An intermediate universe called jumpspace or voidspace connects the realspace universes. A starship enters this liminal space by activating a "jump field" or "drive field" surrounding the ship, and releasing exoplasm to power the transition. In jumpspace, a "correspondence zone" exists for each system: a sphere 75-90 AU in diameter in realspace corresponds to a jumpspace area of only about 5-600,000km in diameter.

Within the correspondence zone, the "gate" is a disc or lens shape about 0.5AU thick, in the plane of the ecliptic. The lens is distorted by the realspace presence of mass/gravity, so the very center of the lens is usually about 1AU thick, and planets with an eccentric orbit will cause a rolling distortion. Very eccentric orbits lead to unpredictability in the presence of the gate effect.

Ships that enter this boundary -- invisible, but for its effects on the jump field surrounding a ship -- and drop their jump fields are ejected into realspace. Jumpspace has invisible "currents" that flow through the gate ("downward" by mapping conventions), so a ship that enters jumpspace "above" the lens will be carried down into it. Ships entering jumpspace thus must be far enough from the gravity field of a planet to be outside the gate effect, and below the plane of the ecliptic.

After entering jumpspace, ships can (and generally must) use the currents to carry them to their destination. A ship's drive rating represents the speed of current it can handle; a jump-1 ship can ride the slowest currents, those between nearby systems. It takes about 120 hours to ride between systems (regardless of distance: a jump-2 current is twice as fast as a jump-1 and so on), meaning an interstellar trip takes about a week.