BY JUPITER, IT'S GALILEO!

SURMOUNTING DELAYS, DISASTER AND CRANKY EQUIPMENT, A PLUCKY SPACECRAFT FINALLY ARRIVES

ON A STARRY NIGHT IN 1610, IN THE city of Padua, Italy, Galileo Galilei pointed his newly handmade telescope skyward, stared into the eyepiece and gasped in excitement. Through the lenses of the world's first astronomical telescope, four white spots were clearly visible floating near a brightly shining planet. Galileo had discovered Jupiter's four major moons, the first (except for Earth's own moon) ever seen around a planet.

This week, after a six-year, 2.3 billion-mile odyssey, a 2 1/2-ton, instrument-crammed spacecraft named after the Italian astronomer will hurtle past two of those moons, Europa and Io, then swing into orbit around...

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