Origins: The two-meter wide flaw that killed the Death Star didn't kill the dream -- the Empire still wanted the ultimate technological terror, and went back to the drawing board to correct the mistakes that fell the first superweapon. In retrospect, we know that this mindset produced the second Death Star, thus retroactively making the Tarkin a kind of interim weapons development test-bed. Only, the creators of the story wherein it first appeared in 1981 didn't know that to be the case. David Michelinie and Walt Simonson at Marvel Comics essentially stumbled upon the second Death Star in their story development.
"We began finding out what would be in the third movie, accidentally," says Simsonson. "We didn't do it deliberately. David's first story after the second movie: the Empire's building a new Death Star. Lucasfilm said: 'Sorry, you can't do that.' Why not? 'We can't tell you.' So, we said okay, how about if we do a giant cannon floating in space, with no circular shell? 'Okay, fine, no problem.' So we called it the Tarkin, wrote exactly the same story with the same gizmo, and nobody cared."
Plausible Non-Draconian Reason to Keep it Around: Think of it as a big statue to the man for which it is named. It just happens to shoot planets, too.
Considerably Less Effective Names: The Wilhuff; Grand Mofference Center.
Achilles Heel: Poor security screening for the Tarkin's support crew means that explosive-laden saboteurs can just stroll in. But they don't even need those explosives. Leia proves that you can rewire the Tarkin's main cannon to shoot itself.
Further Reading: The Tarkin storyline can be found in Star Wars: A Long Time Ago Volume 3 from Dark Horse Comics. Or, if you really want to go old school, dust off issues 51 and 52 of the original Marvel run from the back issue bins, and enjoy all the old comic book ads: 132 Roman Soldiers for $2.98? You really can't beat that.
