Spaceship

In Innocence Seekers, spaceships (宇宙船, uchūsen) are one means of transportation between planets. The existence of spaceships is often a sign that a civilisation is exceptionally advanced, as practical interstellar transportation without the assistance of wormholes, Portal Monoliths or precursor artifacts requires highly advanced technology (travel between Earth and Mars only requires rocketships with only rudimentary protection against the elements and enough fuel to leave a planet's gravity well, while travel between Earth and Ocypsa requires not only sufficient fuel to reach a significant percentage of the speed of light and to slow down upon arrival, but also a high level of protection against hazards such as space dust and blueshifted radiation).

General
In the Innocence Seekers setting, the size and shape of spaceships vary widely, and can differ between species. However, most spaceships follow one basic template. They often consist of a massive armoured body, usually made of metal (typically titanium). The armour covering the spaceship's body serves to protect the ship against physical hazards such as micrometeorites and space dust. Ships also usually come with some form of protection against radiation, particularly high-frequency electromagnetic radiation such as gamma rays (which may originate from actual cosmic sources, but is also often a consequence of the ship's very high speed due to blue shift). All ships have some form of propulsion system attached behind the body; these usually take the form of rockets or other reaction drives (reactionless drives are impossible in the Innocence Seekers multiverse, per Newton's third law of motion and the law of conservation of momentum).

Possible propulsion systems for ships range from hybrid fusion/annihilation rockets and pure matter-antimatter annihilation rockets (which both pose problems regarding the amount of fuel, as well as its containment), to fusion ramjets (which do not require as much fuel as rockets, but are limited to around 0.12c and very difficult to start, having to rely on the proton-proton chain reaction ), to laser sail-based propulsion systems (which poses its own problems), to even more exotic methods of propulsion such as using Hawking radiaiton from a mini black hole, and even magic-based propulsion systems. In general, faster-than-light travel is impossible in the Innocence Seekers multiverse, meaning that all interstellar travel must be conducted at slower-than-light speeds (although time dilation can allow one to cross the galaxy in the space of years). Most apparent observations of faster-than-light travel in Innocence Seekers (in particular, the as-yet-unknown magic-based propulsion method used by the Donsilans, as well as the waystones used by humans) are simply applications of time magic.

One of the main features of human spaceships includes waystones, an item crafted by alchemy which binds a point in spacetime to other waystones which are connected to the waystone in question. Any ship with a waystone can interact with a waystone on a planet, allowing it to enter a strange realm known as hyperspace. Within hyperspace, time functions differently, allowing a spaceship to reach its destination without having the effects of time dilation occurring. This means that the same amount of time will pass in the origin, destination and the spaceship. However, a spaceship can only exit hyperspace by interacting with a waystone, limiting the use of hyperspace to travel between already-discovered planets with a waystone (or to another spaceship). Travel to undiscovered planets requires going the "long way", meaning using conventional magic-based propulsion. Should a spaceship reach a planet with a waystone the "long way", interacting with the waystone will cause the spaceship to travel through time, in order for the waystones to synchronise.

Note that in hyperspace, there is still a significant distance between planets (the distance between Earth and Ocypsa is around 40,000 light years or around 12 kiloparsecs, for example), meaning travel is not instantaneous. Travel through hyperspace still requires conventional propulsion.

Intergalactic travel poses a much bigger problem than interstellar travel. The only practical way of travelling between galaxies within the span of a human lifetime is with magic, and even with magic, the ability to travel is dependent on the dark matter density (as mana is one component of dark matter). Waystones cannot be used, as spaceships cannot be in hyperspace at a distance of more than around 300,000 light years, or over 90 kiloparsecs, from a waystone (as waystones stabilise hyperspace with the assistance of a gravity well, and a gravity well the same mass as that of Earth's sun provides stabilisation at a radius of around 300,000 light years). What method the Donsilans use to ensure their intergalactic colonies follow the same time is currently unknown.

