Galileo gets final reprieve before crash into Jupiter
NASA NEWS RELEASE
Posted: March 16, 2001
Galileo has been orbiting Jupiter for more than five years and survived radiation exposure more than three times what it was built to withstand. Galileo's mission has previously been extended twice and during that time it has returned an enormous wealth of scientific information, including evidence of a sub-surface ocean on Jupiter's moon Europa.
"We're proud that this workhorse of a spacecraft has kept performing well enough that we can ask it to keep serving science a little longer," commented Dr. Jay Bergstralh, Acting Director of Solar System Exploration at NASA Headquarters, Washington, DC.
On May 25, Galileo should pass about 123 kilometers (76 miles) above the moon Callisto, the second largest of Jupiter's 28 known moons. The effects of Callisto's gravity will set up the space probe for a swing over both polar regions of the intensely volcanic moon Io in August and October.
Galileo will take pictures, measure magnetic forces, and study dust and smaller particles. Science goals include studying the extent of volcanism on Io, both in new and previously active sites; determining whether Io generates its own weak magnetic field; and gaining a better understanding of a doughnut-shaped ring, the Io Torus, that encircles Jupiter and contains electrically charged gases.
In 2002, having completed its imaging mission, Galileo will continue studies of Jupiter's massive magnetic field with seven instruments. In January, the orbiter will fly near the equator of Io.
Galileo's final orbit will take an elongated loop away from Jupiter. Then in August 2003, the spacecraft will head back for a direct impact and burn up as it plows into Jupiter's 60,000 kilometer-thick atmosphere. This final act was approved by the National Research Council of the National Academy of Sciences last December.
"Galileo has already succeeded beyond expectations, and we have the opportunity to learn still more in coming months, but it is sad to see the end of the road up ahead," said Eilene Theilig, Galileo project manager at NASA's Jet Propulsion Laboratory, Pasadena, CA. "Exposure from Jupiter's intense radiation belts has impaired some of Galileo's instruments, but it is still producing valuable scientific results."
The science program for the Galileo mission extension was recommended to NASA by a blue-ribbon panel of planetary scientists, who met last July, and will cost $9 million. "This mission extension accomplishes the highest priorities of the review panel in a cost effective way," said Paul Hertz, Galileo Program Executive at NASA Headquarters.
Galileo was launched Oct. 18, 1989, aboard NASA's Space Shuttle Atlantis. On Dec. 7, 1995, a probe released earlier from Galileo made measurements while dropping through Jupiter's upper atmosphere. Galileo's top scientific accomplishments include:
JPL, a division of the California Institute of Technology in Pasadena, manages Galileo for NASA's Office of Space Science, Washington, DC.