General Dynamics Applied Physical Sciences Corp., Groton, Connecticut, was awarded an $8,642,960 modification (P00001) to cost-plus-fixed-fee contract HR001123C0054 to develop models for the Advanced Propulsor, Experimental (APEX) program. The modification brings the total cumulative value of the contract to $18,004,008 from $9,361,048. Work will be performed in Groton, Connecticut (36%); Concord, Massachusetts (35%); Arlington, Virginia (18%); Pawcatuck, Connecticut (9%); and San Diego, California (2%), with an estimated completion date of August 2024. Fiscal 2023 research, development, test, and engineering funds in the amount of $8,642,960 were obligated at time of award. This contract stems from a competitive acquisition in accordance with Broad Agency Announcement HR001122S0046. The Defense Advanced Research Projects Agency, Arlington, Virginia, is the contracting activity.