10 U.S.C. § 20302

(a) Term of Original Enlistments.—The Secretary of the Air Force may accept original enlistments of persons for the duration of their minority or for a period of at least two but not more than eight years in the Space Force.
(b) Term of Reenlistments.—The Secretary of the Air Force may accept a reenlistment in the Space Force for a period determined in accordance with paragraphs (2), (3), and (4) of section 505(d) of this title.

Official source