Sgt. Sean Hackney, a student and team chief at the Marine Corps Civil-Military Operations School, explains some of his team’s findings after an infrastructure assessment exercise Aug. 2, 2013, at Marine Corps Base Quantico. MCCMOS students are required to grasp the concepts taught at the schoolhouse prior to graduation. - Sgt. Sean Hackney, a student and team chief at the Marine Corps Civil-Military Operations School, explains some of his team’s findings after an infrastructure assessment exercise Aug. 2, 2013, at Marine Corps Base Quantico. MCCMOS students are required to grasp the concepts taught at the schoolhouse prior to graduation.