Here is a job announcement for the position of Navy Defense Counsel Assistance Program Complex and Sexual Assault Litigation Highly Qualified Expert (HQE).
The HQE program is authorized by 5 U.S.C. § 9903 to hire civilian employees “from outside the civil service and uniformed services . . . to positions in the Department of Defense without regard to any provision of this title governing the appointment of employees to positions in the Department of Defense.” Appointments under the HQE program are limited by paragraph (c) of the statute to 5 years, except that an appointment may be extended “by up to 1 additional year if the Secretary determines that such action is necessary to promote the Department of Defense’s national security missions.”
DoD policy is that:
HQEs shall be appointed to bring enlightened thinking and innovation to advance the DoD national security mission. HQEs are a temporary infusion of talent and provide non-permanent support for short-term endeavors.