Fleet Expansion - Planetary Fleets, Toss Ships, Busy Skies
Gagarin and CP are now working at full tilt, producing on a larger scale, in larger numbers, and a wider variety of spacecraft than is imaginable today. With access to all the raw materials and power one could want, and a highly robotized workforce, manufacture of spacecraft and space infrastructure explodes. More of all the ships already described are made, as many as is called for, ramping up with the quickly increasing capabilities of the colonies and all the projects they are able to dream up.
The Asteroid Retrieval Fleet targets ever larger and choicer asteroids. It concentrates on carbonaceous asteroids with easily accessible water, which equipment on the Fetchers splits into hydrogen and oxygen to fuel the engines. A few metal asteroids are brought in. Several are used to anchor the Anshar skyhook and the later skyhook constellation. By 5 years into this phase only asteroids over 100 kilotons are being returned, at a rate of dozens per year. By 10 years in, they are several megatons each, coming in at the same rate.
The Pod ships are mostly phased out in favor of Toss ships (discussed below), while the role of LNCs diversifies, and several types are built for different roles. Small ones with small engines serve the regular runs to the skyhooks, once the electric runways take over most of the delta v burden. Ones with big engines do point to point transport whenever more power is needed, such as when going to a point with no receiving runway, or doing heavy lift. At the end of this phase, a few are mother ships - they are designed to safely transport pregnant women.
At the start of this phase, carbon nanotube cable starts being manufactured in bulk, and that means skyhooks get scattered through the solar system, creating the Skyhook Interplanetary Transport Hubs. Both things are discussed below. The traffic level that makes possible, especially from Mercury to the Asteroid Belt, means that each of the inner planets is given its own fleet. Mars and Venus each get several toss ships specialized for the separate routes they ply, and each has two Schooners assigned to it - those are ships like the Roddenberry, fast and powerful. The sailing ships of Mercury are discussed below.
Callisto gets a set of LNC-type vessels for the Jovian system, a Schooner, and a couple of Toss ships as well. The Saturn system gets 2 LNCs, based on Rhea. 2 Galleons (Rumi-class ships) serve those two systems, spending time around Jupiter or around Saturn as needed. A bunch of Galleons shuttle between the outer asteroid belt and the inner planets carrying water ice or metal. Psyche and Ceres get Toss ships of their own.
Earth and the Moon are brimming with ships going here and there. They skip between the various space stations and skyhooks - transport vessels, private vessels, constructions ships, tugs and service vessels. Toss ships dominate. A fleet of Schooners accumulates.
Once skyhooks come into their own, ships start being made that just go from one to the other, around different worlds. They get almost all the speed they need at launch thanks to how much faster the tip of a skyhook is moving than orbital speed, and roughly the right trajectory by choosing the right moment to release from the tether. For less speed on release, they can let go from a spot lower on the upper tether. On arrival, much of the delta V needed to brake and enter orbit is saved by docking to the upper tether of that skyhook, which is already moving fast enough to be close to the speed of the ship when it comes in, meaning only a small burn is needed. If the skyhook tip is moving faster than the ship, it can aim for a point lower down that has the same velocity it has. Then it only has to be lined up to come in at the right angle for smooth docking.
Skyhooks all have their own Hopper fleet, some of which are now specialized for handling Toss ships. On launch, they hang on to the Toss ship and refine its trajectory with their large nuclear thermal engines, also giving it some more delta V if needed. On arrival, they rendezvous with incoming Toss ships and use their engines to do any deceleration and the maneuvers for docking. Normally they take the Toss ship in directly without it even orbiting first.
In normal operations the Toss ships don't even fire their engines. The Hoppers do everything. This way, all the Toss ships need is a complement of solid booster engines they can fire in an emergency to ensure they enter any kind of orbit around their destination world. Such engines are very simple and robust, they can sit unused for years and still work reliably in an emergency.
Toss ships thus are basically a sturdy frame that can take either container pods or haul bulk cargo in a single hold, a few solid rocket motors, and a bit of kit for avionics and comms and such. They are cheap and fast to build but they last a long time with little maintenance. Their cargo is often more valuable than the ship itself. Their purpose is to move lots and lots of mass quickly, and their design allows their numbers to grow rapidly.
Toss ships are big, and scale up more as the phase progresses. Traffic of Toss ships also grows quickly. When the Venus, Mars, Mercury, and Earth skyhooks open, fully loaded Toss ships mass up to 12 kilotons. By the time it ends, fully loaded small ones mass 30 kt, the big ones 100 kt. The 100 kt ships are known as Chukwa[?] class. The Skyhooks manage to carry that mass by ferrying arriving ships down the upper tether to the anchor station after they dock, and berthing them there. Once berthed the tether can launch or dock another Chukwa. In unusual cases, multiple Hoppers can be used to maneuver in a Chukwa for docking right at an anchor station, allowing them to rendezvous with skyhooks whose tethers are too weak to bear their mass.
Passenger Toss ships are globes with shielding made of 1.5 m of liquid ammonia between an inner and outer hull made of aluminum, carbon fiber, and laminated quartz. Only the ones on the Earth - Moon run don't have that, just a solar storm shelter padded with the passengers' own luggage and a modicum of cargo. Cargo pods can also be designed for people, so they can go on cargo vessels. After the space and taken up by the shielding, a large cargo pod still has interior dimensions of 5 m diameter by 37 m long.
Things that need to get where they are going quickly are placed on the smallest Toss ships, which can get more kick from the Hoppers, and can release from the tip of any launch skyhook. If they need to get there even faster, they go aboard Galleons, or even Schooners, for real emergencies. The giant Chukwas often skip from skyhook to skyhook to reach their destination, which makes their journeys much longer.
This is one of the names for the World Turtle in Hindu myth. This turtle supports an elephant on its back, which in turn supports the world.
So this phase sees the heavens filling with ships on all sorts of missions here and there. Too many missions to mention, and normal routine business that quickly is not worth regarding as a mission at all. Robots and AI are so reliable that ships doing cargo runs, mining, servicing, and even construction don't have any people aboard. Even passenger ships have a minimal crew, who don't do much besides maintaining a pleasant atmosphere.
The Schooners travel far and wide through the solar system, visiting everywhere, leaving a trail of observation satellites and rovers in their wake. They even make it to a few Kuiper belt objects. Several probes are sent even further than that, out to the Oort cloud, and to dark Planet 9. Probes launched from Mercury plunge into the sun. People take sky cruises around the Earth and Moon. There are numerous space-based construction projects serviced by various spacecraft. There is so much traffic, that there is official traffic control for the Earth Moon system.
Carbon Nanotube (CNT) Cable
Aside from the explosion in activity caused by advanced robotics, CNT cable is the thing that makes this all possible. It also has a profound impact on architecture. In fact, bulk, high quality CNTs have deep implications in almost every technology sector, as does graphene, which should also be producible in bulk if CNTs are.
