A conversation with three members of the original Cassini science team: Jeff Cuzzi, the mission’s interdisciplinary scientist for rings; Dale Cruikshank, an astronomer and planetary scientist studying Saturn’s icy moons; and Chris McKay, a planetary scientist and one of the original collaborators on the Huygens probe – all three from NASA’s Ames Research Center.

Transcript

Matthew Buffington:Welcome to NASA in Silicon Valley, episode 59. This week we have a special episode in honor of the Cassini mission, which is coming to a dramatic close on September 15. And for the first time ever for a podcast intro, I’m joined by fellow science communicator, Abby Tabor.

Abby Tabor:Hey Matt!

Matthew Buffington:Now, You might recognize Abby’s voice because she has recorded several story features…

Abby Tabor: Yeah…

Matthew Buffington:…for the podcast. These are basically the audio versions of the stories she writes for NASA.gov.

Abby Tabor:Right.

Matthew Buffington:In fact, she pulled together a great panel discussion for the Cassini mission. So Abby, tell us about that.

Abby Tabor: Well, the Cassini spacecraft has been studying Saturn, and its rings and its moons for the last 13 years. But it’s about to plunge into the planet’s atmosphere and end the mission. So, we wanted to mark that occasion and here at Ames, we have 3 scientists who were part of the original Cassini science team. So, we got those guys to come in and talk about it. And that includes Jeff Cuzzi, he’s a specialist of Saturn’s rings. And Dale Cruikshank, he studies the small bodies of the outer solar system, so that includes Saturn’s moon Titan, he’s looking at the surface composition. And then also Chris McKay. He was involved in developing the Huygens probe, way back in the 70’s, and that’s a probe that Cassini carried out there to land on Titan. And so Chris has been studying astrobiology since then. So, these guys helped lay the groundwork for the mission – so they came in to talk about what Cassini taught us.

Matthew Buffington:And for fans of the podcast, we have two veterans, I guess our returning jeopardy champions.

Abby Tabor:That’s right!

Matthew Buffington:There’s Chris McKay and also Jeff Cuzzi, who was just last week’s episode. And Dale Cruikshank is the new, he’s the new guy on the block.

Abby Tabor:The newcomer, that’s right.

Matthew Buffington:But before we jump into the conversation, just for everyone whose listening, fans of the podcast, no matter how or however you found the podcast, it would be really awesome if you like, share, comment, subscribe or do whatever it is you love to do on your favorite podcast app or social media. That really is the best way to help others notice and find the podcast. Also, on top of that, we would love your feedback. We have been using the hashtag #NASASiliconValley on Twitter, but starting today, you can also call and leave us a message.

Abby Tabor:Wow.

Matthew Buffington:Our phone number that we’re going to use is 650-604-1400. Now, we’re going to listen to your messages and, who knows, maybe we will pull some of your questions out for future episodes. And a quick reminder, we are a NASA podcast, but we are not the only NASA podcast! So we always want to give a shout out to our friends over in Houston…

Abby Tabor:Yeah!

Matthew Buffington:…for the Houston We Have a Podcast, but also there was a podcast, one podcast to rule them all I suppose, it’s called NASA Casts. They’ve taken all the RSS feeds for all the podcasts and put them into one big omnibus podcast.

Abby Tabor:Cool.

Matthew Buffington:So that’s how you can find us and listen to us and share us. But for this episode…

Abby Tabor:Yeah, in the meantime, let’s listen to our Cassini tribute episode. And here to tell us about the scientific surprises Cassini revealed, and also how it feels to see your decades-long science mission come to an end, are: Chris McKay, Dale Cruikshank and Jeff Cuzzi.

[Music]

Host (Abby Tabor):We’re here today in a crowded little audio studio at Ames Research Center with three of Ames’ scientists who were on the very original science team for the Cassini mission.

So, we’re going to get a great historical perspective on this mission because it is coming to a close. Jeff, could you tell us a little bit about what is about to happen?

