FTL Drive Technology
Each race has its own unique method to travel faster than light between star systems. In some cases this method of propulsion also affects how ships move in tactical battles. For details on how movement between systems is modeled in the game see Strategic Movement.
The speed of STL travel is dependent on the drive technology of the ships traveling.
Just think of the node drive as "brachiating". Humans swing from branch to branch, and can only swing where the branches grow. That's the ticket! —Arinn Dembo
The discovery of the so-called "subspace" dimension has allowed Human propulsion engineers to take advantage of the gravitational stress fractures of the universe. The principle at work is simple: four-dimensional space time appears to have a crystalline structure, and massive bodies such as stars and black holes create distortions in the space-time continuum. These distortions are connected by breaches of space-time known as "subspace". In essence, subspace is an interstitial dimension, which connects one gravitational distortion to another.
Connections between massive bodies in subspace are formed by means of similar "resonance" frequencies between the two gravitic "nodes". The causes of this "resonance" cannot be fully explained without resorting to the esoteric extremes of Starstring Theory—a pop-culture reference to the part of Superstring Theory which governs node-lines—but the practical result is that the distance between any two nodes in subspace is highly compressed, relative to the positions these two Nodes might occupy in ordinary space-time. A Human vessel equipped with a Node drive can enter and leave subspace at will, and thus traverse the compressed distance between nodes very rapidly. When the vessel emerges from subspace again, it will have traversed a great distance in a short period of time, thus effectively achieving superluminal speed. This "faster-than-light" travel is possible between any two points which are connected by a fracture line.
While most Node lines occur between stars, other massive stellar bodies can also create small node lines. For example, when Blasky Yao Hsiang discovered subspace, he was able to exit the line at Jupiter. This is because Jupiter is a healthy sized gas giant and it does warp the fabric of spacetime just enough that a ersatz experimental node system could actually traverse a subline with the 100 to 1 shot of surviving entry and exit transition. System internal node lines do exist between high G enough bodies but so far they are so tenuous and so risky that they remain a curiosity more than an exploited resource. Vessels the size of a Destroyer are considered to be to large to be able to use these sublines.
Chains of nodal connection between stars are sometimes referred to as "starstreams", a term coined by the first subspace traveler, Blasky Yao Hsiang. However, the phrase "starstream" can be somewhat misleading; although the Node connections between stars do form a sort of chain, if plotted through ordinary space-time, a Human ship traveling in subspace will not be crossing those regions of space as a physical object. The only evidence of the ship's passage in Einsteinian space-time is a series of gravitational pulses, which indicate the presence of the vessel in subspace. Although a sufficiently sensitive scanner might be able to determine the mass of a Human fleet in motion or the number of vessels traveling together, those vessels cannot be contacted or intercepted in ordinary space-time. One quirk of these chains of nodal connections is that sometimes a star does not form node lines. This is due to the specific gravimetric geometry of a star system. As node points are essentially flaws in spacetime, sometimes this geometry cancels out the flawed points.
Humans use the fastest method of FTL drive technology, but are limited by the locations of the node space fractures and thus, their available routes. While Humans may refine the range and speed by which they can access these fracture lines between stars and travel down them, they are tied to this method of FTL travel and will always have to vent reactor plasma for thrust in non-FTL maneuvering. This lack is somewhat compensated for by the fact that only Humanity and the Zuul have mastered subspace: While Human ships can not see out of the node-line and can be detected by the real-space tachyon wake they generate, node ships can not be intercepted by most races until they leave the node fracture line and return to normal space. Human ships cannot exit a node-line except at a Node Fracture Point and any ships without engines in nodespace either disappear forever or re-enter realspace catastrophically.
Human ships will take the fastest, most economic route to a system. It is almost always faster for a human to use the node-lines over STL travel. Node-lines begin and terminate at star systems, requiring a Human fleet to traverse the system using STL thrusters to the next node-line fracture. A Human ship can move toward a star system via the node-lines, traverse whatever space in that star system needed to be traversed in normal space and begin traveling out of the system on a connecting node-line to another star in the same game turn, provided there are no enemy ships in the system.
Human ships are initially limited to traversing node–lines of 9 LY or less. Advances in technology enable them to travel further through subspace, allowing them to take advantage of node lines which were previously inaccessible.
By using STL travel, the Humans can access systems they have no known Node Line connection to.
Humans will always require thrusters to move STL, thus limiting the available weapon expansions on their drive sections. The requirement to mount FTL engines on their ships will also restrict them to slower STL speeds than those the Hivers can obtain.
Hivers have been spacefarers longer than any other species currently known to Humankind, possessing sublight travel technology for over a thousand years. Although much of that time was spent merely colonizing their own home system, the introduction of gate technology allowed them to successfully become an interstellar civilization.
