USS Andromeda (galaxy ship)

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The USS Andromeda was a Federation starship built to specifications of a "Galaxy" class vessel, meaning it was designed to traverse extragalactic voids, in this vessel's particular case, a mission to the Andromeda Galaxy in 2285. (TOS novelization: Star Trek II: The Wrath of Khan)

Presumably, this "Galaxy" class's name was not referring to a class of vessels created after a prototype named USS Galaxy (since that would contradict, or at least confuse, the nomenclature of the later 24th century Galaxy-class starship); it could be presupposed the name referred to the purpose of the series of ships, since the names of the entire class were mentioned (with Galaxy not among them), and all three had an exploratory mission planned in another galaxy.