The idea of colonising other planets has featured in science fiction literature since at least the 1920s and has become a common theme in books and games as well as movies and television. Now it appears that reality will soon catch up with fiction.
Last year, the well-known multi-entrepreneur Elon Musk, the man behind Tesla, SpaceX, and other companies, presented his plans to establish a permanent colony on Mars, and his plans are very ambitious indeed. The first step is the launch of two huge rockets to Mars in 2022 with equipment that can find and extract water and produce fuel. Two years and two months later, when Mars is once again close to the Earth, two additional rockets will follow, one with equipment, and another one with an unspecified number of colonists. The used rockets can be returned to orbit around the Earth, using the fuel extracted on Mars, and can be reused about 1,000 times. In time, up to 1,000 rockets, each carrying 100 settlers or more, will be sent to Mars every 26 months; in this way, Elon Musk hopes to send a million people to Mars during the next 50-100 years.
This is, obviously, an extremely ambitious project, but Elon Musk has realised very ambitious projects before. SpaceX plans to send about 30 rockets into space this year alone, so maybe the capacity exists for making the dream come true.
Elon Musk is not alone in his plans to send people to Mars. The American space agency, NASA, has a more cautious plan of more unmanned missions before sending people to the Red Planet in the 2030s with equipment that will allow them to survive without depending on supplies from Earth. One could also mention the private project Mars One that, in 2011, announced its plans to send colonists to Mars from 2031. This project, however, is generally considered unrealistic, and Mars One has only succeeded in raising about USD 1 million from investors. In comparison, each launch of SpaceX’s Falcon Heavy rocket costs UDS 90-150 million, and the rockets that SpaceX will be sending to Mars will be even bigger.
Colonising Mars is probably possible, but most likely it is more problematic than Elon Musk makes it. He focuses on getting people to Mars, but leaves it to others to find out how they are going to survive there – which is just as much of a hindrance. In time, it may very well become possible, but I will make the objection that survival is not the same thing as thriving – having a good life.
Mars is not a nice place to be – Antarctica is a tropical paradise in comparison. At least, in Antarctica you can breathe outside without dying in a few seconds. There is almost no air on Mars, and the little there is, is mainly carbon dioxide. The lack of atmosphere and magnetic field also means that there is no shielding against cosmic radiation or radiation from the Sun. The average temperature is −63 °C. The colonists on Mars will have to remain indoors most of the time in buildings shielded against cold, radiation and low pressure, and even with insulated spacesuits it will not be healthy to stay outdoors for a long time. We may, with the use of future technology, make Mars more habitable, for instance by bombing the planet with comets to provide water and air, but the costs will be enormous, and even in the best-case scenario, Mars will never become similar to the Earth. Gravity is about one third of that of Earth, and an extended stay on Mars will wear away bones, muscle, and heart. An eternal twilight will prevail – Mars only receives 43 per cent as much sunlight as the Earth, and as it takes nearly three times as much atmosphere to create the same pressure as on Earth, only a small amount of the light will reach the surface. It may be an interesting place to visit, but I wouldn’t want to live there.
When colonising Mars can still arouse so much interest, there are two related incentives at play. One is a pioneering spirit, the old dream of exploring and conquering new regions – a spirit that greatly characterises the North American population who, themselves, have been colonised by pioneers over the last five centuries, which may explain why the dream of colonising Mars is particularly strong over there. The other impetus is an understanding that it would be unwise to put all our eggs in one basket: If something disastrous happens to the Earth, it would be a good thing if there were people elsewhere. But the question remains if Mars is the right place to put the proverbial eggs.
Constructing artificial habitats – in loose terms, cities in space – would be much easier than making Mars habitable. With the international space station, ISS, we are already doing this on a small scale, even if the ISS is very much dependent on supplies from Earth. It is, however, a beginning, and in the attempt to achieve more independence the ISS astronauts are reusing their urine as drinking water, and there are plans to turn their faeces into food as well. This first step is still far from actual independence, but it will be no more difficult to create a self-sufficient space station than establishing a self-sufficient Mars colony. It may even turn out to be easier.
With the aid of robots, metal, carbon, ice, and other important materials can be gathered from asteroids and comets and used to construct large space stations that rotate to create artificial gravity – as we have seen it in the movie 2001: A Space Odyssey, and the Babylon 5 television series. We will be fully able to control the pressure and composition of the atmosphere, and foodstuffs can be cultivated under controlled circumstances or produced artificially from algae. Compared to transporting materials up and down the gravity well of a planet, it will require much less energy to move materials around in space. There will be plenty of solar energy, but fusion power is another option, as the helium-3 isotope that is well-suited for fusion energy is much easier to come by in outer space than on Earth.
Even if space cities have to be shielded against radiation and micrometeorites, the asteroid belt contains plenty of material for building space habitats for millions or even billions of people – particularly if we include the Kuiper Belt, the larger asteroid belt that encircles the Sun outside the orbit of Neptune. The dwarf planets Pluto, Eris, Haumea, and Makemake are situated in the Kuiper Belt which is, however, mainly made up from smaller celestial objects composed of ice, frozen gasses, carbon, minerals, and metals. Here is everything you need to create habitable space cities with fields, lakes, forests, and everything. However, the Kuiper Belt is so far from the Earth that it took the New Horizons space probe nine years to get there, so we probably won’t be moving there anytime soon.
Cities in space will be places where we can settle down and live, but also a kind of prison, for we cannot survive outside, and we can’t even build them ourselves – we need robots for that. Maybe robots will become the true space colonists (see “Space belongs to the robots”, SCENARIO 6/2017).
If we move out from the Earth, we will no longer be keeping all our eggs in one basket, but the eggs will still be confined to the baskets. The eggs will not be able to hatch and become free-flying birds. At least, that would require that we changed ourselves radically so that we could actually survive and thrive in empty space. This may become possible with future technology, but it will not be easy, and it will require that we develop an artificial ecosystem of crops that can subsist in space, too. The space people will have to find food somewhere, and it is a well-known fact that apple trees don’t grow to the sky. In any case, it will not be a life we will recognise as human.
Most probably we will take a middle course, modifying ourselves for a life in weightless condition, for example with extra arms and hands instead of our legs and feet. It would also be practical if you did not need full atmospheric pressure in the space habitats but could make do with almost pure oxygen at a pressure of one-tenth of an atmosphere. We may even become able to survive for short periods in vacuum wearing only an oxygen mask, for instance by acquiring a thicker and tighter skin to keep our blood and organs under pressure by means of elasticity. In that case, humankind will be divided into at least two separate subspecies, one living on Earth and in artificial Earth-like environments, one adapted to life in weightless space cities, and maybe several others, modified for living on Mars, or in the oceans under the surface of the large moons of Jupiter. In the past, Homo sapiens have had to share the world with other human species such as Neanderthals, and it may very well be that we, in the future, will have to share outer space with other, even more different cousins – homo spatialis.