LULU GARCIA-NAVARRO, HOST:
This is Lulu's log, star date, August 6, 2017, where we consider matters of space, the stars and the universe.
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GARCIA-NAVARRO: NASA's Voyager 1 and Voyager 2 have boldly traveled further than any spacecraft have traveled before - to the outer reaches of the solar system. It's been 40 years since they were launched. And in all that time, one man has overseen the mission - chief scientist Ed Stone. He's now 81 years old. And he has dedicated his life to space travel. He joins us now from the studio at NASA's Jet Propulsion Lab in California to mark the anniversary. Thanks so much for being on this morning.
ED STONE: I'm glad to be with you.
GARCIA-NAVARRO: Can you tell us what was significant about the Voyager mission at the time and how has that changed as other Voyager missions have launched?
STONE: Well, Voyager really did a reconnaissance of the outer solar system - first Jupiter, then Saturn, then Uranus and finally Neptune in 1989, starting with Jupiter in 1979. And what it revealed was how complex and dynamic the solar system really is. Before Voyager, the only known active volcanoes were here on Earth. And then we flew by Jupiter's moon, Io, and it has 10 times the volcanic activity of earth. Before Voyager, the only known oceans in the solar system were here on Earth. Then we flew by another moon of Jupiter, Europa, which it turns out has a liquid water ocean beneath its icy crust. So time after time, what we thought we knew based on earth was just much too limited in terms of what nature really does.
GARCIA-NAVARRO: You've been working, as we mentioned, on the Voyager mission since its genesis. What has kept you with this program all that time?
STONE: Voyager - well, Voyager is science. Science is about discovering things, about understanding what's around - what our neighborhood is like, what the universe is like. So as a scientist, this has been a wonderful journey because, especially during the encounters with the giant planets, every day there were a flood of discoveries. Next day - more discoveries. So as a scientist, this has been an incredibly wonderful mission to have been on. And even today at great distances, Voyager is still doing things no spacecraft has done before and still presenting us with puzzles that we are trying to sort through.
GARCIA-NAVARRO: They are still on a voyage. Where are they now?
STONE: Well, this was a mission - we had a four-year mission to Jupiter and Saturn. We had two spacecrafts so that we would have a high probability of at least one succeeding on its four-year journey to Saturn and, of course, both have succeeded and exceeded by a great amount.
GARCIA-NAVARRO: The 40-year anniversary is coming up. As we mentioned, you're 81 years old. Excuse me for having mentioned your age. But that's half your life that you've dedicated to this. Can you imagine life without Voyager?
STONE: Voyager's really been the central part of my life, as you say, for more than 40 years, actually, since 1972 when we began the design and construction of the mission. So that's 45 years. And I hope I'm still around for at least a few more years as the Voyagers continue to explore.
GARCIA-NAVARRO: You must feel an enormous sense of pride that this is a mission that still continues. It was, as you mentioned, only supposed to be four years. And now look at it.
STONE: Now look at it, yes. It's really - I've been very fortunate. All of us who have worked on this mission were very fortunate in the sense of what it did for our careers and what it did for us as scientists or engineers - whatever our role was. It was really very special because this is a kind of journey that happens only once. You can only explore for the first time once. And that's what Voyager did time after time.
GARCIA-NAVARRO: Ed Stone is the chief scientist at NASA's Jet Propulsion Lab. Thank you very much for joining us today.
STONE: Thank you. Transcript provided by NPR, Copyright NPR.