The Alpha Centauri (α Centauri) system is the closest star system to the Sol system. It is made up of three stars: Alpha Centauri A and Alpha Centauri B form together the binary system Alpha Centauri AB. A small red dwarf Alpha Centauri C, which is more often called Proxima Centauri, is the third star. It was one of the first star systems outside of the Sol system that was colonized by humans in Scenario: The Expanse. Its colonization was called Operation Odyssey, this started with sending three ships to the system: SS Chiron, SS Nessus, SS Ixion After this several waves were sent, about 15 ships in total.
The stars[]
The distance between Alpha Centauri A and B varies from the distance between Sol and Saturn (11.2 AU) and almost the distance from Sol to Pluto (35.6 AU), Proxima Centauri orbits the stars at a distance of about 13,000 AU (0.21 ly) it would take an interstellar ship 2 years to complete this journey. The stars of the system are used similarly to Sol. They are obviously way to hot to settle, but they do emit a lot of light. So they are orbited by a lot of mirrors, these mirrors concentrate the light of the stars into several points at these points gigantic solar panels are located similar the ones around Sol. Alpha Centauri A is often just called ”A”, Alpha Centauri B is often called “B” and Proxima Centauri is often called “Proxima” or even just “Prox”.
Proxima Centauri system[]
Proxima Centauri I (Vulcan)[]
Proxima Centauri I, known in our time as Proxima Centauri b and better known as Vulcan, named after the Greek god of volcanoes and smiths has 1.3 times the mass of Terra and a year of 11 Terran days, four hours and just under 30 minutes. The planet is tidally locked and has an orbital eccentricity of just over zero, one side of the planet is in perpetual darkness while the other side in perpetual sunlight. The first colony was build underground in the twilight zone and named Hephaestus after the Greek version of Vulcan. It has countless solar panels which power the facility. The second one that was built was on the night side, but using mirrors humans were able to focus some visible light on the domes, this created an artificial 25-hour day-night cycle. Currently the planet is home to nearly 1.7 billion people along with the largest solar power plant, covering an area the size of 4.04 million km2 , just under half the area of the continental united states. The planet is also surrounded by O’Neill cylinders and Stanford tori. Vulcan is under control of the Vulcan union, a government in which 3 independent nations work together, these nations are: the Dies Stratocracy located on the day side, is the main military power of the alliance, the Nix Technocracy located on the night side is the main technology producer of the planet and lastly the Diliculum Republic, a plutocracy in which the rich hold the power, the Diliculim Republic is by far the richest of the 3 and the other two are often jealous over the territory that it holds.
Proxima Centauri asteroid belt[]
The Proxima Centauri asteroid belt, often called the Proxima asteroid belt, Proxima belt, Proxima Centauri belt or Prox belt is the asteroid belt surrounding Alpha Centauri C inbetween Vulcan and Chione, that orbits the star at a distance of 0.2 to 0.5 AU. This asteroid belt is similar in composition to The Sol asteroid belt. With C-type asteroids compossing about 2/3 of the asteroids, S-types are about 20% and M-types around the 13%. People in the belt live inside cylinders that are buried inside asteroids. Most people work in either agriculture or asteroid mining.
Juno[]
Juno is the largest asteroid in the Proxima belt and has a diameter of 453 km. The asteroid is covered in a layer of ice that is used as both drinking water and is split into oxygen fro breathing and hydrogen as fuel. It is covered in several massive craters, includding the famous Hebe crater, which can be seen on the image. The asteroid is home to 6 cylinders: Hebe, Iris, Hera, Eileithyia, Typhaon and Charites. Each of which are named after either the crater or mountain they are under. Their harbors all work the same: a ship lands in the crater and the people have to get out with a suit, while the cargo is brought with a truck to the inside, the people and cargo are put inside a hyperloop and brought towards the cylinder, these hyperloops begin to rotate, in order to make it easier to get out, and go to one of the cylinders. The cylinders are conected to each other by 2 hyperloop networks: the Hera Hyperloop Network and the Cronus Hyperloop Network.
