The largest planet of Earth's solar system, site of Jupiter Station and other outposts, and the hiding place of the Borg cube that controlled Starfleet on Frontier Day in 2401.
Jupiter is the fifth planet of the Sol system and its largest. It is seen or mentioned across the franchise: the Enterprise passes it on the way out of the system in Star Trek: The Motion Picture, an outpost there reports the Borg cube heading for Earth in The Best of Both Worlds, Part II, and Jupiter Station in its orbit is the workplace of Lewis Zimmerman.
The planet's biggest role comes in the Picard finale The Last Generation. The signal that has taken over the young officers of the Frontier Day fleet is traced to the Great Red Spot, where a decaying Borg cube and its Queen have been concealed inside the storm.
Picard's former crew take the rebuilt Enterprise-D into the atmosphere. Picard, Riker and Worf board to recover Jack Crusher, and Data flies the ship through the cube to destroy its beacon.