Cygnus Institute
Seven phases.One of them isirreversible.
| Phase | Objective | Gate | Timescale | K |
|---|---|---|---|---|
| 0 | Prospecting: ice, global nitrate survey, sulfate/pH mapping, dust–aerosol study | Inventories characterized | to ~2040 | 0.73 |
| I | Paraterraforming: aerogel greenhouses, ISRU, perchlorate remediation | Self-sustaining habitats | 2030s–2100 | 0.75 |
| II | Thermal: aerosol/mirror forcing to +30 K | Seasonal meltwater | decades | 0.80 |
| III-a | Hydrosphere + acidophile ecopoiesis (must precede III-b) | Self-propagating biosphere | centuries | 0.85 |
| III-b | Oxygen via water electrolysis (must follow III-a) | pO₂ rising, H₂ venting stable | centuries | 0.90 |
| IV | Nitrogen import from Titan | 1.5×10¹⁸ kg delivered | ~600 yr at Type I | 1.00 |
| V | Composition closure: pCO₂ < 10 mbar, ozone, obliquity management | Shirtsleeve | millennia | 1.00 |
Iron supplies 42% of the divalent cations available for carbonate formation. Oxygenation converts Fe(II) to insoluble Fe(III) oxide and removes it permanently from the carbon-burial budget. Carbon buried under anoxia can use the iron pathway. Carbon buried afterward cannot. These phases were specified as parallel. They are not. Burial must be run to completion first.
Phases 0–III are individually valuable and reversible. Phase IV is the irreversible commitment, and the true decision point.
The axis is sequence, not calendar time. Everything to the left of Phase IV is individually valuable and reversible. The rising line beneath the axis is the Kardashev level required to sustain each phase.
Prospecting: ice, global nitrate survey, sulfate/pH mapping, dust–aerosol study
Inventories characterized
to ~2040
Stop here and you keep a full inventory of Martian ice, nitrate and sulfate.