Flight controllers are personnel who aid in the operations of a space flight, working in Mission Control Centers such as NASA's Mission Control Center, or ESA's Operations Center. Flight controllers sit at computer consoles and use telemetry to monitor in real time various technical aspects of a manned space mission. Each controller is an expert in a specific area, and is in constant communication with additional experts in the "back room". The Flight Director is the lead flight controller, monitors the activities of others and has overall responsibility for the mission success and safety. A Flight Director leads a team, designated by a color (e.g., Eugene F. Kranz led the White Team, and was known as "White Flight").