Flight Director
From OCE Space Simulation
The flight director acts as the ranking officer in Mission Control during the mission. While the Mission Commander is present for a large part of the mission (between 60-75%) and is considered the ultimate authority in Mission Control command, he/she will usually appoint Flight Directors to take charge of Mission Control at various times. A flight director is assigned for every shift where the Mission Commander is not present. All Mission Controllers report to the Flight Director even when the Mission Commander is present, but the Mission Commander retains the power to overide the Flight Director at any time.
