Teller in a bidding war. At the NOBSKA summer study, Edward Teller made his famous contribution to the FBM program. Teller offered to develop a lightweight warhead of one-megaton strength within five years. He suggested that nuclear-armed torpedoes could be substituted for conventional ones to provide a new anti-submarine weapon. Livermore received the project. When Teller returned to Livermore, people were astonished by the boldness of Teller's promise. It seemed inconceivable with the current size of nuclear warheads, and Teller was challenged to support his assertion. He pointed out the trend in warhead technology, which indicated reduced weight-to-yield ratios in each succeeding generation. When Teller was questioned about the application of this to the FBM program, he asked, "Why use a 1958 warhead in a 1965 weapon system?" Mark disagreed with Teller's prediction that the desired one-megaton warhead could be made to fit the missile envelope within the timescale envisioned. Instead, Mark suggested that half a megaton would be more realistic and he quoted a higher price and a longer deadline. This simply confirmed the validity of Teller's prediction in the Navy's eyes. Whether the warhead was half or one megaton mattered little so long as it fitted the missile and would be ready by the deadline. However, the Navy was deeply dissatisfied with the liquid fuel IRBM. The first concern was that the cryogenic liquid fuel was not only extremely dangerous to handle, but launch-preparations were also very time-consuming. Second, an argument was made that liquid-fueled rockets gave relatively low initial acceleration, which is disadvantageous in launching a missile from a moving platform in certain sea states. By mid-July 1956, the Secretary of Defense's Scientific Advisory Committee had recommended that a solid-propellant missile program be fully instigated but not using the unsuitable Jupiter payload and guidance system. By October 1956, a study group comprising key figures from Navy, industry and academic organizations considered various design parameters of the Polaris system and trade-offs between different sub-sections. The estimate that a 30,000-pound missile could deliver a suitable warhead over 1500 nautical miles was endorsed. With this optimistic assessment, the Navy now decided to scrap the Jupiter program altogether and sought out the Department of Defense to back a separate Navy missile. A huge surfaced submarine would carry four "Jupiter" missiles, which would be carried and launched horizontally. This was probably the never-built SSM-N-2 Triton program. However, a history of the Army's Jupiter program states that the Navy was involved in the Army program, but withdrew at an early stage. The developers of Polaris encountered many issues from the outset of the project, including the outdated technology of the gyroscopes they would be implementing. This 'Stable Platform' configuration did not account for the change in gravitational fields that the submarine would experience while it was in motion, nor did it account for the ever-altering position of the Earth. This problem raised many concerns, as this would make it nearly impossible for navigational readouts to remain accurate and reliable. A submarine equipped with ballistic missiles was of little to no use if operators had no way to direct them. The Polaris developers then turned to a guidance system that had been abandoned by the US Air Force, the XN6 Autonavigator. Developed by the Autonetics Division of North American Aviation for the US Air Force Navaho, the XN6 was a system designed for air-breathing cruise missiles, but by 1958 had proved useful for installment on submarines. By 1965 microchips similar to the Texas Instruments units made for the Minuteman II were being purchased by the Navy for the Polaris. The Minuteman guidance systems each required 2000 of these, so the Polaris guidance system may have used a similar number. To keep the price under control, the design was standardized and shared with Westinghouse Electric Company and RCA. In 1962, the price for each Minuteman chip was $50. The price dropped to $2 in 1968. Polaris A-3 This missile replaced the earlier A-1 and A-2 models in the US Navy, and also equipped the British Polaris force. The A-3 had a range extended to and a new weapon bay housing three Mk 2 re-entry vehicles (ReB or Re-Entry Body in US Navy and British usage); and the new W-58 warhead of 200 kt yield. This arrangement was originally described as a "cluster warhead" but was replaced with the term Multiple Re-Entry Vehicle (MRV). The three warheads, also known as "bomblets", were spread out in a "shotgun"-like pattern above a single target and were not independently targetable (such as a MIRV missile is). The three warheads were stated to be equivalent in destructive power to a single one-megaton warhead due to their spread-out pattern on the target. The first Polaris submarine outfitted with MRV A-3's was the in 1964. Later the Polaris A-3 missiles (but not the ReBs) were also given limited hardening to protect the missile electronics against nuclear electromagnetic pulse effects while in the boost phase. This was known as the A-3T ("Topsy") and was the final production model. == Polaris A-1 ==

