Lockheed Martin Corp., Lockheed Martin Aeronautics Co., Fort Worth, Texas, is awarded an $11,911,903 cost-plus-fixed-fee modification (P00018) to a previously issued order (N0001920F0571) against a previously issued basic ordering agreement (N0001919G0008). This modification adds scope and exercises options to procure material kits and special test/tooling equipment and provide non-recurring engineering in support of engineering change proposal development to support F-35 Joint Strike Fighter aircraft retrofit and modification efforts for the Navy, Marine Corps, Air Force, non-U.S. Department of Defense (DOD) participants and the governments of Israel, Japan, and the Republic of Korea. Work will be performed in Fort Worth, Texas, and is expected to be completed in December 2030. Fiscal 2021 aircraft procurement (Navy) funds in the amount of $3,417,745; fiscal 2021 aircraft procurement (Air Force) funds in the amount of $1,276,182; fiscal 2019 aircraft procurement (Air Force) funds in the amount of $220,104; non-U.S. DOD participants funds in the amount of $814,956; and Foreign Military Sales funds in the amount of $6,182,916 will be obligated on this award, of which $220,104 will expire at the end of the current fiscal year. The Naval Air Systems Command, Patuxent River, Maryland, is the contracting activity.