25 October 1966
USS GEORGE C. MARSHALL (SSBN 654) departed Charleston, S.C., for operational patrol with 16 POLARIS A-3 missiles.

8 February 1973
POSEIDON conversion of USS GEORGE C. MARSHALL (SSBN 654) was completed at Puget Sound Naval Shipyard. This was the 17th SSBN to be provided with C-3 capability.

2 September 1973
USS GEORGE C. MARSHALL (SSBN 654), the 17th POSEIDON-carrying SSBN, departed for operational patrol carrying 16 POSEIDON tactical missiles. During predeployment exercises, MARSHALL launched a C-3 missile during Demonstaration and Shakedown Operations.

30 March 1977
USS GEORGE C. MARSHALL (SSBN 654) successfully launched two POSEIDON (C-3) missiles in a Follow-0n Operational Test.

2 February 1980
USS GEORGE C. MARSHALL (SSBN 654) successfully launched three POSEIDON (C-3) missiles in a Follow-0n Operational Test.

4 February 1980
USS GEORGE C. MARSHALL (SSBN 654) successfully launched one POSEIDON (C-3) missile in a Follow-0n Operational Test.

11 July 1981
USS GEORGE C. MARSHALL (SSBN 654) successfully launched four POSEIDON (C-3) missiles in a Follow-0n Operational Test.

7 April 1984
USS GEORGE C. MARSHALL (SSBN 654) completed a POSEIDON (C-3) re-fueling overhaul at Newport News Shipbuilding and Dry-dock Company, Newport News, VA. The overhaul was completed in 28.9 months.

24 July 1984
The Gold Crew of the USS GEORGE C. MARSHALL (SSBN 654) successfully launched a POSEIDON (C-3) missile in support of its Demonstration and Shakedown Operations.

16 October 1987
The 60th POSEIDON Follow-on Operational Test was conducted with the successful launch of four POSEIDON (C-3) missiles by the Gold Crew of USS GEORGE C. MARSHALL (SSBN 654) .