End of an Era: SSP Disposes of Last Trident I C4 First Stage Motor

16 September 2025

From Shelby Thompson

Magna, Utah - Strategic Systems Programs (SSP) disposed of the last first stage Trident I C4 missile rocket motor on June 25, 2025, one of the most significant strategic weapons systems (SWS) in U.S. Navy history.

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The Trident I C4 missile was a three-stage, solid fuel, inertially guided, submarine-launched missile. It was named after the weapon wielded by Neptune, the Roman god of the sea. Using advanced technology in propellants, electronics, and other materials, the Trident I missile had a much greater range than all previous missiles, carrying its payload to a range of 4,000 nautical miles. Like the Poseidon missiles it replaced, each Trident I was equipped with multiple independent reentry vehicle (MIRV) capability.

The missile’s increase in range and payload, without sacrificing size, was achieved through eye-watering advances in propulsion, microelectronics, and new weight-saving materials. Following these rapid advancements in rocket science and aeronautical engineering, the first Trident I C4 SWS, cast on Dec. 15, 1977 was eventually loaded onto the Benjamin Franklin-class USS Francis Scott Key (SSBN 657) to deploy on tactical patrol on Oct. 20, 1979.

During the 1970s, to offset increased threats to U.S. sea-based strategic forces by the increasing strides in Soviet anti-submarine warfare capability, the Ohio- class submarine program was developed to deploy a vastly improved submarine with a new, long-range missile, and to expand the submarine operating area.

The reliability of the C4 system was proven on the Benjamin-Franklin-class ballistic missile submarines (SSBN), and the C4 SWS ultimately became the initial load out for the Ohio-class boats. In 1982, the first Ohio-class SSBN, purpose-built to carry the Trident I C4, deployed from Bangor, Washington. The development of the C4 allowed for a quieter, more capable submarine platform that was more difficult to detect than any of its predecessors.

The C4 motor disposed of on June 25 was cast 41 years ago in 1984, marking almost two generations of SSP stewardship.

“This really is the end of an era,” said Lt. Cmdr. Justin Laddusaw, Officer-in-Charge for Program Management Office Flight Systems Detachment (SPF(B)), about the Trident I C4 disposal.

The Trident I C4 SWS began phasing out of the submarine fleet in 1990 and was replaced by the Trident II D5 SWS.

As the Navy command that provides cradle-to-grave lifecycle support for the sea-based leg of the nation’s nuclear triad, SSP has a unique responsibility for the Navy’s SWS. The command owns every aspect of the weapons system from design and development, to production and maintenance, and finally, disposal. This responsibility never lapses, making it critical for SSP to maintain its technical expertise with weapon systems of the past, as well as the current SWS deployed today in the SSBN fleet.

One of the reasons for SSP’s unique stewardship role is that all SWS motors must be stored and transported in a very specific manner throughout their lifecycle.

“All motors are considered tactical assets until they are in route [to disposal],” said Spitzer.

This means that, from the moment the motor is offloaded from the SSBN, through its storage, data collection, and transportation, SSP is fully responsible for the safety and condition of the asset.

The disposal process for the submarine-launched ballistic missile (SLBM) motors was developed over the preceding generations of SLBMs, and continually improved through ongoing learning, analysis, and application throughout the C4 Program. The modern process is the most cost effective and environmentally sound method of disposal available to the Navy and will support future systems.

Following their offload from a ballistic missile submarine (SSBN), the C4 rocket motors are stored in a secure, environmentally controlled facility, where they are routinely evaluated. Eligible motors are then selected for disposal. Throughout this stage of the process, data collection and analysis is a priority for SSP.

“The best data we can get is from the oldest motors,” said Walter Spitzer, the Trident boost rocket motor lifecycle manager at SSP.

Eligible motors are then selected for disposal. To do this, SPF(B) and industry partners disassemble the motor; remove portions of the propellant; and examine the motor for any degradation over an extended period to collect data on the aging process. In the final step, the 75th Air Base Wing at Hill Air Force Base executes oversight the U.S. Navy’s submarine-launched ballistic missile rocket motor disposal initiative. Partnership and strong communication at every step of the disposal process is a hallmark of the team that accomplishes this final step in the SLBM life-cycle.

Today, SSP continues to be responsible for sustaining the SWS on the Ohio-class SSBNs and is supporting the integration of the Trident II D5 Life Extension (D5LE) weapon system on the new Columbia-class SSBNs. Looking to the future, SSP is integral to nuclear triad modernization with development of the D5LE2 SWS and creating the regional strike capabilities with the development of the nuclear sea launched cruise missile and the non-nuclear hypersonic conventional prompt strike system.

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End of an Era: SSP Disposes of Last Trident I C4 First Stage Motor

From Shelby Thompson