Saturn: Cassini's Final Chapter

Apr 30, 2017
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LULU GARCIA-NAVARRO, HOST:

Cassini's odyssey through the cosmos has entered its final act. The unmanned spacecraft was launched two decades ago to explore Saturn and its moons. But in a few months, its mission will come to a dramatic end with its plunge into the depths of Saturn's atmosphere. Dr. Carolyn Porco joins me now. She is the leader of the Cassini imaging team. Thanks so much for being with us.

CAROLYN PORCO: Oh, thank you so much for having me.

GARCIA-NAVARRO: So Cassini's having a big finish. What's it up to?

PORCO: Well, we decided to go out in grand style. There was still a lot of verve left in the spacecraft and the instruments. And we knew it was time to bring the mission to an end. All good things must end. And so we put it on an orbit that took it and is taking it through unchartered territory. We're very, very close to the cloud tops of Saturn. We're measuring in fine detail the gravitational field of Saturn. We're going to be measuring the rotation rate of the planet. And then, finally, it will be measuring the composition of the Saturn atmosphere. So in some real sense, this is like a new mission. And, like I said, we're going out in grand style.

GARCIA-NAVARRO: What is the legacy of this mission? What have we learned?

PORCO: Oh, my goodness, where do I begin?

GARCIA-NAVARRO: Give us synopsis.

PORCO: We have basically come to intimately know this incredibly phenomenologically-rich planetary system, kind of the promised land in our solar system. We have come to intimately know it now. And it has shown us so many things. But the thing that I get most excited about is that we have found on some small moon called enceladus - no bigger across than England - a subsurface ocean that we believe is the most accessible habitable zone in our solar system outside the earth. And so there are some of us who are eager to return to find out if life, in fact, has gotten started on this moon.

GARCIA-NAVARRO: You've worked on this mission since its inception. And on the Cassini imaging website, you've kept what you call - and I love this as a "Star Trek" fan myself - a captain's log. It's a journal of the mission's progress, but it's not what I think our listeners might expect a scientist logbook to look like. The entries have titles like, I Dreamed Of Falling, A Year Of Splendor, and The Day The Earth Smiled. It seems as if this mission has really been important to you personally.

PORCO: Oh, my goodness, yes. It's been my life for the last 27 years. You know, for people who aren't in our business and don't participate in flight missions like this, it's hard to describe, you know, how committed you have to be. And there were many years - not months, not weeks, but many years when it required clearing the decks of everything, including any semblance of a normal life, to make it happen. But, you know, through all of it, it's - you know, you're doing something so historic and so incredibly privileged. And there is a poetry to it that, of course, that's what you're picking up.

It's - we feel we're living the explorer's life and immersing ourselves in nature's secrets and mysteries. We're the high priests and priestesses who are trying to tease out what it is that nature is telling us about ourselves, about our place in the cosmos. And we're doing this by trying to understand what is around us, what's our cosmic neighborhood. And I don't think there's anything greater to be doing with one's life than that.

GARCIA-NAVARRO: After investing so much time in this mission, how do you feel now that Cassini is having its finish?

PORCO: Well, you know, when I just sit and think about it myself, I'm thinking, wow, it's been such a lot of work. I think, you know, it'll be a relief when it's over. I'll go camping. I'll spend the next two years - I don't know - walking along beaches and admiring the scenery. But when, you know, I get on a program like this, and I'm hearing someone else say, oh, it's the end, I'm choking back tears. It's an abrupt juncture, you know?

For 27 years up until when it goes into Saturn, I will have spent my life doing this one thing. And then after that, it's over. And that goes for many, many of us on this project. So it's going to be - in some sense is going to be like a death. You know, it's been a huge part of my life. And then it won't be there anymore. But I think also that - I mean, I know that's a legacy that I'm always going to be enormously proud of. And I think I'll enjoy it when I'm, you know, in my rocking chair, you know, as an old lady just thinking about what I did with my life.

GARCIA-NAVARRO: That's Dr. Carolyn Porco. She's the head of the Cassini imaging team. Thanks so much for being with us and congratulations.

PORCO: Oh, thank you so much.

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