10 U.S.C. § 174

(a) The Secretary of each military department may establish such advisory committees and panels as are necessary for the research and development activities of his department and may employ such part-time advisers as he considers necessary to carry out those activities. (b) A person who serves as a member of such a committee or panel may not be paid for that service while holding another position or office under the United States for which he receives compensation. Other members and part-time advisers shall (except as otherwise specifically authorized by law) serve without compensation for such service. (c) The Secretary concerned may delegate any authority under this section to— (1) the Under Secretary of his department; (2) an Assistant Secretary of his department; or (3) the chief, and one assistant to the chief, of any technical service, bureau, or office.