For the USX-1 Defiant sea trials, Hyliion will deliver a drop-in 800 KW power system consisting of four 200 KW KARNO Cores in a keel-cooled configuration. The modular architecture is designed to demonstrate reliable, low-maintenance power generation for an unmanned vessel, where onboard servicing is not available. Trials are aimed at highlighting KARNO technology’s inherent scalability and redundancy, with power units that can be distributed across the ship to support mission reliability.
The USX-1 Defiant was developed under DARPA’s No Manning Required Ship (NOMARS) program, which challenged the traditional naval architecture model by designing a seaframe (the ship without mission systems) from the ground up with no provision, allowance, or expectation for humans on board. The program is part of a broader effort to modernize the US Navy and optimize surface platforms for autonomous operation, enabling simpler hull designs, improved reliability and survivability, and increased flexibility in payload and power system integration. Measuring about 180 feet in length with a displacement of about 240 metric tons, USX-1 Defiant is designed for long-duration autonomous operation in the open ocean, independently or alongside other naval assets. The vessel is designed and developed by Serco-North America as a full-scale technology demonstrator and is currently undergoing sea trials.
“USX-1 Defiant represents a fundamental shift in how naval platforms are designed, powered, and operated,” said Thomas Healy, Founder and Chief Executive Officer of Hyliion. “As the Navy moves toward unmanned surface vessels, power systems must be efficient, resilient, and capable of operating without human intervention. Our KARNO technology excels in these parameters, and we view USX-1 Defiant as the first of hopefully many naval platforms to be powered by this technology.”
Hyliion’s KARNO Core is a heat-powered linear generator designed for high modularity, efficiency, and low maintenance operation, making it well suited for unmanned maritime platforms. For the US Navy deployment, the KARNO Cores will operate on F-76 marine diesel and will demonstrate their ability to supply onboard power for extended durations with a low thermal and acoustic footprint. The KARNO Core generates direct current (DC) power output at 800Vdc, enabling direct integration into modern ship electrical architectures. The KARNO technology is currently undergoing land-based testing and development using simulated US Navy load profiles.
