Commodore Matt Decker's Constitution-class starship, crippled by the planet-killer and finally used to destroy it.
The USS Constellation was a Constitution-class starship of the 2260s, a sister ship of the Enterprise, commanded by Commodore Matt Decker.
In 2267 the Constellation encountered a planet-killer, an immense automated weapon from beyond the galaxy that destroyed planets and consumed their rubble as fuel. The machine knocked out the ship's warp drive and weapons. Decker beamed his crew to the third planet of system L-374 to save them, but the machine destroyed that world, leaving him alone and traumatised aboard the drifting wreck.
The Enterprise found the derelict and Decker, who took command of the Enterprise and attacked the machine until Spock relieved him. Decker then stole a shuttlecraft and flew it into the planet-killer's maw, dying in the attempt. Building on his idea, Kirk had Montgomery Scott restore the Constellation's impulse engines, set the ship on a course into the machine and beamed out just before its engines exploded, destroying the weapon.