Living space
In all manned spaceships, there is always a compartment dedicated to sustaining a number of inhabitants. This "habitat module" usually only takes up a small part of the spaceship, especially for thoes not powered by magic, due to the habitat module contributing additional mass (decreasing delta-v, due to acceleration being inversely proportional to mass at a constant force) and using resources otherwise dedicated for transportation (magic-powered ships have a far higher maximum energy consumption, allowing habitat modules on such ships to be far larger and more palatable to its inhabitants).

At the bare minumum, a habitat module consists of a pressurised hull supplying a suitable atmosphere for its inhabitants, as well as food, water, and waste removal devices. The habitat module should be climate-controlled (i.e. the temperature and humidity must be at specific levels, e.g. 294 K and 40 per cent humidity). The amount of energy a habitat module consumes is dependent on its size and the number of inhabitants; in general, fewer inhabitants and smaller size means less energy is consumed. It is important to note that for logistical reasons, there are no "luxury cruise spaceships" built by purely technological civilisations (the energy requirement and the total mass of the habitat module of a "luxury cruise spaceship" are excessive, meaning that a far larger and more powerful propulsion system and far larger fuel tanks are required, and only magic can meet such requirements with any practicality).

Because gravity requires a gravity well, there will be no actual gravity in the habitat module of a spaceship. Gravity can be simulated through the propulsion system itself (a constant thrust drive generates artificial gravity via inertia), through rotation of the ship (generating artificial gravity via centrifugal force) or through using magic to create a "gravity bubble" (which, if used improperly, may send the ship tumbling or veering off-course due to the law of conservation of momentum, although a computer can make corrections; additionally, the released energy must be dumped somewhere). The orientation of the habitat module actually depends on how gravity is generated (unless the spaceship is capable of controlled atmospheric re-entry, in which case "down" is the "belly" of the ship, the side facing the ground when the ship is on the ground). If the ship uses its propulsion system to generate artificial gravity, then "down" is the side closest to the propulsion system itself; if the ship rotates to generate gravity, then "down" is the side farthest from the axis of rotation (if a ship is capable of both thrust-generated and centrifugal artificial gravity, then there could be the possibility of its inhabitants standing upside-down). If the ship uses magic to generate gravity, then "down" may be configurable.

Weapons and armour
Many spaceships in Innocence Seekers possess means by which they can defend themselves from attack, or attack other spaceships or planets. It is important to note that combat between spaceships in deep space often takes place at ranges measured in light seconds (1 light second = 299,792.458 kilometres), meaning that the enemy fleet would not even be visible to the naked eye. In orbit, however, opposing fleets are going to be closer to each other. Note that even at distances of tens of kilometres (also possible in Innocence Seekers), enemy fleets would not be visible to the naked eye.

On the commencement of combat, spaceships have the option of retracting their radiators, instead relying on internal heat sinks for thermal control. However, leaving radiators retracted for excessive periods may result in the spaceship overheating, which can lead to catastrophic consequences. Conversely, extended radiators are prime targets for enemy fire, as if the radiators are taken out, then the ship effectively becomes a sitting duck as it cannot use its weapons or propulsion drive without overheating. This is less of a problem for magic-powered spaceships, which can have their radiators (if they don't fully rely on magic for thermal control) protected by magic barriers and shields.

Defence
Spaceship defence consists of many systems, which may or may not be present on all spaceships.

Armour
Armour represents the very last line of defence for spaceships. While all interstellar spaceships include multiple layers of thin armour separated from the hull and each other by several inches of empty space to protect from micrometeorites, military spaceships may have more and thicker armour layers to stop hypervelocity kinetic impactors. Such impactors will (theoretically) be vapourised on impact, leaving a hole in the outer layers of armour but keeping the inner layers (and the hull) intact.

Standard anti-kinetic impactor armour is very effective at stopping singularly pulsed directed-energy weapons. However, if a directed-energy weapon is fired continuously at armour, the armour will vapourise at some point. To protect against such weapons, one must use armour which cannot be vapourised easily (i.e. has a high enthalpy of vapourisation per gram). While boron is ideal for anti-directed-energy armour, it is also expensive, so carbon is often used (its enthalpy of vapourisation per gram is well over double that of aluminium and titanium).

