The Crawler Colonies of Titan

Titan.  This massive natural satellite of distant Saturn became far more important than its location might suggest.  This huge moon, almost as large as Ganymede, cannot grow food, has few metals, and the hydrogen clouds of Jupiter are much closer to Earth.  So why would The Pleiades Corporation expend trillions of credits to create the largest ground-mobile structures in the solar system to house colonists on this frozen (average temperature below 95 K/-178 C) world?  The answer is, perhaps, surprising.  Titan happens to offer the largest variety and array of unique organic molecules in the system.  The vast crawler colonies literally wade through tens of meters of muck and mud filled with all manner of organic molecules produced through slow catalytic reactions.  Many of the molecules here are unique in nature, and synthesis requires decades of time for the very slow reactions, reactions that only occur in deep cold, to complete.

In the year 2064 the first deep survey vessels landed on Titan.  It was already well known that shallow hydrocarbon plains covered much of the surface beneath the dense nitrogen atmosphere and organonitrogen haze.  What the survey mission discovered is that the dunes and other apparent "dry" surface structures were merely a thin crust over a thick mud-like muck of mixed hydrocarbon fluid and complex organic and organometallic "dust".  This soft and slushy surface made the initial exploration very difficult, but it was found to, in most areas, be fairly shallow.  In 2068 the first super-crawler, a massive structure that required a tandem lift from two of the largest DSTV available, was delivered to Titan.  This crawler, over a kilometer wide, and two kilometers long, was landed with the help of specially designed cold jet descent engines to avoid destroying the surface where it landed.  It sank ten meters into the muck, but its wide treads and high stance were designed for this and it was able to move about well.  This crawler, and several that followed, prepared the surface for the first colony crawler.

In the year 2072 the first shipment of parts for crawler colony one arrived.  Over the next eight years the automated construction progressed until, in 2080, the first colonists arrived.  Within five years over a million colonists lived in this dark and distant world, aboard a colony that moved, always roaming the surface both to avoid sinking too deep, and to find and harvest the widest array of specialty chemicals which provide a reason for the colony to exist.  Each crawled is unique, but they are similar in size.  Each is about twenty kilometers wide, thirty kilometers long, and one to two kilometers high, depending on how it is measured.  The crawlers attracted the most independent, and least compliant among the people of Earth from the very beginning, and at least one colony is known to have cut all control ties, leaving the facility entirely managed and controlled locally.  Even the fusion power plants are locally controlled, with no maintenance or monitoring connections outside the colony.  Other crawlers are similar, with a far lesser degree of corporate control than other parts of the system.  In 2112 The Corporation attempted to reassert full control over the crawler colonies, but quickly found that technological expertise was not an exclusive province of corporate employees, when the newly installed, upgraded, and interlinked monitoring and control systems went offline less than a week after installation, due to "unforeseen failures".  In fact local technical experts simply reprogrammed the systems to remove the dead-man switches and time bombs, then disconnected them from the interplanetary network.  This saved half a billion lives, substantially all of Titan, when The Great Grieving failed to detonate the fusion power plants on Titan in 2128, enabling the population to continue to live in this frigid world where loss of power would mean a quick death by freezing.