 LC-25A before its maiden flight, September 24, 1958 The initial test model of the Polaris was referred to as the AX series and made its maiden flight from Cape Canaveral on September 24, 1958. The missile failed to perform its pitch and roll maneuver and instead just flew straight up, however the flight was considered a partial success (at that time, "partial success" was used for any missile test that returned usable data). The next flight on October 15 failed spectacularly when the second stage ignited on the pad and took off by itself. Range Safety blew up the errant rocket while the first stage sat on the pad and burned. The third and fourth tests (December 30 and January 9) had problems due to overheating in the boattail section. This necessitated adding extra shielding and insulation to wiring and other components. When the final AX flight was conducted a year after the program began, 17 Polaris missiles had been flown of which five met all of their test objectives. The first operational version, the Polaris A-1, had a range of and a single Mk 1 re-entry vehicle, carrying a single W-47-Y1 600 kt nuclear warhead, with an inertial guidance system which provided a circular error probable (CEP) of . The two-stage solid propellant missile had a length of , a body diameter of , and a launch weight of . was the first fleet ballistic missile submarine (SSBN in US naval terminology) and she and all other Polaris submarines carried 16 missiles. Forty more SSBNs were launched in 1960 to 1966. Work on its W47 nuclear warhead began in 1957 at the facility that is now called the Lawrence Livermore National Laboratory by a team headed by John Foster and Harold Brown. The Navy accepted delivery of the first 16 warheads in July 1960. On May 6, 1962, a Polaris A-2 missile with a live W47 warhead was tested in the "Frigate Bird" test of Operation Dominic by in the central Pacific Ocean, the only American test of a live strategic nuclear missile. The two stages were both steered by thrust vectoring. Inertial navigation guided the missile to about a 900 m (3,000-foot) CEP, insufficient for use against hardened targets. They were mostly useful for attacking dispersed military surface targets (airfields or radar sites), clearing a pathway for heavy bombers, although in the general public perception Polaris was a strategic second-strike retaliatory weapon. == After Polaris ==

To meet the need for greater accuracy over the longer ranges the Lockheed designers included a reentry vehicle concept, improved guidance, fire control, and navigation systems to achieve their goals. To obtain the major gains in performance of the Polaris A3 in comparison to early models, there were many improvements, including propellants and material used in the construction of the burn chambers. The later versions (the A-2, A-3, and B-3) were larger, weighed more, and had longer ranges than the A-1. The range increase was most important: The A-2 range was , the A-3 , and the B-3 . 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 US Navy began to replace Polaris with Poseidon in 1972. The B-3 missile evolved into the C-3 Poseidon missile, which abandoned the decoy concept in favor of using the C3's greater throw-weight for larger numbers (10–14) of new hardened high-re-entry-speed reentry vehicles that could overwhelm Soviet defenses by sheer weight of numbers, and its high speed after re-entry. This turned out to be a less than reliable system and soon after both systems were replaced by the Trident. A proposed Undersea Long-Range Missile System (ULMS) program outlined a long-term plan which proposed the development of a longer-range missile designated as 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 (Ohio-class) was proposed to replace the submarines currently being used with Poseidon. The ULMS II missile system was designed to be retrofitted to the existing SSBNs, while also being fitted to the proposed Ohio-class submarine. 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 6000 miles. Under the agreement, the United Kingdom paid an additional 5% of their total procurement cost of 2.5 billion dollars to the US government as a research and development contribution. In 2002, the United States Navy announced plans to extend the life of the submarines and the D5 missiles to the year 2040. This requires a D5 Life Extension Program (D5LEP), which is currently underway. The main aim is to replace obsolete components at minimal cost by using commercial off the shelf (COTS) hardware; all the while maintaining the demonstrated performance of the existing Trident II missiles. == STARS ==

