Why are we particularly interested in space settlement, rather than simply space exploration, or even just the development of space industry? What are the benefits of actually living there?
Space represents an unlimited supply of valuable resources, including energy, metals, carbon, water, hydrocarbons, gases, and minerals; the building blocks of every useful resource required by our civilization. If the burgeoning human population on Earth is consuming too many resources for one planet, as some experts claim, then space is the answer. Not only can resources from space be used on Earth, but also in space by the new communities we create there. Having access to abundant resources for constructing and powering space cities and vehicles will give rise to a vibrant space economy and civilization, ultimately spanning the Solar System.
- Metals, carbon, silicon, water, oxygen, ammonia, and more are available in abundance from asteroids. There are literally millions of asteroids in our Solar System, many the size of large mountains, composed of valuable materials. Metals, carbon, and silicon can be used to build space stations and ships, and water and oxygen can provide them with propellant and critical life support resources. Ammonia can be used as fuel, fertilizer, a source of nitrogen and hydrogen, and more.
- Solar energy can be collected in space, where the Sun always shines, without impedance by atmosphere or clouds. Solar-powered satellites can be placed in the orbits of Earth, Luna, Mars, and other worlds, to provide continuous energy to settlements on the surface.
- Hydrocarbons, such as methane, can be accessed from icy asteroids and moons. On Earth, much of our technology is still heavily dependent on hydrocarbons, which we mainly utilize for electricity and heat. However, even as we transition to sustainable energy, hydrocarbons will remain important for the production of plastics, lubricants, and other products, and are a valuable rocket fuel.
- Fusion fuels such as deuterium, tritium, and helium-3 (see Table 1, below) can be found in lunar regolith, Martian ice, and in the atmospheres of the giant planets. If fusion becomes a commercially viable energy technology, space will give us access to more fuel than we will ever need. Fusion may be the preferred method of powering settlements in the Outer Solar System, and new forms of high-speed space travel.
- Rare earth elements, required for many modern technological products, can be found in concentrated deposits on both Luna and Mars. These elements can be difficult to refine and recover, which is why such ore deposits are extremely valuable.
Accessing the resources of space will enable the building and supply of space settlements. In this way, settlement of space is analogous to the Americas or Australia, when settlers utilized locally sourced wood, stone, water, animals, and other resources, to build and supply new settlements.
Although space exploration and settlement will initially be supported using resources from Earth, once we begin tapping the resources of space it will become much easier and cheaper to build and do more. Luna, Mars, and especially the asteroids, all have much shallower gravity wells than Earth, which means sourcing resources from these bodies for use in space will eventually be much cheaper. Plus, construction on the surfaces of these bodies will be much cheaper than if materials were supplied from Earth.
As our technological capability increases, we are able to access resources everywhere more easily and cheaply, increasing their supply and reducing cost. However, the exponentially increasing demands of our growing population can sometimes be difficult to meet. Access to the resources of space, and progressively improving the efficiency with which we can obtain these resources, will eliminate that problem, perhaps forever. This abundance will mean an improved quality of life for all people and other creatures on Earth, and everywhere else in the Universe where we may spread.
Main isotopes of hydrogen and helium.
|Isotope name||# protons||# neutrons||Symbol||Nucleus name||Abundance|
or light hydrogen)
or heavy hydrogen)
|1||1||2H or D||deuteron||0.02%|
|1||2||3H or T||triton||trace|
|helium-4||2||2||4He||alpha particle||99.999 8%|
Space research will help to ensure the survival of humanity and other Terran species once we learn how to prevent or limit the damage that could be caused by asteroid impacts. It’s possible that Earth will again be hit by a large asteroid, maybe even as large as the one that wiped out most life on Earth 66 million years ago. While major collisions of this type are extremely rare, there are still plenty of large asteroids out there, and impacts will continue to occur. The effect of a major impact could be globally catastrophic.
Advances in astronomy are improving our ability to detect potential impactors in advance, but the development of an asteroid mining industry may enable us to redirect them or break them into pieces.
It’s fortunate that many asteroids are made of highly valuable materials, because if we aren’t sufficiently motivated by the risk of a major impact to develop the technology to redirect or break asteroids, then maybe the potential for vast profits will do the trick.
Space settlement will provide an additional layer of protection, because if an asteroid arrives which is too large, or moving too quickly for us to divert, and it hits Earth, then the people living in space settlements — especially those on Mars, which may have the potential to be self-sufficient and independent from Earth — will survive, even if people on Earth do not. This underlines the importance of establishing a self-sufficient branch of human civilization on Mars.
Asteroids are nature’s way of asking: “How’s that space program coming along?” — Neil de Grasse Tyson
Space settlement will greatly improve our confidence as a species. We’ve seen this before; the Apollo program gave humanity (or at least the US) immense confidence. For many years afterwards, people had the attitude of: “If we can go to the Moon, we can do anything!”. Similarly, once we start sending people to Mars, we will again believe that we can do anything. We will start to see ourselves as an advanced, spacefaring species capable of achieving great things on vast scales. When people are living in space, no-one will seriously suggest that we cannot feed everyone, clean the oceans and the atmosphere, or construct a global renewable energy grid. We will just point to our cities in orbit, or on Luna and Mars, and say: “Just look at what we can do! We can do anything!”
