The Missiles

I. Polaris A1 II. Polaris A2 III. Polaris A3 IV. Poseidon C3
V. Trident I C4 VI. Trident II D5 VII. Missile Comparison Chart

POLARIS A1 Missile

POLARIS, named for the North Star, is a two-stage ballistic missile, powered by solid fuel rocket motors and guided by a self-contained inertial guidance system independent of external commands or control.

The first successful underwater launch of a POLARIS A1 test vehicle from a submarine was conducted by the first POLARIS submarine, USS GEORGE WASHINGTON (SSBN 598), on 20 July 1960, while cruising submerged off the coast of Cape Canaveral, FL. Less than 3 hours later, she successfully launched a second POLARIS A1 missile, bringing to fruition a remarkable Navy-industry research and development effort, which began only 4 years earlier. SSBN 598 went on operational patrol carrying 16 1200 nautical (1380 statute) mile range POLARIS A1 missiles on 15 November 1960.

POLARIS A1 was officially retired from active duty when USS ABRAHAM LINCOLN (SSBN 602), the last of the first five SSBNs to carry it, returned to the U.S. on 14 October 1965 for her initial overhaul and conversion to A3.

POLARIS A2 Missile

The first launch of a POLARIS A2 test vehicle from a submerged submarine took place on 23 October 1961. The missile was successfully launched from the USS ETHAN ALLEN (SSBN 608) off the coast of Cape Canaveral, FL. SSBN 608 departed Charleston, SC, on operational patrol with 16 1500 nautical (1730 statute) mile range POLARIS A2 missiles on 26 June 1962. A2 was officially retired from the fleet in September 1974 when USS JOHN MARSHALL (SSBN 611) returned to the U.S. for her second overhaul and conversion to A3.

POLARIS A3 Missile

The first launch of a POLARIS A3 missile from a submerged submarine took place on 26 October 1963. The missile was launched from USS ANDREW JACKSON (SSBN 619) while cruising submerged about 20 miles off the coast of Cape Canaveral, FL. The completely successful test was followed by a successful launch of an A2 missile from the same submarine on 16 November 1963, witnessed by President Kennedy from USS OBSERVATION ISLAND.

POLARIS A3 represented a significantly greater technological advancement over A2, than that of A2 over A1. In terms of hardware design, POLARIS A3 was approximately an 85 percent new missile. The POLARIS A3 missile became operational on 28 September 1964 when USS DANIEL WEBSTER (SSBN 626) began her initial operational patrol with 16 2500 nautical (2880 statute) mile range A3s aboard.

The increase in range provided by A3 left no land target inaccessible and at the same time gave the submarines an enormous increase in sea room.

The U.S. POLARIS A3 program commenced retirement / termination of strategic mission on 1 November 1979 with the offload of the USS ABRAHAM LINCOLN (SSBN 602). All 10 POLARIS SSBNs have terminated their strategic mission. The last U.S. POLARIS SSBN offloaded in February 1982. All POLARIS A3 missiles have been retired from service in both the U.S. and U.K. navies.


The Navy's Strategic Systems Program Office directed production of the POSEIDON C3 missile, an improved version of the POLARIS, to maximize the effectiveness of the Navy's FBM weapon system as a deterrent to the outbreak of nuclear war.

POSEIDON, which had its roots in POLARIS technology, was a two-stage, solid propellant missile capable of being launched from a submerged FBM submarine. It was only 2 feet longer than the 32-foot POLARIS A3 missile, but had a much larger diameter, 74 versus 54 inches, and was 30,000 pounds heavier. Despite this increase in size, the growth potential of the FBM submarines allowed POSEIDON missiles to fit into the same 16 missile launch tubes that carried POLARIS.

POSEIDON was also a 2500 nautical (2880 statute) mile range missile; however, it was outfitted with multiple warheads, each of which could be targeted separately. This capability, known as MIRV, enabled POSEIDON to cover an increasing number of targets.

The POSEIDON missile was deployed on 31 of the Navy's 41 FBM submarines. (The first 10 FBM submarines to be built, including the 5 GEORGE WASHINGTON Class and the 5 ETHAN ALLEN Class, were not retrofitted to POSEIDON.) Of the 31 POSEIDON FBM submarines, 12 were backfitted to carry the TRIDENT I (C4) missile.

The first launch of a POSEIDON missile from a submerged submarine was successfully conducted on 3 August 1970. The missile was launched from USS JAMES MADISON (SSBN 627) as she cruised submerged off the coast of Florida near Cape Canaveral.

