A Junior Officer refers to any officer not part of the Senior Staff, and may or may not be assigned to a specific department. Junior officers not specifically assigned to operations (security or engineering), science, or medical will default to a red uniform, but these officers can fill any role as needed.
Junior Officers serving on the bridge of a starship may be expected to take over any console at a moment's notice, as vital ship functions cannot be left attended. Other officers may be tasked with maintenance, security, damage control, and other tasks. Junior officers are typically Ensign, Lieutenant, JG, or in rare cases Lieutenant. Cadets will also fill Junior Officer roles to provide additional manpower for the ship and experience for the cadets. Most officers of higher rank will have obtained a senior staff position.