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As Voyager 1 soared past Saturn, its eyes constantly twisted and turned, switching their attention back and forth from Saturn itself to its satellites and rings. As a consequence, the scientists watching the television monitors inside J.P.L.'s Building 264 found the images more often than not cropping up on target exactly in the center of their screens. The secret of this wizardry lies in the lobes of Voyager's electronic brains. Hours before last week's near encounter, the computer memory banks of Voyager 1 were "sequenced" with a series of explicit instructions radioed from earth. So precisely did Voyager 1 carry out these orders that none of its multitude of observations arrived more than 46 seconds off schedule.
Though Voyager 1 was launched from Cape Canaveral, Fla., in 1977, two weeks after an identical twin, Voyager 2, it followed a less curved trajectory and reached Saturn nine months ahead of the other ship. Voyager 2 is not scheduled to pass Saturn until next August. Because it is taking such a different trajectory, Voyager 2 will be able to study some of the moons that had to be bypassed during last week's encounter. It will also be able to sail on to Uranus in 1986 and Neptune in 1989. Thus, if the spacecraft's instruments are still functioning, J.P.L. scientists and engineers may eventually achieve a Grand Tour after all.
Even if those ambitions are not realized, Voyager 1's conquest of Saturn is already providing an unexpectedly rich scientific payoff from the $500 million program. Almost as soon as the spacecraft began closing on the Saturnian system, the pace of discovery accelerated dramatically. As early as last August, Voyager 1's cameras picked up a red spot in Saturn's southern hemisphere. Another one soon showed in the northern hemisphere. Though these features remind scientists of Jupiter's Great Red Spot, a great whirling storm that has lasted for at least three centuries, Saturn's spots are smaller, perhaps only 12,000 km (7,500 miles) in diameter. Saturn's atmosphere seems at least as violent as Jupiter's. NASA scientists estimate winds at upwards of 1,300 km (800 miles) per hour.
Saturn's rings also yielded puzzling new findings. Barely had Voyager 1's cameras zeroed in on these thin, elegant discs than scientists spotted two new moons no more than 600 km (370 miles) across at the edge of the ring system. They were designated 513 and S-14, because they are the 13th and 14th to be discovered. 513 circles Saturn just outside the so-called Fring, which is about 80,000 km (50,000 miles) from the planet's cloud tops —the gaseous sphere has no real surface. 514 revolves just inside that ring. Like dogs herding sheep along a narrow road, the outer moon seems to be keeping ring particles from flying off into space, while the inner moon stops them from falling toward Saturn—as one scientist put it, "controlling an unruly flock."