The Answer to Earth’s Problems? Massive Space Stations, Say Some
Forget planets — let’s live on space stations instead.
That’s more or less the gist of Blue Origin’s vision. Though Jeff Bezos’s spaceflight company is currently only known for launching the occasional tourist to the edge of space, Blue’s overarching vision is the stuff of sci-fi dreams: with the goal of having ‘millions of people living and working in space for the benefit of Earth’, the company aims to transfer industry and even everyday life onto enormous space stations, conserving our home planet before it succumbs to manmade inflictions.
Preserving life by means of space colonization seems to be all the rage among billionaires these days; Elon Musk’s SpaceX, for example, is taking the approach of using megarockets to colonize other planets, starting with Mars. But while planets — which, in a way, are ready-made space stations themselves — can share some characteristics with Earth, they come with their own set of obstacles, including distance, hostile environments, and limited means of self-sustainability.
Space stations, meanwhile, are already in existence, with the ISS and China’s Tiangong station happily orbiting the Earth with astronauts onboard. The short distance makes for easy trips and swift construction; Tiangong’s assembly only took a year and a half. But life on space stations is anything but cushy, with astronauts dealing with zero gravity, cramped living spaces, exposure to radiation, and isolation, all of which can lead to health problems. The stations, which are not yet self-sustaining, also rely on regular resupply shuttles from Earth. To crack these problems and create that second home for humanity, stations of the future will need to step it up a notch. But in addition to the vast technical difficulties, such outposts may cause political and ethical dilemmas, which could throw humanity’s presence in space into question.
The idea of a man-made habitat in space has been around since long before manned spaceflight began. We have science fiction writers to thank for that; works such as 1937’s Star Maker and 1970’s Ringworld describe structures that were eventually researched and evaluated in a scientific context. There are now countless proposed structures of all shapes and sizes, some more feasible than others.
Among the more well-known concepts (popularized by Star Trek) is the Dyson sphere, inspired by Star Maker; it is basically a gigantic hollow ball built around a star like the sun in order to capture all its energy. As explained here, its radius would be about the distance of Earth’s orbit from the sun, and the spinning of the sphere would mean that gravity would only exist on a band along the sphere’s equator. That’s where people would live. However, according to Stuart Armstrong, a research fellow at Oxford University’s Future of Humanity Institute who has studied megastructure concepts, the concept is unviable due to the extreme ‘tensile strength’ required to keep the ball together against the forces exerted on it. Armstrong instead suggests a so-called Dyson swarm, consisting of many smaller solar panels and mirrors working together to capture the energy, with some modules for human habitation.
Sound ambitious? That’s because it is. The Dyson sphere — and other proposed methods of capturing most, if not all, of the energy put out by a body like the sun — is an important rung in the ladder of the Kardashev scale; developed by Soviet astronomer Nikolai Kardashev in 1964, it describes three ‘types’, or steps, of civilizations on a cosmic level (these steps have since been expanded upon by other scientists). Type I would be harnessing all of a planet’s energy, Type II would be that of a star, and Type III involves the entire galaxy. The scale was initially proposed to classify possible extraterrestrial signals and deduce the civilization’s level of technological advancement from that. But as noted here, humans score a feeble 0.7 on the scale, and building a swarm would require taking apart Mercury, Venus, and perhaps even Earth and Mars for resources. So, while collecting all the sun’s energy — which comes in at a cool 400 septillion watts per second — would surely come in handy, we’re not quite there yet.
Let’s scale back a bit, then. Several more attainable — but by no means easy — design concepts came about in the 1970s and were financed by NASA, still feeling the euphoria of the space race victory. The Stanford torus was one of them; it even featured in the 2013 film Elysium. As described here, the station is donut-shaped and rotates once a minute to create artificial gravity similar to that of Earth. People would live — and farm — on the inside of the donut, with a transparent ‘ceiling’ above them into which sunlight is reflected. About 10,000 people would live on the station; the study remarks that while it would be cramped, the number is not large enough to ensure complete self-sustainability.
The O’Neill cylinder is another proposal hailing from that period — if you’ve seen Interstellar or played Mass Effect, it might look familiar. It was proposed by American physicist Gerard K. O’Neill in 1979 as an advanced, ‘third-generation’ space station and could eventually host up to 700 million people; according to O’Neill, even a population of 200,000 would be large enough to become entirely self-sustaining. The station would consist of two cylinders, one inside the other; each is about 26 kilometers long and 6 in diameter. The cylinders rotate in opposite directions, which produces gravity and keeps one end of the cigar-shaped station permanently pointed at the sun. The circumference of the station ‘is divided into alternating strips of land area… and window area’, with mirrors regulating day and night cycles. The station could even sustain an atmosphere strong enough to have weather.
This idea caught Bezos’ attention; in 2019, he shared his vision for building such a station — or several — to move the bulk of industrial processes off-Earth.
