Jupiter probe regains eyesight

Galileo snapped this portrait of Io on an earlier flyby.

By Richard Stenger
CNN

(CNN) -- A camera onboard the Galileo spacecraft resumed functioning in time to snap a few pictures during a recent flyby of Io, the most volcanic body in the solar system.

Most pictures that the NASA spacecraft was expected to take near the jovian moon were lost due to an electronic problem that has periodically plagued the onboard optical system for more than a year.

But the probe managed to regain use of the camera last week during the dive over the surface near the north pole, NASA said on Friday.

"We're now expecting to get images from five of the 16 planned observations, including global images of Io," said Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory in Pasadena, California.

Scientists are trying to figure out whether Galileo flew through the plume of an active volcano during an August 6 flight over the mottled, molten moon.

When the robot ship flew over the same region seven months ago, it observed a tall plume erupting from the boiling cauldron, known as Tvashtar.

But mission researchers will need time to find out. Galileo will take another eight weeks to beam back the visual and infrared data from the flyby, which brought it as close as 124 miles (200 km) to Io, the closest of five approaches.

Preliminary observations have shed light on one major question about the moon: Does it, like the Earth or Jupiter, produce its own magnetic field?

The volcanic cauldron known as Tvashtar.

The available readings suggest that the moon generates no internal magnetic field or, at best, an extremely weak one, according to Galileo scientist Margaret Kivelson of the University of California, Los Angeles.

Galileo, an orbiting resident of the Jupiter system for almost six years, has endured more than three times the radiation it was built to withstand.

Mission engineers suspect that intense doses of energy from Jupiter's radiation belts have damaged the ship's camera. Io is the innermost of four large moons orbiting Jupiter, which has 28 known natural satellites in all.

Galileo will swing by Io again in October, this time around the south pole instead of the north. The bus-sized craft is scheduled to make a fatal plunge into Jupiter's crushing atmosphere in 2003.