Mil. & Vet. Code, § 453

Special courts-martial may be appointed by the commanding officer of a district, garrison, fort, post, camp, station, or other place where troops are on duty, division, brigade, regiment, detached battalion, or other detached command or corresponding unit of Army or Air Force, and by the commanding officer of any group of detached units placed under a single commander for this purpose. Such courts-martial may also be appointed by superior authority when by the latter deemed desirable. When any such commanding officer is the accuser or the prosecutor of the person or persons to be tried, the court shall be appointed by superior authority. Special courts-martial may be composed of either one officer who shall be a field grade officer of the rank of major, lieutenant colonel or colonel or three or more members as provided for in the Uniform Code of Military Justice and the rules and regulations published thereunder. After final action by the reviewing authority the record of the trial by special courts-martial shall be filed in the office of the Adjutant General.