Interlude FTL Tracking, and Stealth (Patreon)

The rise of Faster than Light travel is a major milestone for any fledgling civilization. It greatly expands the range of worlds they can visit within their own lifespan. Breaking the lightspeed barrier quickly leads to the formation of extrasolar colonies, and before long interstellar trade. Trade routes and colonies that must be defended, not just from aliens but from a culture’s own people as well. Piracy is often one of the first great dangers a civilization will have to contend against within the depths of space. Well, unless they happen to be a hivemind or a species that lacks that inclination.

Weapons, shields, and armor are all well and fine, but defending even a handful of colonies can grow to be bank-breakingly expensive. Especially without the ability to track ships in transit. A prospect made more difficult by the myriad methods used to break the light speed barrier. Hyperdrives for example use hyperspace as the medium of travel, but warp drives bend space and travel through normal space. As such, the methods of tracking them are different.

Let’s start with Hyperdrive. In order to track a ship traveling through hyperspace, a civilization must first develop sensor technology capable of peering into hyperspace. Not an easy prospect, but one that is well worth the effort. Once such sensors exist, a ship traveling through hyperspace could be tracked by the distortions it generates in hyperspace and more easily by its energy signature.

Naturally, military ships don’t like being tracked if they can help it. As such many civilizations quickly look into minimizing those distortions and their energy signature once they are capable of detecting them. There are several methods of doing this, but the easiest lies in modifying a ship’s thruster assemblies. In hyperspace, a ship must continuously produce thrust in order to maintain speed, unlike in normal space where a ship does not. This continuous thrust produces both heat and distortions in the surrounding hyperspace that can be tracked. The typical solution to the heat buildup problem is to outfit a ship with a radiator assembly, allowing it to radiate excess heat into its surroundings. More advanced races often use subspace radiators able to dump that heat into multiple hyperspace layers at once. That heat, however, is also one of two major factors that allow ships in hyperspace to be tracked, as it is the main component of a ship’s energy signature.

By using a low-heat thruster assembly, a ship’s energy signature would notably be reduced. Making it far more difficult for a ship to be tracked. However, the ship could still be tracked by the wake it generates in hyperspace as it moves. There are several ways to reduce a ship’s wake just by modifying a ship’s thruster assembly. Altering the way it produces the thrust can have a major impact. Reducing thrust can also be a viable tactic. Lower thrust however also means a lower speed.

Interestingly, the same technologies that can be used to track a ship in hyperspace can also be used to track ships at warp, but not always. The why of this lies in the fact that warp drive-equipped ships face the same problem that hyperdrive-equipped vessels face, namely heat build-up. Warp drives generate massive quantities of heat as a byproduct of their operation. The solution most cultures use is to employ radiators to dump that massive amount of heat into their surroundings. Ships with subspace radiators would dump that energy into hyperspace, where it can be detected, and tracked. However ships without subspace radiators can still be tracked, but not via hyperspace tracking.

Waste heat from a starship’s main drives is actually the principle method of detecting a ship at long range. Conventional faster than light spatial scanners can be tuned to pick up the heat signature of a ship from lightyears away, whereas things like their mass readings don’t show up until they are much closer.

To counter this, a ship would need to reduce her heat signature. One way is to employ heat recyclers that can absorb waste heat and convert it into usable energy. This has several benefits, not only does it reduce a ship’s heat signature, but it also improves fuel efficiency. However, these recyclers are nowhere near as efficient as a radiator at dealing with waste heat. As such they are often used in combination with a radiator. Stealth ships also typically use this method, but when running silent, they also employ specialized systems to temporarily store excess waste heat.

Solean ships, however, do not employ radiators at all when dealing with waste heat from the engines. Instead, they use a rather ingenious array of energy absorbers and converters that convert the entirety of their drive’s waste heat output into usable energy. This is not to say that they don’t employ radiators, however. Radiator technology does not only apply to propulsion but it can also be applied to shields. Shields absorb incoming energy, but that energy must go somewhere. That energy is radiated away from the ship in several forms, some of it is typically dumped into space through a ship’s main radiators, while the rest is often radiated away as light. That is why shields glow when hit by weapons fire. Solean shields employ advanced subspace radiators to dump the majority of incoming weapons fire into hyperspace, radiators that are dedicated to the shields rather than the main drives. This setup gives Solean ships several key advantages in stealth, fuel efficiency, and shield mitigation rates.

Moving on, jump drives. Jump drives function through subspace aka hyperspace, but they don’t use the same hyperspace domain as hyperdrives Their use of the natural subspace corridors between stars, limits their travel vectors. As such it is very much possible to simply monitor the jump nodes in a system to alert defenders that a ship has entered or left the system. However, the same sensors that can detect ships in hyperspace could detect a ship traveling through a subspace corridor. Do note however that since subspace corridors occur in a different hyperspace domain from that used by hyperdrives, the sensors would need to be tuned to that domain in order to pick up a jump drive equipped ship. However, this tuning also prevents them from detecting hyperdrive-equipped ships. The normal solution for this is to simply use two arrays of hyperspace scanners each tuned to monitor a different domain.

Next up, Inversion Drives. These drives are by far the most interesting to track. They create subspace inversions that effectively allow a ship to teleport between two points. Speed is a function of range and cycle time. This use of subspace inversions however creates a massive energy burst in hyperspace every time the drive is engaged. A burst that can easily be picked up by even the most primitive of hyperspace sensors, but this burst only occurs at their entry point. Where the ship exits no such burst occurs, as all the energy of travel is expended on entry. Not to mention early hyperspace sensor are unable to determine the direction of travel Early tracking of inversion drives is typically done, by marking the coordinates of each burst and drawing a line. This would give both the speed and direction of a ship using an Inversion Drive. Tracking can be thrown off through a number of methods, including the use of subspace decoys.

Finally, Stardrives being organic in nature do present their own challenges. They typically function on principles similar to that of warp drive, but they are not so easy to track via their energy signature. Yet they are also both a sublight drive, and they can through the use of a special form of spatial flux access the jump nodes. When they access a jump node they can be tracked entering, but they don’t produce the same wake patterns that other ships would. Making them harder to track while in transit. As for when traveling at warp, all stardrives are effectively similar to stealth variants of the warp drive. They do not dump energy into hyperspace, and their energy signature in normal space is remarkably small. As such, the best way to track them is by tracking their spatial flux signature. This is inherently more difficult, and requires specialized sensors. Highly specialized sensors, and the range of tracking is also limited to a few dozen lightyears.