The most promising technique for bulk production of extremely long CNTs is widely considered to be chemical vapor deposition. Processes of that kind are likely to benefit from a microgravity environment, which greatly changes fluid dynamics, and a hard vacuum, which makes it easier to produce chemicals of extremely high purity. Here we posit that once humanity manages to fabricate this material in bulk, it can be counted on to have a tensile strength of 30 GPa. Carbon nanotubes have a bulk density of 1.3 to 1.4 g/cm3. (A matrix of another material might be needed to bind them together, but the density of that shouldn't be any higher). This is an estimate of the material properties of the first carbon nanotube cables.[?] To model a skyhook system, it was necessary to choose numbers for these values. It should be noted that as manufacturing techniques advance, it is reasonable to suppose that tensile strengths as high as 100 GPa will be attained. Currently exotic methods, such as cross-linking the nanotubes to produce threads made solely of CNTs, may one day become feasible on an industrial scale.
The Skyhook Interplanetary Transport Hubs (SITH)
Skyhooks are erected all over during this phase. Trips throughout the solar system almost always involve at least one, usually two, and often three. Those for Earth, and the rejigging of the ones for the Moon, are discussed in later subsections. Of the ones in the following list, those at Mars and Venus are constructed first, then Mercury, and finally in order going further outwards from the sun. What takes the longest is transport time of the materials. The CNT cables are so massive it takes several trips to get the whole things to their destinations. This is less of a factor with the inner planets as trip times are shorter and launch windows more frequent.
Surface and Launch Skyhook Pairs
Skyhooks are often specialized for either surface operations, or launch operations. The worlds of the inner solar system all have at least one of each. Surface skyhooks have achor masses that orbit higher, so the speed of their foot platforms is slower relative to the surface. That lowers the energy needed to reach the foot platform, or land from there. Launch skyhooks have anchors that orbit lower to take greater advantage of the gravity well of their primary.
Each launch skyhook is paired to a surface skyhook with a matching orbit, offset by 20° or so. They are in orbital resonance, usually with a ratio of 7:1. For instance, the Venus surface skyhook orbits once for each 7 orbits of the launch skyhook. So, at any given altitude, the launch skyhook is moving 7 times the speed of the surface skyhook.
The upper tether of a launch skyhook masses 10% to 20% less than the upper tether of a skyhook like the original Gagarin skyhook, that combines both surface and launch duties. For interplanetary skyhooks, upper tethers are by far the heaviest, as they bear heavy payloads and have high accelerations at their tips. The cable mass savings of building paired skyhooks remains significant even though there are 4 tethers instead of 2, and the extra tethers add very useful capacity.
The savings in some cases are multiplied by handling Chukwas entirely on the surface skyhook. The upper tethers of these skyhooks have much less acceleration, with just enough range to get a Chukwa to the next hop on their trip. If the 100 kt behemoths stick to that skyhook, and the launch skyhook handles ships massing no more than 30 kt, that cable can mass 30% of what it otherwise would. That's the cable that makes up the lion's share of the mass of all the cables in a skyhook pair.
But most of those savings get reinvested as extra carrying capacity on the foot platform of the launch skyhooks. As they are so short, the cable mass needed to carry each ton of payload is much less than a ton. And there is an imperative to position the center of gravity of the whole skyhook between the two tethers. If it isn't there, and instead is far out along the upper tether because that thing is so heavy, the whole orbit drops down and that is either really wasteful or a disaster that causes the whole thing to crash. However, that same great mass of the upper tether means it takes an awful lot of mass at the anchor shaft to move the center of gravity down within it.
The efficient thing to do is to put a really heavy foot station on the bottom of the launch skyhook. Ton for ton, that moves the center of gravity many times more than putting more mass in the anchor. And since that is the best move anyhow, now we are free to have two stations on these skyhooks instead of one. Those foot stations are all within 100 km of the surface, a couple are only 20 km above it. There is plenty of mass in the budget to put in excellent water shielding, and still have the mass budget left over for a station that houses thousands of people, plus all the bells and whistles for it to be an observation platform, beam power to the surface, and whatever else.
Optimizing Inner Solar System Traffic
The Chukwas are the ones that often use 3 or even 4 skyhooks to get to where they are going. They are too heavy for many launch skyhooks to throw them directly to their destination, in which case they have to hop to an intermediate world. It might take a while for a world to be in range for a decent trajectory, but launch windows can really be stretched by vessels releasing from somewhat higher on the tether than is needed for that destination, so the ship is going faster after release. Also, to go from Venus to Earth or vice versa, it's often faster to launch to Mercury, and then go from Mercury to either planet. Launch windows to either place occur on Mercury usually 3 times a year, whereas launch windows between Earth and Venus happen about every year and a half. There is a greater plane-change to deal with in the case of Mercury, as its orbit is inclined 7° to the ecliptic, but inclining the orbit of the Mercury skyhooks the right way can largely handle that.
Once there is enough traffic that there is more than one ship on a skyhook at a time, incoming ships need to be ferried down to the anchor station and berthed there until it is time for them to leave. That's generally the best way to do things anyhow, though it's easiest if a ship is unloaded before being ferried, so the cable car doesn't have to haul so much at once. It makes loading and maintenance much easier, and passengers can go back and forth from their ship to the anchor station at will.
The high-traffic skyhooks of the Moon and Earth have greater demands on them to manage momentum to keep the orbits of the skyhooks stable. Sometimes giant boulders are thrown from the Moon to Earth or vice versa for no other reason than to transfer momentum. Because the ships that come in to these skyhooks are so big and there are so many, the trick of release and retrieve stops being sufficient to quickly adjust momentum when traffic is heavy. Release and retrieve is when momentum is shed by releasing a massive boulder from a point on an upper tether, or added by releasing it from a point on a lower tether. Those boulders are retrieved when their orbits bring them back to the skyhook. Though there are dozens of such boulders on each skyhook and they can mass up to a kiloton, more momentum can be added or subtracted by catching a boulder thrown from another world, or throwing one to another world. The Earth and Moon play catch this way to trade momentum when needed, and those boulders sometimes mass 30 kt.
Adding Anchor Mass: the Mining of Phobos
At first, the anchor masses of these skyhooks aren't very big. Once they are set up, their fleet of Hoppers, LNCs, and a couple of Fetchers, get to work adding mass to the anchor whenever possible. Maintaining their orbits takes a lot more fuel and trickery with passive masses until the anchors are many times heavier than the cables, and the heaviest ships that come and go. The Fetchers go after anything that comes in range on a convenient trajectory, the LNCs use all their spare time to ferry mass made of whatever to the foot platform, to be taken up and added to the anchor. Accumulating mass this way is far too slow, though. It would take a long time to really stabilize the skyhooks using only what the local fleets can bring in. The issue is that Venus has no LNCs because the surface is far too hostile to send LNCs down there, Mercury doesn't have many asteroids passing by that are easily caught, and at Earth, even with the huge drop in the price of launching to orbit caused by Anshar, shipping rocks to orbit makes no sense.
So, bits of the moon Phobos are spat to Venus, Mercury, and Earth to pump that mass up way faster. Phobos is, in fact, the anchor of the surface skyhook of Mars. It masses 10 million megatons, so it can spare a few thousand megatons for miscellaneous ballast and shielding material in projects elsewhere over the coming decades. Its surface is conveniently composed of dust and small rocks. The biggest issues with mining it for these purposes is keeping the dust contained so it doesn't form a haze around the moonlet that takes forever to settle. Once it's bagged, the bags gets thrown off the end of the upper tether of Phobos on the fast track for Earth, or Venus. We are talking bags of dust and rubble massing 100 kt. The Hoppers refine their trajectories for their destinations before returning to Phobos, and Hoppers on the other end do the same thing, shepherding the bags in to the receiving skyhooks. As the Phobos tether can throw to Earth and Venus good and hard, launch windows are long and trip times are short. Hundreds of these bags can be tossed each time either destination planet is in range. Mercury can get deliveries by the Earth launcher skyhook re-throwing bags its way.