Jeff Cuzzi:Right. The grand finale of Cassini is going to come to a close in September the 15th. Since last December, Cassini has been put on a series of almost polar orbits. It’s going around Saturn, crossing over its pole, plunging in very close. We had 20 orbits where we just skim right by the outside edge of the rings, and 20 more orbits where we actually thread a needle between the rings and the planet. At the last of those 20 orbits, we do a little orbital tweak way out, far from the planet, and it comes in. And when it comes in, it goes right into the atmosphere and burns up. That would be the end of the data taking stage of Cassini.

Host: Oh my gosh. I want to get into how you guys feel about this moment. Is it sad? Is it exciting? Is this the culmination of this mission that you’ve been following for decades, or is there a bit of bittersweetness?

Jeff Cuzzi: Cassini has had a number of stages. We had the planning stage, which goes back to the early ’80s, and that was very exciting, and the construction stage. And the implementation, the flight stage. So, we’re flying, flying. Nothing is happening. And then we had these for the last 13 years or 14 years of actual data taking, and now that stage is over.

Host: For how long is nothing happening in that middle stage?

Jeff Cuzzi:The flight stage was about seven years.

Host: Wow. Yeah

Jeff Cuzzi:We launched in 1997, and we got there in 2004. From the standpoint of the scientists, there wasn’t an awful lot going on during that time.

Host: Okay.

Jeff Cuzzi: I’m starting to think about how we were going to engineer and design the orbits. But the end of the data taking stage, in my mind anyway — Dale and Chris have different feelings about it. To me, it’s not the end of Cassini because we’ve got this vast amount of data. So, there’s another stage to Cassini, and that stage is just beginning. That’s how I feel about it.

Host: Excellent. Cassini lives on after its final plunge.

Jeff Cuzzi:You bet.

Host: Dale, how do you feel?

Dale Cruikshank:I might just add to what Jeff said, that the flight from Earth to Saturn was not without its interesting moments. We did actually fly rather close to Jupiter and made some interesting measurements of both Jupiter and a few of its larger satellites. So, there was excitement along the way, or at least things that gave us opportunities to see how well the instruments were performing and how well our planning exercises could be done. And so, all that was a great success. And then there was the long haul on out to Saturn.

In terms of whether or not this is a bittersweet moment, it’s important, I think, to note that the Cassini spacecraft had on board a limited amount of resources that allow it to point in the particular directions that are required, one of which, of course, is the direction of your target: the moons of Saturn, or the rings, or the planet, and the other is to point back to earth to be able to relay the data that it took.

Host: Right. Of course.

Dale Cruikshank:That all has to be done on a very regular basis. So, the resources — which is really on-board correction fuel, you might call it — has nearly run out. The other part of this is that after this very long run of excellent data taking, and more to come in the analysis, it’s expensive to keep Cassini operating.

Host: I see.

Dale Cruikshank:And so, there are desires to get other planetary missions going. And this one is reaching a very natural and appropriate end, which will, in fact, then free up funds for further exploration by other spacecraft and new ideas that keep coming along the way.

Host: Okay, so it’s like, “Thank you, Cassini. You’ve had a great run, and it’s time for you to retire now.”

Dale Cruikshank:That’s a good way to put it. Yes.

Host: Okay. I see. Chris, can you remind us, first of all, why are we sending Cassini diving into Saturn. And then tell us a little bit about your feelings.

Chris McKay: Inevitably Cassini, when it runs out of power and fuel, will crash somewhere. Most likely, it’ll crash into Saturn. It’s the big object in that system. But there’s a chance that if we just let it go derelict, it would crash into some other object like Titan or Enceladus. We don’t want that to happen because we don’t want to risk the chance that it will contaminate those other objects.

Host: Oh yeah.

Chris McKay:So, we’re purposefully crash steering it towards Saturn. But it really doesn’t have much choice. We can’t push Cassini out of the Saturn system to follow Voyager into interstellar space or anything like that. It is deeply trapped in the Saturn system. And its fate, regardless of what we do, will be to crash into something in the Saturn system. We just want to control that crash.

