Independently survivable human worlds

Independently survivable human worlds, version 1.0

Definition. A world is counted only if it hosts a human population that could sustain itself indefinitely with no resupply from Earth. Every criterion below must hold at the same time, with no time limit, for the whole resident population:

1. Energy. Generates all the energy it consumes from local resources, including the energy needed to maintain and replace its own generating equipment.
2. Food. Produces all calories, protein and micronutrients its population needs from local agriculture or synthesis, including seed stock, inputs and the equipment to keep producing.
3. Water. Sources, purifies and recycles all water needed for drinking, agriculture and industry from local supplies.
4. Air. Maintains a breathable atmosphere for its population indefinitely, whether naturally or through locally built and locally maintained life support.
5. Manufacturing. Can fabricate replacement parts for every system it depends on, from raw materials extracted locally, including the machines that make the machines.
6. Medicine. Can produce essential medicines, medical equipment and train medical staff locally at a level that keeps the population viable across generations.

Population viability also requires a population large and diverse enough to persist across generations; this version does not set a numeric threshold because no candidate beyond Earth is close to the other criteria.

Assessment as of 2026-01-01. Earth meets all criteria. No station, base or settlement beyond Earth meets any of criteria 1 to 6 without resupply. Count = 1.

Unit. Worlds (integer count).

Update rule. The value is reassessed annually and whenever a candidate settlement publishes evidence against the criteria. A change in the count requires a new methodology version citing that evidence. Partial progress (for example a base that is energy independent but not food independent) does not change the count; it belongs in separate progress metrics.