Galileo Millennium Mission Status
May 22, 2000

NASA's Galileo spacecraft has successfully flown past the largest moon in our solar system -- Ganymede, which orbits around Jupiter.

Galileo dipped to 809 kilometers (503 miles) above the surface early Saturday, May 20. This was the spacecraft's first flyby of Ganymede since May 7, 1997.

"It's great that things went so smoothly," said Galileo Project Manager Jim Erickson of NASA's Jet Propulsion Laboratory. "The team was ready for any problems, but they got to relax on this one. We're really looking forward to the new pictures and learning more about this largest of all moons."

At 4 a.m. PDT, mission controllers at JPL received the signal indicating that the flyby took place. The spacecraft's camera and other instruments were set to capture the flyby with images and other observations. If all goes as planned, the data will be transmitted to Earth over the next several months for processing and analysis.

To fly by Ganymede, Galileo had to approach Jupiter's powerful radiation belts. Not surprisingly, the radiation, which can affect spacecraft instruments, components and systems, did cause two main resets of Galileo's main computer. Onboard software correctly diagnosed this as a false indication, and went ahead with the Ganymede encounter unaffected.

"It appears that this workhorse spacecraft has done it again," Erickson said. Galileo has already survived three times the radiation it was designed to withstand.

Ganymede is even larger than Pluto and Mercury. Its surface is a mixture of clean, white ice and dirty, dark ice, with varied geological formations, including craters, basins, grooves and rough mountain areas.

Additional information about the Galileo mission is available at http://galileo.jpl.nasa.gov .

Galileo was launched from the Space Shuttle Atlantis on October 18, 1989. After a long journey to Jupiter, Galileo began orbiting the huge planet and its moons on December 7, 1995, and successfully completed its two-year primary mission on December 16, 1997. That was followed by a two-year extended mission which concluded in December 1999, and Galileo is now continuing its studies under yet another extension, called the Galileo Millennium Mission. JPL, a division of the California Institute of Technology in Pasadena, Calif., manages the Galileo mission for NASA's Office of Space Science, Washington, D.C.