The reason is partly because of Cassini’s own success. It has revealed such interesting worlds from an astrobiology point of view. In particular, my favorites are Titan and Enceladus. As Cassini dies, to me, it’s really closing one book and opening another. It’s let’s go on and do these further missions, as Dale was just saying, to explore these worlds that Cassini has opened up for us: Titan and Enceladus. Let’s go.

Host: That’s so exciting. I’m glad to hear that. I’m glad this is not a sorrowful moment. This is a celebration of the next stage of Cassini’s legacy.

Jeff Cuzzi:Ames was the lead center for NASA for probes, and Ames designed the Galileo probe and the Pioneer Venus entry probes that involves heat shield technology and a lot of specialized technology.

Host: Right. Those are things Ames still works on today, heat shield technology. Yeah.

Jeff Cuzzi:Still works on today. If there are future probes to, say, Uranus or Saturn, I expect Ames will be involved. So, Ames started running the very first Titan probe studies back in the late ’70s. In fact, I was involved in those. Those were one of the first things I did when I came to NASA. We presented to NASA headquarters. They said, “We love this idea so much, we’re going to give it to JPL to implement.”

And then it got passed on to the European Space Agency. As you know, NASA and ESA shared the Cassini-Huygens mission. So, ESA actually built and flew the Huygens probe, of which Chris was a member. But they used pretty much the same plans that were developed right here at Ames.

Host: Okay. So, Ames laid the groundwork for something that became an international collaboration, multiple NASA centers, multiple space agencies.

Jeff Cuzzi:Yep.

Host: We know the world is watching. I see @CassiniSaturn on Twitter, and people are just dying over the beautiful images that it’s sending back. It’s really been a big hit. Dale, tell us how did you get involved and when and what were your feelings back then on the mission.

Dale Cruikshank:I got involved at the point at which the science teams were selected, because I had, up to that time, written a number of papers about telescopic observations of satellites of Saturn and other small bodies in the outer Solar System. I came in on a science wave, basically, and was included in one of the particular instrument teams, a team built around the instrument that makes spectral maps of the targets, whether it’s Saturn rings or the moons.

Host: What do those tell us? What are spectral maps for?

Dale Cruikshank:A spectral map allows you to determine the composition from spectroscopic techniques of a target object, and also see how the chemicals or the molecules that you’ve identified are distributed. That is, you can make a map — If you made a spectral map of the Earth, for example, you’d show that the oceans are made out of water, the polar caps are made out of ice, and the continents are made out of rock and dirt. And so, we make spectral — and you can do this with a spectral map with the kind I’m talking about for these other objects.

We’ve done that with the rings, the moons of Saturn. And we know a lot about what materials are there based on these maps, the molecules, and other materials that they reveal. The distribution of that material is extremely interesting and important in trying to understand the histories of these objects, how they came to be in the first place, and what have the last four and a half billion years of changes in their environments caused to be seen on their surfaces.

I would also point out, since Chris already mentioned Titan, that the instrument I’m referring to, which is called VIMS or the Visible Infrared Mapping Spectrometer, has allowed us to penetrate the clouds and haze of Titan, which often make the other instruments unable to see the surface well.

Host: Okay.

Dale Cruikshank:But we can penetrate that haze because of the particular wavelength characteristics of our instruments. We’ve seen what lurks on the surface of Titan, including the discovery of the hydrocarbon lakes that occur there. The radar instruments on Cassini reveal the presence of lakes. But we can actually tell you what those lakes are made of. And it turns out they’re made of some combination of liquid ethane and methane, which are two hydrocarbons.

Host:So incredible. This still gets me that you can know that about a body so far from Earth. What is the distance to Saturn from Earth? I don’t recall.

Jeff Cuzzi:It’s about a billion kilometers.

Dale Cruikshank:Yeah, eight astronomical units. It’s getting up toward a billion.

Host: Wow. And you’re looking at it. You’re looking at the surface of these moons.

