We once thought extraterrestrial Martians will come for Earth, but it’s turning out to be the other way around. Colonising Mars seems far-fetched a few decades ago, confined to the realms of Hollywood movies, science fiction, comic books, or our creative imagination.
It used to be that the Red Planet, considered as close kin to our Pale Blue Dot, was referenced in pop-culture only as a potential escape planet, an insurance policy of some sort for when the earth comes crumbling down from a terrestrial or extraterrestrial threat that leads to our extinction.
But now, we are living in a generation that might be the first witness to a human settlement on Mars. With the rise of space tech companies like SpaceX, Virgin Galactic, Blue Origin, and Made in Space, the notion of travelling through the cosmos, space tourism, space industrialization, and Martian citizenship are not far-fetched ideas after all.
Stepping in and living on Mars would not just be a giant leap for mankind, but would be a soaring launch towards the future. We will be the first species to become interplanetary, transcending beyond the bounds of nationality and culture. This interest is demonstrated by the number of people signing up to volunteer as first Martian citizens.
But, with the current technology that we have, are we close to getting there? What materials are required to have a thriving Martian colony?
Available Martian resources
Amongst all the planets, we are drawn to Mars because while it is ambitious to live there, scientists believe it is not entirely impossible to do so. It is accessible, right next to Earth, and has a climate and atmosphere that is complicated and constantly evolving just like ours does.
Mars also belongs to the Goldilocks zone or the region around a star where life could potentially exist, with temperatures that allow the presence of water. To design the right equipment and tools for survival, it is essential to understand Mars and its characteristics. Humans must effectively utilise Mars’ resources and its elements in order to sustainably survive.
Water Ice on Mars
Rovers and satellites have discovered that there is a massive amount of water in ice form found in Mars’ regolith, especially in the north pole. At times during a Martian year, liquid water is also observed to be present. Water, with its constituents H2 and O2, together with the abundant CO2 can potentially produce:
- Life support fluids
Atmospheric gas breakdown
The Red Planet has a rusty reddish hue with a surface that is mostly made from fine dust of oxidised iron minerals. Mars’ atmosphere is a hundred times thinner than Earth and is composed of the following gas elements by volume:
- Carbon dioxide- 95.32%
- Argon- 1.6%
- Nitrogen- 2.7%
- Oxygen- 0.13%
- Carbon Monoxide- 0.08%
The mineral composition of Mars is a collection of gathered data through studying Martian meteorites, probe (Viking 1&2) and rover sampling (Curiosity and Opportunity), and spectrometric analysis from orbiters (MAVEN- Mars Atmosphere and Volatile Evolution and MRO-Mars Reconnaissance Orbiter). It is found that beneath the fine dust layer, the crust is mostly made of basaltic minerals such as pyroxene, olivine, and plagioclase.
- Iron – iron on Mars would be a good structural material with the absence of free oxygen, as corrosion will not readily take place. Reduced gravity also makes iron less heavy on Mars.
- Silicon – Martian soil has high concentrations of silicon which can be used for electronic applications, ceramics, and in building solar panels
- Aluminium – aluminium and its alloys are valuable materials for spacecraft repairs, building rovers, and solar panel production
- Nickel and Titanium – NASA has developed metal tires with shape memory specifically for Mars made of nickel and titanium. These metals are also valuable for metallurgic applications.
Materials for colony building
In order to reduce or eliminate dependence on Earth’s resources and to save fuel required to propel materials, living on Mars sustainably using in situ space-based materials is the way to go. Many ideas are explored for habitat building- from the utilisation of existing structures in the surface (lava tubes and ice caves), asteroid mining, up to additive manufacturing with on-site materials.
1) No-bake bricks
Using Martian soil simulant from Hawaii basalt, engineers from the University of California San Diego have found that no additives or calcination is required to produce bricks in Mars.
The simulant soil, called JSC Mars-1a, is made up of 43.48% silicon dioxide and 16.08% iron oxide- a close replica of Martian soil measured at 45.41% silicon dioxide and 16.73% iron oxide.
