The USS Enterprise NCC-1701-A was the second Federation starship to bear the name. The vessel is unique in that it marks the first known time in which Starfleet paid tribute to the previous ship; they allowed the Enterprise to bear unique signage by giving it the same registry number only with a suffix on the end. This Constitution-class vessel was very similar to the ship it replaced, with only a few upgrades and modifications that made the ship more modern. It had modular bridge domes, which were changed numerous times over the ship's service. The vessel was given to James T. Kirk after he was demoted to Captain. He is the only known commanding officer of the vessel. The Enterprise-A went on numerous missions and encountered plenty of strange alien life forms. The ship was hyjacked by the Vulcan Sybok, who took the vessel through the galactic barrier in search of God. Years later, the Enterprise was chosen to escort the Klingon Chancellor Gorkon's ship to earth to begin peace negotiations. Things turned deadly and the Enterprise found itself up against a unique Klingon vessel. The Enterprise was badly damaged during an attack with the ship but ultimately prevailed. After long years of loyal service, the Enterprise-A returned home to be decommissioned.