A C-5 Galaxy assigned to the 436th Airlift Wing takes off from Alpena Combat Readiness Training Center, Michigan, May 18, 2021. Conducted biennially, Mobility Guardian is the Air Force’s only formal, Total Force, service-level mechanism for assessing and validating capabilities in Rapid Global Mobility missions specified and implied within the 2018 National Defense Strategy. (U.S. Air Force photo by Staff Sgt. Joseph Pick)