[Illustration: The best Voyager 1 photos of Europa were obtained on March 4 from a distance of about 2 million kilometers. This view of the hemisphere centered at about 300° longitude has a resolution of about 40 kilometers. Most of the surface is bland and highly reflective, being composed almost entirely of water-ice. No craters resulting from meteoric impacts can be seen. The most striking visual features, which set Europa off from the other satellites, are the dark streaks, as much as several thousand kilometers long, that cross the surface. Just barely visible to Voyager 1, these streaks were dramatically apparent to Voyager 2 in its closer flyby in July. [P-21208C]] Once again, tracking station problems interrupted the smooth flow of data from the spacecraft. Failure at Madrid to reestablish the correct receiver frequency after a spacecraft maneuver resulted in the loss of 53 minutes of irreplaceable data; an additional eleven minutes were lost an hour later. As the first problem was being corrected, the tracking antenna became misaligned, resulting in a noisy data return. Meanwhile, only a few of the watchers at JPL mourned the lost data, so exciting were the other new results that kept pouring in. “For the highlights of this morning Dr. Soderblom will come up and show some beautiful satellite pictures,” Brad Smith announced at the daily press briefing. Larry Soderblom’s excitement was hard to contain. “Today is probably going to turn out to be one of the most memorable days in our exploration program. For the planetary geologists it’s truly Christmas Eve. We see tonight the beginning of the exploration of four new worlds. We’re racing through time and space at an incredible rate—the rate at which we are learning things is awe-inspiring in itself.” Callisto was still too far away to see well “but the things we’re seeing on the closer three satellites have really got us charged in anticipation.” Ganymede—“What can I say? Loops and swirls and incredible patches that are difficult now to hazard a guess about.” Io—an eerie-looking red, orange, and yellow world—“this one we’ve got all figured out. [Laughter from the press and applause.] It is covered with thin candy shells of anything from sulfates and sulfur and salts to all kinds of strange things.”