The U.S. Nuclear Weapons Cost Study Project was completed in August 1998 and resulted in the book Atomic Audit: The Costs and Consequences of U.S. Nuclear Weapons Since 1940 edited by Stephen I. Schwartz. These project pages should be considered historical.
The Polaris A-3 SLBM (left) next to its larger successor, the Poseidon C-3 SLBM, March 1968
The Polaris A-3 was the latest and last version of the Polaris missile, the Navy’s first underwater ballistic missile initially deployed in 1960. The A-3 was deployed between 1964 and 1981. In 1965, the Navy started development of the next generation of SLBMs and beginning in 1971 the Poseidon C-3 was deployed aboard 31 converted Polaris submarines, with 16 missiles on each submarine. The Polaris A-3 carried three W58 warheads, each with a yield of 200 kilotons. The Poseidon C-3 carried an average of 10 W68 warheads, each with a yield of 40-50 kilotons (the missile was tested with 14 warheads but carrying this number would restrict its range).
Credit: Lockheed Missiles and Space Company (courtesy Center for Defense Information)