Thanks to this supply, the anchor masses of all the skyhooks of the inner solar system are piled up to 20 megatons by the end of this phase, and a few exceed 50 megatons.
Skyhooks of the SITH
All of these skyhooks are made of CNT cable. The figures shown are for the configuration attained by the end of this Phase. All of them will be operating long before that, but with less capacity. As more cable is woven into the tethers, capacity increases.
In the rows that show tether mass, this is the mass of just the CNT cable. Those numbers show the mass first in metric kilotons, and then in the brackets, as what multiple it is of the payload mass. Really the payload mass should be multiplied by 1.05 to account for the mass of the climber, the foot platform, and all the infrastructure on the tether for maintenance and power transmission. It also doesn't count the mass of the shaft that joins the two tethers together, around which the anchor mass is built up. That probably adds another 1% or so to the total cable mass. These things aren't done for the sake of simplicity. The grand total of both skyhooks also includes the mass of the foot station on the launch skyhook. As that mass directly bears on the mass of the cables and the strain on them, it is included there. Anchor mass uninvolved with bearing the weight on the cables has little relevance to the overall structure, other than it affects the center of gravity of the whole thing. It goes up and down over time, mostly up, and adds stability in general as it grows.
Tether figures use a safety factor of 2. That factor accounts for what a tether needs to operate safely even despite wear and tear, manufacturing defects, and damage due to any micrometeoroid strikes. Early skyhooks made of Zylon need a safety factor of 3, but because CNTs are much stiffer, can handle a wider range of temperatures, and don't degrade in sunlight, SF of 2 is enough. It means these cables never bear more than 50% of the maximum load they could theoretically sustain according to their ultimate tensile strength.
All skyhooks are made of an open weave of cables known as a 'Hoytether' weave, after Robert Hoyt of Tethers Unlimited. That design makes it easy for maintenance carts to weave in new cables when they detect a weakness on a cable. This may mean that a safety factor somewhat less than 2 would be fine. Because tethers must taper so the top of the tether can sustain the mass of all the cable below it, a change in safety factor affects the total mass of a tether in an exponential relationship. Being able to safely reduce the safety factor can drastically reduce the mass of cable that must be fabricated and delivered to build a skyhook. Thus bear in mind that as in all things here, this number is estimated somewhat on the conservative side.
|Mass, kt (xP)
|Foot Speed, m/s
|Mass, kt (xP)
| Total Mass, kt
|Lower Tether || || || || || || ||
|Foot Station Mass,[?] kt
|Upper Tether || || || || || || ||
|Total Mass, kt
The Mercury colony will be at the north pole, so the surface skyhook has a polar orbit. The launch skyhook needs to have an orbit inclined 7° from the equator or it is rarely aligned for launches to other planets. So, ships coming and going are all going to have to deal with an 83° plane changes when moving between skyhooks. Being able to do the plane change between two upper tethers should reduce the fuel needed compared to plane changes without that assistance.
Because the surface skyhook has a polar orbit, it can't be used to handle launch of Chukwas. The launch skyhook has to do it all. It has to be able to bear 100 kt at its tip.
A skyhook that combined the tasks of launch and surface ops, and had similar capacity to the skyhook pair shown here, would need to mass about 1008 kt, making it 145 kt heavier than the two skyhooks. Even then, its lower tether would only be able to support 3 kt, while the lower tether of the launch skyhook can bear 10 kt, albeit its foot is moving much faster and likely there are few cases where it makes sense to use that tether. Not only does a skyhook pair take less material, a spacecraft going up from the anchor station to launch from the launch skyhook only needs to travel half as far. There are twice as many berths, and 8 times as many launch opportunities. It might be a bit tricky to hop from the surface skyhook to the launch skyhook and vice versa, and it takes a little fuel. Overall though, a big plus to have skyhook pairs instead of one that does it all.
The anchor in this case is actually the moon Phobos, which orbits at an average distance of 5980 km from the equator of Mars. But its orbit is rather eccentric, so sometimes it is as close as 5838 km. This is why the foot of these skyhooks can only come down to 50 km, even though since Mars has such a thin atmosphere, and Phobos is such a giant reservoir of momentum there is no need to think about performing orbital corrections to compensate for drag. In fact, the orbit of the launch skyhook will be matched in eccentricity, to make it easier to keep them far apart with little orbital maintenance. However, as the orbit of Phobos is inclined 26° to the ecliptic, a plane change of 26° will be needed to hop to the launch skyhook, as it is best for it to be aligned to the ecliptic to minimize the energy spacecraft launched from it need for plane changes.
This isn't enough to get to any other world. It's about 2/3 what's needed to get to Venus, but would rarely be used for that, as this skyhook is in a polar orbit. Venus would rarely be properly aligned with it for a good trajectory to result from a launch from this skyhook. (Mercury's orbit is quite eccentric for a planet, and when it is at aphelion it would be able to launch to much closer to the orbit of Venus, but Venus is unlikely to be there when that ship arrives.) This upper tether exists to assist with transfers between skyhooks, and to give the sailing ships an initial boost.
This is a bit more than is needed to reach Mercury and Mars, and plenty to reach Earth.
Plenty for going to Mars or Venus, almost enough for Ceres
Three times what is needed for Earth, lots of extra going to Venus or Mars
Twice what's needed for Earth, Vesta, and Ceres, plenty for Venus, almost enough for Jupiter
Double what's needed for Ganymede, almost enough for Europa
Twice what's needed for Hyperion, just enough for Iapetus and Rhea
Gets you most of the way to Venus. Everything coming and going from Mercury will need to make use of the sailing ships.
Twice the speed needed for Earth, Mercury, or Mars. Vesta or Ceres with speed to spare.
Earth is of course the hub of everything, and Anshar's sister skyhook fits that role. It throws things so hard, you can launch for Venus, Mars, or Mercury anytime and have a short trip, get to Jupiter anytime and shave some months off transit , and just reach Saturn.
The sister skyhook of Gagarin throws hard to Venus or Mars any time. Ceres is also a short trip, though sometimes a little fuel will be needed to maintain the schedule. Mercury is in easy reach, Jupiter is just in range.
Really fast trips to Earth any time. Almost the same for Ceres. Twice the speed needed for Venus and Jupiter. Mercury just in range.
All Jupiter's moons in reach. (Because Jupiter's gravity is so strong, this actually takes a lot of speed to achieve. This skyhook can throw to Jupiter itself, but it is on the edge of its range.) Twice the speed needed for Mars. Earth and Venus with plenty to spare, not much margin for Mercury.
All Saturn's moons in range. Twice the speed needed to reach Saturn. Throws hard to anything closer to the sun. Laughably overpowered for reaching Earth.
