Hemmer arrived on the decks of the U.S.S. Enterprise in the year 2259, replacing the once-doting Louvier as the ship’s chief engineer. Although blind like many of his Aenar counterparts, Hemmer refuses to accept this trait as a hindrance, instead relying on sight granted through telepathy. He will actively refute any offers of help or assistance that would imply him to be at a physical disadvantage to his fellow crew members. It wasn’t long before Hemmer was presented with an opportunity to prove his worth as chief engineer. His work in the field of photon torpedo retrofitting was integral in altering the course of the comet C/2260-Quentin, which was on a collision course with the planet Persephone III. This cataclysmic event would have likely led to the destruction of all life on the planet. However, thanks to Hemmer and the crew of the Enterprise, this fate would not come to pass.