It's been a long piggyback ride. For seven years, a dish-like probe named Huygens (HOY-gens) has been riding through space on a bus-size spacecraft named Cassini. Following a 1997 launch from Cape Canaveral, Florida, the duo cruised more than 3.4 billion kilometers (2.1 billion miles) on a meandering route to reach Saturn last July (see map, p. 14). But that's only the beginning of their adventures.
On December 25, 2004, the two will finally part ways. Cassini will spend the ...