Proxima Centauri II (Chione)[]
Proxima Centauri II is a colder planet and the second to orbit Alpha Centauri C. It is a small planet with a gravity of only 0.67 G, that orbits outside of the habitable zone at a distance of 0.78 AU. Though it has an atmosphere and even water ice, it is not home to any native life. It became the ice-trading center of the Alpha Centauri system. The planet houses only about 120 million people, but many more live in orbiting habitats and work in the ice mines. The planet’s inhabitants live inside caverns underground and grow their plants on the surface in giant domes, mirrors orbit the planet to make it warmer and some people plan to terraform the planet, this terraforming will normally start around the year 3600 and will be completed somewhere in the 4400s. The planet is often better known as Chione, named after the Roman and Greek nymph of the snow. If Chione will ever be terraformed, it will probably still be pretty cold, but warmed up by the orbital mirrors. There will still be a lot of ice, enough to trade around the system and keep the planet the main supplier of ice. The planet is controlled by the Chione Commonwealth, this government controls the ice trade and ice mining and controls most orbital habitats.
Alpha Centauri A system[]
Auroran system[]
Alpha Centauri A I (Aurora)[]
Aurora is a terrestrial planet with a gravity of about 0.8 G, that orbits in the habitable zone of Alpha Centauri A. Aurora has a really thick atmosphere, making it look like a gas giant from mid orbit or higher. It even has a ring system which was probably made when an asteroid came too close to the planet and was ripped apart. Alpha Centauri B varies greatly in how bright it is in the night sky, but even at its farthest it is still brighter than the full moon on Terra, Proxima Centauri is so dim and far that it appears as a normal star, while Sol is visible throughout the system. Because of A and B the planet rarely experiences a true night as most of the time the night seems closer to a really cloudy day on earth. The planet is home to a large amount of habitats on the surface, located within domes, because of the high concentration of nitrogen inside the atmosphere, the Auroran people were genetically engineered in order to be able to live in an atmosphere with less oxygen, the nitrogen is traded throughout the entire system. Because of the dense atmosphere landing is incredibly easy, though taking of can only be done cheaply by using one of the launch loops. The planet is controlled by the Aurora Federal Republic, this government is in a constant cold war against Apollo, though the tensions have lessened over the years.
rings and moon[]
Aurora’s ring system was probably created when an asteroid, called Eos came too close and was destroyed, it is probable that Eos was not a single asteroid, but a group, maybe even a small moon that was hit by an asteroid and knocked out of position, destroying it when it came too close, the rings are mostly silicate and a small amount of metals, even some gold. The people from Aurora however see the rings as a personal pride and make sure no one mines them.
Erigeneia[]
Aurora has 1 moon, namely Erigeneia. The moon is small and barely spherical, with a gravity of 0.026 G similar to Ceres. The moon has several cylinders under its surface and tori on top. The main city on the moon is Tithonos, named after one of the offspring of Aurora in Greek mythology. The moon is covered in craters, which serve as the harbors. It is located just outside of the rings. The main materials on Erigeneia are the same as in the rings: silicate, metals, carbon and some sulphur. The moon is not independent from Aurora, but is planning on holding a referendum on independence in the near future.
Alpha Centauri A asteroid belt[]
The Alpha Centauri A asteroid belt, often just called The A asteroid belt, the Alpha Centauri A belt or The A belt is an asteroid belt that orbits Alpha Centauri A. The asteroid belt is similar in composition to the Proxima Centauri asteroid belt. With C-types being the most common asteroids while S-types are the way less common and M-types are even rarer. There is not a single truly massive asteroid in the A belt, but the most important one is Anchiale. This C-type asteroid is home to several underground cylinders and a torus on its surface. The cylinders are named: Iapetus, Hecaterus, Phoroneus and Daktyloi, the torus on the surface is named Oaxos. The cylinders each are connected to each other by the Kydnos Hyperloop Network and Oaxos (the torus) is the habitat that is closest to the Hekaterides, the harbor of Anchiale. Every habitat controls a part of this harbor and all ships that dock in said part have to pay to that habitat and their goods are also first delivered to said habitat, even if the one they are meant for is closer. There is also a central part of the harbor which is controlled by no one, the cost here is the same as elsewhere it is just distributed fairly among the habitats and brought straight to the one it needs to be.
