Flashy Jupiter moon gets another look

A picture of Io taken by Galileo on September 7, 1996

By Amanda Barnett
CNN

(CNN) -- NASA's Galileo spacecraft is getting ready for another swing by Io, a mottled moon circling Jupiter that scientists believe is the most volcanic body in the solar system.

On Monday, August 6, at 12:59 a.m. EDT, Galileo will fly over Io's north pole and take magnetic readings. Scientists are trying to determine where Io has its own magnetic field.

"It's important for understanding Io," said Eilene Theilig, manager of the Galileo mission. She added that learning about magnetic fields on other planets and moons could help scientists learn more Earth's magnetic field.

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The flight path also means Galileo will revisit Io's Tvashtar Catena region. The last time the spacecraft flew over the area it photographed an active volcanic plume.

Theilig said Galileo will swoop to within 125 miles (200 kilometers) of Io, making this the closest of the five flybys Galileo has made of Io.

Io is the innermost of Jupiter's four large moons. In all, Jupiter has 28 known moons.

Beyond the call of duty

Galileo was carried into Earth's orbit aboard the space shuttle Atlantis on October 18, 1989 and then launched out of the shuttle's cargo bay on a journey to Jupiter and its moons.

Galileo spotted this volcanic eruption in Io's Tvashtar Catena region on November 25, 1999

On December 7, 1995 Galileo began its study of the jovian system. The spacecraft's primary mission ended on December 7, 1997. Despite enduring more than three times the radiation it was built to handle, Galileo's mission has been extended three times.

The spacecraft currently is scheduled to make a fatal plunge into Jupiter's crushing atmosphere in 2003.

The spacecraft is named in honor of Galileo Galilei who made the first observations of the skies using a telescope in 1610.