Given all the logistics involved, it is unlikely that humanity will ever see our way out of the solar system to colonize exoplanets. But the possibility of settling elsewhere in the solar system is not so far-fetched.
NASA is planning an advanced place on the Moon. Crew missions to Mars are not far away. Heck, we even already have humans living off the planet (even for temporary seasons) on the International Space Station.
So, is there any other place in the Solar System that humans can make from home? Well, according to physicist and astrobiologist Pekka Janhunen of the Finnish Meteorological Institute in Finland, the dwarf planet Ceres is not entirely improbable.
Ceres is an interesting piece of rock. It hangs from the asteroid belt between Mars and Jupiter and, with a diameter of 952 kilometers, is considered the largest known asteroid in the solar system and the only dwarf planet closer to the Sun than Neptune.
Why Ceres? Janhunen believes it marks many desirable boxes.
“The motivation,” he writes in a prepress paper published in arXiv, “is to have a settlement with artificial gravity that allows growth beyond the Earth’s habitable surface, while providing easy travel between settlements and a population density. reasonably low of 500 [people per] square kilometer “.
Mars and the Moon, he argues, may not be the best places for human colonies, because their natural gravity is very different from that of Earth. We know that astronauts face health problems when they return to Earth from a low or zero environment; we have very little idea of the effects of growth to low gravity maturity.
An alternative to the planetary colony model is an artificial space colony orbiting the Sun, a space station that rotates to generate enough centrifugal force to mimic a g: the gravity of the Earth.
That would also be terribly logistically. If the population grows too large for one settlement, several settlements may be needed. If several colonies are in orbit around the Sun, they could separate, creating other problems, such as travel between settlements. If they orbit a common body, collision avoidance becomes a problem.
Janhunen’s solution is quite orderly, really, at least in concept: use Ceres as the base around which the rotating settlement nodes, connected by a fixed frame, could orbit.
This would not only solve the problem of holding settlement nodes together without the potential for collision, but it would also perfectly solve the problem of materials, as they could be assembled directly from the dwarf planet. Nitrogen is of special importance, Janhunen said, as it makes up much of the Earth’s atmosphere.
But we also know that Ceres is quite salty, and recent research suggests that it may also have a lot of water below the surface. Solar panels on the surface of the dwarf planet could easily power a space elevator on the satellite.
“Lifting Ceres materials is energetically cheap compared to processing them in habitats, if a space elevator is used,” Janhunen explains. “Because Ceres has little gravity and rotates relatively fast, the space elevator is doable.”
He said radiation shielding could be built from 80% regulated silicate (Ceres rock) and water. Habitats would be divided into rural and urban areas, with a soil depth of 1.5 meters to 4 meters depending on the need for trees and gardens.
(P. Janhunen, arXiv, 2020)
Because Ceres is so far from the Sun, mirrors could be used to direct sunlight into the habitat, for the purpose of growing crops, illuminating them, and feeding them solar energy. These mirrors would be fixed on one side of the satellite in the form of a disk, like a make-up compact, and could be adjusted to collect as much sunlight as the dwarf planet moves around the Sun.
“We use a disk geometry for the megasatellite because its symmetry eliminates the tidal torque so that no reaction wheels are needed to maintain the attitude,” Janhunen writes.
“Habitats are illuminated by natural sunlight. Sunlight is collected from the disk by two flat mirrors tilted at a 45-degree angle and concentrated to the intensity desired by the parabolic mirrors.”
This could be cultivated, as needed, simply by adding more habitats to the edges of the first, potentially millions of habitats, for a lifestyle that might perhaps be even better than life on Earth.
After all, there would be no natural disasters or undesirable weather, and its modularity would mean that it could only continue to grow with the population. In principle, Ceres could support, according to Janhunen, 10,000 times the current population of the Earth.
Of course, everything is very speculative and has yet to be tested. In addition, Janhunen points out that orbital artificial gravity remains a goal yet to be achieved.
However, space elevators, giant mirrors, and radiation protection are enough to protect a space colony. Ceres’ orbital simulations and the logistics of transporting many humans out of Mars are also factors yet to be considered.
However, once these problems are planned, it would only take about 22 years to build a human satellite orbiting Ceres, Janhunen calculates.
“The overall level of difficulty in executing this project is probably similar to the settlement of Mars,” he writes.
“The delta-v and triptime to Ceres are longer, but on the other hand, planetary landings and atmospheric climate and dust are avoided. In Ceres an effort is required to elevate the materials into orbit. by lift, but it is energetically cheap. Once the materials are in high orbit of Ceres, the thermal environment is uniform and energy is easy to obtain due to the absence of eclipses. “
Definitely worth thinking about, right?
Janhunen’s article, written in the framework of the Finnish Center of Excellence in Sustainable Space Research, is available at arXiv.
H / T: Phys.org