The "Planet Killer" or "Doomsday Machine" was an automated, self-propelled doomsday machine capable of destroying entire planets.
- Its origins were unknown, but based on its apparent trajectory, it was believed to have come from outside the Milky Way Galaxy.
- It was believed the Doomsday Machines were created by the Preservers to be used against the Borg. Though it also seems they may have been unsuccessful and that the Borg, who designated them "Species 4672", were able to vanquish the creator race.
Construction and Weaponry
Doomsday machines featured a Neutronium hull capable of resisting many known types of weapon fire.
Doomsday machines required a constant "diet" of planets to maintain their peak performance. This need to consume planetary matter was believed to be part of the machines' design to destroy planets the Borg had assimilated. The matter obtained from planets, or other targets, such as Borg Cubes, increase the ships' power reserves and even allowed them to repair themselves.
Doomsday machines were equipped with a devastating Antiproton beam even the Borg were incapable of resisting. These ships had a powerful tractor beam, which was used to drag either starships or planets into their maw.
Despite their powerful defensive and offensive abilities, doomsday machines were generally slow compared to other starships.
- 2267 - Federation starships Constellation] and Enterprise encountered the first Planet Killer. The USS Constellation was destroyed, but the Planet Killer was disabled.
- 2420 - Attack on the Borg Megasphere - Two assimilated speciments believed to have retreated from interior of Megasphere.