; (B) the challenges encountered and the lessons learned; (C) the modifications made or planned so as to incorporate such lessons learned into subsequent efforts to address challenges; and (D) the cost, schedule, and performance effects of such modifications. (c) Review of reports and briefing by Comptroller General With respect to each report submitted under this section, the Comptroller General shall review and provide to the congressional defense committees a briefing on a date mutually agreed on by the Comptroller General and the congressional defense committees. 1616. Requirements for phase 2 of acquisition strategy for National Security Space Launch program In carrying out phase 2 of the acquisition strategy for the national security space launch program, the Secretary of the Air Force— (1) may not— (A) modify the acquisition schedule or mission performance requirements; or (B) award missions to more than two launch service providers