Jump gate are portals to and from different quadrants. To use a jump gate fly up to it you will be checked for contraband as you approach the jump gate. In order to use the gate you first must check to see if you have jump fuel and you can check how much you have by looking at the bar on the far right of the screen. If you don’t have any jump fuel go land on a planet to refuel (automatic) and than go back. After you have been checked for contraband if you are clear you can approach the gate, fly over the blue circle in the center and while over it press [J] a jump animation will start than the screen will flash and you will appear on the other end. After exiting the jump gate you will be searched again for any contraband.