Exective Officer

On ships, the Executive Officer acts out the captain's orders and advises him or her. In Starfleet, this function is usually accompanied by the rank of Commander or Lieutenant Commander. First officers may also be referred to as First Officers. First officers are often colloquially known as "XO" or "Number One."

The Executive Officer is nominally responsible for the smooth running and organization of a ship or starbase, and will often be head of his/her own Executive Department/Division, whose officers and crew manage many of the day-to-day administrative tasks for the XO.

Executive Officers are generally responsible for training and officer personnel administration, as well as non-judicial discipline in most cases. It is often said that the XO represents the "hard face of command."

Executive Officers will assume command when the Commanding Officer is unavailible. First Officers also typically command away missions.