UGM-27 Polaris

In the mid-1950s the Navy was involved in the 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 rockets on board ships, and some consideration was given to a 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.^[1]


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 SSBNs in the U.S. Navy by the MIRV-capable Poseidon missile beginning in 1972. During the 1980s, these missiles were replaced on 12 of these submarines by the Trident I missile. The 10 George Washington- and Ethan Allen-class SSBNs retained Polaris A-3 until 1980 because their missile tubes were not large enough to accommodate Poseidon. With USS Ohio beginning sea trials in 1980, these submarines were disarmed and redesignated as attack submarines 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.

After Polaris[edit]

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 1,500 nautical miles (2,800 kilometres), the A-3 2,500 nautical miles (4,600 kilometres), and the B-3 2,000 nautical miles (3,700 kilometres). 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 U.S. 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 U.S. government as a research and development contribution.^[24] 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.^[25]