The five stages of terraforming

The quest to terraform Mars for human habitation will be complex and difficult. Remember that this isn’t the first time this mission has been attempted! As you explore Mars, you’ll discover countless failed attempts scattered throughout the surface of the Red Planet. We’ve divided the terraforming process into five distinct stages, each with their own unique challenges, innovative projects, and rewards:

1. Sublimating the dry ice poles
   
2. Creating an atmosphere
   
3. Ecopoiesis
   
4. Green Mars
   
5. Breathable Atmosphere
   

Once you establish your base and welcome your first colonists to their new home, you’ll need to begin the first stage of the terraforming process: melting the poles. Why is that the beginning of your journey to terraform a new home? Mars’s ice poles contain an immense amount of CO₂. Releasing these gases are necessary to warm the climate: they’ll trap heat and trigger a runaway greenhouse effect!

A ring of greenhouse gas factories and biodomes working to terraform Mars!

Once the poles are sublimated, the next step is to create an atmosphere that increases pressure and aids rising temperatures. There will be many different ways to accomplish this: one example is by building greenhouse gas factories that free the CO₂ trapped in Mars’s regolith.

J.M Graham’s mountain model for ecosynthesis on Mars.

The next three stages involve introducing oxygen into the environment and eventually balancing the planet’s overall CO₂ and O₂ levels. “Planetary Ecosynthesis as Ecological Succession.” by J.M Graham explains these stages elegantly by comparing ecosynthesis to a mountain descent. “The present climate of Mars can be compared to a very high mountain on Earth, one higher than any real mountain that exists in fact. The prebiotic stage of ecosynthesis employs planetary engineering techniques to bring the climate of Mars at some latitudes into the range of that in the terrestrial Dry Valleys of Antarctica. At that point the introduction of the first microbial ecosystems can begin. Continued modification of the planetary climate will permit the introduction of a sequence of ecosystems from tundra through boreal forests to temperate ecosystems.”

An aquadome slowly propagating bioengineered cyanobacteria over time into an ocean.

In other words, once Mars’s climate becomes similar to an Earth polar desert, we can begin to introduce extremophile life forms. These microbial ecosystems will begin to slowly convert CO₂ into much needed oxygen. Present-day scientists are currently experimenting to see whether bioengineered extremophiles can survive on (and even modify!) Mars’s harsh environment. By creating a simulated engineered Martian environment, scientists tested five genera of cyanobacteria and three eubacterial strains. Based on preliminary results, some specific extremophiles can survive! You can read more in this absolutely fascinating paper: “Extremophiles for ecopoiesis: desirable traits for and survivability of pioneer Martian organisms” by Thomas, Boling, Boston, Campbell, McSpadden, McWilliams, and Todd.

An airship full of colonists travelling to a Martian research outpost over a blue lake!

By building aquadomes and biodomes in Per Aspera, you’ll begin to spawn cyanobacteria, lichens, and green algae across Mars. Eventually as you progress further down the proverbial mountain, continue to research innovative biotech, and get closer to fulfilling the dream of a habitable Mars, your planet will be able to support more advanced lifeforms. Your biodomes and aquadomes will then begin to introduce genetically modified plants and eventually even animals!

This is fine.

In the final stages of terraforming, it will be incredibly important to control your levels of oxygen, limit your CO₂ to 5% or lower, and to introduce nitrogen into your atmosphere. All of these carefully combined will allow humans and animals to naturally breathe on Mars sans any gear! While simple in theory, this balance will be tricky to achieve. If you allow your oxygen levels to surpass 30%, you may personally discover that high levels of oxygen are incredibly flammable. Work quickly to get it under control or run the risk of watching your colony burn down.

Another important part of this stage is reducing radiation. Once your space elevator is complete, you’ll be able to launch a special project designed to tackle this problem: the magnetic dipole shield. Launching this large dipole in L1 (between Mars and the sun) leaves Mars in a safe magnetotail and stops the stripping of the atmosphere. You can learn more in the talk “A Future Mars Environment for Science and Exploration” which begins at the 1 hour and 36 minute mark.



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