Introduction

The Missile

The Poseidon C-3, a U.S. submarine-launched ballistic missile (SLBM), was a significant evolution from its predecessor, the Polaris program. This two-stage, solid-propellant missile was notably larger in length and diameter than the 32-foot Polaris A3 missile. It was also considerably heavier by 30,000 pounds.

Technologically, the Poseidon C3 represented a substantial leap forward. It doubled the payload capacity and added the capability of deploying multiple warheads, each targetable independently over a range of targets within a single missile’s “footprint.”

This feature, known as Multiple Independent Reentry Vehicles (MIRVs), significantly broadened the missile’s strategic utility, allowing for more warheads and the capacity to saturate Soviet ABM systems

As a result, each Poseidon C3 weighing 64,000 pounds, could carry up to ten Mark 3 reentry bodies with W-68 50 kt warheads to an operational range of 2,500 nautical miles or up to 14 to a shorter distance.

Subsequently, the more advanced Trident I C4 missile replaced the Poseidon C3 in the 1980s. We recommend you to read more about this missile in our Poseidon C3 Missile article!

C3 Launchs

During its service from 1971 to 1990, the U.S. Navy conducted more than 270 launches to test and verify the missile readiness.

Between 1968 and 1970, there were 20 “Flat pad” launches from Cape Canaveral.

The first successful launch from a submerged submarine was conducted on August 3, 1970, from the USS James Madison (SSBN 627). This was the first of the five performance evaluation missiles (PEMs) that were launched from SSBNs before the first deployment

Officially, the Poseidon C3 entered operational service on March 31, 1971, with the USS James Madison embarking on its initial patrol armed with sixteen Poseidon C3 missiles. The Poseidon missile was initially deployed across thirty-one of the U.S. Navy’s forty-one FBM submarines.

Following deployment, the missile saw extensive testing and demonstration, with 61 Demonstration and Shakedown Operations (DASOs) from 1970 to 1990 and 62 Operational Tests (OT) / Follow-on Operational Tests (FOT) operations between 1972 and 1990.

The last launch of a C-3 missile from a submerged submarine occurred on April 30, 1990, from the USS Kamehameha (SSBN-642), marking the end of the era of Poseidon.

The launch list

Each Poseidon missile launch could be classified as one of the following types:

• C3X – Development missiles. These were test missiles flown from a flat pad at Cape Canaveral into impact areas of the Eastern Test Range.
• PEM – Production Evaluation Missile. PEM missiles were produced employing the manufacturing processes, tooling methods, test checkout, and assembly procedures intended to be used in the production program.
• DASO – Demonstration and Shakedown Operation. These were launches conducted to demonstrate the readiness of the Poseidon Weapon System and its crew for deployment.
• OT – Operational Test. These tests provided initial data on the reliability and accuracy of the missile.
• FOT – Follow-on Operational Test. Annual launches designed to ensure that the reliability and accuracy factors were preserved during the life of the system and carried out under tactical conditions to exercise all elements of the weapon system.

The table below details the Poseidon C3 launches from 1968 to 1990:

Further reading

• United States Submarine-Launched Ballistic Missiles (SLBM)
• Poseidon C-3 (UGM-73)

Bibliography

• Facts/Chronology: Polaris, Poseidon, Trident, 50th Anniversary, Strategic Systems Programs, 2005
• Hearings on Military Posture and H.R. 1872 (H.R. 4040), Department of Defense Authorization for Appropriations for Fiscal Year 1980, and H.R. 2575 (S. 429), Department of Defense Supplemental Authorization for Appropriations for Fiscal Year 1979 Before the Committee on Armed Services, House of Representatives, Ninety-sixth Congress, First Session: Seapower and Strategic and Critical Materials Subcommittee. (1979). United States: U.S. Government Printing Office.
• H.R. 9861. (1975). United States: U.S. Government Printing Office.