Next-Generation MK 54 MOD 2 Torpedo Takes Shape with Validated Power Plant

Defense Feeds – Next-generation MK 54 MOD 2 propulsion technology reached a critical milestone

On August 1, 2025, when L3Harris Technologies successfully completed testing of its new power plant system designed for theStored Chemical Energy Propulsion System (SCEPS), the core propulsion innovation powering the U.S. Navy’s advanced lightweight torpedo.

This achievement is a significant step in validating the system’s performance and reliability ahead of planned full system design verification later this year.

The SCEPS power plant, central to the next-generation MK 54 MOD 2, converts heat from a lithium boiler into steam that drives a turbine, providing efficient underwater propulsion.

This cutting-edge system replaces the previous Otto II fuel external combustion engine, promising improved speed, extended endurance, and enhanced resistance to countermeasures—key advantages for the modern anti-submarine warfare environment, especially in complex littoral waters.

Scott Alexander, President of Missile Solutions at Aerojet Rocketdyne, a subsidiary of L3Harris, underscored the importance of this power plant for the next-generation MK 54 MOD 2 torpedo, stating, “This system is at the core of what will power the MK 54 MOD 2 torpedo.

The strong performance in these tests positions us well for upcoming integrated system evaluations.” He emphasized L3Harris’ ongoing commitment to advancing propulsion technology with a focus on the torpedo’s tail and afterbody assembly integration.

Enhancing the MK 54: A Proven Foundation with Next-Generation Propulsion

The MK 54 torpedo is a modular, lightweight, and versatile anti-submarine weapon used extensively by surface ships, P-8A Poseidons, and MH-60R helicopters.

Originating from Raytheon’s defense portfolio, the MK 54 merges design elements from previous torpedoes like the MK 46 and MK 50, providing a balanced mix of range, speed, guidance accuracy, and payload power with its 43.9kg high-explosive warhead.

The new MOD 2 Increment 2 variant equipped with SCEPS aims to push these capabilities even further.

Through its innovative lithium boiler and steam turbine propulsion, the torpedo is expected to operate longer and move faster with improved precision tracking of underwater threats.

This advancement will help the U.S. Navy maintain undersea dominance, particularly in crowded coastal and shallow waters where detection is challenging and adversaries deploy various decoys or noise countermeasures.

L3Harris’ manufacturing hub in Orlando, Florida, is the only site within the U.S. industrial base that produces SCEPS components, underscoring the strategic importance of domestic capability development.

The company is investing independently in prototype testing and fabrication alongside fulfilling Navy contracts to speed technology maturation and operational readiness.

Strategic Implications for U.S. Naval Warfare Capabilities

L3Harris’ breakthrough demonstrates not only technological progress but also reinforces the U.S. Navy’s broader goal to maintain a technological edge in undersea warfare.

Lightweight torpedoes such as the MK 54 are fundamental to countering increasingly sophisticated submarine threats posed by peer and near-peer adversaries in contested maritime zones.

The enhanced propulsion system, leveraging chemical energy storage and thermal efficiency, will extend operational reach and flexibility—enabling faster intercept times and longer missions without compromising stealth or reliability.

This capability will be vital for U.S. surface fleets and naval aviation platforms tasked with protecting carrier strike groups, amphibious forces, and maritime trade routes.

Looking ahead, L3Harris plans to complete design verification testing of the fully integrated propulsion system later in 2025, moving closer to deployment readiness.

As the sole U.S. manufacturer of this advanced propulsion technology, L3Harris plays a critical role in sustaining the nation’s undersea combat power while supporting the Navy’s focus on innovation, resilience, and speed in defense modernization efforts.