1
Consistent with this recommendation, the 5
th
through 8
th
Tridents were converted to carry the
same D5 missiles carried by the 9
th
through 18
th
Tridents. These Trident D5 conversions are not
(continued...)
Order Code RS21007
Updated May 22, 2008
Navy Trident Submarine Conversion (SSGN)
Program: Background and Issues for
Congress
Ronald O’Rourke
Specialist in Naval Affairs
Foreign Affairs, Defense, and Trade Division
Summary
The FY2006 budget completed the funding required in the Shipbuilding and
Conversion, Navy (SCN) account for the Navy’s program to refuel and convert four
Trident ballistic missile submarines (SSBNs) into cruise-missile-carrying and special
operations forces (SOF) support submarines (SSGNs). Initial Operational Capability
(IOC) for the program was declared on November 1, 2007. The total estimated cost of
the program is about $4.0 billion. This report will be updated as events warrant.
Background
Trident Submarines. The Navy procured 18 Ohio (SSBN-726) class nuclear-
powered ballistic missile submarines (SSBNs) between FY1974 and FY1991 to serve as
part of the U.S. strategic nuclear deterrent force. They are commonly called Trident
submarines because they carry Trident submarine-launched ballistic missiles (SLBMs).
The first Trident entered service in 1981, the 18
th
in 1997. The first 8 (SSBNs 726
through 733) were originally armed with Trident I (C4) SLBMs; the final 10 (SSBNs 734
through 743) were armed with larger and more powerful Trident II (D5) SLBMs. The
boats were originally designed for a 30-year life but were later certified for a 42-year life,
composed of 20 years of operation, a two-year mid-life nuclear refueling overhaul, and
then another 20 years of operation.
Origin of SSGN Conversion Concept. The Clinton Administration’s 1994
Nuclear Posture Review (NPR) recommended a strategic nuclear force for the START II
strategic nuclear arms reduction treaty that included 14 Tridents (all armed with D5
missiles) rather than 18.
1
This recommendation prompted interest in Congress and
