Hyliion USX-1 Defiant USV Chosen as Launch Platform for KARNO Core Sea Trials

Hyliion Holdings Corp., a developer of modular power plant technology, announced that the U.S. Navy’s Office of Naval Research (ONR), in partnership with the Defense Advanced Research Projects Agency (DARPA), has selected the USX-1 Defiant as a candidate test vessel for Hyliion’s KARNO technology. Initial sea trials are funded under a development program from the Office of Naval Research (ONR) to advance the use of KARNO Cores for onboard power generation in U.S. Navy vessels.

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 U.S. 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.

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 U.S. Navy deployment, the KARNO Cores will operate on F-76 marine diesel and to demonstrate its 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 U.S. Navy load profiles.