10 U.S.C. § 3551

(a) Ten-Year Contract Period .— The Secretary of Defense may enter into a contract for a period of up to 10 years for the purchase of dinitrogen tetroxide, hydrazine, and hydrazine-related products for the support of a United States national security program or a United States space program. (b) Extensions .— A contract entered into for more than one year under the authority of subsection (a) may be extended for a total of not more than 10 years pursuant to any option or options set forth in the contract.