Introduction to the Galilean satellite source data

The Jovian system has now been visited by 5 spacecraft: four flyby missions in the 1970s and one orbiter in the 1990's:


Encounter date(s)

Type of


Significant discoveries
Pioneer 10

3 December 1973


Io's ionosphere
Pioneer 11

2 December 1974


refined masses of satellites
Voyager 1

5 March 1979


active volanism on Io
Voyager 2

9 July 1979


Frozen ocean on Europa
Galileo 7 December 1995 to 31 December 1999

(nominal and extended missions)

Jupiter orbiter

  • Io and Ganymede magnetic fields
  • Io volcanic resurfacing
  • More evidence for Europan ocean
  • The maps of the Galilean satellites (the four largest satellites of Jupiter, discovered by Galileo Galilei in 1610) on this site are based on data from the Voyager 1 and Voyager 2 missions.

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    To index maps: Mercury Venus Moon Mars Jovian satellites Io | Europa | Ganymede | Callisto
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