Notwithstanding any other provision of law, the Secretary may, subject to such terms and conditions as the Secretary considers appropriate, issue credit instruments to United States commercial providers of in-space transportation services or system , with the aggregate cost (as determined under the provisions of the Federal Credit Reform Act of 1990 (
2 U.S.C.
661 et seq.)) of such instruments not to exceed $1,500,000,000, but only to the extent that new budget authority to cover such costs is provided in subsequent appropriations Acts or authority is otherwise provided in subsequent appropriations Acts.