Rolls-Royce Corp., Indianapolis, Indiana, has been awarded an estimated $500,870,458 indefinite-delivery/indefinite-quantity contract with a six-year base period for B-52 Replacement Engines, with a potential total of $2,604,329,361 if all options are exercised. This contract provides for 608 commercial engines plus spare engines, associated support equipment and commercial engineering data, to include sustainment activities, to be used on the B-52H bomber fleet. The location of performance is Indianapolis, Indiana, and work is expected to be completed by Sept. 23, 2038. This award is the result of a competitive acquisition in which one solicitation was posted and four offers were received. Fiscal 2021 research and development funds in the amount of $5,464,452 are being obligated at the time of award. Air Force Life Cycle Management Center, Tinker Air Force Base, Oklahoma, is the contracting activity (FA8107-21-D-0001).