Fold space is the region of the universe that exists between normal space. Several scientific laws regarding time, physics, and space do not apply within fold space.
A ship with a fold drive rated at FD2 or higher, can plot a course to a far away destination in its astrogation computer. Locations that were very recently visited or are part of high traffic areas have courses that are easier and faster to plot. Remote locations, particularily the Ruins, are difficult and hazardous to navigate.
Once the course is plotted, the ship needs to extend a sufficient distance away from a large gravitational body such as a planet or star. Failure to do so can result in a fold tear, where part of the ship moves through fold space and other sections (normally the fold drives) are stretched out between the departure and arrival locations with disastrous results. The closer one is to the gravitational body, the chance of a tear increases exponentially.
Once the ship enters fold space, the universe snaps away in a once quick second. All that is left is complete blackness. Crew members not securely seated both during the fold entry and the arrival risk bodily harm as most inertial dampers cannot completely dissipate the associated turbulence.
In fold space, a ship is all to itself. It cannot see or interact with any other ship. It cannot collide with any object and most vessels have no way to communicate until they fold out into normal space. The ship is able to move through this special dimension which connects all other points in the universe through smaller distances. So what might take several centuries to travel in normal space takes just six days in fold space. The average trip time is close to one week. The minimum trip time is near 30 hours. Ships with higher rated fold drives can go greater distances in a single fold (or jump) while other fold drives focus not on distance but on speed.
While in fold space, the ship is completely surrounded by black though the vessel is normally shrouded in a soft light (aka “the glow”). Movement on the surface of the ship is possible, but becoming disconnected from the vessel in a suit or via a shuttle normally leaves the individual left behind and lost.
Upon exiting fold space, it is necessary to recharge the ship’s batteries. Folding near a gravitational body helps recharge the system in several hours before another fold can be attempted. Folding out in deep space can dramatically increase that time to several days. Navigators usually plot a course that keeps them close to planets to recharge but not so much as to endanger the ship.