- Doomed World — The world is doomed, and the locals may or may not know it. Some cosmic catastrophe looms before them, and the locals have no realistic way to get everyone to safety. To the extent that the public is aware, society is disintegrating into a combination of religious fervor, abject hedonism, and savage violence.
- Quarantined World — The world is under a quarantine, and space travel to and from it is strictly forbidden. This may be enforced by massive ground batteries that burn any interlopers from the planet’s sky, or it may be that a neighboring world runs a persistent blockade.