Alpha Centauri B system[]
Alpha Centauri B I (Minerva)[]
Minerva is the closest planet to Alpha Centauri B. The planet is extremelly hot, covered in lakes, rivers and even oceans of molten lava. The planet has a year of only 12 Terran days and is only 0.1 AU from the star. It has a lot of materials similar to Mercury, but is simply too hot to be mined on. Only a few mining operations ever started on the planet’s surface and most of these were stopped or ended in disaster. Currently 3 small mining operations take place on the planet, 2 of these 3 will be discontinued by 3475 and the third will most likely similarly be discontinued by the 3480s if it does not end in a tragedy. The planet is small, even smaller than Mercury with a gravity of only 0.2 G. Minerva is also extremely geologically active, with several massive volcanoes, most notably Tritogeneia in the north, Athena on the equator and inbetween them Pallas. There is a fourth (Minerva Mons) and even a fifth (Nike) massive volcano on the other side.
Alpha Centauri B II (Aquilo)[]
Aquilo is the second planet orbiting Alpha Centauri B. It has a gravity of about 1.25 G, more than on Terra even though it is smaller, this is because the planet is surprisingly dense. Alpha Centauri B II is too close to Alpha Centauri B to harbor life, but far enough away that it isn’t a hellfire like Minerva. The planet is still covered in lakes of lava, but none of these are larger than Texas. Aquilo is tidally locked and because of this the nightside is just a rocky wasteland with some water ice, not nearly enough to be a major export, but enough to serve as drinking water for the planet’s population of 376 million. The planet has a thin atmosphere and the heat differences caused by the 2 stars cause the almost constant storms, which is the reason why the planet was named after a Roman god of the wind.
Alpha Centauri B III (Apollo)[]
The planet before the paraterraforming started
Apollo orbits at a distance of 0.7 AU, within the habitable zone of Alpha Centauri B, which it orbits every 225 Terran days. The planet has a thin atmosphere of mostly carbon dioxide. It has been partially paraterraformed, people live inside domes on the surface. Originally they lived mostly inside orbital habitats and not on the surface, but after several decades they decided to start settling the surface. It began with a station called Ladon, named after the father of Daphne, a love interest of Apollo in Greek mythology. Quickly more and more settlements were built and eventually the planet came under control of a single government: The Apollo Teleshrin, in contrast to almost everywhere else in the system the people here speak their own language: Castalian. The planet’s population is against the idea of a president or any single ruler, no matter if (s)he is elected by the people or not, even if (s)he has very little or even no actual power it is seen as a disgrace to the people of Apollo. Therefore they are in almost constant conflict with the rest of the Alpha Centauri System, though mostly with Aurora, the most powerful planet, on par with Apollo.
Alpha Centauri AB system[]
Dianean system[]
Alpha Centauri AB I (Diana)[]
Alpha Centauri AB I, better known as Diana is one of 2 planets that orbits both A and B, the other one is Liber. It is a gas giant. The planet is mostly made up of hydrogen, helium and methane, the last one gives it its blue atmosphere, because of the strong winds some other gasses flow up into the atmosphere and create the white bands on the planet. The planet has no colonies besides some small magnetic launchers like on Jupiter, these stations take gas, charge it and than use magnets to launch them to a station, hydrogen and helium-3 are important for fusion and methane is used for the manufacturing of organic chemicals or a fuel to make heat or light.
moons[]
Diana has 3 major moons, allong with several dozen smaller ones. The 3 big moons are Leto, Artemis and Delos.
Leto[]
Leto is the first of the 3 major moons. The moon is mostly made up of different types of ice like water and dry ice. It is a little bit smaller than Luna and sometimes seen as a twin, though besides the size and gravity it has very little in common with Luna. Leto houses about 1.08 billion people, who live mostly inside cylinders on the surface and mine the ice which is transported throughout the Dianean system and the rest of the Alpha Centauri system.
Artemis[]
Artemis is the second moon from the planet, it is located outside of the radiation belt that surrounds Diana. The moon has an atmosphere of about half the size of the one on Terra. It has several massive methane and ethane lakes, similar to the moon of Saturn: Titan. The gravity on Artemis is also in the same ballpark at around 0.129 G instead of 0.138 G. The temperatures on the moon range from -175ºC to -165ºC, warmer than Titan, but still cold enough to allow liquid methane and ethane. The surface is covered in several massive factories that produce usable objects from materials brought in from around the system. It has no permanent population.
