Galileo's End

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Most missions to other planets just sort of fizzle out. Their batteries die, they run out of fuel, or their radios fall silent. But a mission that ended five years ago today went out in a blaze of glory. It streaked through the skies of Jupiter like a brilliant meteor, its molecules scattering through the giant planet's atmosphere.

The spacecraft was Galileo. It entered orbit around Jupiter in late 1995, and dropped a probe into the planet's atmosphere. Its entry was relatively gentle; it rode beneath a parachute, and returned the first direct readings of conditions beneath Jupiter's clouds.

Galileo was hobbled by a bad primary radio antenna, so it couldn't transmit as much information as scientists had hoped. But engineers found a way to boost the data return with a smaller antenna, so Galileo was able to carry out a good portion of its mission.

Galileo orbited Jupiter 34 times, and made dozens of close passes by the planet's moons. It snapped pictures of volcanoes on the moon Io, and found evidence of an ocean beneath the icy crust of Europa.

The presence of liquid water means there could also be life on Europa. Scientists didn't want to run the risk of Galileo ramming into the moon and depositing any germs that might have survived the trip from Earth. So as Galileo's fuel began to run out, they aimed the craft at Jupiter. As it slammed into the atmosphere it disintegrated and burned up -- a fiery end to a voyage of discovery.

Script by Damond Benningfield, Copyright 2008

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