Spacecraft Flybys

Below is a list of spacecraft encounters of Io, including both Pioneers, both Voyager, Galileo, Cassini, and New Horizons.  Encounters with altitudes of less than 10,000 kilometers are highlighted.

Spacecraft Date Orbit Altitude Notes
Pioneer 10 December 3, 1973 N/A352,170 km First Spacecraft to fly through Jupiter System
Pioneer 11 December 3, 1974 N/A310,990 km First spacecraft images of Io
Voyager 1 March 5, 1979 N/A18,740 km Hundreds of Io images, including images with a peak resolution of 250 m/pixel; Discovery of Ionian volcanism
Voyager 2 July 9, 1979 N/A1,127,900 km Monitoring of Io's volcanoes
Galileo December 7, 1995 J0897 km First close encounter with Io; no remote sensing observations
Galileo June 28, 1996 G1695,200 km Change detection from Voyager era
Galileo September 7, 1996 G2438,950 km Plume search; changes over anti-Jupiter hemisphere
Galileo November 6, 1996 C3243,180 km Clear-filter topography; sodium cloud imaging
Galileo December 18, 1996 E4319,210 km Multi-spectral imaging
Galileo January 19, 1997 J5363,260 km Solar conjunction; no science
Galileo February 20, 1997 E6400,090 km
Galileo April 3, 1997 G7529,210 km
Galileo May 7, 1997 G8953,940 km Plume monitoring
Galileo June 28, 1997 C9605,080 km Pillan eruption
Galileo September 19, 1997 C10318,110 km Pillan plume
Galileo November 7, 1997 E11790,940 km Plume monitoring
Galileo December 16, 1997 E12483,980 km
Galileo January 27, 1998 E13436,160 km Solar conjunction; no science
Galileo March 29, 1998 E14249,720 km Multi-spectral imaging; I24 context
Galileo May 31, 1998 E15310,950 km Color aurorae
Galileo July 20, 1998 E16698,760 km
Galileo September 25, 1998 E17799,060 km
Galileo November 23, 1998 E18965,770 km
Galileo February 2, 1999 E19851,530 km
Galileo May 2, 1999 C20779,480 km
Galileo July 2, 1999 C21124,350 km 16-frame color mosaic over anti-Jupiter hemisphere; Grian plume
Galileo August 12, 1999 C22745,650 km Plume inventory
Galileo September 14, 1999 C23438,530 km
Galileo October 11, 1999 I24611 km First close-up images; Camera anomaly
Galileo November 26, 1999 I24301 km Tvashtar eruption
Galileo January 4, 2000 E26214,180 km Multi-spectral color over Loki-Pillan region
Galileo February 22, 2000 I27198 km High-resolution imaging and spectra
Galileo May 21, 2000 G28378,430 km
Galileo December 30, 2000 G29984,410 km Distant imaging simultaneous with Cassini flyby
Cassini December 30, 2000 N/A9,370,800 km Eclipse movies; Distant imaging
Galileo May 23, 2001 C30341,740 km
Galileo August 6, 2001 I31194 km Galileo flies through Thor plume; distant imaging
Galileo October 16, 2001 I32184 km Last images of Io by Galileo; high-resolution remote sensing
Galileo January 17, 2002 I33102 km Most remote sensing lost
Galileo November 5, 2002 A3445,370 km
Galileo September 21, 2003 J35
Galileo impacted into Jupiter; no science observations of Io
New Horizons February 28, 2007 N/A2,237,800 km Distant mapping observations; plume inventory; Eruptions at Tvashtar and East Girru