Science For Everyone: Welcome back to "Science For Everyone", ABP Live's weekly science column. Last week, we discussed greenhouse gases, their importance, and what role they play in climate change. This week, we discuss why colonising Mars is still a far-fetched idea, and the challenges that must be overcome before living on the Red Planet becomes a reality. 


When we talk about Mars, one of the first names that comes to our mind is that of SpaceX CEO Elon Musk, who founded an aerospace company because of his dream to take humans to the Red Planet. One of the reasons why scientists speak about colonising Mars is that they want a backup planet where humans could be transported to in the wake of an apocalyptic event striking Earth. 


NASA plans to launch humans to Mars by the late 2030s or early 2040s. The aim of the Artemis Programme is to prepare humans for future missions to Mars. 


But building a human base on Mars and living there is still far from reality. If humans were to colonise Mars, there may be many challenges to meet. Some of the most obvious ones are an adequate supply of water, negotiating the thin atmosphere in order to be able to breathe, and surviving the radiation on the Red Planet.


Mars's thin atmosphere


An atmosphere is extremely important for survival because it contains the gases required for different biological processes such as respiration and photosynthesis, protects the planet, and also keeps everything warm. Earth has oxygen, carbon dioxide and nitrogen in its atmosphere in the appropriate proportions. Also, the ozone layer in the atmosphere protects Earth from the Sun's harmful ultraviolet radiation. 


However, Mars has a thin atmosphere, and does not have gases essential for sustaining life in the required amounts.  


The amount of carbon dioxide in the Martian atmosphere is 95.1 per cent, while the gas makes up only 0.04 per cent of Earth's atmosphere. 


Our planet's atmosphere has 21 per cent oxygen, while the Martian atmosphere has 0.16 per cent oxygen. 


Plants, especially the leguminous crops, require atmospheric nitrogen to survive. Earth's atmosphere has 78 per cent nitrogen, while the Martian atmosphere has 2.59 per cent of the gas.


The atmospheric pressure on Mars is 6.518 millibars, while Earth's sea level atmospheric pressure is 1013.529 millibars, according to NASA. This means that the pressure on Mars is more than 100 times thinner compared to that of Earth.


Exposure to this low pressure could make human blood boil. 


Since Mars has a thin atmosphere, it does not trap heat, and allows the thermal energy to escape, as a result of which Martian temperatures are very low. The temperatures can be as low as minus 153 degrees Celsius.


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Water for survival


The Arizona State University describes Mars as a "planet-wide desert" compared to Earth. However, although it is not apparent immediately on sight, water does exist on Mars. The University cites four possible sources: frozen layers on the surface; underground water, water in the atmosphere; and water trapped in rocks and minerals. The challenge, therefore, is to access these sources.


While the most obvious target would be to access the water from the subsurface, no technology has been decided yet. NASA holds an annual competition, the Mars Ice Challenge, in which engineering students display prototypes of designs that simulate the extraction of water from the Martian subsurface.


Harmful radiation 


Harmful radiation is everywhere, but on Earth, we are protected from these charged particles by the planet’s magnetic field, which diverts most of these particles back into space. If humans were to live on Mars, they would receive no such protection from radiation, which is several times more than the radiation on Earth.


For humans to be able to colonise Mars, future technologies would need to create shields to protect people from radiation. Apart from protective clothing, habitable structures would be necessary. These would be of materials that are not only sturdy but also protective against radiation.