Galileo mission may end in a blaze of glory

February 21, 2000
Web posted at: 3:26 PM EST (2026 GMT)

PASADENA, California (AP) -- NASA is considering a spectacular finish for Galileo's mission to Jupiter: A suicide plunge into the gaseous planet or one of its moons.

The probe was not designed to withstand such conditions for long, but it could send back a few minutes of valuable data before frying from radiation, melting under the pressure of Jupiter's atmosphere or crashing onto a moon, scientists say.

The alternative is to let the aging spacecraft run out of propellant or wait for a critical navigation component to fail, and either would turn it into a worthless piece of Jovian space junk.

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Galileo must first survive Tuesday's close encounter with Io and the intense radiation in the vicinity of Jupiter's nearest moon. Two more encounters are being planned for the moon Ganymede through the end of the year.

The spacecraft could be given its final marching orders sometime next year, although details are still being worked out, said Duane Bindschadler, Galileo's manager for science planning and operations.

Plunging into Jupiter could shed new light on the planet's magnetic fields, Bindschadler said, although the amount of information received would be limited because Galileo sends back data at a slow rate.

"We would go into an environment where the radiation would be steadily and very quickly increasing, up to a certain point," he said. "If we survived past that point, we could probably send data as we were getting closer and closer (to the cloudtops)."

A probe that flew with Galileo took the plunge in 1995, sending data on the composition of the atmosphere before melting under the extreme pressure.

Galileo also could be sent into one of Jupiter's moons. Volcanic Io has been discussed.

Galileo won't be flying into Europa, where last month its instruments discovered the best evidence yet of a liquid ocean beyond Earth.

The reason? Galileo could still be carrying microbes, 11 years after its launch from the space shuttle Atlantis.

"We don't want to get anywhere near Europa, simply because of the possibility of life there," Bindschadler said.

"They don't want to crash this contaminated spacecraft into Europa," said Andrew Ingersoll of the California Institute of Technology.

A mission-ending plunge isn't unprecedented. Last year, NASA's Lunar Prospector dove into the moon in search of water. Telescopes in space and on Earth watched for the impact but saw nothing.

Regardless of how Galileo's mission ends, scientists say they will miss the spacecraft.

"It's not going to go on forever," Ingersoll said. "Everything has to end. It's going to be a sad day, though."

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