Hyperspace is a full alternate reality, coexistent to our own; together they make up two of the six sectors of reality. The native mass, rather than forming star-like spheres, forms filaments due to a sort of spin induction(hyperbolic gravitic effects establish a "grain", and angular momentum bends to follow the grain). There is also some danger, while in hyperspace, of a filament cracking nearby(or just sweeping through), so "wild" filaments are tracked like weather.
A ship needs a hypershunt to cross over, and will later need it to cross back. Travel along major lines follows anchored filaments, using "filrails" on the ship as roton antennae. The large investment needed to have a suitable filament caught and anchored leaves a hefty market for the little guys; filrails also get more efficient at large sizes.
Looser ships still use hypershunts, but instead of filrails use magnon ramjets, with full six-axis freedom. Any line too small to pay for a filament is run by ramjet ships.
An unknown number of "hypercrystal" ships sneak around this whole system. Such a ship does not use a hypershunt, but uses a hypercrystal focus to "crystallize" hyperspace while remaining in protospace. This process takes minutes to hours as a crystal grows at each end. Once sufficient, the ship matches position with the near end and bounces a polaron burst off its edges, collapsing the crystal to teleport the ship to the far end(back in protospace). This crystallized space is noticeable only as a refraction, and the crystal collapse traps the energy unless something goes wrong, so this is very stealthy.
A hypercomm sends mass excitons through a filament itself, thus a signal travels very quickly along major lines. Communications away from a filament are handled by courier ships, or simple radio. (There are no elementary hyperparticles with zero rest mass, thus mass excitons are the only convenient way to use the local C.)
A hypershunt is safe and fairly easy to operate; once the battery is charged, it takes 10sec for the computer to perform an automated "slow shunt". Under combat pressure, a "fast shunt" may be attempted; while in an inertial frame, this takes 1sec and an unmodified roll against Electronics Operation: Parachronic. If accelerating(for example, if dodging), apply a penalty of -[3×gees], round near. A static gravitational field, like a star's gravity well, counts triple. Success instantly drains the battery and shunts the ship; a failure wastes only time; a critical failure is a "drop shunt", draining the battery and going nowhere. (This produces an energetic explosion on the other side.) Military ships may have a second battery for a second chance at a fast shunt.
Filrails are even easier, and usually automated since they mostly just go back and forth on the filament. The roton interaction is low-friction, but the friction still imposes a "top speed".
Magnon ramjets are "point the ship and go" thrusters, usually using Piloting: High-Performance Spacecraft. Navigation: Hyperspace is needed to spot your destination based on where the filaments were. They're effectively reactionless, but the "magnon soup" has a reference frame imposed by nearby filaments, and friction with it imposes a "top speed". Fighters use all-vectored-thrust at several hundred gees, but other ships usually use one fixed ramjet and an array of smaller vectored ramjets for maneuvers. Civilian craft use a more moderate 100-200 gees. Even then, inertial damping is all but required.
A hypercrystal focus is pretty tricky, requiring a Navigation: Space roll up front to plot the course. The GM should roll in secret, and on a failure the target is off by [Margin × 10]% in a random direction. Tuning the polaron burst takes an Electronics Operation: Parachronic roll; if accelerating(for example, if dodging), apply the same penalty as for a hypershunt. On a success, the teleport happens. On a failure, the ship takes a bunch of internal burn sur damage from gamma rays as the energy grounds out into protospace. On a critical failure, the damage's armor divisor is only (10), but the bright flash of gamma rays escapes outwards as well.
A hypershunt system is normally half hypershunt, half battery. The only reason to have more hypershunt is redundancy. A second battery may be installed as a half-size system; a second and third battery may be installed together as a system, etc. Each battery can take up to 10 power points; a shunt attempt takes 300 power-point-seconds. Two half-charged batteries or three third-charged batteries, etc, can be used to attempt a shunt.
Each filrail system is a stardrive, with ×1/10 cost and a top protospace speed of [2 400 × FTL] c. (Hyperspace distance is 120 000× shorter, so FTL:25 is about .5c in hyperspace.) Their hyperspace acceleration is [.5 × FTL] gees.
Each magnon ramjet system is a stardrive, with a top protospace speed of [1 200 × FTL] c. (FTL:50 is about .5c in hyperspace.) They're useful in combat, with a hyperspace acceleration of [50 × FTL] gees; a vectored-thrust ramjet array has half the thrust and speed.
Each hypercrystal focus is a stardrive, with ×10 cost. The maximum distance is [10 × FTL] parsecs. Crystallizing hyperspace takes [Tonnage^(1/3) × Parsecs / FTL] minutes. Damage on a failure is [Tonnage^(1/3) × Parsecs × 11] dice. (Note that this is not d-Damage.)
TL11^ systems provide ×2 FTL rating, TL12^ systems provide ×4. They also consume power points of their own TL.
A magnon is a collective excitation of the electrons' spin structure in a crystal lattice. It can be viewed as a quantized spin wave.
A roton is a collective excitation associated with the rotation of a fluid (often a superfluid). It is a quantum of a vortex.
A polaron is a quasiparticle composed of a charge and its accompanying polarization field. A slow moving electron in a dielectric crystal, interacting with lattice ions through long-range forces will permanently be surrounded by a region of lattice polarization and deformation caused by the moving electron. Moving through the crystal, the electron carries the lattice distortion with it, thus one speaks of a cloud of phonons accompanying the electron.
An exciton is a bound state of an electron and hole which are attracted to each other by the electrostatic Coulomb force. It is an electrically neutral quasiparticle that exists in insulators, semiconductors and some liquids. The exciton is regarded as an elementary excitation of condensed matter that can transport energy without transporting net electric charge.