The Constellation was was destroyed in the incident with the Planet Killer.
The USS Constellation was launched in 2245 along with the Enterprise, commanded by Commodore Decker, with the registry NCC-1017.
The Planet Killer Incident EditIn 2267, the Constellation was doing a survey in L-374 when it was attacked by the Planet Killer. Soon after, the Enterprise arrived. The Enterprise finds Commodore Decker on board. He says that they were doing a survey to investigate why the fourth planet of L-374 was breaking up. But when they got there, he says, they found this giant robot slicing out chunks of the planets with a pure antiproton beam. By the time he said this, there were two planets left. Then Kirk asks Commodore Decker where his crew is, but he responds saying that his crew are on the third planet. But just then, an object appears on the Enterprise's view screen, the Planet Killer.
After Kirk realizes that a detonation of the Constellation's impulse engines would turn off the planet killer, he asks Scott to rig a 30-second countdown to detonation. Scott then beams off. Kirk sets a course for the mouth of the Planet Killer. Then he throws the switch for the 30-second detonation. The Enterprise attempts to beam him off, but are unsuccessful. But at the very last second, he beams off just before the Constellation explodes.