Europa

The Road to Hell

Navy Submarine JGS Trilobite

Subsurface Ocean, Europa

Like on Io, and to a lesser extent on Ganymede, powerful tides stretched and released Europa as it whirled around Jupiter. The tides had created great stress cracks in the brittle, icy skin of the moon, giving it the appearance of a badly scratched ball of white marble.

The heat released by the tidal kneading had also bequeathed Europa a great, briny ocean, a hundred kilometers deep, ten times deeper than the deepest trenches of Earth.

Similar hydrospheres - for the word "ocean" was far too puny for these shells of water - existed on many of the Outer System's icy moons, most famously on Ganymede, Titan and Enceladus. The depth of the hydrospheres and their icy coverings varied from moon to moon. On Ganymede and Titan, the hydrospheres lay under icy crusts more than a hundred kilometers thick - thicker than the rocky crust of Earth.

On Europa and Enceladus, however, the oceans lay much closer to the surface - ten kilometers instead of a hundred. This rendered them accessible to human exploration, commerce... and war.

The JGS Trilobite was optimized for speed, deep diving, and stealth. As such, it had the familiar cigar shape of classical terrestrial submarines, lacking only the sail (often inaccurately referred to as the conning tower). The sail was designed to give submarines a place with enough height above the waterline to mount a hatch that wouldn't let water in. In the Europan hydrosphere, which had an icy roof in place of a surface, such a feature would be completely useless.

All this meant that JGS Trilobite looked like a very large torpedo, as did its quarry, a European submarine arbitrarily designated Tango-One.

In a full-blown shooting war, the JGS Trilobite would blow Tango-One out of the water with a torpedo (or, more likely, with one of the JGS Trilobite's underwater drones).

However, 'uneasy peace' was the word of the day, and Commander Maurice Wan knew it. JGS Trilobite would not be shooting off anything more dangerous than sonar pings - the undersea warfare equivalent of taunts.

"Helmsman, give me five knots. Close to one hundred meters. When we ping their butts, I want those Euros to know we had them dead to rights."

The sonar operator, watching the output from the hydrophones, whispered into his microphone. "The computer says Tango-One is ascending."

The navigator nodded. "The Euros have an active sonar station here. They may turn it on to check their subs."

"Give me a hiding spot, navigator."

Differences in water salinity and temperature significantly affect the propagation of sound through water, masking sound signatures and sonar returns or making their interpretation extremely difficult. This was true in the North Atlantic, and was true in the Europan hydrosphere, dotted as it was with gargantuan plumes of heat ascending from Europa's icy mantle, sinking currents of very salty fluid squeezed from the crust above, and everything in between.

The Joint Government Navy, of course, always had the best hydrographic maps.

The navigator replied. "Turn forty-two degrees to port. Descend three hundred meters at an angle of thirty degrees."

"Navigator, we must maintain contact with Tango-One."

The navigator sighed. "This trajectory comes with an increased risk of detection. Turn five degrees to port and ascend five hundred meters at an angle of sixty degrees."

"Take us up, helmsman."

The sub began rising at a steady pace. The sonar operator whispered in the microphone, his voice thick with alarm. "Active pings, active pings!"