Tethering is a mechanics that allows you to safely remain in space right next to a Citadel or Engineering Complex without being targetable.
Tethering grants players with docking permissions invulnerability mimicking the functionality of starbase forcefields with a number of additional changes. Tethering is activated upon undocking or entering a 10 km range from the citadel docking ring. You will not be tethered however while under the effect of a weapons timer or currently being aggressed. Tethering is also not applied to unmanned ships. Tethering is indicated as an external effect on your ship along with a visual indicator of a faint blue line projecting towards your ship from the citadel.
While tethered you cannot be locked or affected by AoE based modules. But you can still move in space and use the directional scanner and will begin to have any Shield, Armor, Structure and heat damaged modules repaired (Modules that are burnt out will be repaired but will not be onlined) along with the rapid recharge of Capacitor. You are still able to move around in space and use the directional scanner while tethered.
Tethering however will prevent the activation of the following modules:
Tethering ends should you attempt to lock a target, move outside of the tethering range or activate any of the following types of modules.