2015 Event Scientists have concluded that a large ocean exists beneath the icy surface of Ganymede, the largest moon of Jupiter; the discovery was made by using the Hubble Space Telescope to observe aurora movements at the moon's poles 1997 Event Galileo, Ganymede Observations, Orbit 9 1997 Event Galileo, 4th Ganymede Flyby (Orbit 8) 1997 Event Galileo, 3rd Ganymede Flyby (Orbit 7) 1610 Event Galileo discovers 1st 3 Jupiter satellites, Io, Europa and Ganymede
