The Earth Defense Network was the name for Earth's planetary defense system in the 23rd century. In the mid-2270s, V'ger, with knowledge gained from an examination of USS Enterprise's computer, was able to render the network inoperative. This left the planet vulnerable to attack from plasma energy bolts fired by V'ger. Knowledge of the status of this network was broadcast to the USS Enterprise and was seen in a tactical display on the main viewscreen of the bridge. (Star Trek: The Motion Picture)