Asteroids with elliptical orbits that cross inside the orbit of Mars are called Amor asteroids. (If they cross inside the orbit of Earth they are called Trojans.) In 2088 the Amor asteroid known as 2034 B crossed the path of Mars some eighteen million kilometers behind the planet, and a clutch of robotic landing vehicles originating from Luna docked with it shortly thereafter. 2034 B was a rough ball about five kilometers in diameter, with a mass of about fifteen billion tons. As the rockets touched down, the asteroid became New Clarke.

Quickly the change became obvious. Some landers sank to the dusty surface of the asteroid and began drilling, excavating, stamping, sorting, conveying. A nuclear reactor power plant switched on, and fuel rods moved into position. Elsewhere ovens fired, and robot stokers prepared to shovel. On other landers payload bays opened, and robot mechanisms spidered out onto the surface and anchored themselves to the irregular planes of rock. Tunnelers bored in. Dust flew off into the space around the asteroid, and fell back down or escaped forever. Landers extended pipes and tubes into each other. The asteroid’s rock was carbonaceous chrondrite, with a good percentage of water ice shot through it in veins and bubbles. Soon the linked collection of factories in the landers began to produce a variety of carbon-based materials, and some composites. Heavy water, one part in every 6,000 of the water ice in the asteroid, was separated out. Deuterium was made from the heavy water. Parts were made from the carbon composites, and other parts, brought along in another payload, were brought together with the new ones in factories. New robots appeared, made mostly of Clarke itself. And so the number of machines grew, as computers on the landers directed the creation of an entire industrial complex.

After that the process was quite simple, for many years. The principal factory on New Clarke made a cable of carbon nanotube filaments. The nanotubes were made of carbon atoms linked in chains so that the bonds holding them together were as strong as any that humans could manufacture. The filaments were only a few score meters long, but were bundled in clusters with their ends overlapping, and then the bundles were bundled, until the cable was nine meters in diameter. The factories could create the filaments and bundle them at speeds that allowed them to extrude the cable at a rate of about four hundred meters an hour, ten kilometers a day, for hour after hour, day after day, year after year.