HyperSpace is a "higher dimension" or set of dimensions that forms an alternate space-time adjacent to TrueSpace. Modern technology has allowed spacefaring civilizations to use HyperSpace as a medium for communication (Hyperwave) and transport (Hyperdrive). HyperSpace was the first non-TrueSpace dimension to be discovered, and after the work of the Androsynth and the discovery of QuasiSpace by the Alliance is now known to be only one of many such dimensions. Some of the terminology associated with HyperSpace travel, as well as the term HyperSpace itself (literally meaning "above space" in English), appear to be influenced by the use of a tiered-structure analogy to represent reality phase difference, placing HyperSpace "above" TrueSpace.
The most striking feature of HyperSpace is the different properties electromagnetic radiation has within it; HyperSpace's different physical constants cause the speed of light to be much greater than the speed of light in TrueSpace. Observers in HyperSpace thus perceive electromagnetic radiation as "red-shifted", as the increased speed of propagation of light waves causes their wavelengths to become longer. Beyond this oddity, the physical laws in HyperSpace are similar enough to those in TrueSpace to allow vessels and their passengers safe passage. However, some humans entering HyperSpace have encountered intense feelings of disorientation and discomfort, effects of HyperSpace's unique attributes.
While most of HyperSpace is cast in a blood red light, there are some regions that do not appear red. The majority of these regions are strong TrueSpace gravity wells, which under certain conditions create transdimensional vortices into HyperSpace. These vortices are regions of overlap with TrueSpace, creating natural exit points from HyperSpace to TrueSpace. There is also a constant display of bright explosions and bursts of light in HyperSpace. Though the nature of these energetic (but harmless) events is unknown, they are theorized to be manifestations of objects moving quickly through HyperSpace into adjacent dimensions.1 Similar events have been observed in QuasiSpace.
Hyperdrive ships operate by generating hyperdrive warp fields (usually huge in size, the portal through which the Androsynth exodus took place was 500 metres wide), allowing ships to "push up" or "translate" into HyperSpace. This may be similar to the focused dimensional fatigue beams used to access QuasiSpace. The independent development of Hyperdrive technology has been a near universal among modern civilizations, the notable exception being the Arilou who also make use of QuasiSpace. This technology is usually accompanied by HyperWave, a process that involves transmitting information at seemingly superluminal speed via HyperSpace. Even vessels originally designed for subluminal speeds, when equipped with Hyperdrive, can be practically used for short-distance HyperSpace travel as evidenced by the Syreen migration from Syra and the Androsynth exodus from Earth.
While a Hyperdrive field allows TrueSpace vessels to travel through HyperSpace, the slightly different laws of physics within HyperSpace however impose a constant drag force on a vessel, forcing ships in HyperSpace to constantly thrust and expend fuel in order to make headway. Similar to TrueSpace gravity wells, a ship contained in Hyperdrive fields creates a shadow, or "spoor," in HyperSpace that indicates its presence visually but also masks the identity of the ship. When the Hyperdrive fields of different ships collide, the fields interfere with each other, causing them to dissipate and return their contents to TrueSpace. Any interaction with a Hyperdrive field and a natural gravitational intrusion into Hyperspace has the same effect; thus, large local gravity sources prevent the formation of stable Hyperdrive fields (hence the impossibility of "pushing up" within a star system). Very short-range Hyperspace maneuvers, however, are possible within a star system. Such maneuvers are usually only used to disengage from combat, and the energy requirement is only noticeable for large ships. The Arilou have very nearly mastered such HyperSpace transitions with their Skiff vessel's HyperSpace Shunt, which allows them to teleport to a random point within a short range.
The distance between any two stars in HyperSpace tends to be astoundingly shorter than in TrueSpace; the apparent travel time of voyages of thousands of light-years in TrueSpace is reduced to a matter of weeks from the reference frame of a HyperSpatial traveler. However, the correspondence between points in HyperSpace and TrueSpace may not be one-to-one and certainly does not preserve the geometric orientation of their TrueSpace relationships. Not all stars generate TrueSpace intrusions into HyperSpace, and, although all local HyperSpace gravity wells are clustered in a single galaxy that appears to be an analogue of the local TrueSpace galaxy (called the Milky Way Galaxy by Humans), the spatial relationship between the Hyperspatial locations of stars is often greatly distorted from their TrueSpace locations. Additionally when two hostile vessels encounter and force re-entry into TrueSpace, the ensuing combat invariably takes place near some rogue planetary body — though this may be just a gameplay simplification.
In mapping HyperSpace, Chenjesu astronomers have divided stars located in HyperSpace into groups or constellations, which Humans have freely named after notable stars and constellations from TrueSpace astronomy, even though most of these stars (whose TrueSpace labels are mostly just numbers) bear no relation to the TrueSpace stars for which they are named. This is rarely a problem, since the advent of HyperSpatial travel in Human civilization has reduced TrueSpace astronomy to primarily an academic concern (as no TrueSpace-based method of communication across the stars is commonly used or even possible). The Chenjesu standard coordinate system contains a certain set of constellations that have been well-mapped and explored by their scientists; this map defines the safely traversable bounds of "known space" for most races. No extant races native to this region have had the resources to extend the boundaries of Chenjesu maps very far; only such races as the Ur-Quan or Melnorme are known to have extensively traveled and explored the galaxy outside the Chenjesu starmap.