Hyperspace in the Twin Stars setting is a vast void of nothingness which is phyiscally linked to points in our own universe, so you can enter hyperspace, move, and then exit it at another point in our space. This allows faster than light travel at an average of 1 light year a day because hyperspace is infinitely denser than normal space, so a short movement in hyperspace is a huge distance covered in realspace terms. This is problematic because it makes it very difficult to judge the exit points into realspace when you want to come back. You might end up next to your destination, or extremely far away from it if you’re off in your transition point by even a small amount. Add to this that sensors don’t work well in hyperspace, and that there’s a slight natural “drift” due to inertia from realspace and it becomes extremely easy to get lost.

This problem was somewhat solved with the Jump Point system. Jump Points are man-made points of space in hyperspace where ships can centre themselves and be sure to come out at the location of their choosing. They are also connected by powerful beams of energy being transmitted between them that also acts a form of “guide rope” to allow ships to travel between the two points in hyperspace. This “rope” is limited in length to about 10 light years (after which it’s too diffuse to be followed), which is part of the reason the Jump Point network exists.

The issue with the Jump Point system is that because ships need to be within a few kilometres of the “guide rope” to detect it they must enter and exit hyperspace near it’s end points or risk not being able to find the ‘rope” and becoming hopelessly lost. Also, were a ship to lose the guide beacon they would likely be unable to find it again, and again become lost and unable to find their way back to the network again except by incredible luck.

The alternative to the Jump Point system is the Squire Hyperspace Navigation System used by the Imperial Military. In this system, telepathic squires enhanced by their ship’s navigation system use their instantaneous natural link with each other to navigate based on the locations of a few Imperial installations located semi-permanently in Hyperspace which at as reference points for navigation. In those installations are a few specially enhanced squires whose presense is easily detectable by other squires over vast distances. It is not a direct two-way link in the sense of a conversation, but rather a clear sense of direction towards the location of others of their kind.