Terraforming Mars is a hypothetical process of planetary engineering by which the surface and climate of Mars would be deliberately changed to make large areas of the environment hospitable to humans, thus making the colonization of Mars safer and sustainable. There are quite a few proposals, which will be summarized below, but the issue of feasibility is always an issue.

Motivations for terraforming Mars include future population growth, demand for resources, and an alternate solution to the Doomsday argument may require human colonization of bodies other than Earth, such as Mars, the Moon, and other objects. Space colonization will facilitate harvesting the Solar System’s energy and material resources. If humans decide to terraform mars, there could be the potential displacement or destruction of potential indigenous life.

The time taken to terraform mars would take anywhere from 900 to 100,000 years, depending on how the terraforming is performed, how ambitious the desired timetable, and goals. Nevertheless, it is worth noting, that humanity has advanced a great deal in the past 100,000 years. In this 100,000 year timeframe, humanity has expanded out of Africa, expanded across the world, colonized animals and created agriculture, mixed with Neaderthals, and much more. Even the “optimistic” 900 year timeframe still has seen a lot of changes in human lifestyle that would make any person who went back to live in that time totally out of frame as life and language would be totally different. This takes time and should be planned considerably as during the time required to terraform the planet, humanity on Earth would change, such as increases in technology, medicine, and environment that could change the entire terraforming plans.

Advantages, Challenges, and Limitations

Advantages to helping terraforming mars would include the soil and atmosphere of Mars may contain many of the main elements crucial to life, and that Mars exists on the outer edge of the habitable zone. The existence of resources on the planet suitable for live can help reduce the amount of material required to transport to the planet by humanity. 

Challenges that occur when terraforming a planet, considerations need to include the gravity, atmosphere, solar radiation, and space weather. For the planet Mars, these challenges manifest themselves as:

• Reduced light levels, equivalent to about 59% of the light seen by Earth 
• Low surface gravity, which is equivalent to 38% of Earth’s gravity
• Toxic atmosphere
• Atmospheric pressure about 100 times lower than Earth, which iswell below the Armstrong limit
• Ionizing solar and cosmic radiation at the surface 
• Average temperature −63 °C, which translates to 210 K or −81 °F, compared to Earth average of 14 °C, or 287 K; 57 °F
• Molecular instability – bonds between atoms break down in critical molecules such as organic compounds
• No liquid water
• Global dust storms
• No natural food source
• Toxic soil
• No global magnetic field to shield against the solar wind

Proposed methods and strategies

Importing ammonia or hydrocarbons

By importing ammonia and hydrocarbon into the atmosphere, these gases would help generate global warming through the greenhouse effect. The issue with these concepts include the gases escaping the atmosphere quickly and be only useful for short periods of time.

Use of fluorine compounds

Capable of warming the planet Mars for many years, releasing Flourine compounds into the atmosphere would be the best option if gases wanted to be released to the Mars environment.

Use of orbital mirrors

Mirrors made of thin aluminized film could be placed in orbit around Mars to increase the total insolation it receives by directing the sunlight onto the surface to directly increase the surface temperature. If done properly, it could contribute to the warming greenhouse effect.

Albedo reduction

Reducing the albedo of the Martian surface would also make more efficient use of incoming sunlight in terms of heat absorption. This could be done by spreading dark dust from Mars’s moons or by introducing dark extremophile microbial life forms.

Ecopoiesis

This would mean the implementation of sealed biodomes that would employ colonies of oxygen-producing cyanobacteria and algae for the production of molecular oxygen (O₂) on Martian soil. These biodomes would be implemented with the goal of human habitation.

Protecting atmosphere

To protect a future atmosphere from blowing away and build a current atmosphere, some scientists hypothesize that creating a planet-wide artificial magnetosphere would be helpful in resolving this issue. According to two NIFS Japanese scientists, it is feasible to do that with current technology by building a system of refrigerated latitudinal superconducting rings.

Magnetic shield on the L1 orbit

Proposed by NASA scientist Jim Green, this would involve placing a magnetic dipole field between the planet and the Sun to protect it from high-energy solar particles. It would be located at the L1 orbit. It is said that if constructed properly, the shield may allow the planet to restore its atmosphere.

References And Further Study

https://www.space.com/41318-we-cant-terraform-mars.html

https://www.science20.com/robert_inventor/trouble_with_terraforming_mars-126407