# § 635. Retirement for years of service: regular and Space Force brigadier generals; regular Navy rear admirals (lower half)
**(a)** **Army, Navy, Air Force, and Marine Corps.—** Except as provided under section 637(b) or 637a of this title, each officer of the Regular Army, Regular Air Force, or Regular Marine Corps who holds the regular grade of brigadier general, and each officer of the Regular Navy who holds the regular grade of rear admiral (lower half), who is not on a list of officers recommended for promotion to the regular grade of major general or rear admiral, respectively, shall, if not earlier retired, be retired on the first day of the first month beginning after the date of the fifth anniversary of his appointment to that grade or on the first day of the month after the month in which he completes 30 years of active commissioned service, whichever is later.
**(b)** **Space Force.—** Except as provided under section 637(b) or 637a of this title, each officer of the Space Force who holds the grade of brigadier general who is not on a list of officers recommended for promotion to the grade of major general shall, if not earlier retired, be retired as specified in subsection (a).
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**Source Credit**: (Added Pub. L. 96–513, title I, § 105, Dec. 12, 1980, 94 Stat. 2863; amended Pub. L. 97–86, title IV, § 405(b)(1), (5)(A), Dec. 1, 1981, 95 Stat. 1105, 1106; Pub. L. 98–525, title XIV, § 1405(13), Oct. 19, 1984, 98 Stat. 2622; Pub. L. 99–145, title V, § 514(b)(1), (5)(A), Nov. 8, 1985, 99 Stat. 628; Pub. L. 114–328, div. A, title V, § 505(b)(3), Dec. 23, 2016, 130 Stat. 2108; Pub. L. 116–283, div. A, title IX, § 924(b)(4)(F), Jan. 1, 2021, 134 Stat. 3822; Pub. L. 118–31, div. A, title XVII, § 1722(b)(6)(C), (E)(iii), Dec. 22, 2023, 137 Stat. 669, 670.)
## Editorial Notes
### Amendments
2023— substituted “and Space Force brigadier generals; regular Navy” for “brigadier generals and” in section catchline; designated existing provisions as subsec. (a), inserted heading, and substituted “or Regular Marine Corps” for “Regular Marine Corps, or Regular Space Force”; and added subsec. (b).
2021— substituted “Regular Marine Corps, or Regular Space Force” for “or Regular Marine Corps”.
2016— inserted “or 637a” after “637(b)”.
1985— substituted “rear admirals (lower half)” for “commodores” in section catchline and “rear admiral (lower half)” for “commodore” in text.
1984— substituted “30” for “thirty”.
1981— substituted “commodores” for “commodore admirals” in section catchline and “commodore” for “commodore admiral” in text.
## Statutory Notes and Related Subsidiaries
### Effective Date of 1981 Amendment
Amendment by effective , see , set out as a note under .
### Effective Date
Section effective , but the authority to prescribe regulations under this section effective on , see , set out as an Effective Date of 1980 Amendment note under .