Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 33A, § 5

(a) This code shall apply at all times and in all places subject to jurisdiction as provided in article 2 or, if not in a duty status, when there is a nexus between the act or omission constituting the offense and the efficient functioning of the state military forces; provided, however, that this grant of military jurisdiction shall not preclude or limit civilian jurisdiction over an offense, which is limited only by the prohibition of double jeopardy.

(b) Courts-martial and courts of inquiry may be convened and held in units of the state military forces while those units are serving outside the commonwealth with the same jurisdiction and powers as to persons subject to this code as if the proceedings were held inside the commonwealth, and offenses committed outside the commonwealth may be tried and punished either inside or outside the commonwealth.