A new frontier
Space exploration and industry will open the way to the final frontier, but space settlers will claim it for their own. A physical frontier is arguably essential for human evolution, due to its powerful stimulating effects on the mind. Frontiers break us out of established living patterns. Comfort and safety have their virtues, but too much can be dangerous, potentially encouraging slothfulness, decay, weakness, and complacency. Frontiers, by contrast, can be difficult and dangerous, but they encourage innovation, resourcefulness, and growth.
It will be much more of a challenge to live permanently in space, or on Luna or Mars, than it will be to simply visit, because ongoing supply and maintenance of settlements will require significant local agricultural, mining, manufacturing, and other capabilities. Space settlement entails much bigger challenges than exploration, and will require bigger thinking and better planning. It will mobilize capital and human resources to a much larger degree, and will require significant innovation. The process of settling new worlds will push humanity to higher levels of achievement than we ever dreamed possible.
The frontier also advances and develops the higher spiritual functions of the human mind, not only stimulating new technological ideas, but also philosophical ones. Our physical frontier is thus paralleled by an intellectual frontier, and it may be that expansion into the Universe is necessary for ongoing development of our intellect, consciousness, wisdom, and civilization. The frontier forces us to rethink the established patterns of our culture in the context of new environments and new technologies, producing a new society which is at least partially legacy-free. It encourages reinvention, not only of physical systems, but also of social, political, and economic ones. The space frontier will afford us the opportunity to foster the good aspects of ourselves, and leave the bad ones behind.
Living in space will give us much more scientific knowledge than can be gained from simply visiting. The more time we spend somewhere the more we learn about it, and this is as true in space as anywhere else. If we really want to understand Mars, we need to be there, on the ground, experiencing its unique astronomical cycles, climate, weather, rocks, dust, sky, landforms, etc., and its relationship with the Sun, its moons, and other celestial bodies. When we make Mars our home, it will become part of us, as we become part of it. We’ll really learn a lot as Mars’ unique environment challenges us in many unforeseen ways. Over time we will unlock more and more of its mysteries, and the increase in our scientific understanding, as well as our technological capabilities, will open up more new worlds for settlement.
The frontier, and the freedom and incentive to invent new things from available resources, has always produced new technologies. We only have to look at the history of the frontier in America, Australia, and many other regions of Earth for evidence. Expand into new environments always involves challenges, yet the resources available to meet these challenges may be scarce, different, or unfamiliar. However, if the desire to expand (or, indeed, survive) is powerful enough, then solutions will be found. Such situations bring out the best in human creativity, and is what drives innovation.
It will be much harder to reside permanently in space than to merely explore it. The process of learning how to live on Luna and Mars, and the development of the space economy, will produce tremendous innovation. We will develop robots and telerobotics for tunneling into rock and carving out habitable volumes; efficient and inexpensive renewable energy technologies; efficient food production systems; advanced water recycling and purification systems; super-intelligent computers, vehicles and robots; new technologies for manufacturing and recycling; high-speed space transportation; low-latency, high-bandwidth space communications systems; artificial gravity; and many other new and wonderful technologies, all of which will accelerate humanity to new levels of achievement.
Right now, we’re observing exponential advancements in technological development due to the rapid evolution of the Internet, emergence of a common language, crowd-funding, and an abundance of venture capital. This trend will only continue as we expand into space, and the unique challenges of space development trigger a cascade of new inventions.
Many new technologies that are being developed now, and that will be developed as we learn how to live in space and on Luna and Mars, will find applications on Earth and elsewhere as we expand to new places in the Solar System.
More environmental benefits!
Space settlement will help to create a cleaner, healthier Earth. Living in space requires in-situ production of energy, water, air, food, and materials; efficient recycling and waste management; environment control and life support; mining and manufacturing; advanced robotics and telerobotics; and much more. These same technologies, applied on Earth, will reduce waste and pollution, increase abundance and health, and enable people to live in new regions, while also improving living conditions in many existing regions, and reducing our environmental footprint.
Space habitat design produces insight into air and water recycling, food production, waste management, mass and volume optimization, and more. We know how much volume and energy people really require to live, and it’s much less than what we habitually use on Earth. This suggests opportunities for more efficient use of land, water, energy, and other resources.
Learning how to live in space will teach us how to live, affordably and safely, in more exotic niches of Earth; in particular, underground. This will reduce the need to destroy Earth’s biosphere for the sake of cities or agriculture.
Food systems developed for space will be high-tech, potentially modular, and capable of producing a healthy, nutritionally complete diet, reliably, unaffected by weather, and requiring only a fraction of the usual energy, water, land, and fertilizer. This technology can be used on Earth to feed people while reducing land requirements for agriculture, potentially freeing up cleared land for restoration of the biosphere. It may even be possible to reduce the total amount of land and fresh water we require for food production, even as Earth’s population grows.
