; or (B) be discharged in the grade then held, in the case of an officer whose case was brought under subsection (b) of section 20501 of this title. (c) Separation pay for discharged officer An officer who is discharged under subsection (b)(2) is entitled, if eligible therefor, to separation pay under section 1174(a)(2) of this title. 20506. Officers eligible to serve on retention boards (a) In general The provisions of section 1187 of this title apply to the membership of boards convened under this chapter in the same manner as to the membership of boards convened under chapter 60 of this title. (b) Retired air force officers (1) Authority In applying subsection (b) of section 1187 of this title to a board convened under this chapter, the Secretary of the Air Force may appoint retired officers of the Air Force, in addition to retired officers of the Space Force, to complete the membership of the board. (2) Limitation A retired officer of the Air Force may be appointed to a board under paragraph (1) only if the officer served in a space-related career field of the Air Force for sufficient time such that the Secretary of the Air Force determines that the retired Air Force officer has adequate knowledge concerning the standards of performance and conduct required of an officer of the Space Force. . 1719A. Retirement (a) In general Subtitle F of title 10, United States Code, as amended by section 1719, is further amended by adding at the end the following new chapter: 2013 VOLUNTARY RETIREMENT FOR LENGTH OF SERVICE Sec. 20601. Officers: voluntary retirement for length of service. 20602. Officers: computation of years of service for voluntary retirement. 20603. Enlisted members: voluntary retirement for length of service. 20604. Enlisted members: computation of years of service for voluntary retirement. 20605. Applicability of other provisions of law relating to retirement. 20601. Officers: voluntary retirement for length of service (a) Twenty years or more The Secretary of the Air Force may, upon the officer’s