What might have seemed like an utter impossibility a few years ago is being thought about seriously by the scientists, astrophysicists, researchers, etc. Yes, extraterrestrial building and construction it is! NASA, ISRO, and other private organizations like Elon Musk’s SpaceX are leaving no stones unturned to bring to reality what seemed like a distant dream when we all saw the movie Martians. Apart from that, many competitions are being conducted to encourage innovative design solutions for space.
However, lunar and Martian architecture would have a lot more complexities as compared to what is shown in the movies. The behaviors of materials, transportation to space, and other such intricacies have narrowed the possibilities of how we can build in space.
Let us look at some materials which are currently being considered to be used for extraterrestrial construction.
Aluminium was used for the spacecraft, Apollo 11, in the first-ever mission to land on the moon. Owing to its lightweight and the ability to form alloys with other materials and withstand pressure during launches, landing, and transit; the mission to build on Mars would be incomplete without Aluminium.
While Aluminium might not be considered to construct complete structures, it would form an important part of the structures. In addition to its apt properties, an added benefit is that aluminium oxides are available in abundance on the Mars surface. Aluminium is often alloyed with other materials to increase mechanical stability, dampening, thermal management, and reduce weight.
2. Martian Dust
What would be better for constructing in space than using the materials available in space itself! Regolith is a pulverized crushed rock layer that has been deposited on the surface of Mars over the years. Scientists are working on technologies to either build bricks or use it in other forms like 3D printing to construct on Mars. This would not only prevent the heavy expenditure of transporting materials from the Earth to Mars, across 225 km of space distance but also encourage in-situ resource utilization.
By developing a technique to form aggregates of this layer and build a layer on layers to construct buildings, there is a possibility of sending robots to Martian environments before astronauts to create settlements.
3. Lunar Crete
In 1985, a professor from the University of Pittsburgh, Larry A Beyer, proposed a hypothetical material Lunar Crete, also known as Moon Crete, to construct structures on the moon. It is an aggregate similar to concrete but made with materials available on the moon surface which include lunar regolith, cast regolith, glass and glass composites, metals, and concrete.
Owing to the low gravity of the moon, a heavy material like concrete is more suitable due to its strength, durability, and excellent shielding properties. Hence, the scarcity of water on the surface of the moon reduces the possibility of conventionally using concrete. LunarCrete can be prepared both with and without water, which makes it a favorable material for further research and development.
4. Mars Ice
Unlike the Moon, water exists on Mars. Many experiments are being conducted to be able to use the cold temperature on Mars to our benefit and construct ice colonies. A prototype has already been tried on Earth where water was used to 3D print a house in an environment cold enough for the water to freeze as soon as it gets printed. This experiment was carried out with the help of expert scientific advisors, astrophysicists, geologists, structural engineers, and renowned 3D printing experts.
Similar to the Martian dust, with this method, colonies can be constructed before astronauts head to the planet by robots. These robots too have been designed and are called iBo and WaSiBo. They have a triple nozzle that dispenses a composite of water, fiber, and aerogel to construct a structurally sound, layered translucent structure.
While finding materials on Mars and Moon is a viable option to avoid the transport cost, many designers have also been pondering over the possibility of transporting earthy, light materials to build in the extraterrestrial. The ‘Seed of Life’ proposal by Warith Zaki and Amir Amzar is one such example where they propose a bamboo colony on the Red Planet. Each modular pod is envisioned to be built over six years through a series of processes.
Firstly locating underground frozen ice to be used as a water source; then, sending a self deployable plastic habitat with bamboo shoots; waiting for three years for the bamboo to fully grow; then, weaving of the fully grown bamboos by autonomous robots into a structure, and finally, pumping water into the bamboo of the structure so that it freezes in the cold climate of Mars.