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After a marathon journey of 12 years and more than 4 billion miles, the remarkable Voyager II space probe is finally approaching its final port of call. Having made historic fly-bys of Jupiter in 1979, Saturn in 1981, and Uranus in 1986, it is poised for an Aug. 24 rendezvous with Neptune, the most distant of the giant planets.
What is who, what and when?