Backing up life
Space settlement can help to ensure the long-term survival of numerous Terran species. Species can become extinct due to hunting, predators, climate change, rising or falling sea levels, loss of habitat or food sources, pollution, or disease. Generally speaking, extinction is caused by an inability to adapt to changed conditions or to migrate to more suitable areas.
There have been five mass extinctions in Earth’s history, in which a large percentage of Earth’s species became extinct within a short time frame. These were caused by supervolcanoes, climate change, and asteroid impacts.
When we begin to inhabit other worlds, we will take many species with us, including bacteria, plants, fungi, and animals. Once a species is living across multiple worlds, it will be protected from most possible causes of extinction, because of the extremely low probability that all worlds where that species is present will become uninhabitable at the same time. And, if a species does become extinct on one world, its population can be restored from individuals of the same species from other worlds.
An Earth-compatible planetary biosphere on another world could potentially support millions of Terran species. If a world already hosts a compatible biosphere then it would be unethical or at least unwise to transplant Terran species to that world, due to the risk of unbalancing the local ecosystem and adversely affecting indigenous species, just like when cane toads, rabbits, and other species were introduced to Australia. However, if a world lacks such a biosphere, but can be engineered to support one — i.e. terraformed — then potentially millions of Terran species could be transplanted there and thus protected. Mars is widely believed to be terraformable, which is a major part of its appeal.
Right now we’re losing countless species across the planet due to climate change and habitat destruction. The current extinction rate is estimated to be on the order of 1 000 times greater than the usual background rate, and this accelerated rate of species loss has been called the “sixth mass extinction”. Unfortunately, space settlement is not a solution to this particular problem, and we must learn to value the natural environment more highly and protect it from farming, mining, and industry. Nonetheless, many species on Earth will always be under pressure due to the large human population, and the sooner that some can spread to new worlds, the better.
Population growth of species is often imagined to be exponential. However, this is only true while resources are plentiful. Limits on available resources cause the growth rate to gradually decrease as the population approaches the carrying capacity. This curve is called a logistic function.
On Earth, we have already passed the “point of maximum growth”, when the growth rate of Earth’s human population peaked in 1969 at about 2.1% (see graph below). Experts predict that Earth’s population will stabilize at around 11–12 billion.
Birth rates worldwide are decreasing in line with economic development.
In developing countries, especially where there’s significant gender inequality, the number of children per family is often higher. This is due to a higher infant mortality rate, lack of social security (because the more children a family has, the more income there is to support the elderly who can no longer work), and because females earn less, which creates an incentive to have more children in order to have more boys.
However, in developed countries, it’s common for couples to have two or fewer children, due to better nutrition, health care, education, and social services, and because women have access to higher education and are free to pursue options other than motherhood.
Death rates are also decreasing. The average human life span is increasing as medical science and technology improve, and life spans of over a century and potentially much longer will be more common in the future (especially when people stop consuming so much animal-based food, refined carbohydrate, alcohol, tobacco, and other drugs). Premature death is also less likely due to a steady decline in war, crime, famine, disease, and dangerous work.
The decline in both birth and death rates produces an aging population, in which a decreasing number of young people are supporting an increasing number of elderly people. This may not be as much of a problem in a highly automated, post-scarcity economy, but a birth rate that is too low is undesirable regardless. In addition to their important contribution to the economy, we need young people for the energy, idealism, and vision that they bring to the world.
The human population, as with any species, has a tendency to increase, because we’ve evolved for survival and reproduction. However, it cannot increase indefinitely on a single planet because of the limitations on natural resources.
To be fair, the carrying capacity of Earth will steadily increase, as technological advancements, especially in areas such as renewable energy, food production, desalination, genetics, and recycling, make it possible for humans to utilize available resources more efficiently and to live in more places, including the polar regions, on oceans, in deserts, underwater, and underground. However, this will only delay the inevitable, and there will always be a maximum sustainable carrying capacity while we remain confined to a single planet.
Space settlement is the only practical way to continue increasing the human population beyond the maximum carrying capacity of Earth. The number of people who can move to or be born in space will increase exponentially as we get better at building space settlements, and especially at planetary engineering. Birth rates can then be maintained at a high enough rate to ensure a sufficient youth population, and deaths due to resource shortages can be avoided as people move off-planet.
Once we start living in space, limits on the human population will then be defined by the maximum carrying capacity of the Solar System. This, too, will increase over time as we improve our technology and learn how to live in more places.
The terraforming of Mars will probably be the most important project we can undertake to increase the carrying capacity of the Solar System, as this will provide land, water, and other resources to enable the large-scale habitation by millions of organisms; not only humans but many other Terran species as well. Perhaps we can terraform Venus, too.
The human population will eventually reach a sustainable maximum within the Solar System, and that may be enough; since, by that time, our long-term survival will be assured, at least until the death of the Sun. However, considering human nature, and the research already being done into terrestrial exoplanets and interstellar travel, it seems far more likely that we’ll expand to nearby star systems and continue to prosper and increase for billions of years to come.
And here’s us, at the beginning of history, dreaming it.