Technology

The current level of technology in Xenosea is around parity with late 20th century Earth. Even though the colonists departed from Earth in the late 2300s, they did not have the population or industrial base to sustain that level once away from the support systems of earth. This was expected, however, and the original colonists were provided with extensive documentation on the entire history of human technological development. Over the centuries much of this information has been lost, corrupted, or destroyed.

Technology has been slow to recover, as the population of Xenosea is only in the tens of millions, and not a lot of spare effort is available for research and development. What progress has been made is almost entirely focused on survival in the strange and hostile world.

## Housing

Almost all human settlements are in seafloor stations, each of which is composed of several modular sections connected by tunnels. The so called Hudson Model is the most popular, consisting of habitation towers, each of which is composed of several stacked segments. This design allows for fairly easy construction, and isolating compromised areas in the case of a leak or breach.

How comfortable the accommodations are varies greatly by individual wealth and location. The average person lives in what you might consider a cramped apartment.

## Energy

The primary energy source on Xenosea is through molten salt thorium reactors. These reactors power nearly every station and submarine. Some geothermal power is used where appropriate, but the moon has an abundance of thorium deposits that have lead to a near universal adoption of nuclear power.

Minisubs are too small for reactors, and so they use hydrogen fuel cells instead. This fuel is produced onboard the host submarine or station, using energy from its reactor. This allows for minisubs to quickly and efficiency refuel when docked.

## Computers

Computer technology is limited in xenosea. Microprocessor technology is very limited, and as such computers are large, cumbersome, and slow.

Computer networks are basically nonexistent, with long distance communication being limited to a telegraph system running on cables between some stations. Where there aren't telegraph cables, messages must be carried by submarines.

## Submarines

All long ranged travel is performed by submarines of varying sizes. Aside from short ranged minisubs, these are all nuclear powered. There are many different classes of submarine filling every niche from small independent prospectors all the way up to military battlesubs.

Typical size ranges are between 25 and 80 meters long, displacing between 700 and 12,000 tonnes, with a crew between 12 and 200 sailors.

Both public and private ownership of submarines is common, even armed submarines. It's easy to hide in the ocean, and even the most honest merchant needs to be able to defend themselves against pirates.

Many submarines also have onboard hangars to carry minisubs. These are small submarines with powerful but time limited engines. They can fill a wide array of roles, and add significant versatility to their parent submarine. They are commonly used as scouts or combatants, able to make attack runs on distant targets or in conjunction with their parent.

## Submarine Weapons

Submarines are armed with two primary weapons systems: gun turrets and torpedoes.

Gun turrets typically fire jetshells. These are projectiles ranging from 8cm to 20cm in diameter, tipped with sodium, and containing a rocket sustainer in the base. When the gun fires, a small amount of gas leaked forward in the barrel, clearing it from seawater for the projectile's initial acceleration. The projectile exits the barrel travelling at over 700 m/s and entering an area of low density, foamy water caused by the barrel clearing. The sodium tip reacts violently with the seawater, creating a gas bubble that the projectile can travel through. Meanwhile the rocket sustainer in the base of the projectile helps it maintain speed for a handful of seconds. Upon impact the shell may explode, or merely punch a hole in the target.

Torpedoes are launched from tubes on the submarine, and swim out to the target under their own power. Torpedoes typically have both an onboard sonar system and a wire linking them to the launching submarine. Though this wire the submarine provide targeting data or even change the torpedo's target. If the wire breaks, however, the torpedo will operate under it's own guidance, potentially even locking on to a friendly submarine.

## Agriculture

One of the most crucial developments by the early colonists was genetically engineering some of the plant species brought along the colony ships to be suitable for xenosea. None of the local lifeforms are compatible with earth biology, so food production was a crucial concern early in colonization. Although the technology is now lost, the early colonists were able to produce several crops that could grow in the local seabed and produce products.

The most common of these is called kelp, although it's more closely related to grass than real Earth kelp. It's grown in vast fields outside stations with suitable soil, lit by lights powered by the station's reactor. Once fully gown the kelp is harvested by divers or tractors, and brought inside for processing into a variety of goods. Kelp can be processed into food, alcohol, or even resin to produce plastics.

Some modified species of Earth fish are also farmed.