Consideration must also be given to radiation from nuclear weapons. While alpha radiation (from nuclear weapons; not from particle beams, which are far more intense) can easily be stopped by standard armour, special consideration must be given to X-rays/gamma rays and particle radiation. Note that completely different materials need to be used to stop gamma radiation in comparison to those needed to stop charged particles (using gamma-ray shields to block charged particles will only result in a storm of X-rays). The best way to block particle radiation is to use materials with low atomic number (particularly materials full of hydrogen, such as hydrocarbons or water), while X-rays and gamma rays require materials with high density (which happen to have high atomic number, such as lead and tungsten). The best configuration is to have the gamma-ray shield right next to the hull, with the charged-particle shield set next to the gamma-ray shield.

Shields
Note that spaceships built by civilisations which do not use magic at all do not have energy shields for defence. This is because creating energy shields is impractical, if not impossible, using technology alone. There are actually three types of magical defence available for spaceships, which are the same types available for personnel: barrier, shield, and field defence. Barriers protect the entire spaceship against threats, and do not hinder its weapons, but are not as strong as shield defences. Shields only protect a portion of the ship, but are the toughest magical defence available to spaceships. Field defences serve to reduce the impact of enemy attacks within a certain range of the ship, but they are the weakest form of magical defence, and may reduce the effectiveness of the ship's attacks.

The best configuration for magical defence involves having a inner barrier, surrounded by shields on the outside of the barrier. Field defences extend beyond the shields.

Point defence
Point defence refers to taking out threats by spotting them and attacking them as they come. They are particularly effective against incoming nuclear warheads (as they are inherently failsafe), but have less effectiveness against antimatter warheads (inherently "fail-dangerous", and the defender may be caught up in the blast) and hypervelocity kinetic impactors (which will just keep on going even if blown up), and completely useless against directed-energy weapons and magic.

Point defence systems often consist of kinetic impactors, anti-warhead missiles (using chemical explosives) and directed-energy weapons. Spaceships originating from magic-using civilisations may also have magical weapons as part of their point defence systems. The main way of defeating point defence systems is simply to overwhelm it with massive amounts of warheads and kinetic impactors, such that the computer can no longer keep track of everything. Therefore it is important to ensure that the computer is capable of handling the expected storm of impactors and warheads.

Offence
Spaceships are often fitted with many different types of weapons. Note that the use of ship-to-ship weapons on planets is regulated.

Kinetic weapons
One of the possible weapons a ship can be fitted with is kinetic weapons. These fire hypervelocity rounds at the enemy ship, which then deal damage by directly impacting the hull or armour. Kinetic weapons can be classed as hypervelocity weapons and relativistic weapons. Hypervelocity weapons include railguns and coilguns. Relativistic weapons are often magical in nature.

Both railguns and coilguns are weapons which use electricity to propel a projectile at massive speeds. Railguns consist of two electrically charged rails, which, when the circuit is completed by a projectile or its sabot, cause the projectile to accelerate down the rail. Coilguns consist of many electromagnetic coils along the length of the barrel, which successively attract and repel the projectile to accelerate it down the barrel. The projectiles fired by both of these weapons are nearly impossible to detect, but deal incredible damage (often several times their mass in TNT) and will keep going even if they are shot down. However, they use a lot of energy, some of which is wasted as heat. Railguns and coilguns are best used at close range (tens of kilometres); attempting to use them on first contact will almost always result in them missing (and possibly ruining someone else's day).

No known form of nonmagical technology can practically accelerate a projectile to significant fractions of the speed of light (other than deliberately crashing an interstellar ship on a planet). So relativistic weapons are primarily used by magic-using civilisations. What these weapons do is accelerate a projectile to beyond around 0.14c (at which point γ = 1.01); however, relavisitc weapons typically accelerate the weapon to beyond (√3/2)c (around 0.866c, γ = 2). At this point, putting any payload on the projectile (even antimatter) is pointless, as the projectile has more kinetic energy than its rest mass. Such a projectile is extremely difficult to defend against (in fact, it is practically impossible without magic); because of its speed, one will only get a little warning before the projectile impacts (via its blueshifted signal), regardless of where the ship or planet actually is. And should one of these projectiles impact a planet, it will cause massive devastation on a global scale, and may wipe all life from it. As such, all galactic organisations, including the Zodiac Warriors and Puella, ban relativistic weapons (it is also illegal to delibrately crash a ship onto a planet at speed). If one were to use this weapon (despite its possible legal consequences), one must make sure to be completely accurate; the weapon will ruin someone's day should it miss.

