10 U.S.C. § 8023: Office of Naval Research: appropriations; time limit

(a) Sums appropriated for the Office of Naval Research may be used to pay the cost of performing its duties under section 8022 of this title including the cost of—(1) administration; (2) conduct of research and development work in Government facilities; and (3) conduct of research and development work under contracts with individuals, corporations, and educational or scientific institutions. (b) Sums appropriated for the purposes of this section, if obligated during the fiscal year for which appropriated, remain available for expenditure for four years after the end of that fiscal year. Any balance not spent after that four-year period shall be carried to the surplus fund and covered into the Treasury.