Celebrating Voyager’s 40 Years in Space with Ed Stone

I came to Caltech in 1964. I came as a postdoc and then became
a faculty member in 1967, setting up a research group in
space physics with Robbie Vogt. Then in 1972, I was asked
to spend part of my time at JPL as chief scientist for this new mission, which was called at that time
MJS ’77, but which became Voyager. * We have liftoff of the Titan Centaur,
carrying the first of two Voyager spacecraft to extend man’s senses farther
into the solar system than ever before. * I hesitated because I was a
fairly young professor at that point, and I still had a lot of research I wanted to do.
We had some discussions about how to focus on the science leadership, and I felt I could
continue my research here on campus, working with students and building instruments;
some students actually worked on Voyager with me. Our first encounters with Jupiter were in 1979. The next encounter was Voyager 1 with Saturn in
Nov. 1980, followed in Aug. 1981 by Voyager 2. After the Saturn flyby, we had a nice cruising period
until 1986 for Uranus, and so I did, in fact, teach Physics 1 again. The wonderful thing about planetary flybys is there’s a lot of freshman physics that you can talk about – the encounters, the trajectories.
What we see often has some very basic physics you can talk about. I found a wonderful way to include in the classical physics that you get in Physics 1 some relevant things that are happening now. Caltech is really a unique place.
It has the community that you expect from a small college, but it’s
doing really major world-class research. Caltech founded JPL, and then when
NASA was formed in 1958, it became owned by NASA and run by Caltech.
So that makes it possible for a professor here to actually go to JPL on a part-time
basis for an extended period of time, because it’s all the same university. * The event which really altered our view and our expectation for the rest of the mission was the discovery of the volcanoes on Io. * When we saw Io, we had never seen anything like it.
It had these large features. There was this heart-shaped pattern, all these black spots. We had no idea what we were looking at,
even though we had had all these hints. As we got to closest approach, the
Infrared PI, Rudy Hanel, came in and said “You know there’s some peculiar spectrum here on Io. One possibility is we have a calibration problem. Or maybe it’s a new kind of material, which has
this particular temperature profile.” Another was “maybe there’s
more than one temperature on Io.” We all sat there and listened to this, and not one of us said, “That explains what we’re seeing!” When I went to Optical Navigation,
here was this white appendage on Io. Occasionally I’ll have little sketches here and there. Here it is. There’s Io, and see
that little thing I drew there? This was the sunset line, and you
could see this bright thing up above the dark surface. She had done a lot of work – Linda Morabito – and
was convinced it was not just another satellite that happened
to get in the same field of view. A couple days later, Rudy Hanel came in and
said “We have hot spots, which are lava lakes!” It’s really a remarkable story, how
hard it was for us to take the leap that there could be a small moon with
10 times more volcanic activity than Earth. And that really opened up our eyes that we were in for
a mission that was going to really stretch us in terms of our understanding of planets and understanding of Earth. I think time after time we just found that nature
was much more inventive than our models. Usually, it’s the things that we don’t anticipate
which turn out to be the most important. It’s just that we didn’t know that
they were out there, whatever they were.

About the author


  1. Absolutely astonishing. This man has assisted humanity to go deeper than ever before into the unknown depths of the far reaches of the universe.

  2. I would like to go to JPL Pasadena just to shake hands with Dr. Ed Stone ,, if this would possible just advise !!! E.B.

Leave a Reply

Your email address will not be published. Required fields are marked *