In the early twenty-first century, starprobes went out, launched by Sol Station, which diring the interval of the starprobes' travel, became a great economic power in Earth's politics.
Sol Station, a self contained orbiting "multifactory," pulled in metals, minerals, and ice from the asteroids, abandoning the practice of lofting anything up from Earth's gravity well. Since the majority of industrial cost on Earth was either in fighting gravity (lifing and transporting heavy objects) or heating things up and cooling them down (smelting and refrigeration), once a spacestation achieved the machinery to separate and smelt metals by solar power (thus becoming a "multifactory," a combination of industries all locked together in the production of goods for export to Earth (medicines, electrical power, scientific data, and processes) and for its own consumption (machinery, construction materials, oxygen from ice, and foodstuffs (from orbiting fishtanks and farms operating at industrial pace thanks to total environment control possible in such facilities.)
The result was a station capable of replicating itself endlessly at little expense; and a balance of trade which made investment and experimentation possible.
Hence, the robot starprobes which reported several stars much like the Sun, lacking habitable planets but potentially rich in metals and ice.
The theory of cryogenic suspension in sublight starflight was rejected. After all, Sol Station and the one traveling scientific station which had already been in orbit about Venus and Mars and now ventured the turbulent gravity well of Jupiter, proved that there was little difference between a working solar station and a ship.
So the first startship was modular, and while it would take years under light speed to reach the chosen star, there was no reason for the people aboard not to carry on life much as it was carried on in huge Sol Station. When it reached its destination, its payload, containing manufacturing units, would go into orbit in some rich and stable area of the designated starsystem, while the engine module would break free after assisting in this process and return to Sol Station.
It proved hardly more expensive in effort to make the mission multistage, that is, to colonize several starsystems in the same vector by using several engines and compartments and shedding each into deceleration at the time appropriate for each star. So if one part of the mission failed, another might succeed, and if anything went wrong with one engine, they had the capacity to continue on the others, or to return should it become necessary.
As it happened, all three stages worked without a hitch, and Earth had three functioning starstations. They had no ambition at all to land on a planet. Planets were too expensive at this stage, too wasteful of energy in getting up and down; mankind had decided that starstations (of which Sol Station was one) were more productive for small populations than planets were.
The voyaging starships never lost touch with Sol Station, and continually transmitted the data the scientists and tehcnicians in the colony mission were developing enroute. Life aboard went on in a mundane fashion, under the one gravity produced by acceleration; and when decelerated and parked in orbit, each starstation began a continual dataflow to Sol Station, and to each other, and to ships in passage. The result of this close community of scientists at work in new environments, as well as the research and development necessary for the guidance systems and engines for the mission, was a technological acceleration for Earth, a period of great prosperity and wild speculation as new discoveries multiplied.
The engine modules had a small crew compartment: they were designed to move greater mass than their own -- to push, in other words. Their crews had the harder life, since they were few in number and had to give up their associations with the colonists, who would live normal Stationer-style lives, hardly different than they would have lived on Sol Station. The engine-modules might have been robotized, but it was felt, first of all, that the chance of failure would be less with crewed modules, in such long voyages; and secondly that the occasional contact of human beings who had seen Earth would serve to keep the colonies from becoming too different in their isolation; the chance for instance, that a colony would grow completely alienated from Earth and shut off its contacts had occurred to Sol Station. So the primary reason for crewed ships was a psychological one.
The small crews must pass years together, and must have as normal a life as possible. Families happened, in spite of mild official discouragement, and when the first ship returned to Earth, they were offered a chance to stay. They refused, having spent too long at this to give up what to them had become a way of life. Crews grew larger (as did crew quarters) as second-generation crew took husbands and wives. Children ran and played throughout the ships, did small maintenance, and grew into crew work with the passing years, children whose lives were measured in calls at this and that starstation.
This was the origin of the merchanters and the stationers, whose lives became vastly different one from the other, but who were linked together in mutual necessity.
The arrivial of any ship in those early days was occasion for holiday.
Trade began, conducted without substance (of data by commmunications net) and with (of goods and parts carried by the ships).
What did the merchanters get out of the exchange? The improvement and care of their ships, which were their homes. Their food. Their whole lifestyle. And the freedom which began to be their whole way of life. A merchanter "family" was tightknit, even developing an accent unique to a particular ship: everyone aboard seemed to be a cousin or aunt or uncle.
Stationers got the same sort of thing -- but their populations were larger. They liked their security, the benefits their trade brought in.
Starstations expanded, built new modules and boosted them by ship to stars as near to them as Barnard's Star and Alpha Centauri are to Sol; and Sol had to get news of some of these stations secondhand, because of their distances.
There were nine such starstations -- ten, counting Sol.
They were: Alpha Base and Beta Base, Bryant's Star, Glory, Venture, Galileo, Olympus, Thule, and Eldorado.
The next starstation was sent to Pell's Star. And that star had a planet which had life, which had a sapient species, which had agriculture and the kind of luxuries which Earth had been supplying.
Scientists flocked to Pell. Everyone wanted to be in on the find. Meanwhile, word of the discovery traveled at lightspeed back to Earth.
By the number of years it took that lightspeed message to get to Earth and for Earth to debate the matter and send another message the same number of lightyears distance back, trying to adjust the trade patterns to accommodate the new discovery, it was too late. Some starstations had shut down and emigrated because goods were reaching their trading partners from Pell, not Earth, and they were suddenly in a backwater area, out of the future line along which goods would flow.
Pell not only succeeded as a starstation, it was being overloaded by immigrants and sent out new colonies to Viking and Mariner; and Mariner, having discovered by telescope a planeted star near it, colonized Cyteen, which had another agricultural world.
Earth just did not cope with these changes fast enough. The value of its goods plummetted. It suffered an economic crisis and there began to be an outcry that the starstations and the merchanters ought to be taxed to support Earth, who after all, started the space program.