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About 70 000 years ago, in an event which would fundamentally change the course of human history, homo sapiens set foot out of Africa. Today, the descendants of those humans, having conquered Earth’s four corners, are preparing for their next big step: Mars.
Humanity's aspirations for setting foot on Mars appear in literature as early as the 17th century AD, in the works of German scholar, Athanasius Kircher. In recent years, numerous space agencies, including NASA, ESA, Roscosmos, and SpaceX have all set their plans for sending humans to Mars before 2050. In fact, SpaceX plans to land the first humans on Mars in just five years’ time - in 2024.
Sending humans to Mars is by no means an easy feat; once achieved, it could very justifiably be viewed as humanity’s greatest achievement. However, while human missions to Mars are expected to be regular throughout the 21st century, establishing permanent settlements on Mars and colonising the Red Planet will, most likely, not happen anytime soon. There are immense hurdles which space scientists and astronauts have to face and overcome.
Whereas Mars was once a warm planet with liquid water and a thicker atmosphere, making it a - potentially - hospitable planet, today, temperatures on Mars can reach as low as -60°C. Mars’ incredibly thin atmosphere, which is about 100 times less dense than Earth’s, means that the planet does not have a shield which protects it from cosmic radiation. Exposing astronauts to large amounts of radiation poses a serious neurocognitive risk that effects can persist if astronauts are not protected against it. A number of solutions have been proposed as to how we can overcome this problem, the most prominent being thickening Mars atmosphere, part of our plan to terraform Mars, or establish human-made ‘lava tube’ shelters.
In thickening Mars’ atmosphere, scientists can take advantage of the large amounts of carbon dioxide which are trapped beneath its soil, especially in its poles. Release of carbon dioxide is expected to thicken the planet’s atmosphere and also cause an increase in its average temperature. Increasing the planet’s average temperature through the release of carbon dioxide already present on Mars will create an insulating layer around the planet and will prevent heat from dissipating into space, allowing the planet to release its own carbon dioxide, thus becoming a self-sustaining system.
Lack of a global magnetic field on Mars, however, does not help in retaining an atmosphere as it does not protect against solar wind and is another issue which needs to be resolved. The idea of providing Mars with an artificial magnetic field by placing a satellite in orbit between the planet and the Sun has been proposed in order to protect Mars from high-energy solar particles, and to allow it to restore its atmosphere causing an increase in its atmospheric pressure and temperature.
The process of terraforming Mars to make it habitable to humans, however, is expected to take hundreds or thousands of years to complete. In the short-term, then, humanity must turn to other solutions which are more feasible and will make it possible for humans to start building martian colonies. This will be possible through paraterraforming Mars.
Paraterraforming refers to the construction of an enclosure on a planet, the atmospheric pressure, atmospheric composition, and environment of which are Earth-like and thus allow habitation by humans. Thus,instead of exploring the ambitious plan to fundamentally alter the climate and atmosphere of a whole planet, scientists can only choose to focus on a small part of Mars.
The Biosphere 2 project at the University of Arizona is considered the world’s largest earth science experiment and tested whether Earth’s ecosystems could be recreated in a closed, controlled, artificial environment in which humans would live for a long period of time. From 1991 to 1993, eight brave individuals lived in the Biosphere 2 dome on a permanent basis, without breaks. Although the mission produced both successes and failures, an overlooked aspect of colonising another planet was unveiled, and that concerned the social aspect and group dynamics of cohabiting with other humans. Besides the scientific hurdles, psychological and sociological aspects must also be taken into consideration when considering colonizing an entire other planet.
As the day the first humans will step on Mars comes closer, we can be certain that that will not be a ‘small step’ for humans. Landing on Mars will establish something that humankind has only been dreaming of: the idea that it could spread out amongst the stars and become an interplanetary species.