DARPA's autonomous Unmanned Surface Vessel (USV), the USX-1 Defiant, took a major step toward operational status as a bottle of spirits was broken over its bow at the Everett Ship Repair in Everett, Washington on August 11, 2025.
Since 2020, DARPA has been pushing its No Manning Required Ship (NOMARS) program to create a new class of medium-size warship that can operate autonomously at sea for up to a year without human supervision or intervention.
It's not an easy task. Science fiction notwithstanding, producing such a vessel requires a blank sheet approach with everything being designed from the keel up, leaving out all of the gubbins required for a crew. That means no gangways, no crew spaces, no ventilation, no stores, no controls, and no bridge.
The result is a ship that looks surprisingly small and dagger-like, with just enough beam to accommodate engines, sensor platforms, and weapons. In the case of Defiant, you get a craft 180 ft (55 m) long and displacing 240 tonnes that can do 20 knots (23 mph, 37 km), reducing to 15 knots (17 mph, 27 km/h) after a year at sea.
Along with the lightness and sleekness, the systems aboard Defiant are more like those of a deep-space probe, with an emphasis on reliability and redundancy that allows it to operate at sea for up to a year without human intervention. It can even refuel itself autonomously. Where a conventional ship would have technicians aboard for repairs and routine maintenance, Defiant can tolerate wear and tear on its system and can switch to backups as needed.
Another aspect of the design is that it's highly simplified, so it can be manufactured quickly and refitted in any port that can handle yacht, tug, and workboat customers. This means that in the near future, autonomous ships can be deployed in large numbers to act as force multipliers for the US Navy, take over boring routine duties like sub hunting or harbor patrols, and carry out missions in hostile waters without risking human lives.
After completing sea trials, Defiant will be transferred to the Navy's Unmanned Maritime Systems Program Office (PMS 406).
"Defiant is a tough little ship and defies the idea that we cannot make a ship that can operate in the challenging environment of the open ocean without people to operate her," said NOMARS Program Manager Greg Avicola. "While relatively small, Defiant is designed for extended voyages in the open ocean, can handle operations in sea state 5 with no degradation and survive much higher seas, continuing operations once the storm passes. She’s no wider than she must be to fit the largest piece of hardware and we have no human passageways to worry about."
Source: DARPA
