Is human colonisation of Mars truly within our reach?

Dhruv Mandhar
May 24
5 min read

The last time humanity stepped on a celestial body other than Earth was over five decades ago. So, is it actually realistic for us to even think about going to Mars in the near future? And even if we manage to reach there, will we ever see humans living on Mars for extended periods in our lifetime?

Well, to begin, the journey to Mars is an obstacle in itself. The distance to the Red Planet is, on average, 225 million kilometres, resulting in a travel time of around 6 to 9 months, using today’s technology. A massive challenge that arises is that during the journey, the astronauts would face roughly 300-600 millisieverts (mSv) of radiation from various sources in outer space; in comparison, the average natural background radiation dose on Earth is approximately 2.4 millisieverts (mSv) per year. One of these sources is galactic cosmic rays, these are high-energy particles that originate from outside our solar system and can lead to lead genetic damage, increased risk of cancer and deteriorating kidney function. To protect themselves from the radiation, Astronauts can line the walls of the spacecraft with water storage tanks, as water is a highly effective, hydrogen-rich radiation shield. When radiation penetrates water, it is reduced by half every 18 cm. These water-based solutions also provide essential hydration, as the water is recycled from human waste.

Landing on Mars presents a different but equally complex challenge. The Martian atmosphere is thick enough to generate enormous amounts of heat, yet too thin to slow a spacecraft using only a parachute. A proposed solution involves a combination of supersonic retro propulsion (SRP), large heat shields, and autonomous preparation of landing sites. SRP is a landing technique in which a spacecraft fires its engines in the opposite direction to its descent, whilst moving at supersonic speeds, to slow down. This technique has been successfully used in the past, most notably by SpaceX during the recovery of the Falcon 9’s first stage boosters in 2015. Since then, SpaceX has continued to use SRP to decelerate its boosters, allowing for recovery and reuse. Landing site preparation involves a robotic mission to clear the target zone, allowing a human lander to arrive safely and minimise the risk of cratering by blowing away debris during landing.

Now comes arguably the most difficult aspect: surviving on Mars. Mars is much colder than Earth, with average surface temperatures of around -60 °C. Not only is the freezing weather a challenge, but the atmosphere is composed of 95% carbon dioxide and only trace levels of oxygen, making breathing in those conditions impossible. As a result, any future settlement on the Red Planet would have to rely on complex life-support systems to provide oxygen, water, and temperature regulation. The artificial habitats that would be required on Mars would have to be reliable and recycle resources with extremely high efficiency, as humans would die without water after days, and deliveries of water would be too expensive and take too long.

Another significant challenge limiting human exploration to Mars is exposure to cosmic radiation. The planet has a weak magnetic field and a relatively thin atmosphere – approximately 1% of Earth’s – meaning that radiation reaches the surface much more easily. The lack of planetary protection means radiation exposure is a serious health concern for astronauts on the surface, and exposure on long missions is unavoidable. One solution to this problem is to use Martian soil (regolith) to cover habitats or to form bricks. Placing only a few metres of regolith over habitats can drastically reduce radiation, and it’s estimated to be equivalent to the shielding effect of Earth’s atmosphere.

To sustain human presence on Mars, food will need to be produced locally, as it would be extremely costly to regularly transport supplies from Earth. As a result of the regolith being toxic with high concentrations of perchlorates, a component of rocket fuel, there would be a need for soilless farming methods such as hydroponics and aeroponics to successfully grow crops. Whilst hydroponics involves submerging roots in nutrient-rich water, aeroponics involves roots being suspended in the air and they are misted with nutrients. Furthermore, the use of Genetically Modified Crops would be useful if they could be engineered to withstand high radiation, low gravity, and high salinity. However, the soil would need to be remediated for long-term use by using bacteria to consume the toxic perchlorates and by adding nitrogen to support future crop growth.

Despite all these obstacles, the colonisation of Mars could drive technological advancements and enhance our knowledge and understanding of planetary science, not to mention the long-term safeguarding it would provide humanity with. However, huge engineering solutions must be found to even successfully land on Mars. Future research would require billions in funding, and there is no certainty that it will be successful. Furthermore, the Outer Space Treaty prohibits countries from claiming Mars as sovereign territory, and there have been many debates amongst researchers whether colonisation would repeat colonial patterns or risk contaminating possible Martian life.

In my view, the challenge of colonising Mars is one of the most complex ever and is far from realisation, as it requires breakthroughs across multiple engineering fields to even be possible. The world ‘colonise’ may be too unrealistic for today’s technology, and it is more likely that short-term human missions would be feasible rather than a permanent civilisation.

In conclusion, while colonising Mars remains an extraordinary engineering challenge, it is not too unrealistic. Although it may not occur in the next few decades, the attempt to reach Mars itself will push the boundaries of engineering and physics, leading to innovations that will benefit life on Earth as well.

Bibliography

Front Cover Image - SpaceX Starship concept on Mars (Credit: SpaceX)

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