Star Trek has confirmed that Spock quit Starfleet after the Original Series to escape one terrible decision. Spock devoted his life to Starfleet, which made his decision to abandon it after the Enterprise’s five-year mission shocking. Fans have speculated as to what could have led to this decision, and in 2009’s Star Trek: Mission’s End #5, fans learn the heartbreaking reason Spock left the service.
Star Trek: Mission’s End #5 was written by Ty Templeton and drawn by Steve Molnar. After the Enterprise has evacuated the people of Archernar IV, Spock is not satisfied. As the ship debated a course of action, Spock wished to leave the planet, which would by his calculations save as many people as possible. However, this was not the right course of action. McCoy tells Spock that it is guilt he feels. Spock does not like it and feels he will be a liability to Starfleet if he continues on.
![“It’s Called Guilt, Spock”: Spock Quit Starfleet After TOS To Escape 1 Terrible Decision](https://static1.srcdn.com/wordpress/wp-content/uploads/2023/12/star-trek-spock-leaving-starfleet.jpg)
He then leaves to return to Vulcan, to undergo a ritual to purge his remaining emotions.
Star Trek’s Trinity Was Split After the Five-Year Mission Ended
![Spock on Vulcan in Star Trek: The Motion Picture](https://static1.srcdn.com/wordpress/wp-content/uploads/2021/12/Spock-Traits-Logic.jpg)
When Star Trek: The Motion Picture debuted in movie theaters in 1979, both Spock and McCoy had left Starfleet for reasons then unknown. Spock had returned to Vulcan to study Kholinar, which was designed to finally cleanse Vulcans of their emotions. Spock was unsuccessful, and returned to Starfleet just in time for the V’Ger incident. Fans never learned why Spock left and underwent Kholinar in the first place, becoming one of the franchise’s greatest unsolved mysteries.
Spock’s decision to forsake Starfleet and return to Vulcan was even odder in light of his background. Although he came from a prominent family, Spock was an outcast in Vulcan society. The child of a Vulcan father and an Earth mother, Spock did not fit into either one, and was bullied as a child. Various Star Trek shows and movies have touched on Spock’s troubled childhood and how those experiences led him to Starfleet. While in the service, Spock found purpose and was accepted for who he was. For the first time in his life, Spock has friends.
![Spock and Picard with the USS Enterprise-D from Star Trek: The Next Generation.](https://static1.srcdn.com/wordpress/wp-content/uploads/2020/02/Spock-and-Picard-Star-Trek-The-Next-Generation.jpg)
Spock Failed Picard as His First Mentor – Now Star Trek Reveals How
In Star Trek: Picard’s Academy #2, Mister Spock tries to impart an important life lesson on the cadet, but fails miserably at it.
One Bad Decision Nearly Derailed Spock’s Career
![Spock investigating V'ger in Star Trek: The Motion Picture](https://static1.srcdn.com/wordpress/wp-content/uploads/2021/12/Spock-Traits-Curiosity.jpg)
And it was this human side, and the emotions that come with it, that led Spock to abandon Starfleet and the Enterprise. The tinges of guilt that he was feeling over his decisions were too much for him to take. Spock felt these human emotions would compromise him as a Starfleet officer, so he took leave to undergo Khloniar and get rid of them. Ironically, Spock would fail to obtain Kholinar and return to Starfleet, where he would serve for many more years, before becoming a diplomat. Star Trek has confirmed that one bad decision led Spock away from the Enterprise and nearly ended his career.