USS Enterprise (NCC-1701-A)
The Enterprise-A was commissioned a short time after the destruction of the original NCC-1701 in Star Trek III: The Search for Spock. It was apparently a reward to Kirk for saving Earth from the mysterious friends of the Humpback Whale in Star Trek IV: The Voyage Home.
The ship's first mission in Star Trek V: The Final Frontier is a rescue at Nimbus III, "The Planet of Galactic Peace". There, Kirk and company fall into a trap and the ship is stolen by Spock's half brother Sybok, who takes the ship to the "Center of the Galaxy", where he believes the world of Sha Ka Ree can be found.
Following these events, in Star Trek VI: The Undiscovered Country, tragedy strikes the Klingon moon Praxis, causing it to explode. The explosion causes significant environmental damage to the Klingon home world, Qo'noS, and the Klingons agree to peace talks. Kirk and the Enterprise are assigned to escort the Klingon chancellor to Earth but are framed for an attack on the Klingon ship. Later, at the second attempt at peace talks, the Enterprise and USS Excelsior destroy a prototype Klingon Bird of Prey that was responsible for the initial attack and prevent another assassination attempt.