Ed Stone

Project Scientist

Voyager Project Scientist

Burlington, Iowa

For me, the highlights of Voyager were clearly the planetary encounters. All six of them were wonderful experiences where every day we saw and learned new things. We had a lifetime of discovery packed into each one.

There was a regular routine: In the afternoon we had a science meeting where individuals would say, "This is what we’ve seen" or “This is what we think" or “This is what we don’t understand.” Members from all 11 science teams participated, packing the conference room. These daily science meetings were a form of real time peer review that was also a way to choose which observations to report at the press conference the following morning. After the meeting, I would work with the investigators in outlining graphical illustrations that could be prepared overnight for use at the press conference at 10 a.m. In parallel, the imaging team would choose the images and prepare the captions for those that would be printed overnight for distribution to the reporters gathered at JPL. That afternoon, we would do it all over again with another day of observations and analyses.

If I had to pick a favorite memory, it would be the discovery of active volcanoes on Io. It was Friday afternoon, March 9, 1979, four days after Voyager’s closest approach to Jupiter. The final press conference had wrapped up the day before. So, the reporters had already left and many of the scientists had gone home for the weekend. It was a very quiet afternoon. Andy Collins -- who worked with the Imaging Team -- came to get me, saying, “You’ve got to see this.” He took me to Linda Morabito, an optical navigator, who determined the precise locations of Jupiter’s moons by analyzing Voyager pictures of them with a background of stars that had known positions. The latest picture of Io revealed a feature extending well beyond the moon’s disk -- it was an erupting plume shooting far above Io’s surface, an active volcano.

The eruptions on Io were the first direct evidence of active volcanoes elsewhere in the solar system. Even though Io is much smaller than Earth, it had ten times as much volcanic activity. This astonishing discovery clearly signaled that we could expect many more surprises. And Voyager has certainly revealed a remarkable diversity of planets and their moons, rings and magnetic fields that has changed our view of the solar system.