Lockheed Martin Corp., Lockheed Martin Aeronautics Co., Fort Worth, Texas, was awarded a $678,442,004 modification (P00009) to a cost-plus-fixed-fee, firm-fixed-price order (N0001923F0002) against a previously awarded basic ordering agreement (N0001919G0008). This modification adds scope to procure various material modification kits, special test/tooling equipment, and associated seed assets to support the F-35 Joint Strike Fighter aircraft retrofit and modification efforts for the Air Force, Marine Corps, Navy, non-U.S. Department of Defense (DoD) F-35 program partners, and Foreign Military Sales (FMS) customers. Work will be performed in Fort Worth, Texas, and is expected to be completed in December 2028. Fiscal 2024 aircraft procurement (Air Force) funds in the amount of $163,792,190; fiscal 2024 aircraft procurement (Navy) funds in the amount of $163,078,071; fiscal 2023 aircraft procurement (Navy) funds in the amount of $22,586,072; fiscal 2023 aircraft procurement (Air Force) funds in the amount of $20,809,905; non-U.S. DOD participant funds in the amount of $281,331,708; and FMS funds in the amount of $26,844,058, will be obligated at the time of award, none of which will expire at the end of the current fiscal year. The order and contract being modified were not competed. Naval Air Systems Command, Patuxent River, Maryland, is the contracting activity.