Hivers move through space using a combination of slower-than-light and instantaneous-transport technology. A fleet of Hiver ships, driven by standard STL engines, begins by traveling a great distance the hard way: It may take them months or years, moving at near-relativistic speed (Hiver STL drives are the fastest on the Strategic view, it takes all other races much longer when traveling using their STL drives.), to reach their destination. However, once they arrive, a ship with the Gate Section can build a teleportation gate. Should other Hiver ships choose to follow, they can travel instantly to the newly erected gate from any other gate in the Hiver Empire.
Hiver gate technology entered development some 500 years ago, finally granting them a quick and reliable method to travel between stars-- once they reached them. Although a few ships were sent out in the pre-Gate era to reach and colonize more distant worlds, these early colonization attempts did not fare well; the distances involved were too great, and it was too hard to develop transport routines that would allow the building and maintenance of adequate domes or terraforming efforts for a pioneer colony. Gates were revolutionary, as they allowed new colonies to access more settled worlds for much-needed support.
Hiver gates function by manipulating the Menisceal Principle, which states that the obervable universe is merely a thin 'skin.' Anything that can leave this 'skin' temporarily becomes a non-event in space-time, and certain technologies can manipulate it in different ways. The Gate mechanism employs the non-event property to remove and re-insert matter at different locations of the universe. Each Gate represents a nexus of simultaneity; a ship passing through the Gates is briefly everywhere and nowhere at once. Hiver ships become one with the skin for a moment, and then re-coalesce at the desired coordinates. Tarka ships use the same effect in the exact opposite way, though neither civilization realizes the common basis of their FTL methods.
While technological improvements do increase the speed at which their fleets traverse space, Hivers never achieve FTL speeds with their ships.
The first Hiver colony is typically formed 50–100% later than other species. However, they are balanced by the ability to go anywhere they have an active gate in a single turn, thus providing the best defensive posture of the game.
These gates require the radical curvature of space-time found deep in a star system in order to punch through space-time and connect to the gate network; physically, there is no way to set-up a gate far away from a gravity well, and consequently, all gates must be near one. Furthermore, there can be only a single active gate per Hiver network in each system, though each Hiver faction develops their gates using slightly different frequencies and polarities so their overlapping networks don't interfere with each other. One can keep multiple Gate Section ships in a system in their inactive travel form so that if the currently active gate is destroyed a new gate can be easily deployed. Once deployed, the gateship is incapable of further travel or conversion and can only be destroyed.
The high energy requirement of phasing ships between gates is met by the reactor systems of the individual ships the gates are mounted upon. Thus, any gate not actively involved in transporting ships across the network can add its power to the total network, and the per-turn limit on ships transported rises with the number of nodes. Due to the design of the gate system, cruiser and destroyer gate sections provide the same capacity increase to the network; however a cruiser gateship has significantly increased firepower and hull strength. Larger Hiver ships take up a greater amount of the network's overall capacity to transit between gates.
Hiver ships only use reaction thrusters, so any space allocated to FTL drives on the ships of other species is instead packed with weaponry. The number of weapons mounted on their drive sections typically remains the same throughout the game, with some nominal changes as miniaturization of other components allows. Their STL speeds can be as much as 50% higher than other reaction-based STL drive systems, as they are specially designed for high-speed inter-stellar travel.
The Liir have been independent space farers for 100 years.
The Liir use an inertia-less "stutter" drive, which creates movement through space by teleporting the entire ship in tiny spatial increments of a millimeter or so. The implications of this drive system are many: for example, a Liirian ship does not use thrust to accelerate or decelerate. It also allows for the mass of a Liirian ship to be a non-issue, as the ship never develops the inertia of a body in motion; it simply changes its space-time coordinates. The Liir DO use reaction thrusters for close maneuvers and rotation. So a Liir ship with a destroyed drive can still rotate. For combat maneuvers, they use both...their reaction thrusters are used as secondary systems.
The "speed" of a Liirian vessel is determined by the number of teleports per second that its engine can perform. It is not difficult for the Liir to achieve relativistic speeds in open space, but the stutter drive has a distinct disadvantage when operating near a gravity well. Any object massive enough to cause a large space-time distortion—be it a planet, star or black hole—can severely slow the movement of a Liirian ship.
Liirian drive technology possesses some interesting tactical possibilities. The "stutter" drive is also used for STL travel, speed being dependent on proximity to gravitational distortions, such as planets and stars. Thus the Liir battleground of choice is deep space where their tactical engines are faster, in comparison to the abilities of the other races. The inertia-less quality of the Liirian "stutter" drive allows for quick accelerations and decelerations, although they cannot ”stop on a dime". The energy required by the drive is so great that if a Liirian vessel abruptly raised the drive to full operating capacity from naught, instead of gradually increasing in speed, the engine would be likely to explode from the stress.