Delos[]
Delos during summer, you may notice a thin layer of ice on the southern hemisphere
Delos is the third large moon that orbits Diana. It is smaller than the others with a gravity of just 0.1 G. Most of the moon is covered in ice and it has a subsurface salty ocean. This salty ocean is not home to any native life, but was aquaformed similarly to Europa, by placing several gigantic fusion reactors inside the subsurface oceans. These heat up the water and after filling the water with nutrience and microorganisms it began to become inhabitable, more and more species were added. The fusion reactors heated up the water so much the ice melted almost completely and turned Delos into a moon-wide ocean with a thin layer of ice (a few hundred meters) on top during winter and almost no ice (a few meters) during summer. Delos is not home to any colonies, except the fusion reactors and some research outposts which are used to observe the process of accelerated evolution.
Liberian system[]
Gannet ship
Alpha Centauri AB II (Liber)[]
Gannet ship
Liber is the largest gas giant in the Alpha Centauri system. It is a little bit bigger than Jupiter ,which has a diameter of 139,822 km, while Liber has a diameter of just over 142,000 km. The gas giant is mostly made up of hydrogen and helium allong with several other gasses. The planet itself is mostly abandoned. Small ships fly into the atmosphere similarly to the ones on Jupiter and Saturn and scoop up gas, mostly helium-3 but also hydrogen and deuterium, they fly back up before they get to heavy and filter out the useless gas which gets ejected into space. This technique is called the Gannet Technique and the ships used are called gannet ships, these ships usually have the appearance of a space shuttle or plane and normally don’t have any artificially generated gravity like acceleration gravity or centrifugal gravity. The gas giant also has strong winds, which causes the atmosphere to look covered in bands, the winds on this planet can reach a speed of 190 kilometers per hour and in a big storm on the surface, called Bacchus, the winds can reach a speed of nearly 620 kilometers per hour.
Semele[]
Semele and the SS Bacchus
Semele is the first and largest of the moons of Liber. Its size is similar to Luna and its composition is similar to Mars, the moon is covered in a layer of rust. Semele has a thin atmosphere which consists mostly of carbon dioxide and some oxygen. It is home to iron mines and most people that live in one of the cylinders under the surface work in one of the mining facilities on the moon. Semele has a total population of 540 million people and exports hundreds of thousands of tons of iron every day to the rest of the Liberian system and is even home to a laser array that is planned to be used for a future mission similar to Breakthrough Starshot from the 22nd century.
Ariadne[]
Ariadne is the second, smaller moon of Liber, it is covered in a dessert of rust similar to Semele or Mars. The moon is much smaller with a gravity of just 0.09 G, while Semele has a gravity of 0.2 G. It is covered by craters, ravines and mountain ranges, allong with massive plateaus, like Priapos in the northern hemisphere, which can be seen on the picture as a spot that is lighter than the rest. Most cities on the moon are subsurface cylinders which are conected with each other through the Methe Hyperloop Network (MHN), this hyperloop network also connects them to the surface. The surface is mostly covered in giant factories that process the iron and other metals from Ariadne into usable, sellable materials, which are traded through out the Alpha Centauri system. The surface also has several domes which are used to grow crops, to feed the inhabitants.
Alpha Centauri AB Kuiper belt[]
The Alpha Centauri AB Kuiper belt, better known as the Alpha Centauri Kuiper belt is located 60 to 100 AU from the Alpha Centauri AB binary star. The kuiper belt is similar to the one in the Sol system, with the majority of asteroids actually being comets and some dwarf planets. Most of these comets have a single cylinder in them and a small harbor on its surface. The comets were colonized in a similar way to what is planned for Project Sealion.
Ichor[]
Ichor is a dwarf planet which is similar in size to Pluto. The planet is mostly made up of ice, some copper, rust and iron, the latter ones giving the planet its red look that granted it the nickname: The bleeding planet. The majority of people live inside underground cylinders and surface tori. The major employer on the dwarf planet is mining, the copper and iron is used to build ships, computers, stations, colonies and much more. The rust is placed inside a vacuum and electrically bombarded with hydrogen molecules, which react with the ferrous oxide, or rust. After several hours most of the rust converts to hard iron. The planet has a population of just about 2 million people.