Sgt. Melvin Ortega (left) and Cpl. Thomas Brown (right), Joint Fire Observers (JFO) with Marine Forces Reserve, conduct a simulation fire mission during Tactical Air Control Party (TACP) training as a part of a Close Air Support Exercise (CASEX) at Camp Shelby, Mississippi, Feb. 26, 2021. JFOs help integrate both air-to-surface fire and surface-to-surface fire by providing six to ten-digit grid coordinates to Joint Terminal Attack Controllers.