To create the brick, the simulant regolith is placed on a flexible cylindrical rubber tube, pressed and compacted by a piston. When tested, the result is a brick that is stronger than steel-reinforced concrete even without rebar. This could be a feasible long term building block in expanding the Martian city.
2) Biopolymer composite homes
NASA’s Centennial Challenges are one of the methods used to engage the public in the conceptualisation of testing advanced technology that will solve these challenges, one of which is the 3D Printed Habitat Challenge.
MARSHA by AI Spacefactory won the competition with its settlement architecture that utilises recyclable biopolymer composite material made from Martian basalt fibre extracted from Martian rock and polylactic acid from plants grown on Mars.
It is a thermoplastic, thus reforming for other applications is feasible. From ASTM lab testing, this renewable composite was able to outperform NASA’s concrete in strength and compression. It was also tested to withstand Mars’ thin atmosphere, shield from cosmic radiation, and survive freezing conditions.
CO2 utilisation and propellant production
The presence of water ice and the abundance of CO2 can be used for local propellant production. The Sabatier process can use carbon from the carbon dioxide atmosphere, and water ice to produce methane (CH4) and O2. The CO2 from Mars can also be utilized to develop carbon nanotubes, a high strength, lightweight composite material that can be used for building spacecraft components and nuclear shielding applications.
Glassmaking and metal processing
Production of clay and glass is also feasible as the samples gathered by the Viking lander constitute silicon dioxide (SiO2) by 40% weight. Silicon dioxide is a basic constituent of glass and can be produced by conventional sand-melting techniques. The presence of iron oxide (Fe2O3) at 17% will pose a challenge for producing optical quality glass products though.
Glass products like fibreglass do not have to be optical quality but if required, iron must be removed to produce one. The iron can then be collected for other metal applications.
With Reverse water-gas shift (RWGS) reaction and the presence of carbon, hydrogen, and oxygen in Mars, synthetic ethylene can be produced as well as propylene as a side reaction. Combined with 3D printing technology, plastic production for machine and rover spare parts, piping, and structures can be executed.
Launching humans to Mars
Approximately every two years, Earth and Mars align in opposition with the Sun. That’s the best time to travel as the two planets are closest to each other. With that in mind, SpaceX aspires to send the first mission to Mars by 2022 with its two Super Heavy ship capable of carrying up to 150 tons of cargo.
The second mission is scheduled two years later in 2024 with two cargo and two crew ships. The first mission is intended to confirm water viability and supply, setting up a power source, mining equipment, and life support infrastructure.
With the success of the first mission, the second launch will follow to create the propellant plant, establish the first Martian base, and prepare for incoming missions. With the gravity of Mars only a third of Earth’s, boosters are theoretically not required for launch. And with in-situ propellant creation, it should make planetary travel easier and economical in the long run.
Martian settlement challenges
The challenge of Mars residency is not only limited to the 225 million kilometre voyage to get to the planet but to the day-to-day logistics of human survival in a foreign environment. Below are areas that currently require more in-depth research to figure out the best way of tackling the constraints imposed by Mars’ atmosphere.
Radiation shielding – materials to be used for clothing and shelter on Mars must be able to protect humans from the radiation coming from the solar particles and flares. Mars’ lack of magnetic field exposes explorers to more radiation and cosmic rays that can damage DNA, increase cancer risk and other health issues.
Food source – the materials required for creating a sustainable system for growing plants in space is essential for long term survival. Martian soil fertilization could be an option with the addition of essential soil nutrients such as nitrogen, potassium, and phosphorus. The utilization of organic food waste could also be useful besides the creation of controlled environments for plant growth.
Waste management – Without the presence of organic matter and decomposers that we currently know of, managing biological and material wastes in Mars is crucial for long term planetary colonization.
If SpaceX is on track to send the first humans to Mars by 2024. Advancement in these areas must equally progress in order to make the dream of Martian settlement a reality. What do you think? 🧐