Torrence Johnson Biography and Timeline — Page 2

Europa November Flyby

Galileo performs another Europa flyby during the Europa Mission extension.

Europa February Flyby

Galileo completes another close pass of Europa before shifting the extended mission toward Callisto and Io encounters.

Callisto May Flyby

Galileo uses a Callisto encounter as part of a campaign to reshape its orbit for later close passes of Io.

Callisto June Flyby

A second 1999 Callisto flyby further lowers Galileo's closest approach to Jupiter in preparation for Io observations.

Callisto August Flyby

Galileo performs another Callisto gravity-assist encounter during the perijove reduction campaign.

Callisto September Flyby

Galileo completes the final Callisto encounter in the sequence used to prepare for close Io flybys.

Galileo October Io Flyby

Galileo passes roughly 611 kilometres above Io, beginning exceptionally close extended-mission studies of the volcanic moon.

Galileo Close Io Flyby

Galileo passes close to Io to investigate active volcanism and the moon's interaction with Jupiter.

Role range: 1948-

Callisto Interior Differentiation

Galileo gravity and magnetic observations improve models of Callisto's internal structure and possible subsurface conductive material.

Europa Millennium Flyby

Galileo begins the Millennium Mission with another close flyby of Europa.

Galileo February Io Flyby

Galileo flies about 198 kilometres above Io, obtaining close measurements of its active volcanic environment.

Galileo Ganymede Close Encounter

Galileo makes another close Ganymede pass, extending measurements of its surface and magnetic environment.

Role range: 1948-

Ganymede December Flyby

Galileo performs a distant Ganymede encounter while coordinating broader Jupiter-system observations with Cassini.

Galileo Close Callisto Flyby

Galileo passes only about 138 kilometres above Callisto during a close encounter.

Role range: 1948-

Galileo Io Volcano Survey

A close Galileo flyby examines Io's rapidly changing volcanic surface at high resolution.

Role range: 1948-

Galileo October Io Flyby

Galileo passes about 184 kilometres above Io during a late-mission encounter focused on volcanic and plasma activity.

Jupiter Ring Dust Source

Galileo observations support the conclusion that Jupiter's faint rings are continually replenished by impact-generated dust from small inner moons.

Final Galileo Io Flyby

Galileo completes its final Io flyby at an altitude of roughly 102 kilometres.

Galileo Amalthea Flyby

Galileo makes its final satellite encounter, passing close to the small inner moon Amalthea.

Role range: 1948-

Galilean Moon Exospheres

Galileo results support the presence of extremely thin surface-bound exospheres around Europa, Ganymede and Callisto.

Io Extreme Volcanism

Galileo observations establish that Io's volcanic activity is vastly more extensive and energetic than volcanism on modern Earth.

Galileo Flight Team Operations End

Routine Galileo flight-team operations end after the final playback of stored scientific data, months before the spacecraft's planned Jupiter impact.

Galileo Mission End

Galileo is deliberately sent into Jupiter to prevent possible contamination of Europa.

Role range: 1948-

Galileo Data Return Legacy

Over its mission, Galileo returns about thirty gigabytes of scientific data and roughly fourteen thousand images from the Jupiter system.

Galileo Jupiter Magnetosphere Legacy

Galileo's years in orbit provide the first long-duration investigation of the global structure and variability of a giant planet's magnetosphere.