Illustration of Galileo at Jupiter

The first scientific results from the Jupiter-bound Galileo spacecraft were released today by scientists attending the 1989 Fall Meeting of the American Geophysical Union in San Francisco.

Galileo, launched Oct. 18, used its magnetometer and Heavy Ion Counter (HIC) in experiments to test the magnitude and content of solar flare few days after launch.

Dr. Margaret Kivelson, UCLA, the principal investigator on the Galileo magnetometer experiments, said the instrument was turned on before the spacecraft was separated from its upper stage booster.

"Shortly after the launch very major solar flare occurred and the heated plasma from the solar wind arrived near the orbit of Earth two days later," she said.

"The instrument observed very enhanced (solar) magnetic field comparable with the largest that has been observed at the times of major interplanetary disturbances in the past."

Kivelson noted the sun was near the peak of its 11-year solar maximum, expected in 1991 and that many such events are likely to occur in the next few years.

Galileo will monitor the solar wind in the inner solar system during period of great scientific interest, she said.

Dr. Edward Stone of California Institute of Technology heads science team working with the HIC experiment. NASA added the instrument to Galileo's primary scientific payload to help track the spacecraft's response to strikes by ionized sulfur and oxygen atoms trapped in Jupiter's magnetic field.

Stone, working with project scientist Dr. Torrence Johnson of the Jet Propulsion Laboratory, said the data from the instrument gave the scientists detailed mass spectrum of the particles emitted from the sun's corona by the solar flare. The data were being analyzed but the results were not immediately available.

The instrument was not designed to measure the normally lower levels of charged particles from the sun, but the solar activity has been extremely high since the spacecraft was launched.

The scientists said the solar flares and the massive extrusion of charged particles also served as test for Galileo's specially hardened computer chips. The chips were hardened to protect the spacecraft's sensitive microcircuits from damage in Jupiter's harsh radiation environment.

Galileo is on trajectory for Venus fly-by in February of next year. Additionally, it will make two Earth fly-bys to gather sufficient velocity to hurl it to Jupiter.

The Galileo project is managed by JPL for the National Aeronautics and Space Administration.


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