Dale Cruikshank:Yes, and in detail. We can see things as small as a half a mile or even better on the surfaces of some of these objects. In the case of the rings, as Jeff can tell in great detail, we see some very small details of objects and ripples in the ring system.

Host: Yeah, I’ve seen those images. That’s amazing. When Cassini started sending back its data and its images, were you surprised by this level of detail that you were seeing, or was this always expected to be the kind of information you would have?

Jeff Cuzzi:For the rings, the big eye opener was really Voyager. Voyager revealed for the first time that the rings were just full of structure. What Cassini has done is reveal yet finer structure, more in-depth observations of that structure. It’s allowing us to untangle what is it really caused by. That’s the thing Cassini is really doing for the rings. For Enceladus and Titan, it’s a whole different story, I think.

Host: That’s also cool, the variety of science that Cassini is bringing you. It’s not just a Saturn’s rings mission. It’s all these other astrobiological implications and other things we’re learning. That’s exciting.

Dale Cruikshank:Just to add to the list of things that Cassini does that was mentioned before. It also makes an in-depth study of the magnetic field surrounding the planet and the variations in that field because of changes in the activity of the sun, the orientation of the planet, and so on. It’s not just Saturn the solid or the discrete body. It’s the environment, the space environment, of Saturn as well.

Chris McKay: One of the big surprises when the Cassini-Huygens mission arrived was Titan. We had ideas of what it was like. In fact, there was this consensus as we were building the probe that Titan’s surface would be an ocean, a global ocean. So, the probe was built as a boat to float in this ocean that we were sure we were going to land on.

Host: Wow.

Chris McKay:When Cassini and Huygens arrived, it was a very different world. When we finally got through the haze, could see down to the bottom of Titan and land with the probe, the probe landed in what looked like a desert.

Host: No kidding?

Chris McKay:At first, the orbiter — the images and the radar — did not reveal any liquid at all. We thought it was going to be a dry, maybe Mars-like world. But then, there was images of a lake in the southern hemisphere, and then radar data, and then VIMS data of lakes in the northern hemisphere. Yes, there’s liquid there, and it’s very interesting liquid. It’s not the ocean that we thought when we built the probe.

Host: Amazing.

Chris McKay:So, there were big surprises in our understanding of Titan. And in a way, the picture that emerged, from an astrobiology point of view, is more interesting.

Host: Oh, good.

Chris McKay:The global ocean is neat, but it’s water, water every — well, it’s liquid, liquid everywhere. It’s not water, it’s liquid. Liquid everywhere. What we’re finding instead is a mix of wet land, dry land, and lakes. If you’re a little organism that likes to live in that liquid, that mixture of dry and wet and lakes and streams is more dynamic, more interesting, and more conducive to a good life.

Host: Right.

Chris McKay:So, in a way, Titan emerged from the Cassini-Huygens mission more interesting than we imagined when we built it.

Host: That is cool. That must have been an exciting moment. What did you know — ? You’ve answered some of this, but I was going to ask. What did you know about the Saturn system when you were planning this mission that made it the target you had to go after?

Jeff Cuzzi:A lot of ring structure. Enceladus was very puzzling. Enceladus was unlike any other moon. It was centered in this very diffuse ring of Saturn, the E ring which is just all fine dust. It was suspected that there was something funny going on in Enceladus that maybe was creating all this dust. As Dale and Chris have alluded to and can say more about, that we have all these volcanic jets now coming out of Enceladus. Just fascinating.

But that was a puzzle. We didn’t know that. Titan, as seen by Voyager, was this fuzzy orange tennis ball. We knew that from a radio wave passing through the atmosphere, had a very thick atmosphere, pressure like surface of the Earth, and all this nitrogen. So, I would say the combination of the promise of Titan, of Enceladus, and these fascinating rings, really drove the Cassini planning.

Host: Interesting. Were you thinking about the search for life at that point?

Chris McKay:The search for life wasn’t part of Cassini’s mission. It really is only now emerging from the Cassini results that the search for life makes sense. That, I would say, is part of the next step. What Cassini did was reveal that there were habitable worlds there. That was a big revelation.

