A review of the Trident Submarine and Missile program's cost, schedule and technical performance was conducted. A particular concern was to determine whether the submarine and missile will be operational in September 1979, as planned. Navy and contractor officials were interviewed, and records provided by the officials were reviewed. The Trident submarine will be the successor to the Polaris/Poseidon ballistic missile fleet. At the time of GAO's review, the Navy was reporting an estimated cost of $18.8 billion for an 11-ship program. As of December 31, 1976, the Navy reported a 13-ship program at a cost of $21.4 billion. The planning documents called for 16 Trident submarines. Costs estimated to be about $12 billion are not included in the total program costs. This includes the costs for five ships beyond the 11 included in the Selected Acquisition Report, backfit of the Poseidon submarines, propulsion plant and warhead, construction, and other items which, if included, could bring the total program costs to over $30 billion. The Trident deployment date has been postponed 5 months because of delays in submarine construction. The missile developmental flight test program is on a very tight schedule with little margin to absorb any additional delays. Should any new problems or further delays develop, it could affect the entire test program.