Terraforming of Mars
[1] Justifications for choosing Mars over other potential terraforming targets include the presence of water and a geological history that suggests it once harbored a dense atmosphere similar to Earth's.
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.
The lack of a magnetic field, its relatively small mass, and its atmospheric photochemistry, all would have contributed to the evaporation and loss of its surface liquid water over time.
For comparison, while Venus has a dense atmosphere, it has only traces of water vapor (20 ppm) as it lacks a large, dipole-induced, magnetic field.
It is estimated that there is sufficient CO2 ice in the regolith and the south polar cap to form a 30 to 60 kilopascals [kPa] (4.4 to 8.7 psi) atmosphere if it is released by planetary warming.
[23] Current conditions in the Martian atmosphere, at less than 1 kPa (0.15 psi) of atmospheric pressure, are significantly below the Armstrong limit of 6 kPa (0.87 psi) where very low pressure causes exposed bodily liquids such as saliva, tears, and the liquids wetting the alveoli within the lungs to boil away.
[27][clarification needed] This might look similar to mountain climbers who venture into pressures below 37 kPa (5.4 psi), also called the death zone, where an insufficient amount of bottled oxygen has often resulted in hypoxia with fatalities.
[29] Mars exists on the outer edge of the habitable zone, a region of the Solar System where liquid water on the surface may be supported if concentrated greenhouse gases could increase the atmospheric pressure.
[23] The lack of both a magnetic field and geologic activity on Mars may be a result of its relatively small size, which allowed the interior to cool more quickly than Earth's, although the details of such a process are still not well understood.
[30][31] There are strong indications that Mars once had an atmosphere as thick as Earth's during an earlier stage in its development, and that its pressure supported abundant liquid water at the surface.
[33][34] The soil and atmosphere of Mars contain many of the main elements crucial to life, including sulfur, nitrogen, hydrogen, oxygen, phosphorus and carbon.
Significant amounts of water are located at the south pole of Mars, which, if melted, would correspond to a planetwide ocean 5–11 meters deep.
Because its atmosphere consists mainly of CO2, a known greenhouse gas, once Mars begins to heat, the CO2 may help to keep thermal energy near the surface.
Large amounts of ammonia are likely to exist in frozen form on minor planets orbiting in the outer Solar System.
Even if a method could be found to prevent it escaping into space, methane can exist in the Martian atmosphere for only a limited period before it is destroyed.
[52][53] Especially powerful greenhouse gases, such as sulfur hexafluoride, chlorofluorocarbons (CFCs), or perfluorocarbons (PFCs), have been suggested both as a means of initially warming Mars and of maintaining long-term climate stability.
It has been estimated that approximately 0.3 microbars of CFCs would need to be introduced into Mars' atmosphere to sublimate the south polar CO2 glaciers.
[54] This is equivalent to a mass of approximately 39 million tonnes, that is, about three times the amount of CFCs manufactured on Earth from 1972 to 1992 (when CFC production was banned by international treaty).
[24] Typical proposals envision producing the gases on Mars using locally extracted materials, nuclear power, and a significant industrial effort.
A 2024 study proposed using nanorods consisting of a conductive material, such as aluminum or iron, made by processing Martian minerals.
[55][56] Mirrors made of thin aluminized PET film could be placed in orbit around Mars to increase the total insolation it receives.
Carbon dioxide and water vapor are greenhouse gases, and the resultant thicker atmosphere would trap heat from the Sun, increasing the planet's temperature.
[57][62][63] Another criticism is that it would stir up enough dust and particles to block out a significant portion of the incoming sunlight, causing a nuclear winter, the opposite of the goal.
If algae or other green life were established, it would also contribute a small amount of oxygen to the atmosphere, though not enough to allow humans to breathe.
Since 2014, the NASA Institute for Advanced Concepts (NIAC) program and Techshot Inc have been working together to develop sealed biodomes that would employ colonies of oxygen-producing cyanobacteria and algae for the production of molecular oxygen (O2) on Martian soil.
[69] They intend to send small canisters of extremophile photosynthetic algae and cyanobacteria aboard a future rover mission.
[76] Rebecca Mickol found that in her laboratory, four species of methanogens survived low-pressure conditions that were similar to a subsurface liquid aquifer on Mars.
During the Planetary Science Vision 2050 Workshop[19] in late February 2017, NASA scientist Jim Green proposed a concept of placing a magnetic dipole field between the planet and the Sun to protect it from high-energy solar particles.
[80][81][19] A plasma torus along the orbit of Phobos by ionizing and accelerating particles from the moon may be sufficient to create a magnetic field strong enough to protect a terraformed Mars.
NASA's NIAC is sponsoring NC State which is working on designer plants/trees or genetically modified vegetation that could survive better on Mars.