Auxiliary Space Elevators
Ceres already has a space elevator, and during this phase it is expanded so it can throw fast to Mars or Jupiter. Most of the Chukwas that come and go hop first to one of those planets and then hop again once or twice to get to their destination. Ceres is less important now for water, and more for its valuable salts - ammonium chloride, sodium carbonate and others. It also seems to have graphite, which would be very valuable indeed. During periods when there are better trajectories from Ceres to the inner planets than from Callisto, Toss ships from Ceres partly carry water, otherwise Callisto is the major shipping point for water.
Psyche is given a small space elevator too. Psyche (more properly known as 16 Psyche) is an asteroid made of metal 200 km across. Solid mixed metal, mostly iron. Since it is purely metal, it is a convenient place to set up a small plant to refine out the other metals dissolved in the iron. There is so much iron in small asteroids collected by the Fetchers around the inner solar system, it has almost no value. The semi-conductors and platinum group metals dissolved in it though, those have value. Even the copper in it does.
Its elevator can bear the mass of a fully loaded Schooner - 3 kilotons. It is able to throw ships to Mars or Jupiter with a little speed to spare. It has a mini-Toss ship of its own rated for its maximum payload. Mostly it loads it with only a few hundred tons or so of metals at a time, but by the end of this phase it is able to load it to the brim, and another new one just like it. With each run the Toss ships return with more mining equipment.
Anshar is the surface skyhook for Earth. It is the first skyhook built out of CNT cable. That cable was spun in Gibraltar's manufacturing sphere using carbon extracted from carbonaceous asteroids. Soon after the skyhook opens, another CNT facility is constructed on its anchor mass. That facility then provides the cable for expanding Anshar, and for the rest of the skyhook constellation around Earth that springs up over the coming years.
The initial anchor mass is a metal asteroid massing 300 kt, and then carbonaceous asteroids are tacked onto that. Within 2 years the anchor masses over 2 megatons. By the end of this phase, both it and it's sister skyhook have anchors massing over 20 megatons.
An impressive complement of high-specific-impulse VASIMR and Neumann drives are attached to its tip platform and its anchor. In addition to solar panels, there are nuclear reactors providing electricity for the drives. Those reactors can also power nuclear thermal LANTR engines in an emergency for quick orbital corrections or avoidance maneuvers. In fact even the high-Isp drives aren't used much, and rarely at full power. Most orbital correction is done with the release and retrieve and by playing catch with the Moon, as described above under Optimizing Inner Solar System Traffic. The drives have to be there in case of emergency. Sometimes they are useful for helping a troubled ship come in to dock, by putting the dock in front of it.
As the Van Allen belts have been drained, they are no issue for Anshar. It and its sister are tilted 25° to the equator to put them on the plane of the ecliptic.
High Volume Traffic on Anshar
The foot of Anshar Station moves above the surface of Earth at only 2.4 km/s. That is less than a third of the speed needed to attain orbit. The first stages of rockets get up to speeds around 1.5 to 1.8 km/s during launch. Most of the ships arriving at its foot platform are two stage rockets designed for complete reuse thousands of times. A few use other technologies and are also completely reusable. The market for rockets that fly directly to space disappears almost completely.
Scramjets would be another possibility for reaching the foot platform, but they are much more demanding technology. Standard rockets are likely to remain the cheapest and most reliable option. Air launch might become more attractive. The impact on launcher design of the low speed and low altitude of the platform would be great.
Whatever the cheapest launcher design for high volume traffic is, the cost of launching a kilogram to Anshar would be a tiny fraction of that cost today. Building Anshar of course was expensive, but maintenance and repair of it is cheap. This is true of all the skyhooks. The price offered to get from the surface of Earth to Anshar Station quickly drops to US$30 per kg. The price from there to a lunar colony is another US$30 per kg.
Cargo coming in from Anshar costs considerably less. Slag left over from other processes happening on the anchor is used to make simple disposable heat shields, and cargo pods fitted with such a shield are simply dropped from the foot platform to splash down in an ocean. The pod has a beacon so it can be recovered, and parachutes to brake its descent during the last kilometer or two. The pods don't weigh very much, once the heat shield is popped off and allowed to sink to the bottom of the ocean. A standard cargo flight returns hundreds of them to Anshar Station. A standard pod for 3 metric tons of cargo weighs only 50 kg when empty, and without its heat shield. Cost per kg for that incoming trip is only US$2.
A hollow sphere of metal can be dropped for even less. Stick a disposable heat shield on the bottom and give it a cheap beacon, and forget about the pod and the parachutes. Mining asteroids for any metal with a price higher than a few dollars a kilogram then becomes competitive.
Further aspects of Anshar are discussed under the Anshar Station section.
Earth Skyhook Constellation
Construction on the sister skyhook of Anshar, which is the launch skyhook in the table above, starts right after Anshar is complete. It is named after another ancient sky god, Hepit. Its upper cable masses 2.2 megatons all by itself, far bigger than any other cable. To seat the center of gravity of the skyhook at the correct point, a foot station is built on it that masses 400 kilotons.
Then 10 mini-skyhooks are built to complete an observation and telecoms infrastructure for Earth. 4 fill in the rest of the plane Anshar is in, 72° apart on it. The other 5 are in a plane that complements that, with an ascending node exactly on the other side of the planet. They have orbital periods that match Anshar, circling the Earth every 4 hours and 15 minutes. They can only bear spacecraft massing 200 tons, and their upper tethers are only 1000 km long.
These skyhooks take over a large fraction of Earth's internet and telecoms service. The skyhooks are bases for servicing and launching of satellites, taking over those duties from the free-flying space stations, as access to them is cheaper and easier. Small Hoppers stationed on them do orbital debris cleanup duty. They are observation platforms with a broad suite of instruments - telescopes across all wavelengths, radar, lidar, monitoring of the magnetosphere and radiation around Earth, gravimetry.
Together, this set of skyhooks eliminates the necessity for most other satellites in Earth orbit. That allows the vast majority of them to be cleared away so the skyhooks need not worry about colliding with them. Deals are made with operators of satellites being cleared to move their operations onto the skyhooks. Debris in orbit has been mostly handled by the time these events occur and satellites have been slotted into orbits posing no risk to the planned skyhooks for the previous 15 years or so.
The space stations are moved to orbits just in front of and behind Anshar, where shuttles can very easily hop between them and the skyhook.
Electric Runways, and Rejigging the Lunar Skyhooks
As shipping volumes increase, and construction at scale becomes widespread, new shuttles are scaled down from the size of recent generations. They are for a fixed system that launches them at a high cadence. They can still haul up to 60 tons, but their engines are smaller, and no longer nuclear. They have enough thrust to overcome lunar gravity, with a thrust-to-weight ratio of around 1.5 when fully loaded. When they launch to Gagarin, they lift off from a runway that accelerates them up to the needed speed and throws them off the end in an arc that peaks just above the altitude of Gagarin's foot platform. Their engines fire only to do the maneuvering for matching vector and speed with the platform. During normal operation, the launch is so precise their engines barely fire at all as they come in and dock. On return, their engines brake their descent, and the runway brakes their horizontal motion.
This runway is 15 km long and sloped 60° at the end. The speed at lift-off is about 300 m/s. There is another runway running north-south for traffic with polar skyhooks, with the same length and upward slope at the end. There is also an east-west runway designed for launch to Magnificent Desolation. The horizontal speed needed to reach its foot station is 860 m/s, so it is longer, with less of an upwards slope - 27 km and 17°.