STARS, the Strategic Target System program, is a BMDO program managed by the US Army Space and Strategic Defense Command (SSDC). It began in 1985 in response to concerns that the supply of surplus Minuteman I boosters used to launch targets and other experiments on intercontinental ballistic missile flight trajectories in support of the Strategic Defense Initiative would be depleted by 1988. SSDC tasked Sandia National Laboratories, a Department of Energy laboratory, to develop an alternative launch vehicle using surplus Polaris boosters. The Sandia National Laboratories developed two STARS booster configurations: STARS I and STARS II. STARS I consisted of refurbished Polaris first and second stages and a commercially procured Orbis I third stage. It can deploy single or multiple payloads, but the multiple payloads cannot be deployed in a manner that simulates the operation of a post-boost vehicle. To meet this specific need, Sandia developed an Operations and Deployment Experiments Simulator (ODES), which functions as a PBV. When ODES was added to STARS I, the configuration became known as STARS II. The development phase of the STARS program was completed in 1994, and BMDO provided about $192.1 million for this effort. The operational phase began in 1995. The first STARS I flight, a hardware check-out flight, was launched in February 1993, and the second flight, a STARS I reentry vehicle experiment, was launched in August 1993. The third flight, a STARS II development mission, was launched in July 1994, with all three flights considered to be successful by BMDO. The Secretary of Defense conducted a comprehensive review in 1993 of the nation's defense strategy, which drastically reduced the number of STARS launches required to support National Missile Defense (NMD)2 and BMDO funding. Due to the launch and budget reductions, the STARS office developed a draft long-range plan for the STARS program. The study examined three options: • Place the program in a dormant status, but retain the capability to reactivate it. • Terminate the program. • Continue the program. When the STARS program was started in 1985 it was perceived that there would be four launches per year. Because of the large number of anticipated launches and an unknown defect rate for surplus Polaris motors, the STARS office acquired 117 first-stage and 102 second-stage surplus motors. As of December 1994, seven first-stage and five second-stage refurbished motors were available for future launches. BMDO is currently evaluating STARS as a potential long-range system for launching targets for development tests of future Theater Missile Defense 3 systems. STARS I was first launched in 1993, and from 2004 onwards has served as the standard booster for trials of the Ground-Based Interceptor. == British Polaris ==

, London From the early days of the Polaris program, American senators and naval officers suggested that the United Kingdom might use Polaris. In 1957 Chief of Naval Operations Arleigh Burke and First Sea Lord Louis Mountbatten began corresponding on the project. After the cancellations of the Blue Streak and Skybolt missiles in the 1960s, under the 1962 Nassau Agreement that emerged from meetings between Harold Macmillan and John F. Kennedy, the United States would supply Britain with Polaris missiles, launch tubes, ReBs, and the fire-control systems. Britain would make its own warheads and initially proposed to build five ballistic missile submarines, later reduced to four by the incoming Labour government of Harold Wilson, with 16 missiles to be carried on each boat. The Nassau Agreement also featured very specific wording. The intention of wording the agreement in this manner was to make it intentionally opaque. The sale of the Polaris was malleable in how an individual country could interpret it due to the diction choices taken in the Nassau Agreement. For the United States of America, the wording allowed for the sale to fall under the scope of NATO's deterrence powers. On the other hand, for the British, the sale could be viewed as a solely British deterrent. All Royal Navy SSBNs have been based at Faslane, only a few miles from Holy Loch. Although one submarine of the four was always in a shipyard undergoing a refit, recent declassifications of archived files disclose that the Royal Navy deployed four boatloads of reentry vehicles and warheads, plus spare warheads for the Polaris A3T, retaining a limited ability to re-arm and put to sea the submarine that was in refit. When replaced by the Chevaline warhead, the sum total of deployed RVs and warheads was reduced to three boatloads. Chevaline The original US Navy Polaris had not been designed to penetrate anti-ballistic missile (ABM) defenses, but the Royal Navy had to ensure that its small Polaris force operating alone, and often with only