Jump gates allow a commander to send a ship, or fleet of ships, from one Jump Gate to another Jump Gate regardless of the distance between the gates. This allows a commander, separated by vast distances from his Federation, to remain in physical contact. It also allows a commander to reach his more distant planets if those planets are cut off by accident or enemy action. Because Jump Gates are connected to other federation members, the Jump Gate system also allows for the creation of Federations based on ideals, rather than who the neighbors are.
In order to build a new Jump Gate, a commander will need 4000 goods, 3000 metal, 5000 energy, 2000 food, and 2000 population available on the planet. The planet selected to build the new Jump Gate will also need a minimum 400 Shipyard and Astrogation technology prior to attempting to construct the new Jump Gate. The Jump Gate construction item is found on the planetary infrastructure page.
Once the Jump Gate has been constructed, it is at level 1. This means that all traffic departing through this gate will travel at one half of its normal speed to whatever destination gate has been selected. While the new gate will allow for federation network travel, it is strongly recommended that the developing commander upgrade the gate to level 2 at his earliest convenience. Once the Jump Gate is at level 2, it will allow fleets traveling through it to travel at their normal speed.
Jump gates need to research and maintain 400 Astrogation technology and 400 Shipyard technology for each upgrade level. This means that the Jump Gate will need Astrogation and Shipyard at 800 in order to upgrade to level 2, 1200 for level 3, etc. The Jump Gate will also need the resources specified for each Jump Gate upgrade level. Each Jump Gate upgrade level increases the speed of the ships by one half of their original speed. So a level 1 gate results in one half speed, a level 2 gate results in regular speed, a level 3 gate results in one and a half times regular speed, etc.
Once the tech levels have been met, you will need to be sure that the required resources are also available. The required resources will increase with each Jump Gate level. The amount of resources needed for the next level can be shown by clicking on the Jump Gate link on the Planet Infrastructure page and viewing the Cost Per Unit block. When both the tech and resource conditions have been met, and a planetary build slot is available, the Jump Gate can then be upgraded as an item build.
In order to send a fleet through the Jump Gate, select your desired fleet In System Ops page. Select the numbers of each type of ship that you wish to send, and the fleet from which you are selecting the ships . Select the 'Traverse Gate' mission, and select the destination gate from the 'Target Jump Gate' list. Select your commitment level, then select execute, and the ships that you have chosen will traverse the gate and begin their journey to the other gate. When they arrive at the destination gate, your fleet will be in orbit of the destination gate. They can then be sent on the next leg of their journey.
If traveling through a Jump Gate, into or out of a gate with a hostile fleet in orbit, your fleet will engage in combat when it arrives. This combat will be the same as any other fleet combat orbiting a planetary body, with one difference: Your gate arriving fleet's retreat route will be back through the Jump Gate, at that jump gate's level's speed. This means that if your fleet has cripples, and it traveled a long distance to get there, and it has to retreat because it did not beat the enemy fleet, it might be a VERY long voyage home.
Hostile jump gates can be subjected to invasion or genocide just as any other planetary body. Jump Gate invasion works the same as any other planet. The commander's fleet goes into orbit around the Jump Gate, and engages any hostile fleet and the PDB defenses. Once you have successfully wiped out the orbital defenders, you will then need to land your Marine Transports on the Jump Gate. This also works the same as any planetary invasion. The commander will need enough marines to overwhelm the defending Soldiers. If your invasion has been successful, the Jump Gate becomes yours. This does not mean that your new Jump Gate will access the enemy's federation's Jump Gate network, but in fact means that you have added the Jump Gate to your federation's network as an additional gate, functioning as a new beachhead into your enemy's territory.
If occupied by enemy forces, an abandoned jump gates will revert to the previous owner. If there was no previous owner, the Jump Gate will become owned by a non player character. Should a commander want to add the Jump Gate back into their empire, the Jump Gate will need to be conquered like any other enemy territory.
Fleets traveling between star systems can torque the local space which may destabilize the star. This destabilization is called star wobble. Fleets using Jump Gate to travel between stars do not add star wobble. If the star wobble reaches a certain amount, it will enter the supernova state. Should star wobble continue to be added, the star may collapse into a blackhole. When a blackhole event happens, all the planets and fleets at that star system are destroyed. Jump Gate can be used to control and mitigate these events.
Each star will stablize a small amount each day. The Jump Gate level will increase the amount of daily stabilization. Additionally, the jump gate owner has the opportunity to use the Jump Gate to either engage or disengage the star wobble. This is done by using the Jump Gate to put the star wobble into stasis. The gate owner also has the chance to set the Trigger Fleet Size using the Jump Gate. The Trigger Fleet Size is the approximate amount of ships which may cause the star to collapse into a blackhole, once it has entered the supernova state. Blackholes leave behind a natural wormhole which must be explored to find their other end point.