Easier said than done, though; the sheer mass of materials needed for construction, let alone the mechanisms to do so, is unimaginable. O’Neill proposes starting with the construction of a ‘Model 1’ base with a population of 10,000, which in itself would require 500,000 tons of mass and a 2,000 person construction crew. For raw materials, O’Neill suggests mining the moon, remarking that it is ‘a rich source of metals, glass, oxygen, and soil’, and that an as-of-yet hypothetical mass driver could be used to transport these resources; such a mechanism, described by O’Neill as a ‘linear electric motor’, would accelerate small packages of mined materials until they are fast enough to escape the moon’s gravity and travel to the construction site. But space mining, though a promising industry, is in its earliest embryonic stages, and lunar colonies required for the installation of such hardware are still a pipe dream.
Even if one were to somehow pull this off, there is still the question of self-sustainability and In-Situ Resource Utilization (ISRU): using locally available materials rather than those shipped from Earth. As with any off-world colony, the importance of no longer relying on Earth grows as our planet is threatened by nuclear warfare, global warming, or asteroid strikes. But colonizing planets — as opposed to free-floating space stations — comes with the benefit of preexisting resources waiting to be mined or extracted (such as Mars and its ice caps).
Space stations are tricker in this regard. The structures must have enough room for agriculture and incorporate methods of recycling of water and oxygen; the ISS has mastered this particular art, reusing 90% of its water and 40% of its oxygen, although it still relies on Earth for the rest. As space mining will be a prerequisite for the construction of larger stations, water could eventually be harvested from certain asteroids, and then further split into oxygen and hydrogen (both of which could technically be used for rocket fuel, too). As for energy, solar arrays could provide a lot of it, with nuclear reactors (preferably fusion) providing another possibility.
Once the structures are in place, however, there’s the human factors to consider, including simple biology; at some point, a colony might become completely isolated from Earth or other stations, and genetic variation will become essential to the wellbeing of its inhabitants. One day, such an isolated community may find itself on a so-called generation ship: like a cosmic Noah’s Ark, these hypothetical ships could reach faraway star systems while traveling below light speed, with journeys spanning centuries to millennia.
As its name suggests, the trip would encompass several generations (unless someone solves ageing, or passengers are put to sleep for the journey), and though early estimates suggested a crew as small as 160 passengers would be enough for a 200-year trip, a more recent study recommends a crew of 40,000 for 150 years — which also could survive ‘at least one severe population catastrophe’.
What that could be is anyone’s guess, but given the harsh conditions of isolation in space, just one disaster seems like a lowball estimate. Sticking with the topic of genetics, inadequate protection from cosmic rays and radiation could cause damage to DNA and widespread cancer, leading to population depletion (as detailed here). Not only that, but limited resources mean that sick individuals may not receive the care they require to lead pain-free lives.
On the flipside, who gets selected for the trip (which is a matter in itself) determines what spacefaring generations of humans will look like. Depending on the length of the journey, our species could physically evolve and adapt to the new environment, with certain traits becoming desirable; with such a small population, breeding for these traits might even become selective, causing conflicts onboard.
Speaking of conflicts, how these stations would be run politically is another concern. Whether they are led by one nation, several, or even corporations: looking back at our terrestrial history, you’d be hard-pressed to find a century without some sort of conflict between states, and it is difficult to imagine how the population of a moderately sized city with severely limited room and resources could avoid the odd spat. In such a perilous environment, a small issue — such as deciding how to care for the sick, or how to handle selective breeding — could easily escalate into a mutiny of sorts; think Lord of the Flies, but on a larger scale… and in space. By the end, we may not even be the same species as when we started — physically as well as morally.
Finally, someone needs to maintain the station, and if it’s on its way somewhere, somebody should be able to drive the thing or know a thing or two about where it’s headed. Artificial intelligence might be able to help out here, but some human input will be inevitable. As a result, every generation must be educated and trained for the environment, which makes for yet another ethical dilemma: due to the small population, every single person born onto the ship — and their destiny — is inextricably bound to the mission, whether they like it or not. They will have no choice but to devote themselves to the journey with very little personal freedom; even things like whether or not to have children, and if so, how many, might not be up to the individual.
In addition, most generations onboard the ship will only ever know the inside of their artificial habitat, with no connection to their planet of origin or their destination (as mentioned by Neil Levy, senior research fellow of the Oxford Uehiro Centre for Practical Ethics and professor of philosophy at Macquarie University in Sydney). Sure, they’ll be shown some pictures, but their very existence will amount to being a lifelong bridge between one unknown and the next — a mere footnote in the pages of humanity’s greatest journey. Whatever we find out there… will it be worth inflicting this onto our descendants?
Whatever the answer, this decision is still way down the line. Even structures that will reside near Earth and allow for frequent population exchange are but a glint in Bezos’ eye, with Blue Origin’s first attempt at a space station — Orbital Reef — only planned for the second half of the 2020s. The station, along with competitors such as Axiom’s design, won’t even feature artificial gravity, let alone an Earth-like habitat. And while many proposed stations will focus mainly on research and tourism — and plans for lunar and Martian colonies are much further ahead than these megastructures — such stations might, in the distant future millions of years from now, provide the only way to leave our solar system when the sun toasts our planet. Staying would mean certain death. But leaving will change us forever.
Originally published at https://notrocketscience.substack.com on March 26, 2023.
