General Dynamics Electric Boat Corp., Groton, Connecticut, is awarded a not-to-exceed $66,637,726 undefinitized contract action modification to previously awarded contract N00024-20-C-2120 for lead yard support and development studies and design efforts related to Virginia-class submarines. Work will be performed in McLeansville, North Carolina (34%); Riviera Beach, Florida (26%); Annapolis, Maryland (21%); and Hanover, Maryland (19%), and is expected to be completed by November 2024. Fiscal 2022 research, development, test, and evaluation (Navy) $5,557,989 funding will be obligated at time of award and will not expire at the end of the current fiscal year. This contract was not competitively procured. The statutory authority for this sole source award is in accordance with Defense Federal Acquisition Regulation 6.302-1(a)(2)(iii) — only one responsible source and no other supplies or services will satisfy agency requirements. The Naval Sea Systems Command, Washington, D.C., is the contracting activity.