It would be far cheaper to build underground bunkers on Earth, or fund prevention of specific risks like this one. Building a permanently self-sufficient colony

It would be far cheaper to build underground bunkers on Earth, or fund prevention of specific risks like this one. Building a permanently self-sufficient colony isn't just ridiculously expensive, it may not even be possible with our technology for a very long time. And it's still only a last resort. Civilization and everyone on Earth still perishes in the apocalypse. It would take significantly more than this to wipe out humanity btw. Even the worse case scenarios, civilization still recovers eventually.