The landing gear on the shuttles is powered through electrical contact made with a rail down the middle of each runway. That power is what accelerates them up to speed, through electrical motors that turn their wheels. After the shuttles have loaded and unloaded at the foot platform, they wait until the skyhook's next pass over Lalande, and then drop off. They return to the same runway, braking their descent with their own engines and touching down at the other end. On landing, electrical contact is made with that same rail, and as their wheels are slowed with magnetic braking, the generated energy is passed back into the system.
It becomes typical to launch a bunch of these shuttles in quick succession while Gagarin is in range, up to 50. They can be launched at a cadence of up to one every 10 seconds. Each one docks in one of the docking spaces in the vertical stack that now extends up the foot of the skyhook. They are called Geese for the organized way they usually fly all in a row.
Landing gear modules for the big LNCs are made so they can use these runways too, when delivering objects too big or heavy for the Geese, to Gagarin, polar skyhooks, or Inukshuk. The electric current infrastructure is sized to accelerate a fully loaded LNC up to the speed needed to rendezvous with Maggie's foot station. In fact, it is sized to launch a mother ship to Maggie. LNCs are designed for point to point service anywhere on the Moon, if need be. Though they get to places whenever possible by hitching rides on skyhooks, sometimes that is too slow. On such missions, their landing gear can be removed to maximize their payload capacity. In that case, they lift off and land vertically, as they did in the past.
Gagarin is moved to a higher orbit, at 7000 km, and all the polar skyhooks are raised to the same altitude to maintain their staggered orbital rhythm. Magnificent Desolation is converted to the launcher skyhook. For this purpose its orbit is lowered to 1000 km, so it passes by Lalande 7 times for each time Gagarin passes by.
Over time, all the lunar skyhooks are converted from Zylon to CNT. The maintenance carts work on that as they are able. Maggie has to be changed so much that is all done during it's conversion to the launch skyhook.
The sunlight at Mercury is ten times as intense as at Earth, so a sail that catches that light and uses it to push a ship can gain or shed speed ten times faster. Building on experience gained when probes and small ships were sent to Mercury to test solar sails, truly giant sails are made and connected to a sort of tug ship. These tug ships attach to the Toss ships coming and going, and stay connected until they have imparted the speed they need to get to their destination in good time. Then they detach and tack back to Mercury. It is a delicate business, moving around those sails so they pull on vessels as desired, and never get tangled in anything.
Great Sailing Ships
The sail tugs almost never go beyond the orbit of Venus. They aren't needed that far out.
A laser system is built at Inukshuk that can be used with a special version of the solar sails (that can handle extremely intense light) to push small probes to relativistic speeds (speeds fast enough to be regarded as a fraction of the speed of light). A series of trials is done with it. Work is done on how to use the extensive infrastructure now spread across the solar system to deploy tools to keep lasers tightly focused on the sails longer. Tests using lenses orbiting several AU from Earth are done, to refocus the beam once the probe passes by. After a while, a second, and then a third laser is built and placed in orbits further from the sun. Schooners reposition the lenses and lasers between trials to align them such that they can focus or fire on a probe once it passes their position.
This is done in preparation for interstellar missions. A capacity to accelerate probes massing up to a kilogram to as much as 30% of the speed of light is created. Though the probes must be small, many can be sent. At the end of this stage, many such probes are launched to our closest neighboring stars.
Robots move from being able to execute a step-by-step plan, to being able to make a plan that will satisfy a set of objectives they have been tasked with fulfilling. The first mega-project they are then tasked with is the construction of Lalande City. The robot team that does it is presented with detailed engineering plans for the city and some parameters for the resources they may use, and told 'go'.
They start by building the new factories for the various materials the city requires. They prototype the robots needed for all the different construction tasks, test them, improve them, and prototype again until they are satisfied they meet suitable standards. Then they build the factories for those robots, and the power plants needed to run them. The first robots stabilize and seal the interior of the crater, prepare the rim with the foundation for the dome that will cover it, and the foundations of all the towers dotted throughout it. The next wave starts building the central towers, and uses them to support the frames of the dome sections. The dome frames and the towers both are slowly expanded, upwards and outwards, until all the towers are their full height and the full armature of the dome is sitting atop them, and the rim structure ringing in the crater. A temporary membrane is used to seal the dome and a thin atmosphere is pumped into the crater, so that the millions of glass sections for the dome can be laid in their frames and built up layer by layer. More power plants are built, and all the infrastructure to supply the city - air, water, thermal control, waste recycling, supplementary greenhouses, telecoms, computation, transit systems, centrifuges, airlocks, lighting, monitoring, emergency services... The city is pressurized up to a full atmosphere and all systems tested.
They lay down topsoil over the crater's interior, setting up terraces and mesh to retain soil on slopes. They plant initial cover crops and test the artificial waterways, the intricate web of irrigation and drainage pipes, and the artificial rain system. Once satisfied, they plant all the trees, bushes, vines, and cacti - anything that lives for years. They build the roads and paths all through the gardens. Humans help a bit during this part, where they want to put in a few personal touches or enjoy the gardening.
At the end of this phase, 15 years after the project started, the city is ready for habitation and rated for a population of a million people. As the robots finish each phase of construction, the ones specializing in that phase are reassigned to the other mega-projects being undertaken elsewhere - the build Anshar Station, and then Hepit Foot Station, then the cylinder colonies of Magnificent Desolation. The factories that built those robots first refit or replace the robots working in the factories of Cernan's Promise, and expand those factories to help supply the mega-projects. Then they build new robot crews so they can build the cylinders for all the other skyhooks.
Once all these robots finish, shortly into the next phase, they need to be assigned to something else. Some are instructed to keep building more cities on the Moon. Those next cities start without an initial colony nearby to support the initial phases of the project, or even detailed plans. But that's okay. They figure out how to build that initial base for operations, and how to adapt the previous plans to the new craters. They start turning out a new city every decade, rated for populations of one to two million. The implications of all this are discussed in Birth of Worlds
Robots become sort of invisible hands that look after all the details, leaving humans free for creative, intellectual, and spiritual pursuits. They do not develop wills of their own.
The dome over Lalande Crater is 23 km across on average. The rim ring is 250 m wide, rises 400 m above the rim, and extends 300 m below it. It is heavily reinforced with thick cables that connect to the cables of the dome, and anchor them to the bedrock through shafts at hundreds of points. There are over 80 towers spread throughout the crater that anchor the dome at those points, containing the outward strain of the atmosphere pushing against it. Though the total thickness of the laminated glass of the dome is 3 m, it is still only a fraction of what it would take to counterbalance the pressure of the city's atmosphere. The towers are built around central cores of CNT cable. They are very solid structures of metal, glass, basalt, and composites capable of supporting the dome even if the city loses 95% of its atmosphere. In the center of Lalande they are 5 km tall, near the rim they are 1 km tall. The dome has been built around Cernan's Promise, now it is entirely indoors. It's buildings are preserved for history.
The towers and rim are where people live in Lalande. The ground is set aside for 'nature'. It has a few facilities for physical activity or public gatherings, but 95% is vegetation or water bodies. Institutional buildings and hospitals are dotted around the crater floor, but they are subterranean, built inside artificial hillocks, hobbit style. Maintenance facilities are all truly subterranean, and inhabited solely by robots. Factories and research facilities are all outside the rim, as are power plants and supplementary greenhouses. Factories are also clustered along the tunnel to the space port 35 km northeast of the city.
