DARPA is moving into Phase 2 of the No Manning Required Ship (NOMARS) program to develop a 210 ton robotic naval ship. In Phase 2, Serco will finalize ship design, build the ship, and work through a series of rigorous testing activities before taking it to sea for a three-month demonstration event.

The first robotic navy ship will be called Defiant. The 210-metric ton MUSV-class [medium unmanned surface vessel] ship aims to maximize performance, reliability, and maintenance efficiency while still carrying significant payload at tactically useful ranges. The goal is to achieve ultra-reliability objectives by integrating distributed hybrid power generation, podded propulsors, and high-capacity batteries.

A key philosophy of NOMARS is “graceful degradation,” which allows individual equipment to fail over time by having enough system-level redundancy to meet full system requirements at speeds of at least 15 knots after one year at sea. The major system components of the selected design are modularized, so repairs can be conducted with equipment typically found in yacht-yards worldwide. This maintenance philosophy supports rapid turnaround, allowing the ships to spend a majority of their lifetime at sea performing missions.

DARPA has also been working on an unmanned ship to kill submarines.

The Navy wants to develop and procure three types of large unmanned vehicles (UVs) called Large Unmanned Surface Vehicles (LUSVs), Medium Unmanned Surface Vehicles (MUSVs), and Extra-Large Unmanned Undersea Vehicles (XLUUVs). The Navy’s proposed FY2023 budget requests $549.3 million in research and development funding for these large UVs and LUSV/MUSV-enabling technologies, and $60.7 million in additional funding for core technologies for XLUUV and other Navy UUVs.

US Navy studies outline potential future fleets with 27 to 153 large USVs and 18 to 51 large UUVs.

US 500 Ship Navy Plan Proposes 150 Unmanned Ships
On July 26, 2022, the Navy released a document, Chief of Naval Operations [CNO] Navigation Plan 2022, that, similar to the above-discussed BFSAR, calls for a future fleet of 373 manned ships, as well as about 150 large unmanned surface and underwater vehicles, with the 373 manned ships to include 12 ballistic missile submarines, 66 attack submarines, 12 nuclear powered aircraft carriers, 96 large surface combatants, 56 small surface combatants, 31 larger amphibious ships, 18 smaller Light Amphibious Warships (LAWs), and 83 combat logistics, command, and support ships.

These are part of the US Navy’s 30 year ship building plans. In the next ten years, these funded prototypes are made and tested and if they are successful there would be significant purchases in the 2030s and 2040s.

Sizes of Robotic Ships

The Navy envisions LUSVs (large unmanned ships) as being 200 feet to 300 feet in length and having full load displacements of 1,000 tons to 2,000 tons, which would make them the size of a corvette. (i.e., a ship larger than a patrol craft and smaller than a frigate). The Navy wants LUSVs to be low-cost, high-endurance, reconfigurable ships with ample capacity for carrying various modular payloads—particularly anti-surface warfare (ASuW) and strike payloads, meaning principally anti-ship and land-attack missiles. Each LUSV could be equipped with a vertical launch system (VLS) with 16 to 32 missile-launching tubes. Although referred to as UVs, LUSVs might be more accurately described as optionally or lightly manned ships, because they might sometimes have a few onboard crew members, particularly in the nearer term as the Navy works out LUSV enabling technologies and operational concepts. Under the Navy’s FY2023 five-year (FY2023-FY2027) shipbuilding plan, procurement of LUSVs through the Navy’s shipbuilding account is programmed to begin in FY2025.

The Navy defines MUSVs as being 45 feet to 190 feet long, with displacements of roughly 500 tons, which would make them the size of a patrol craft. The Navy wants MUSVs, like LUSVs, to be low-cost, high-endurance, reconfigurable ships that can accommodate various payloads. Initial payloads for MUSVs are to be intelligence, surveillance and reconnaissance (ISR) payloads and electronic warfare (EW) systems. The Navy’s FY2023 five-year (FY2023-FY2027) shipbuilding plan does not include the procurement of any MUSVs during the period FY2023-FY2027.

XLUUVs are roughly the size of a subway car. The first five XLUUVs were funded in FY2019 and are being built by Boeing. The Navy wants to use XLUUVs to, among other things, covertly deploy the Hammerhead mine, a planned mine that would be tethered to the seabed and armed with an antisubmarine torpedo, broadly similar to the Navy’s Cold War-era CAPTOR (encapsulated torpedo) mine. Under the Navy’s FY2023 five-year (FY2023-FY2027) shipbuilding plan procurement of additional XLUUVs through the Other Procurement, Navy (OPN) account is scheduled to begin in FY2024.