US Navy Enhances Undersea Strike Capabilities with New Propulsion System for Future MK 54 Torpedo.

On August 1, 2025, L3Harris Technologies announced that it had reached a critical milestone in the development of the next generation of lightweight torpedoes for the US Navy. The company completed testing of the first version of the energy module for the Stored Chemical Energy Propulsion System (SCEPS), which is intended to power the MK 54 MOD 2 Increment 2 torpedo. These tests aimed to validate the performance and reliability of the core propulsion component, a necessary step before beginning system-level design verification tests scheduled for later this year.
Follow Army Recognition on Google News at this link

The MK 54 torpedo, initially developed by Raytheon Integrated Defense Systems, is a lightweight and modular anti-submarine warfare weapon (Picture source: L3 Harris)

This technological milestone is part of a contract between L3Harris and the US Navy to deliver a proof of concept for SCEPS propulsion. The agreement covers not only the energy system but also the integrated assembly of the tail and afterbody of the torpedo. A key objective is to demonstrate that this new propulsion system can be integrated effectively into the MK 54 MOD 2 architecture while enhancing underwater performance, particularly in terms of endurance, speed, and resistance to countermeasures in littoral environments.

The MK 54 torpedo, initially developed by Raytheon Integrated Defense Systems, is a lightweight and modular anti-submarine warfare weapon. It is designed for deployment from surface vessels, P-8A Poseidon aircraft, and MH-60R helicopters. It replaces the MK 46 torpedo by incorporating technologies from the MK 46, MK 48, and MK 50 systems. It measures 2.71 meters in length, weighs 275.7 kilograms, and carries a 43.9-kilogram high-explosive warhead. Its guidance system includes a TG-6000 inertial measurement unit and an active/passive acoustic homing system that enables it to distinguish decoys and engage targets accurately, even in complex acoustic environments.

According to Scott Alexander, President of the Missile Solutions division at Aerojet Rocketdyne (a subsidiary of L3Harris), the energy module is “the heart of the propulsion system that will power the MK 54 MOD 2 torpedo.” He also noted the performance demonstrated during testing and stated the company’s intent to continue testing the full afterbody section in the coming months.

L3Harris' Center of Excellence for undersea propulsion manufacturing, located in Orlando, Florida, is currently the only industrial site in the United States capable of producing SCEPS components. In addition to US Navy contracts, the company is also independently funding prototype development and testing, underscoring its strategic commitment to advancing this propulsion technology.

The SCEPS system uses a lithium boiler to generate heat, producing steam that drives a turbine to propel the torpedo. This propulsion method, based on thermal efficiency and extended endurance, is intended to increase the effectiveness of US torpedoes in intercepting increasingly sophisticated underwater threats. It will eventually replace the existing external combustion engine powered by Otto II fuel used in earlier versions.

The successful tests of this first energy module represent a key step toward operational integration of the SCEPS technology in future lightweight torpedoes. They also reinforce L3Harris’ role in the development of propulsion systems for undersea warfare at a time when technological advantage in the maritime domain is once again a strategic priority for the US Navy.