Space agencies and star-eyed billionaires are now more than ever focused on finding a new home for humanity outside of Earth’s orbit. March is an obvious candidate, given its relative proximity, 24-hour day / night cycle and CO2-rich atmosphere. However, there is a school of spatial thought that suggests that the surface of another planet – any planet – is more problematic than it is worth.
Now, a new article published on January 6, dates from the preprint database arXiv offers a creative counter-proposal: Ditch the Red Planet, and builds a giant floating habitat around the dwarf planet Ceres, instead.
In the paper, which has not yet been peer-reviewed, astrophysicist Pekka Janhunen of the Finnish Meteorological Institute in Helsinki describes his vision of a ‘megasatellite’ of thousands of cylindrical spacecraft, all linked together in a disk-shaped frame that Ceres permanently revolves. – the largest object in the asteroid belt between Mars and Jupiter. Each of these cylindrical habitats could accommodate more than 50,000 people, support an artificial atmosphere and generate an earthy gravity through the centrifugal force of its own rotation, Janhunen wrote. (This general idea, first proposed in the 1970s, is known as a O’Neill cylinder).
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But why Ceres? The average distance from Earth is comparable to that of Mars, Janhunen wrote, which makes travel relatively easy – but the dwarf planet also has a major elemental advantage. Ceres is rich in nitrogen, which would be crucial in developing the atmosphere of the orbiting settlement, Janhunen said (the earth’s atmosphere is about 79% nitrogen.) Instead of building a colony on the surface of the small world – Ceres has a radius of about 1/13 of the Earth – settlers can use space elevators to transfer raw materials directly to the surrounding habitat of the planet.
This orbital lifestyle will also address one of the biggest reservations Janhunen sees in the idea of a Mars surface colony: the health impact of low gravity.
“My concern is that children in a Mars settlement will not develop into healthy adults (in terms of muscle and bone) due to the too low Mars severity,” Janhunen said in an email to Live Science. ‘That’s why I searched [an] alternative that would offer [Earth-like] gravity, but also an interconnected world. ‘
Nevertheless, Janhunen’s proposal comes with its own reservations that could work against a successful Ceres colony, an outside researcher said.
Welcome to disk-world
According to Janhunen’s proposal, each cylinder of the Ceres megasatellite will produce its own gravity by rotation; each cylindrical habitat would measure approximately 10 kilometers long, have a radius of 1 kilometer, and complete a full revolution every 66 seconds to generate the centrifugal force needed to simulate the earth’s gravity.
According to Janhunen, a single cylinder could comfortably accommodate about 57,000 people, and would be next to powerful magnets, such as those in magnetic levitation.
The mutual commitment points to the other great advantage of megasatellite life, Janhunen said: new habitat cylinders can be added indefinitely to the sides of the colony, allowing for almost unlimited expansion.
“Mars’ surface is smaller than Earth’s and therefore cannot accommodate a significant population and economic expansion,” Janhunen told WordsSideKick. A Ceres colony, on the other hand, “can be cultivated from one to millions of habitats.”
See the light
In addition to the cylinders and their massive disk frame, the colony will have the most important features of two enormous glass mirrors, which are 45 degrees relative to the disk, to reflect just enough natural sunlight into each habitat. A portion of each cylinder will be devoted to the cultivation of crops and trees, planted in a bed of 1.5 meters thick soil derived from raw materials from Ceres, Janhunen wrote. The natural sunlight should make them grow strong. (The “urban” part of each cylinder would meanwhile rely on artificial light to simulate an earthy day / night cycle. Janhunen does not determine where the settlement of the settlement came from.)
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This society of floating, cylindrical utopias may sound a little strange, but it has its proponents. In 2019, Jeff Bezos (Amazon’s CEO and founder of the private space company Blue Origin) spoke at an event in Washington, DC on the benefits of building ‘O’Neill colonies’ similar to those described by Janhunen here. Bezos was skeptical that such a colony could exist in our lifetime and asked the audience, ‘How are we going to build O’Neill colonies? I do not know and no one in this room knows. ‘
However, Janhunen is more optimistic. In an email to Live Science, he said the first human settlers could start moving to Ceres within the next 15 years.
Next year on Ceres?
Manasvi Lingam, an assistant professor of astrobiology at the Florida Institute of Technology, who studies the habitability of the planet, said the Ceres proposal offers an “acceptable alternative” to colonizing the surface of Mars or the Moon, but still does not have some important considerations.
“I would say there are three reservations,” Lingam, who was not involved with the newspaper, told Live Science. “The first is a matter of other essential elements besides nitrogen.”
One important element that is not mentioned in the paper is phosphorus, Lingam said. The human body relies on phosphorus to create DNA, RNA and ATP (an important form of energy storage in cells). All organisms on earth – including any plants that colonists may hope to grow in their floating habitat – need it in some way, but Janhunen’s proposal is not about where or how this critical element would be obtained.
The second warning is the technology, Lingam said. To extract nitrogen and other raw materials from Ceres, the planet’s surface would have to be mined and those important elements extracted from the rocks. This operation would probably not be possible without a fleet of autonomous mining vehicles ready to deploy on Ceres, plus satellites to lead them to the most viable nutrient-rich deposits. The idea is plausible, Lingam said, but technologically we are not there yet; recently (on January 15), a NASA Mars robot was pronounced dead after failing to bury himself just 5 meters into the Mars surface, he ended a two-year mission.
These technological limitations point to Lingam’s third warning, which is the proposed time frame. Janhunen’s proposal suggests that the megasatellite’s first group of orbiting habitats could be completed 22 years after mining on Ceres began. But according to this estimate, the available power supply of the settlement increases exponentially every year and starts immediately due to technological or logistical problems. The estimate “is not inconceivable,” Lingam said, but it should not be taken for granted.
“That 22-year time scale may be the lower limit under optimal conditions, but I would argue that the right time scale could be much longer,” Lingam said.
Originally published on Live Science.