Navy Large Unmanned Surface Vessels (USVs): Background and Issues for Congress

Among the Navy’s programs for acquiring unmanned surface vessels (USVs) of various sizes are programs for acquiring large USVs that would be about the size of a large patrol craft, and which would deploy directly from pier rather than from the deck of a crewed Navy warship. Navy plans call for equipping large USVs with weapons and/or sensors or other electronic payloads and operating them in conjunction with crewed Navy ships. In such operations, large USVs would serve as adjunct weapon magazines and/or sensor platforms and thereby help the Navy implement the service’s Distributed Maritime Operations (DMO) concept, which calls for spreading the Navy’s weapons and sensors across a wider array of ships and aircraft, so as to avoid “putting too many eggs into one basket.” Until 2025, the Navy planned to develop and procure two types of large USVs—Large Unmanned Surface Vessels (LUSVs) and Medium Unmanned Surface Vessels (MUSVs). The LUSV and MUSV programs were a focus of congressional oversight and legislation for several years, particularly regarding the Navy’s acquisition strategies for the two programs and technical risk in the programs. Congressional oversight issues included but were not limited to the reliability of USV propulsion machinery for making transoceanic voyages to distant deployment areas, and the maturity of technology for enabling USVs to operate autonomously. In 2025, the Navy merged the LUSV and MUSV programs into a new program called the Modular Attack Surface Craft (MASC) program. MASCs are to be equipped with containerized weapons and/or sensors or other electronic payloads. Multiple defense contractors—both Navy shipbuilders and other firms—have expressed interest in the MASC program and in some cases are offering USV designs as candidates for the MASC program. Certain elements of the MASC program, including the total number of MASCs that the Navy might want to procure, annual procurement quantities, and the number of firms to be involved in building MASCs, have not yet been announced. Navy ship force structure plans suggest that the Navy might want to procure as many as several dozen MASCs. An issue for Congress is whether to approve, reject, or modify the Navy’s annual funding requests and proposed acquisition strategy for the MASC program. Congress’s decisions on this issue could substantially affect Navy capabilities and funding requirements, and the U.S. defense industrial base.