Titan

The ice lake

By stopping its drive engines Titan Alpha slowed its sinking into the ice-covered lake. Still it slid sluggishly, inexorably, deeper into the frigid water. The central computer swiftly reviewed its damage tolerance specifications and confirmed that its body was designed to be watertight. Checking internal sensors, it determined that structural integrity was being maintained: no leakage could be detected.

Its slow downward slide stopped abruptly. The vehicle’s forward treads had bumped into a ridge of ice. A quick sensor check of the ridge’s density showed that it should be able to hold Alpha’s weight indefinitely, particularly since Alpha was now partially buoyed by the water.

Other programs within the computer complex tested the water. It was liquid water, despite the frigid -180-degree-C. temperature of the atmosphere. Logic circuits concluded that the water could remain liquid because its sheathing of ice protected it from the air’s freezing temperature.

But how did the water become liquid in the first place? the master program demanded. Reviewing the geology program, the central computer inferred that the water was heated deep below Titan’s surface by tidal friction, the relentless squeezing of the moon’s interior by the inexorable gravitational pull of massive Saturn.

The biology program, activated by the detection of liquid water, directed the sensors in the sunken forward part of Alpha to scan the water for biological activity and to take samples.

For hundreds of billions of nanoseconds Alpha remained half immersed in the ice-covered lake, its forward sensors busily recording the activities of the protocellular organisms drifting lethargically in the frigid water. But the sensors also reported that the lake surface around Alpha was swiftly refreezing. Within another two trillion nanoseconds Alpha would be locked in the ice. The drive engines were powerful enough to break the ice, according to the propulsion specifications and a sensor scan of the ice’s tensile strength, but the data on the ice were tenuous enough to raise a warning flag for the master program’s attention.

The master program weighed the importance of acquiring additional data against the importance of avoiding being locked permanently in the ice. With the incoming data safely recorded and the water samples adequately stored in sealed and heated containers, Alpha engaged its drive treads in low-low reverse gear and slowly began inching backward out of the lake.

Data was of primary importance, of course—second only to survival.