Very little of the vegetation is ornamental. It all produces something of value. Trees bear fruit and nuts, bushes are herbals or yield berries, vines have edible roots or fruit, whatever doesn't has medicinal bark, roots, or leaves, or perhaps is a host to a highly valued fungus or edible insect. The ecosystem requires constant adjustment, but only in ways subtle enough that to the untrained eye it is self-sustaining. Small vegetable gardens are scattered all over. Flower plots are set beside path intersections, benches, fountains, and plazas. Small animals and insects live in this groomed wilderness. Some are for food, some are pollinators, some balance the ecosystem.
For the most part, it isn't identifiable as farmland, though it all is. The robots don't plant single crops in neat rows, they mix everything together in careful ratios according to what is the best fit for the local soil and terrain, guided by the ecosystem engineers that oversee them. Lush natural ecosystems are imitated as closely as possible. They are able to monitor the environment so carefully that all animals roam free and live pretty natural lives - until it's time to roast them for dinner. In that case, the needed number are promptly captured and cleanly killed. Farming robots work so intimately with the ecosystem they almost seem like part of it. The colonists thus don't refer to it as the gardens or the farms, they call it the countryside.
Once the countryside matures it is able to supply most of the population's food. The air has 2000 ppm carbon dioxide. The rains and irrigation are meted out for best growth. Strings of tiny lights woven into vast nets are carefully spread over everything during the lunar night to provide enough light energy to sustain all the plants. Each patch of these light-blankets provides light for stretches of 8 hours, and then switches off for 16, all through the night. There are no pests, no infections, no droughts, no frost, no storms, and no winter. Most woody plants and vines provide a harvest three times a year. Those harvests are staggered by design so that the supply of fresh produce is almost constant.
A few key crops are grown in the supplemental greenhouses, mostly grains and legumes. Those greenhouses are completely optimized for maximum yield of whatever crop is in them. They have little free space and feel like factories. For maximum crop density, they are grown in trays that are supplied with sun by fiberoptic cables during the day, and by LEDs at night.
In a similar fashion there are water and air treatment plants that use bacteria and algae to filter out toxins and disease agents. The algae tanks have light piped to them, the bacterial sludge is kept warm with waste heat.
Broad suspension bridges link the towers, wide enough to be landscaped with gardens of their own and have kiosks and cafes dotted along them. They are spaced every kilometer up the towers. The arches between towers that support the dome also have several levels of walkways hanging beneath them.
It takes a decade for the population of the city to fill out. While it does, the countryside fills out with it, the trees rising and thickening into forests, moss covering rocks, vines climbing the towers.
A mix of power sources is developed for the Moon. Nuclear reactors run on thorium and uranium, solar thermal plants produce power while melting regolith to extract volatiles and produce molten feedstock for production of glasses, ceramics, and metals, microwave rectenna grids receive power from orbital solar wings. Flywheels are used to smooth out the matching of supply and demand.
As mentioned in the Anshar Skyhook section, mass is added to the anchor of Anshar as quickly as possible. Much of it arrives as rubble - fragile rubble pile asteroids are intentionally allowed to disintegrate during transport so they are easily mined to extract their carbon and water. The metal asteroid that arrived first and formed the initial anchor during skyhook construction is slowly processed to recover the metals dissolved in the iron that forms 92% of its mass. All of that metal is in high demand, but there is so much iron, and so many of its traditional uses have been taken over by other substances, it has little value. While it is still molten, at the end of the refining process, it is drawn into rods of between 10 and 100 m in length, whose ends are fused together into a gigantic latticework of tetrahedra. This latticework extends outward from a section three-quarters of the way up the enormous stone shaft bridging the center of gravity of the skyhook, where the upper and lower tethers are joined together. It is employed as bulk shelving and support frames for processing and fabrication units that operate within the lattice.
As asteroid material is refined into carbon, water, pure metals, and metal oxides, these products are warehoused in the lattice. Slag, tailings, unused waste rock, and unused particles from gravel to dust, are carefully organized and stored in the lattice too, in case they prove useful later. They are archived according to composition, particle size, and origin. This forms the bulk of the mass of the anchor. A significant fraction of the mass is bags of compacted dust from Phobos.
The stone shaft is a tube formed of a matrix of slag with fibers of high-strength glass and CNT mixed into it. Cables of CNT also run through it from end to end, and the tethers are fixed to the points where these cables protrude from the ends of the shaft. It is 100 km long and 50 m in diameter, with a hollow core 30 m wide. The climber cars travel through that hollow core on their way to the transfer hubs along it - Anshar Station, the industrial and shipping docks on top of the lattice, and the passenger spaceport just above those. The section where the iron lattice attaches to it is 5 km long.
The center of gravity of the skyhook always stays within this length. It is designed to support any kind of forces either tether could ever be subjected to, and provide rigid support to all the structures built around it. Anshar Station is tucked under the lattice. The bulk in the lattice shields the station from radiation and impacts. It turns and extends downwards outside the station to protect its sides as well as its top. Only the station's bottom is unobstructed, and that side is mostly protected by the Earth itself.
Anshar Station is shaped roughly like a punctured puck. It is 1 km in diameter, 250 m high, and the anchor shaft pierces the center of it. The top side, facing the lattice, arches shallowly between the central shaft and the outer sides. The side facing Earth arches much more deeply. That side is almost entirely glazed, receiving lots of light from the Earth below.
The station rotates to simulate 0.8 g on its outer rim. Every 50 m from the rim to the hub there is a floor ringing the interior. Each successive floor is narrower than the one below, leaving more open space between its edge and the glazing. This allows more of the view to reach more of the interior, and better distribution of the sunlight piped in through clusters of fiberoptic cables bunched around the hub. Sunlight shines down from their outlets. The hub of the station rotates around the shaft of the skyhook a bit slower than once a minute.
Anshar is mostly a workplace. People usually come for stints of between one to five years, but almost nobody moves there to stay. Most people come for work or pleasure, and spend only a few days to a few weeks there.
Manufacturing on Anshar
Several double spheres like the ones at the Gagarin Shipyard are built on top of the lattice. All the manufacturing techniques pioneered on Gagarin are shortly also being done at Anshar. Gagarin concentrates on spacecraft and space construction equipment. Anshar gets into all sorts of things.
As mentioned under Anshar Skyhook, mining of all sorts of metals is profitable at Anshar. As operations expand and economies of scale take hold, even more become profitable. But not much bulk metal is sent to Earth. It is used to make things that are much more valuable, and those things are shipped to Earth - or to the Moon.
Anything that can be made from the materials available in asteroids, can withstand deceleration forces of roughly 10 g, and has a value higher than about US$20 per kg, is a viable option for manufacturing on Anshar. This represents a very wide range of technology.
And here we are only talking about the market for Earth. All sorts of things are both more valuable deeper in space, and cheaper if bought from a company on Anshar instead of an Earth-based competitor. Companies at Gagarin and Cernan's Promise have an advantage here too, of course.
