Illustration of Galileo

"The Galileo Mission: Jupiter and its Moons Revealed" will be the theme for a free public lecture at 7 p.m. on Thursday, Dec.18, in JPL's von Karman Auditorium. Seating is limited and will be on a first come, first-served basis.

The lecture will be presented by Bill O' Neil, project manager of the Galileo Primary Mission. Employed at JPL since 1963, O'Neil has served on a number of space flight missions including the lunar Surveyor mission, the 1971 Mariner mission to Mars and the Viking mission to Mars. He also was manager of the JPL Mission Design Department and the Galileo Science and Mission Design before being appointed Galileo project manager in 1990.

On Dec. 7, 1995, the Galileo spacecraft entered orbit around Jupiter after a six-year journey and deployed its scientific probe into the planet's gaseous depths. It was the first time a spacecraft had entered orbit around an outer planet and the first time a probe had been deployed to penetrate an outer planet's atmosphere.

The Galileo spacecraft has now spent more than two years in orbit around Jupiter, studying the giant planet and its moons Io, Ganymede, Europa and Callisto. Observations made by Galileo of the Jovian system have included:

Jupiter: a dynamic climate of wet and dry regions and auroras in its atmosphere.

Io: massive volcanic eruptions and an ionosphere.

Europa: a metallic core; ice rafts hinting at the possibility of a liquid ocean lying underneath; an atmosphere.

Callisto: no core but hints of an atmosphere.

Ganymede: a magnetosphere, magnetic field and metallic core; strong tectonic processes.

Galileo is now in the second phase of its mission, called the Galileo Europa Mission (GEM), the main objectives of which are to conduct a detailed study of Europa over 14 months, then plunge repeatedly through the Io plasma torus to reach the volcanic moon Io. This talk will summarize Galileo's scientific findings to date and provide an overview of the Europa mission scheduled to continue through 1999.

This lecture is part of the von Karman Lecture Series held monthly by the JPL Public Information Office. A web site on the lecture series is located at For directions and other information, call the Public Information Office at (818) 354-5011.

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