When NASA sent the Galileo spacecraft plummeting into Jupiter Sunday, it closed one of the most successful chapters in space exploration.
Speeding 2.8 billion miles through space over 14 years, Galileo gave astronomers 30 gigabytes of new data and a new understanding of the solar system's grandmother of all planets and its family of moons. Its discovery that the moon Europa may have a large ocean of briny water capable of supporting organic life provided the reason for its destruction - scientists didn't want to risk the human satellite crashing into Europa and contaminating it with earthly organisms. As it is, the probe's eight-year orbit of Jupiter lasted six years longer than planned.
Time and again, the tough little satellite overcame adversity. It was supposed to be launched in 1986, but that was delayed by the Challenger accident. When shuttle Atlantis finally bore it aloft in 1989, scientists had to devise a "slingshot" trajectory taking it around Venus, around Earth, out to the asteroids, and around Earth again to power it to Jupiter. Then its antenna didn't fully deploy, and the onboard computer would suddenly go to sleep with no warning. Engineers had to rewrite Galileo's software to fix the problem. The craft had so many glitches it became synonymous with the general failures of the National Aeronautics and Space Administration.
But Galileo bounced back. It fired off a probe that rewrote the book on the Jovian atmosphere, upsetting astronomers' theories on planetary formation. It found incredible volcanoes on the moon Io, photographed a comet colliding with Jupiter, and measured an unknown magnetic field on the moon Ganymede. It transmitted data right up to the end.
NASA's unmanned space program gets little attention, but its scientific results far outweigh those obtained through the manned program - as valuable as the latter is. The space agency already plans a return next decade to the three Jovian moons on which Galileo found evidence of water. Congress should give that mission its full support.