Hepit Foot and Anchor Stations
Hepit is the 400 metric kiloton foot station of Hepit Skyhook, Earth's launcher skyhook. It is a half dome made of a honeycomb of cells of laminated quartz filled with water, 1.5 m thick, measuring 300 m across and 150 m high at the center. Its floor and internal structures are made of plastic and aluminum alloys reinforced with graphene or CNT. The lower tether of the skyhook pierces the dome at the center, and its cables are used to support a building that spans the middle 100 m of the dome, and extends through its floor. That building descends 100 m below the floor of the dome, and rises to 50 m from the dome itself. Hanging below it are the docks for the craft coming and going from that tether. A tube at the core of that building cuts through the whole dome, so the climber cars can pass through it to reach the docks, load and unload, and transfer people and cargo to the skyhook's anchor station.
On top of the building, and in the whole area around it, is garden and leisure space. There are many swimming pools and sport areas. Hepit Station is a resort more than anything else. Because it moves at a large fraction of orbital velocity, the pull of gravity is only 0.3 g inside it. It orbits every 100 minutes. At its altitude of 100 km, it offers a gorgeous view of the Earth below. With a sunset or a sunrise every 50 minutes, it has an oddly timeless feel. It can accommodate up to 40,000 people.
The foot stations on the launch skyhooks of all the other planets in the network are of a similar overall design, though much smaller. When first built, the mass needed at the foot is just a bunch of rocks, until the proper station can be built.
Hepit's anchor station is all business, designed almost entirely simply to facilitate traffic between Hepit and Anshar. Most traffic on Hepit is either people or cargo arriving from other worlds and headed to Earth's surface or the manufacturing in the lattice of Anshar, or leaving on the way to other worlds. In all these cases, a hop from Hepit to Anshar, or vice-versa, is involved. Traffic to and from Earth's surface occurs almost exclusively on Anshar. The first waystation on the upper tether is a release point for Hoppers headed to Anshar, that gives them an orbit with an apoapsis at the altitude of its main docks. Hoppers coming in from Anshar release from a similar waystation that gives them a periapsis at the altitude of the anchor docks of Hepit.
Most of the activity at the station is simply robots moving back and forth in the hollow core of its stone shaft, ferrying cargo and passenger pods. The only bits of it that are pressurized are a few small maintenance modules and an emergency shelter. Three-quarters of the way up the anchor shaft, many bags of Phobos dust are strapped to it. They form almost all the anchor mass of this skyhook. The material is of no mining interest, it is strictly bulk for stabilizing the skyhook.
As discussed below in Birth of Worlds, O'Neill cylinders are crucial to development across the worlds of the SITH. At Gagarin and Anshar, the superstructure of cylinders for all the surface skyhooks is fabricated by the end of this phase. The Chukwas take them to their destinations, along with the robot crews that assemble them and then complete the construction of the cylinder colonies.
The first twin-cylinder colony is built on Magnificent Desolation. Like Gagarin, it gets a cylinder that extends south of the tuning-fork shape of the climber docks. In its case, there is another cylinder just the same that extends to the north. Ships are ferried down the upper tether and berthed above the two cylinders. While they are still under construction, many of those ships arrive bearing Phobos dust for their radiation shields. Slag from Gagarin and Anshar is added to the shielding too.
These are the family cylinders for colonists that are pregnant or have small children, which is discussed in the Children section. As it will take time to truly establish how to ensure the health of these colonists, these cylinders are made as big as possible. It is taken into consideration that they may be needed for colonists whose health can only be aided by constant full gravity, which may include others besides the very young and the pregnant - as the population of the Moon grows, they may need to support many people. Also, they are further greenhouse spaces, providing a buffer to the food supply.
They measure 2 km in diameter and 3 km long, each. The whole interior is open below the 200 m closest to the tethers, which is ring after ring of floors, from the outer wall to the hub, each one experiencing slightly less simulated gravity than the one below. Hills created within the cylinders also have buildings under their overlay of soil and plant life. Most of the inner surface has at least two levels of floor space underneath the forest, grasslands, and gardens receiving the sunlight coming in through the expanse of glazing at the far end of each cylinder.
Crossroads, Sagan, and Babel then all get cylinders like this too. In their case, this is principally for farming, and ecosystem research. Part of their harvests are shipped to Anshar and Hepit, and also to all the other cylinder colonies around other worlds.
To support upcoming development on all the worlds of the SITH, they are all slated to have O'Neill cylinders incorporated into the anchor masses of their surface skyhooks. Work on this begins at the end of this phase and continues afterwards. Ceres and Psyche are included in this drive. Wherever a continuous human presence is being planned, it is best to have such a colony. There is as much industrial activity in space as there is on the surface of these worlds, except for the Moon and of course Earth. In many places, most industry is in space. Cities that will float in the atmosphere of Venus are prepared at the anchor of the surface skyhook and then deployed into the atmosphere bit by bit. Microbes and fungi native to Mars have been found (we shall suppose), and so while they continue to be studied, heavy industry in their environment is forbidden. Instead, machines and habs for the surface are made in orbit and then delivered by the LNCs, and humans are permitted on the surface only in very specific areas, under very specific conditions. Psyche and Ceres have so little gravity, access to the full gravity in the cylinders is important for complete health. The surface of Titan is too hostile for a human habitat. In all these places, the real action is in orbit, on the skyhooks. People who go to these worlds on business usually stay in the cylinders, and may never go to the surface. The cylinders are welcoming, pleasant places thanks to their scale. The lack of time on the worlds below them is not much sacrifice.
We are conjecturing that a full gravity environment is required at all times for the proper health of unborn children, and that toddlers are slowly able to adapt to lunar gravity for ever longer stretches. It is critical for healthy development of growing children that they maintain a vigorous exercise regimen that includes swimming, physical exercise while in centrifuge environments, and lots of jumping, acrobatics, vertical playgrounds, and lunar parkour. As similar activity remains important for adults too, all this activity is heavily integrated into lunar society and its architecture. Children may need supplements or medicines to help regulate their growth and their bodies, perhaps more so at certain stages of development.
We shall say that children need to sleep in centrifuges under a full gravity, and spend at least an hour a day in them doing some form of exercise. This need is nicely supplied by inflatable centrifuges that are erected and inflated each evening in the courtyards of Lalande City. Each tribe has a courtyard, either on their level of their tower, or in the middle of their collection of houses, if they live in the rim. The interior of these centrifuges is basically a ring-shaped, sideways bouncy castle. The children rarely need any motivation at all to jump around inside them and get up to general shenanigans. In the morning after they wake the centrifuge is stopped, they get out, and it's deflated and stored away until needed again that evening.
They also need to swim pretty much every day. They are taught how while they are infants. Swimming pools are everywhere in the lunar colonies, including a bunch in each tower. This exercise is important for adults too. Families and often whole tribes share the activity. Vertically oriented playgrounds that are scaled-down versions of the ones adults use are dotted throughout the towers as well.
Based on the information we have now (which is very little), this is a reasonable guess as to a physical regimen that would keep kids healthy. The radiation environment in the colonies is as low as on Earth by the time children are present, in that regard there is no concern. However, they would not be allowed to venture outside (in the cab of a surface rover or in a shuttle) unless we know they can tolerate those brief exposures to elevated radiation. Children would be transported to Lalande City from Maggie's cylinders in mother ships once they are old enough, and would not leave until they reach the age research has shown is safe for such things.
