Workings of the FTL drive (hyperspace insertion drive)

Hyperspace is a catchall term for the myriad sub-dimensions of which our own dimension is part of one. To use the classic 'balloon' analogy, hyperspace (the dimensions we use to travel faster than we could in normal space) are 'inside' the balloon, while our dimension is on the surface.

There is nothing different about the other dimensions, except that, of course, those inside the balloon allows a vessel to travel faster relative to our own dimension. You can't go faster than light, but you can go to a dimension where you can get more bang for your buck.

There appears to be several 'bands' of hyperspace, beyond which it seems impossible to travel past. The first band is just 'above' our own dimension, and the second band is around 25 dimensions 'below'. Hyperspace scientists propose that there might actually be a sort of 'technology exam' that we have to pass to break through and possibly--so the more radical exponents of the theory say--meet alien lifeforms. A ship actually has, it appears, broken through the second band, but whatever they saw they didn't tell, and the secret went to their grave.

Travel in the lower dimensions of hyperspace is very fast indeed, but those close to our own dimension are less so.

The formula for working out the speed of light relative to our own dimension is:

D^3

Where D represents the dimension (normal space is 1). So for the 25th dimension, the furthest you can travel, the SOL is:

15625 times the SOL here.

Most civilian transport travels in the 10th hyperspace dimension (1000 x SOL). With a top speed of, say, 10% SOL, that means they can travel 50 LY in half a year, which isn't too bad. Military ships sometimes go as low as the 20th dimension, which is 8000 x SOL, which means it can do the same trip in three weeks. Only couriers and other similar vessels travel lower down.

(Note: I've changed my mind with twenty-one factions. I'd have a hard time trying to design them, much less write them up. So I'm downsizing the project and re-naming it--the Triumvir-Verse)