What was the name of the captain of the USS Constellation?

The captain of the USS Constellation was Commodore Matt Decker. In “The Doomsday Machine,” the USS Enterprise finds the Constellation badly damaged after it encounters a gigantic planet-destroying machine. Decker is the only surviving crew member aboard, having watched helplessly as the machine destroyed both his ship’s crew and the planet where he had evacuated them.

Although Decker holds the rank of commodore, he is the commanding officer of the Constellation, so “captain” in this question refers to the ship’s commander rather than his formal rank. That distinction is a common source of confusion: Captain Kirk commands the Enterprise, while Decker commands the Constellation.

Decker’s grief and survivor’s guilt drive him to steal a shuttle and sacrifice himself against the machine. His action gives Kirk the crucial idea of destroying the Constellation inside the planet killer. The episode first aired on October 20, 1967, and is one of the Original Series’ best-known dramatic stories.