one submarine on deterrent patrol, could penetrate the ABM screen around Moscow. Britain's submarines featured the Polaris A3TK missiles, a modification to the model of the Polaris used by the US from 1968 to 1972. Similar concerns were present in the US as well, resulting in a new American defense program. The program became known as Antelope, and its purpose was to alter the Polaris. Various aspects of the Polaris, such as increasing deployment efficiency and creating ways to improve the penetrative power were specific items considered in the tests conducted during the Antelope program. The British's uncertainty with their missiles led to the examination of the Antelope program. The assessments of Antelope occurred at Aldermaston. Evidence from the evaluation of Antelope led to the British decision to undertake their program following that of the United States. Despite the approval of the program, the expenses caused hurdles that augmented the time it took for the system to come to fruition. The cost of the project led to Britain's disbanding the program in 1977. The system became operational in mid-1982 on , and the last British SSBN submarine was equipped with it in mid-1987. Chevaline was withdrawn from service in 1996. Though Britain adopted the Antelope program methods, no input on the design came from the United States. Aldermaston was solely responsible for the Chevaline warheads. Replacement The British did not ask to extend the Polaris Sales Agreement to cover the Polaris successor Poseidon due to its cost. The Ministry of Defence upgraded its nuclear missiles to the longer-ranged Trident after much political wrangling within the Callaghan Labour Party government over its cost and whether it was necessary. The outgoing Prime Minister James Callaghan made his government's papers on Trident available to Margaret Thatcher's new incoming Conservative Party government, which took the decision to acquire the Trident C4 missile. A subsequent decision to upgrade the missile purchase to the even larger, longer-ranged Trident D5 missile was possibly taken to ensure that there was missile commonality between the US Navy and the Royal Navy, which was considerably important when the Royal Navy Trident submarines were also to use the Naval Submarine Base Kings Bay. Even though the US Navy initially deployed the Trident C4 missile in the original set of its Ohio-class submarines, it was always planned to upgrade all of these submarines to the larger and longer-ranged Trident D5 missile—and that eventually, all of the C4 missiles would be eliminated from the US Navy. This change-over has been completely carried out, and no Trident C4 missiles remain in service. The Polaris missile remained in Royal Navy service long after it had been completely retired and scrapped by the US Navy in 1980–1981. Consequently, many spare parts and repair facilities for the Polaris that were located in the US ceased to be available (such as at Lockheed, which had moved on first to the Poseidon and then to the Trident missile). == Italy ==

During its reconstruction program in 1957–1961, the was fitted with four Polaris missile launchers located in the aft part of the ship. The Italian usage of Polaris missiles was partially the result of the Kennedy administration. Prior to 1961, Italy and Turkey were equipped with Jupiter missiles. Three factors were instrumental in the movement away from the Jupiter project in Italy and Turkey: the president's view of the project, new understanding about weapons systems and the diminished necessity of the Jupiter missile. The Joint Congressional Committee report on Atomic Energy accentuated the three previous factors in Italy's decision to switch to the Polaris missiles. enabling European allies to participate in the management of the NATO nuclear deterrent. The MLF plan, as well as the Italian Polaris Program, were abandoned, both for political reasons (in consequence of the Cuban Missile Crisis) and the initial operational availability of the first SSBN , which was capable of launching SLBMs while submerged, a solution preferable to surface-launched missiles. Italy developed a new domestic version of the missile, the SLBM-designated Alfa. That program was cancelled in 1975 after Italy ratified the Nuclear Non-Proliferation Treaty, with the final launch of the third prototype in 1976. Two Italian Navy cruisers, commissioned in 1963–1964, were "fitted for but not with" two Polaris missile launchers per ship. All four launchers were built but never installed, and were stored at the La Spezia naval facility. The , launched in 1969, was also "fitted for but not with" four Polaris missile launchers. During refit periods in 1980–1983, these facilities were removed and used for other weapons and systems. == Operators ==

; • Royal Navy ; • United States Navy ; • Marina Militare (tests only, never fully operational) == References ==