Directed-energy weapons
Directed-energy weapons are weapons which send beams of energy straight towards the target. These include laser weaponry and particle beam weapons. Note that both types of weapons have their advantages and disadvantages, and both use a lot of energy.

Laser weapons shine a very powerful laser beam on an enemy ship. Unlike what one would see in most science fiction, laser beams are practically invisible in space, and this will also be the case in Innocence Seekers. Lasers can use any wavelength of electromagnetic radiation, but anti-ship lasers are typically X-ray lasers and anti-planet lasers are in the visible spectrum (typically red, as X-ray and ultraviolet lasers may be partially absorbed by the atmosphere, possibly increasing collateral damage and reducing the amount of damage on the target). The point of laser weapons is to drill a hole into the enemy ship's armour, either by firing continuously, or by firing in regular pulses at very short intervals; singularly pulsed lasers can barely affect state-of-the-art armour. They can be used at any range (if the technology is good enough, they can be used on first contact); however, they are most effective at close range. And unlike kinetic impactors, lasers will diffuse into nothingness via diffraction should they miss.

Particle beam weapons work in a similar principle to lasers, but they fire beams of subatomic particles such as electrons, instead of light. They are better at penetrating armour than lasers, and if charged, can irradiate the enemy ship with bremsstrahlung and knock out its electronics; however, they have a shorter range, and can only be reliably used in the absence of a magnetic field (unless a neutron beam is used). Field defences can deflect charged particle beams. Unlike laser weapons, particle beam weapons are harder to disable. Like lasers but unlike kinetic impactors, particle beams will diffuse into nothingness should they miss.

Nuclear weapons
Nuclear weapons use nuclear reactions to create a massive explosion in order to damage the target. They largely come in three forms: pure fission, hybrid fission/fusion, and pure fusion.

Pure fission weapons work by splitting the nucleus of heavy atoms (such as uranium-235) into lighter nuclei. This releases a massive amount of energy, in the form of gamma rays, neutrons and neutrinos, and the fission products themselves are radioactive. On a planet, this results in significant fallout, but against a ship, the fallout is simply dispersed into space. Hybrid weapons have fission and fusion stages. The fission stage used to initiate the fusion stage, where lighter nuclei (typically deuterium, tritium and helium-3) are fused into heavier nuclei. This may or may not trigger the second fission stage (if the tamper is uranium). Pure fusion weapons use exotic technology (or magic) to directly initiate fusion. If used on a planet, they will produce very little fallout. In general, pure fission weapons are the weakest nuclear weapons, with strengths measured in kilotons (hybrid and pure fusion weapons have strengths measured in megatons).

Regardless of the nature of the weapon, they have similar effects on spaceships. Should a nuclear weapon score a direct hit on a spaceship not protected with magic, the spaceship will be (at least partially) vapourised. If vapourisation is partial, then there is the chance of a breach in the hull (meaning the ship is lost) as much of the armour is vapourised. There is also the possibility of an electromagnetic pulse (EMP) which will fry the electronics of the ship. There could also be depressurisation, if the attack breached a pressurised compartment (such as the habitat module). If there is insufficient radiation protection (or the armour is breached), then the personnel will be irradiated with potentially lethal levels of radiation. The damage is even worse if there is a direct hit from a nuclear shaped charge.

One advantage nuclear weapons have over many other ship-to-ship weapons is the potential for splash damage. Even if the warhead missed, it could still detonate close to the target and damage it somewhat. A one megaton bomb at 500 metres can still cause impulsive shock on the ship. If the warhead completely missed, then it can simply be ignored; nuclear weapons are inherently failsafe, meaning that they will not properly detonate unless a specific sequence of events occurred.