The principal contribution of POSEIDON to weapon system effectiveness was its flexibility, which provided a capacity for delivery of multiple warheads, widely spaced, on separate targets over a variety of target footprints. The C3 missile had a substantially larger target diameter and much greater payload capacity than the POLARIS missile.

The POSEIDON C3 became operational on 31 March 1971, when USS JAMES MADISON (SSBN 627) began her initial operational patrol carrying 16 tactical POSEIDON C3 missiles.

With MADISON's deployment, the POSEIDON missile was introduced into the nation's arsenal of operational deterrent weapons and brought to successful fruition the development program that was announced in January 1965 as a successor weapon system to POLARIS. All U.S. POSEIDON SSBNs have terminated their strategic mission. The last POSEIDON SSBN offloaded 16 September 1992.

TRIDENT I C4 Missile

TRIDENT, the popular name given to the next sea-based strategic weapon system, stems from Roman mythology.

Using advanced technology in propellants, electronics, and other materials, the TRIDENT I (C4) missiles have a much greater range than POSEIDON, carrying a full payload to a range of 4000 nautical (4600 statute) miles and a reduced payload to even greater ranges.

Like POSEIDON, each TRIDENT missile is equipped with MIRV, which gives it a multiple target strike capability.

To offset increasing strides in Soviet antisubmarine warfare capability, which could present a threat to the sea-based strategic forces, the TRIDENT program was established to develop and deploy a vastly improved missile-carrying nuclear submarine with a new long-range missile to expand the submarine operating area. This would provide the U.S. with a credible deterrent to nuclear war in the 1980s and beyond. The Director, Strategic Systems Programs, was delegated authority for managing the strategic weapon system (missile and guidance, launcher, navigation, fire control, test instrumentation) and its interfaces with the submarine system.

The TRIDENT I (C4) missile is a three-stage, solid propellant, inertially guided, submarine launched missile. It has a range and payload greater than the POSEIDON missile, thus providing a several-fold increase in the operational area of the U.S. submarine fleet. The C4 is deployed in the new TRIDENT submarine. In addition, one of the C4 design requirements was the capability to be backfitted into the then existing POSEIDON submarines.

The increase in range and payload, without a commensurate increase in physical dimension over the C3 missile, was achieved through several technological advances in the following key areas: propulsion, microelectronics, and new weightsaving materials. Missile range is controlled by trajectory-shaping with generalized energy management steering (GEMS).

In addition, TRIDENT I uses an extendible aerospike to increase its aerodynamic performance. The spike attaches to the front end of the missile and telescopes into position after launch.

The C4 missile development flight test program commenced on 18 January 1977 when C4X-1 was launched from a flat pad at Cape Canaveral, FL.

The first tactical patrol of a backfitted POSEIDON submarine was in October 1979, and the first TRIDENT submarine deployed in September 1982 from Bangor, WA. The TRIDENT/OHIO Class SSBNs are quieter, more capable, and more difficult to detect than their predecessors, the POSEIDON Class SSBNs.


In October 1980, at the direction of the Secretary of Defense, the Navy embarked on a 3- year advanced development program directed toward achieving significantly enhanced performance characteristics in a new submarinelaunched ballistic missile (SLBM) designed to utilize the full volume available in the TRIDENT SSBN's launch tube. Primary among the specific performance objectives were improved accuracy and increased payload.

In February 1981, the Secretary of Defense reconfirmed the mission and need for qualitative improvements to our SLBM systems and directed the Navy to proceed with Phase I (Demonstration and Validation) of the SLBM Modernization Program. The Secretary of Defense further directed that the Navy prepare for a Defense System Acquisition Review Council (DSARC) II review before the end of fiscal year (FY) 1983 to select an SLBM modernization option having an initial operational capability (IOC) not later than 1989.

In October 1981, the Deputy Secretary of Defense directed the Navy to fund the development of the D5 missile to support a late 1989 IOC.

IOC was delayed 3 months by initial Performance Evaluation Missile flight failures. The TRIDENT II (D5) missile was deployed in 1990 and will be the U.S.'s strategic seaborne deterrent well into the next century.

The TRIDENT II (D5) is a three-stage, solid propellant, inertially guided missile. TRIDENT II (D5) is launched underwater from the OHIO Class of nuclear-propelled TRIDENT submarines, each of which has 24 launch tubes.

The TRIDENT II and its predecessor TRIDENT I have ranges of more than 4000 nautical miles (4600 statute miles). TRIDENT II is more sophisticated, with a significantly greater payload capability.

Missile Comparison Chart

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