After completing its construction in early February, the U.S. DARPA agency reported that the new medium-sized unmanned experimental vessel USX-1 Defiant has been launched. This vessel is designed to operate without any crew on board, marking a significant step toward the development of larger unmanned platforms for the U.S. Navy. The latest advancement in the No Manning Required Ship (NOMARS) program was spotted in the waters of Washington State, at the shipyard operated by Serco.
Expanding on this, U.S. defense media outlets, citing local witnesses, reported that the 55-meter-long, 240-ton displacement vessel was towed through the Saratoga Passage in Puget Sound, located north of Seattle and near the U.S. Navy’s Whidbey Island Naval Air Station (NAS). Although the vessel’s current mooring location remains unknown, it is expected to undergo a rigorous two-month testing period at sea and in port during the Northern Hemisphere spring to assess its performance.
Due to the program’s significance, DARPA has maintained strict secrecy regarding specific details of the new vessel, stating in general terms:“The NOMARS program aims to challenge the traditional naval architecture model by designing a naval hull (the vessel without mission systems) from scratch without considering the presence of humans on board. By eliminating the human element from all ship design considerations, the program seeks to demonstrate significant advantages, including size, cost, offshore reliability, greater hydrodynamic efficiency, survivability in rough sea conditions, and resilience against adversarial actions through stealth and tamper resistance.”
Such is the secrecy surrounding the project that in officially released images, the vessel remains almost entirely covered by a tarp, revealing only its hull and a centrally located mast. Equipped with navigation radars and various types of antennas, the vessel’s design currently lacks further disclosed details. However, it remains within the standard size limits set by the U.S. Navy for medium-sized Unmanned Surface Vessels (USVs)—specifically, a length of less than 200 feet and a displacement of under 500 tons.
Based on illustrative images of DARPA’s conceptual model, there is potential for the vessel to include up to four Adaptable Deck Launching (ADL) Systems, capable of accommodating 16 Mk. 41 Vertical Launch System (VLS) cells. Additionally, it features a large deck space that could be used for additional weapons systems or even containerized supplies. Furthermore, DARPA’s disclosed design requirements indicate that the ship should achieve considerable autonomy at sea before requiring refueling, incorporating a distributed hybrid power generation system and high-capacity batteries.
Following this trend, it is worth noting that the U.S. Navy and Serco have successfully tested a new autonomous refueling system, with trials conducted in September. According to reports following the tests, the U.S. Navy used its Ranger and Mariner offshore support vessels—while classified as unmanned systems, these vessels still retain the ability to carry personnel. This issue is critical because, for DARPA, autonomous refueling remains one of the key challenges in developing fully unmanned systems of this kind.
In DARPA’s official statement from December, the agency highlighted:“Unmanned Surface Vessel (USV) refueling at sea (FAS) presents a problem that must be solved, as current FAS solutions rely on personnel to handle lines and hoses on the receiving platform (…) Requiring personnel on the USV for refueling operations imposes significant design and operational constraints, as the vessel must be built with human safety in mind—even if only for short periods. It can also be risky and, at times, dangerous to transfer personnel to a USV in rough seas or strong winds.”
Finally, it is important to emphasize that the USX-1 Defiant project, awarded to Serco in 2022 under a $68.5 million contract, also stands out for the wide range of facilities that could potentially manufacture and maintain it. As reported by The War Zone, the platform’s characteristics allow even companies that do not typically participate in U.S. Navy programs to contribute to its production. This could help ease the burden on the already strained U.S. shipbuilding network.
Cover image: DARPA
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