Nuclear weapons are typically delivered on missiles; depending on the missile itself, they can be used at any range (at long ranges, such as thousands of kilometres or even light seconds, the missile or its warhead(s) can coast the rest of the way). Railguns and coilguns can also be used to deliver nuclear weapons. Because of their blast radius, it is inadvisable to use them at close range.

Antimatter weapons
Due to the nature of antimatter, special technology or magic is required to store it. Antimatter is a form of matter which, when it comes into contact with normal matter, undergoes an annihilation event, releasing a massive amount of energy (in fact, it is the purest form of Einstein's equation E = mc2). As such, antimatter weapons are far more powerful than nuclear weapons.

Antimatter warheads are most effective with a direct hit. If a warhead impacts the target ship, it will bury itself in the armour of the ship (or it may even breach the hull), at which point it can be detonated (or it may detonate on its own if its protective casing is breached). A direct hit has the capability of completely vapourising the target ship, if the yield is high enough. Should the warhead miss, it will be set to detonate, regardless of its effectiveness on the target at its distance; this is because antimatter weapons are inherently unstable, meaning a controlled detonation is needed to eliminate the chances of it ruining someone else's day. While point defence systems can stop antimatter weapons, it must be done at medium range, otherwise the ship will be caught in the potential blast.

Antimatter weapons are typically delivered on missiles; depending on the missile itself, they can be used from medium (hundreds to thousands of kilometres) to first contact range (light seconds). Railguns and coilguns can also be used to deliver antimatter weapons. They cannot be used at close range.

Magic
For magic-using civilisations, they have the option of attacking ships with magic spells. Magic can easily bypass any and all forms of armour and cannot be stopped by point defence; the only way to defend against magic is by using magic defences.

Ramming
At close range, ramming is a possible option. However, it must be conducted with a shielded spaceship; unshielded ships would effectively be kamikazes if they attempted to ram an enemy ship, since no amount of armour would protect the ramming ship. There is also the possibility of being brought down by a spell or nuclear weapon when trying to ram.

Drone fighters
Unlike in many science fiction stories, there will not be any manned space fighters in Innocence Seekers; they are impractical. However, it is possible to deploy drone fighters to attack enemy ships at close to medium range. They can be used to directly attack enemy ships or their drone fighters, to deliver nuclear or antimatter weapons, or to act as part of the point defence system.

Propulsion drives
At close range, it is possible for a spaceship to point its propulsion drive at the enemy and activate it. While every ship has this option, it can reduce remaining delta-v (if the drive is reliant on internal reserves) and one runs the risk of having an enemy destroy the drive, leaving the ship stranded. However, if used properly, it can deal heavy damage to enemy ships.

Espatiers
Many races have an elite force of "space marines", or espatiers. They can be placed in a boarding pod and the pod itself shot at an enemy ship by a missile, railgun or coilgun. Once at the enemy ship, the pod or the espatiers will attempt to breach the hull and board the ship. Note that boarding pods have their own protections against point defence, including lasers and missiles to shoot down enemy point defence projectiles and missiles. Some boarding pods also have magic defences.

Since only a select few races have individuals able to use magic directly, the espatiers of most races are covered head-to-toe in magic powered armour. Races whose individuals can use magic directly, such as humans, use mage outfits in place of powered armour. The powered armour or mage outfits ensure that the espatiers can operate in whatever conditions await them in the enemy ship (whether it be temperature extremes, or unbreathable air, or other hostile conditions).

In later sagas of Innocence Seekers, humans often use magical girls as espatiers, as they are often the most powerful humans available.

Innocence Seekers: The Black Rose
In Innocence Seekers: The Black Rose, spaceships do not appear until Innocence Seekers: Akari of the Light, when the first interstellar spaceships built by humanity are unveiled. Constructed by Likkra and Namari, they are powered primarily by magic, and use waystones for transportation between planets. The spaceships are capable of acceleration in hyperspace of around 13.5 parsecs per hour per hour, allowing them to reach Earth from Fuenod in around 60 hours. In normal space, safety protocols limit their maximum proper velocity to 18,000 astronomical units per hour (γ ≈ 2500) outside of a planetary system, and 20 astronomical units per hour (γ ≈ 2.95) within one.