Titan

The ice mountain

Titan Alpha crunched cautiously across the frozen landscape beneath the perpetual gloom of dirty orange-brown clouds. Imagery in the range that its sensor program called “visible light” was reasonably good, although infrared was better, even though ground temperatures outside Alpha’s armored shell were so low that the infrared images were weak and needed boosting.

Still, Alpha trundled along in its lowest gear, picking its way around craters whose walls were too steep to crawl into. The master program compared the incoming sensor data against its memory files and decided that such steep-walled craters were young, formed recently by the impacts of meteors. It stored the information for such time as the primary restriction was lifted or superseded.

One of the master program’s basic commands was to gather data from the sensors, and Alpha was faithfully obeying that fundamental command. Since it had started moving across the landscape and turned off its receiving antennas and tracking beacon, the barrage of incoming commands had ceased and the conflicts generated by the primary restriction had faded from its memory.

Alpha remembered that before it had touched down on Titan’s frigid surface it had orbited the moon, mapping its surface and analyzing its atmosphere remotely. All that data had been uplinked, as commanded.

Now, with no fresh commands coming in, Alpha decided to repeat the orbital operation as nearly as it could. It would circumnavigate Titan, traversing completely around this frozen dark world as many times as it could. The master program checked the status of its nuclear power source, then reviewed the energy losses from propulsion and sensor usage, and decided that Alpha could circumnavigate Titan at least seven hundred times before the power drain became prohibitive and it automatically shut down everything except the sensors.

The master program reviewed the incoming data as it was registered by the sensors on a leisurely microsecond time scale. Nothing unusual. The ground was basically water ice, covered with a slushy mixture of frozen methane that contained significant impurities such as ethane, acetylene, and minor amounts of other organic hydrocarbons. Some of the organics were motile: they moved over the surface at rates of a few centimeters per minute.

Alpha’s thick treads sank through the muddy ground cover and crushed the topmost layers of the underlying methane ice and the complex hydrocarbons beneath its massive bulk. It used the megajoule laser at full power to flash the crushed remains into gas, which the mass spectrometer remotely analyzed. Only the crushed ices were analyzed that way; the untouched ground stretching all around Alpha was analyzed passively, without even the light touch of the laser disturbing it.

After more than a hundred hours of traversing Titan’s surface, Alpha’s forward battery of sensors detected a sharp projection rising three point seven kilometers ahead. The projection was four hundred and thirty-six meters high. It was composed of frozen water, bright and glittering, without any dark methane slush covering it.

Alpha stopped when it came within half a kilometer of the ice mountain and turned its full panoply of sensors upon it, spending a full trillion nanoseconds scanning the mountain. Frozen water, laced with carbon compounds. Cautiously, Alpha began to circle around the base of the mountain. As it did so, its sensors detected a ring of smooth ground surrounding the base of the mountain for two point nine kilometers. The smooth area was also frozen water, although it was dusted over with some methane and other hydrocarbon compounds.

Alpha’s master program consulted the geology program. The ice formation, it decided, was the result of a fairly recent cryo-volcanic eruption that had ejected a geyser of liquid water from deep underground through a vent in the surface. The water had quickly frozen in Titan’s frigid atmosphere, creating the ice mountain and the ring of smooth ice around it.

Water from deep underground, even frozen, was at the top of Alpha’s geology program. It engaged its drive treads and moved across the broken, rugged ground to the smooth circle of ice. If a machine can be said to be eager, Alpha’s geology priorities drove it eagerly out onto the frozen lake.

The microphones built into Alpha’s outer shell detected the crisp snapping sound within milliseconds of the strain gauges on the treads reporting that the ice was giving way beneath them. The master program ordered the drive engines to stop but it was too late. The crust of ice crumbled beneath Alpha’s ponderous weight and the machine began to sink slowly into the frigid water, nose first.