Slipstream space

Slipstream space is an alternate spatial dimension, existing in parallel with normal space-time, that is used by starships to achieve faster-than-light travel.
== Mechanics ==
The mechanics of the slipspace drive and the way it manipulates quantum fields have an effect on the time it takes for a ship to cross distances, with more sophisticated drive technology and navigation computers allowing ships to cross distances more efficiently. A ship's sublight velocity correlates with the velocity at which it traverses the slipstream. Frequent traffic, especially when moving objects of considerable mass, will also slow slipspace traffic down on a galactic scale, although this is only known to have occurred when the Forerunners moved the Halo installations across the galaxy.
== Velocities ==
However fast it may appear, slipspace travel is by no means instantaneous; "short" jumps with a Shaw-Fujikawa drive routinely take several days, and "long" jumps can last weeks or even months for the crew. Modern UNSC Navy ships are known to have a maximum safe cruising speed of 15 light years per day, with a war emergency speed of 30 light years per day - though maintaining war emergency speed for longer than 72 hours risks damaging the drive and the ship itself. Certain Covenant ships can reach speeds of 900-1,500 light years per day, dependent on drive specification.