US Navy’s First Fully Autonomous Ship Christened

The Baltimore Sun reports that the USX-1 Defiant, is a fully autonomous vessel, “which can sail without a crew….”  Baltimore Sun (Aug. 17, 2025).  The ship is the product of five years of work and: “The premise of the project was to make a naval ship that operates like a Roomba.”  Id.

The ship must still pass one final test – “a long voyage out on the open seas, facing different sea conditions and navigating itself on its own.”  It will do so without any onboard crew members. Id.

A program manager said that, “[f]or the surface Navy, most of the people on the ship, most of the time, are there to keep the ship running….”  The autonomous technology reduced the ship’s cost because it did not have to be large enough to hold sailors and related facilities.  Id.

As an Army veteran, I can attest that no military story would be complete without acronyms.  “DARPA” is the “Defense Advanced Research Projects Agency.”  The acronym “NOMARS” refers to a “No Manning Required Ship.”

From the design’s outset, the 180-foot-long, 240-ton vessel was designed without considering human habitation or protection features. According to DARPA, the NOMARS program “intends to demonstrate significant advantages,” including at-sea reliability, hydrodynamic efficiency, and stealthy features.

A. Lariosa, Serco, DARPA Launch NOMARS USX-1 Defiant – Naval News (Apr. 3, 2025). “[T]he removal of berths, galleys, and other facilities provides a ‘much larger payload fraction’ on Defiant.” Id.

The “unmanned ship” is intended to revolutionize the Navy.  DARPA christens unmanned ship aimed at revolutionizing naval capability | DARPA (Apr. 11, 2025).  One goal is to accelerate shipbuilding.

“Defiant class vessels provide cost-effective, survivable, manufacturable, maintainable, long-range, autonomous, and distributed platforms, which will create future naval lethality, sensing, and logistics,” said DARPA Director Stephen Winchell. “Defiant will protect and expand the capabilities of manned ships, multiply combat power at low cost, and unlock new American maritime industrial capacity.”

Id.

Congress appropriated $2.1 billion for development, procurement, and integration of purpose-built medium unmanned surface vessels.”  The ship will be turned over to the Navy’s “Unmanned Maritime Systems Program Office….”  Id.

“It’s designed to survive 30-foot waves and operate autonomously at sea for up to a year, DARPA said.”  At-sea refueling has been tested.  DARPA christens USX-1 Defiant autonomous ship ahead of at-sea demonstrations | DefenseScoop

A brief YouTube video of the ship   is posted at Sneak Peek: USX-1 Defiant – No Manning Required Ship (NOMARS)