The first children appear in the colony in the last two years of this phase. Their parents return with them from Earth when they have reached the age of five. Extensive animals studies in primates and higher mammals such as dogs and cats show this age to be adequate for safety. Initial evaluations are done at Anshar station over a few months to check that everything is in order. The children seem to be able to adapt fine, perhaps after some adjustments are made as to physical routines, diet, and supplements. The families continue on to Cernan's Promise once the medical staff judge the children will be safe if they follow the regimen.
The children are greeted by the tribes with glee. There are only about a hundred in the colony at the end of this phase, when Lalande City opens. Their tribes share the task of raising them, largely because their 'uncles' and 'aunts' insist. There are no tribes that have more than one child, and most have none. Wherever the children go, they are carefully watched over by everyone around them. They thus become really quite confident and trusting.
At the end of this phase, hundreds more families are shortly expected to arrive with children of their own. Pregnant couples are now staying on Magnificent Desolation, near to home and in close contact with their tribe. The tribes are eager to have children in their ranks, and so most of them reorganize so they are smaller, and have space for a few couples planning to have children.
Everything is centered around tribes on the Moon. They ensure humanity in a place that is heavily robotized, automated, and computerized. They provide social cohesion in a place composed of a mish-mash of every culture on Earth, while allowing enough autonomy to preserve different ways of life. They prevent authority from becoming concentrated in a place where all the needs of life can only be provided by using a ton of complex technology, which could easily be abused if control was in the hands of few people. From the beginning, tribal organization was fostered in order to keep people looking out for each other and holding together in a dangerous, alien place. Once it seeps into the fundamental fabric of lunar society, it is enshrined as the central pillar of everything.
Each year or each month, tribes receive an allotment of robots, food and cargo mass, even a little transit capacity to other colonies and the skyhooks. They use it as they decide among themselves. This is strong incentive for them to learn to make plans as a group, and wrestle through tough decisions. As individuals aren't entitled to any free supplies themselves, and some of these things are expensive to buy (like cargo mass and seats on shuttles), if they can't work with their tribe to get what they want, they aren't going to get it.
Tribes are perfectly free to use their allotments for business. Successful tribes figure out what skills they have and use them together to make a little money. Or a lot of money. Their tribal space is one of the resources that can be important in this - each tribe has a compound that can accommodate a small business or two if cleverly used. How earnings are shared within the tribe is up to them.
There is a catch to this, one a healthy tribe doesn't even notice, and an unhealthy tribe is keenly aware of. Tribe is for life. They can't expel a member. Even if a member commits a serious crime, one for which there is a penalty of confinement - the confinement is with the tribe. It's a form of house arrest, which their own tribe must monitor.
This can cause resentment, but people rarely criticize the system in general. It's better than any alternative that anyone has. That same tribal responsibility also means that people who are aged and need constant care are cared for by their tribe, as are people who have a serious chronic illness. It's a social guarantee. It makes people feel very secure and fosters a sense of social responsibility. Thanks to that guarantee, and the essential guarantee on top of it, tribes vote according to their conscience, not according to any fear they have for the future. This is important to the effective leadership of the colonies.
Once it is time for the colonies to decide how to run the Moon Agency, tribes elect the Moon Agency Director and the Moon Agency Council, who then make decisions during their terms. Each tribe gets one vote. They may decide how they determine their vote - simple majority, consensus, secret ballot, show of hands, whatever Jane says - then it is publicly cast on behalf of the whole tribe. It is like having a huge number of very small constituencies. The dynamics this creates mean that votes are normally considered much more skillfully and thoroughly than voting in other democracies.
Many measures are taken to keep tribes strong, and create new tribes that are strong. The maximum number of people a tribe may have is 50, and the minimum is 40 - a pretty narrow range. Long-standing tribes are permitted to 'adopt' people to maintain balance and variety in their numbers. There must be enough young people to easily look after old people, for instance. Children provide vitality and all tribes want to have a few around. When people marry one partner moves to the tribe of the other partner.
People up for 'adoption' come from tribes with too many people. Those people must choose freely to switch tribes - expulsion isn't allowed under any circumstances. Sometimes a new tribe is made out of handfuls of people from several tribes that have gotten too big.
The private citizens that come in the last rounds of the Residence Program train with a group of people before they come, just like residents always have, and that group becomes their tribe. That's a requirement. The ISA and the MA have become highly skilled at matching people to create good tribes. That skill grows out of the skill space agencies today already have, in putting together teams and training them to act together effectively even under high stress. The training they go through is more about forming social bonds and becoming a team than anything else.
After the Residence Program ends, and immigration begins, the tribe system is maintained by holding those training programs on the Moon itself. Colonists help arriving immigrants organize themselves into groups, and impose a few basic requirements on the makeup of groups. There must be a range of ages and a gender balance, for instance.
If a tribe is really in trouble, it can be disbanded. The members must be picked up by other tribes. Possible reasons could be something like having too many elderly members. This happens with a few of the original tribes, who got complacent and didn't renew themselves enough with young members. A tribe may request disbandment, or it may be imposed on them. When requested, it is not granted lightly. The tribe must go through a long process and in the end the request may be denied.
Tribes receive an incentive package to encourage them to adopt 'strays' without tribe due to disbandment. They are probably going to be a lot of work or difficult to integrate into their group, so incentives are needed. Disbandment is pretty rare, though. Strays start to be a minor phenomenon when immigration begins. Some arriving immigrants want to be part of existing tribes and seek to get adopted by one. Ones with children or planning to have children have no trouble swinging such a deal. The MA doesn't offer incentives in such cases. If an immigrant can't convince a tribe to take them, they usually get placed in a new tribe like most immigrants. Sometimes the MA decides to offer an incentive package for a mature tribe to take them, if they see trouble ahead with them.
Businesses and projects the Moon participates in now provide a large chunk of Earth's electrical power, and most of its communications, surveillance, and observations of all kinds, from weather to traffic. All of these markets are large and highly profitable.
Many of humanity's most talented roboticists now live on the Moon or work closely with Moon projects. The Moon is robotics heaven. The robotics knowledge acquired through lunar development is open source, but the Moon still makes a lot of money on it. The Moon exports high-end robots to businesses doing manufacturing in Earth orbit. Moon residents form their own companies doing the same thing. Now that Anshar is complete, manufactured goods from orbit are far more competitive, so that is a huge market. The Moon both provides most of the robots working on Anshar, and thanks to the price drop for delivery to Earth Anshar provides, now sells a lot of robots to companies on Earth itself.
Software for robots, and software in general, remains a gigantic market. Programming of advanced robots is a very carefully regulated business in which lunar colonists form a large percentage of the top people. They are paid extremely well for these services when contracted, and launch a number of companies specializing in it.
The Moon Agency and the Moon Fund have a slice of almost everything happening in space. New enterprises seeking to enter the field are wise to play ball with them and the ISA. The more people move into space, and the more infrastructure on other worlds develops, the more this snowballs.
The Moon is crammed with very wealthy people who hold as central values that all people deserve the basics of life and it's best for everyone to ensure everyone has them. They believe in a close-knit society which also accommodates a wide range of cultures and lifestyles. They are, both individually and collectively, highly influential. The Moon is now a seat of power.