Edward C. Stone, Explorer. 1936-2024
Edward C. Stone, former director of NASA’s Jet Propulsion Laboratory and longtime project scientist of the Voyager mission, passed away on June 9, 2024. He was 88 years old. In this 2018 video, Stone talks about the Voyager 2 spacecraft reaching interstellar space, six years after Voyager 1 reached the same milestone. The twin Voyager spacecraft were launched in 1977 on a five-year mission that is still operating today. Stone served as the mission’s project scientist for 50 years, from 1972 to 2022.
In addition to his work on Voyager, Stone was the director of JPL from 1991 to 2001. Under his leadership, JPL was responsible for 21 missions and instruments and developed six new missions. Highlights during Stone’s tenure included landing NASA’s Pathfinder mission with the first Mars rover, Sojourner, in 1996 and launching the NASA-ESA (European Space Agency) Cassini/Huygens mission in 1997. The first Saturn orbiter, Cassini was a direct outgrowth of the scientific questions that arose from Voyager’s two flybys, and it carried the only probe that has ever landed in the outer solar system (at Titan).
Transcript
Mission Control:
We have ignition, and we have lift-off of the Titan-Centaur carrying the first of two Voyager spacecraft to extend man's senses farther into the solar system than ever before.
Ed Stone:
We launched two Voyager spacecraft. They were basically the same, but they were on different paths.
Voyager 2 was the one that was chosen to do the Grand Tour, that is, to fly by Jupiter and then Saturn, and then Uranus and then Neptune.
And then after 1989, we began what is now called the Voyager Interstellar Mission.
We were on a path we hoped to get to reach interstellar space while we still had power on the spacecraft to transmit the data back. And that's what Voyager 1 did in 2012. And that's now what Voyager 2 is starting to do in the 2018.
The sun creates this huge bubble of plasma, ionized material. It goes outward at a million mph and creates a bubble. And inside the bubble, most of the material has come from our sun, and the magnetic field has come from our sun. Outside the bubble, most of the material comes from other stars that exploded five, ten, 15 million years ago.
We have an instrument which measures the wind coming from the sun, and we saw that, in fact, there was no longer any measurable solar wind. We had left the bubble, basically.
Well, this just contributes to the number of discoveries that Voyager has been making, and this is one we'd hoped we would have the chance to do. And fortunately, the spacecraft were still operating when they reached interstellar space.
It's really quite, quite remarkable. Voyager changed our view of the solar system, really. I mean, we saw these active volcanic activity on Io. We saw the possibility of ocean on Europa. Just time after time, we were discovering things that we had not really even imagined some years before in Voyager mission.
What makes it so exciting is not only do we confirm what we thought we knew, but more, even better, it tells us where we didn't know that there was something to be discovered.