The frequency of these stutterwarps—the incremental teleportations that move the ship along—rises with technological improvements, to the point where a moving Liirian vessel is "not there" for a significant portion of time. Hence, as the Liir develop full "stutter" drive there will be an increase in the small probability of incoming ordnance passing through the vessel while it is 'elsewhere'.
Since Liirian ships do not require the large Newtonian thrusters used by other races to maneuver in STL, the number of weapons mounted on Liirian engine sections is initially second only to the Hivers. The number of weapons on Liir drive sections will typically remain the same throughout the game with some nominal changes as miniaturization of other components allows.
The Morrigi ("Travellers" in Trade-Language) are an ancient race, but only recently encountered by the other races.
The Morrigi use a Void Cutter gravitational drive. A Void Cutter engine, once engaged, uses gravimetric focusing to bend space-time around the ship, accelerating it to FTL speeds. When it does so, it creates a ripple behind the ship like a "bow wave" which other ships using a similar drive can join, and allow more efficient FTL travel, increasing the speed of all the ships in the "flight". This is known as a "Flock Effect". Morrigi travel is slowest alone, and fastest when in large numbers. Special Gravitation boost ships can increase the speed of the fleet further.
The Tarkas have been a space faring race for the last 500 years.
The basic principle at work in the Tarkasian faster-than-light system is the generation of a warp "field"—an envelope of force, which surrounds the body of a Tarkasian ship. Within this envelope, the ship is essentially a non-event in space-time, having very limited interaction with the standard four dimensions of the Continuum. Once the warp engine of a Tarkasian ship is fired, the normal physical laws governing mass, energy and acceleration no longer apply to that ship. This affords them a very basic but effective form of FTL travel.
Although neither the Tarka nor the Hivers realize it, their FTL drives in fact use the exact same Menisceal Principle in exactly opposite ways (see Hivers for description). The difference in the Tarka use of the meniscus is that a Tarka ship slips in and out of the skin of the universe like a needle. This is relatively easy; the only challenge is learning to exchange communications while in the meniscus. It takes a highly sophisticated computer and message-tagging system to pull a coherent message out of it, because every energy pulse from the beginning of the universe to the end of the universe is contained within the warp bubble.
A Tarkasian vessel can achieve superluminal speeds and travel at these speeds for any distance, its range limited only by the available fuel for thrust and its speed only by the available power for the generation of the warp envelope. Therefore—given enough logistical support—a Tarkasian fleet can cross the entire map even at the beginning of the game.
The Tarkasian method of FTL travel is initially the slowest of the three FTL drive technologies in the game. As technology improves, their speed over short distances begins to rival and surpass the Liir's.
Initially the hyperdrive field is crude and can only be used for FTL travel and, much like the Humans, the Tarkas are forced to vent drive plasma for Newtonian maneuvers. This limits the available weapons on the drive section.
Eventually Tarkasian field booms become advanced enough to manipulate a warp field precisely enough to mimic Newtonian combat maneuvers, allowing Tarkasian ship designers to do away with space consuming drive vents, increasing the availability of weapons on drive sections and improving tactical speed and maneuverability.
The Zuul are introduced in the first expansion for Sword of the Stars, Born of Blood. They are scavengers and their ships are rough, random things made of chunks of other race’s ships and technology. The Zuul use something known as a Tunnel Drive to tear through the fabric of space-time and down into the nodespace flow between stars.
Where humans use their node drive to access node space through natural fractures, the Zuul tear apart space-time to get what they want when they want it. Once a tunnel has been “dug” by a special tunnelship, any Zuul vessel can access the artificial node line to travel at speeds rivaling human ships. The down side to this drive system is that artificial node lines tend to decay over time and with usage so the Zuul player will have to keep an eye on his FTL network. And if a node line collapses with a fleet traveling down it, that fleet is utterly destroyed. And like the human ships, any Zuul ships without engines in nodespace either disappear forever or re-enter realspace catastrophically.
Currently, nothing is known about how the Zuul move in tactical combat.
All fleets traveling at STL speeds can be intercepted. Liirian and Tarkasian fleets can be intercepted while traveling faster-than-light. Humans and Zuul are the only two races to use nodespace for FTL. As such they can only be intercepted by one another.
And as far as STL fleets intercepting FTL fleets?
It is physically possible in the game, but like shooting a bullet with an arrow, it pretty much has to be head on and very, very lucky.
If the intercepting fleet is slower than their intended targets then the target fleet may outpace the interceptors.