Just three decades ago, this was all solid rock. The orbital prospecting telescope arrays found it in 2035, a fat black asteroid that resembled a three-kilometer soda can, speckled with green silicate crystals.
A lonely prospector bot landed a few years after that. The robot had crawled, sipping power from its batteries under an umbrella of solar panels that dwarfed it, for several years before it issued a final report. The rock was riddled through with blobs of ferrous metal, silicates and carbon, some water and even some nitrogen. The mix was good and so was the neighborhood; a cluster of metallic asteroids, all in nearby orbits.
In 2044, a spark in the darkness descended and slammed into the roughly cylindrical rock at its sun-facing end. Robots laid out an array of solar panels. They spooled out a network of power lines along the cylinder’s length, sniffing and probing as they went. A large shelter was rolled out and a factory switched on.
The robots started to work, gathering silicon and oxygen. Piles of ore and dirty slushes of oxygen and nitrogen began to build up. The factory started, chewing up the silicon and printing out more solar cells. After about a year, the factory began refining metals, a process helped along by the discovery of some very pure carbon and a nice stash of catalysts. It printed out a half-dozen little machines and beamed a quick question back to Earth.
NASA agreed. The robots, which had by this point carved out a number of serviceable little roads, began hauling carbon and slag from the factory to the new machines, which drew down a bit of power and fired the waste pellets off into space. The asteroid’s orbit nudged a bit, and it began picking up spin. The process increased in speed as newly built robots began chewing a hole down the asteroid’s spine. In 2056, Low South was in its final orbit, its mass drivers on standby. A thin corridor about 50 meters wide ran down the length of the asteroid. A few emergency shelters were printed up and towed into place, full of freshly minted oxygen and full-spectrum lights and even generous libraries. No human was within 30 million kilometers, but the shelters had their IR and visual beacons on. The mass driver network was linked into a constellation of satellites. As they came online, Low South sent a second message to NASA. Low South began sweeping local space with radar and lasers. It began broadcasting on the universal navigation frequency. A communication laser was aimed at a relay station at the inner end of the Asteroid Belt. Low South was open for customers.
The first one arrived six years later, while Low South’s robots were carving concentric channels out of the asteroid’s slowly rotating core. In an unending stream of car-sized chunks, the asteroid’s resources were being cataloged and assembled. In the darkness behind Low South, carbon and metal girders were forming the skeleton of a vast shipyard, twice the length of Low South itself. The piles of useful organics and frozen gases had become giant gridded cubes.
The robot shuttle from Titan matched Low South’s orbit and velocity and rotation. It landed softly, leaving behind a giant cylinder of precious nitrogen. It was launched back to Saturn with a million tons of nickel and gold aboard.
In 2067, Low South’s central chamber was sealed up, 3.4 cubic kilometers of empty space filled with pellets of frozen nitrogen and oxygen and water. The factory diverted waste heat to internal radiators, and there was much more of that these days, now that it had supplemented its solar panels with a few fusion plants. The mass drivers began firing on a regular rhythm, spinning the cylinder, and soon the icy pellets became a swirling fog, the water settling in nooks and crannies along the walls as centripetal force created artificial gravity. As the atmosphere thickened, a process helped along as Low South continued pulling frozen gases out of the chunks of rock stacked on its surface, packets of bacteria and various other little creatures were seeded. Within a month, the interior was roughly as welcoming as the summit of Mount Everest, and three years after that, a young man stepped out of an airlock. He smiled, his breath fogging slightly in the air, and saw a butterfly sunning itself on a rhododendron. He knelt and took a deep breath, the only human in eleven square kilometers of living habitat and the only human in eleven billion cubic kilometers, and prayed.