I would say that the Cassini result from Enceladus have shown that world to be habitable, more so than any other world beyond Earth in our solar system. Enceladus went from this obscure little world interesting to the rings folks because of the E ring to being the star center stage of astrobiology and our understanding of habitable worlds. So, Cassini really did a wang bang job when it came to astrobiology and searching for habitable worlds.

Host: Yeah. That is a big, big world of possibilities to have opened up during the course of a mission. Right? Is that typical of these kinds of space missions, that you go in with one big goal and you find a whole bunch of other ones?

Chris McKay:We’re often surprised and we’re often wrong. The ocean on Titan is a good example. I think, as Jeff indicated, we knew something was happening with Enceladus. But the full richness of the geysers and their organic content and the biologically available nitrogen and the biologically available energy sources inside the geyser, that was just — Even now, I pinch myself to think “Did we really discover that?” It is just so amazing. It is. Every astrobiologist’s dream.

Host: Amazing. Every astrobiologist’s dream, even. Dale, did I cut you off? Did you want to add something?

Dale Cruikshank:No, no. I could go on for hours, but I won’t. I was interested in Chris’s highlights, as he just spoke. A highlight for me was the opportunity to study up close and in detail one of the other satellites of Saturn, which we have known for about 300 years, is really very interesting. In fact, the study of this satellite, which is called Iapetus, goes back to the Pioneer space mission — which was operated out of Ames, by the way — in the ’70s. And then we got some more information with Voyager in the ’80s. But now we are able with Cassini to look at this very strange satellite up close.

First of all, it’s fairly large. Smaller than our moon, but still fairly large. It’s mainly made of ice. But one of its surfaces, one hemisphere, is almost entirely coated with some kind of black, reddish, low-reflectivity material. What is that stuff and where did it come from?

With Cassini and the VIMS instrument that I work with, as well as some other instruments, we’ve come to an understanding that this is some kind of an organic, solid material, complex organics. We can measure its spectrum and its distribution on Iapetus. We now even know where it came from, the dark stuff. Because it turns out that another of Saturn’s moons has apparently been hit by some projectile, some comet or asteroid from space, and has liberated a huge amount of dust. This is the outermost large moon called Phoebe.

Host: Yep.

Dale Cruikshank: And that dust has spread itself into a gigantic ring, much larger in size than the rings we’re more familiar with. The dust from this ring slowly filters in towards Saturn. As it does, some of it is intercepted by my favorite satellite, Iapetus, and Iapetus gets a coating on one of its hemispheres. So, we now know where this dust comes from. We even have a pretty good idea of how thick it is, which is about 10, 20 inches. It’s not much. And it’s still falling. It’s still getting dusty on Iapetus.

Now from the VIMS instrument study, we know that it’s made of complex organic material. This then feeds back into this whole issue of the organic content of the solar system, and must, in some way that we haven’t yet, I think, uncovered, relate to the organic material that’s on Titan and Enceladus, and the other objects that we still want to explore in greater detail.

Host: Very cool. Could you explain a little though? What do we know about this organic material? That doesn’t mean it’s necessarily related to life. Right?

Dale Cruikshank:That’s correct. In fact, it almost certainly isn’t. We’ve found in space, both in our solar system, in our galaxy, and in other galaxies far beyond, that carbon and hydrogen like to get together and make the rudimentary material that we would call organic. So, the term organic doesn’t necessarily imply the origin in any relationship to life itself. It’s a common process throughout the universe, apparently. Some of it has happened in our neighborhood and what we see on Iapetus, and certain other objects in the Solar System is evidence of that material that has formed in abundance and has been spread around and accumulated in interesting ways.

Host: Neat, and that’s what we’re going to continue learning about?

Dale Cruikshank:Yes.

Host: That’s the future that Cassini has made possible. Right? Fascinating.

Now I’d like to ask something that I’ve always wondered about. We hear about these space missions, and when you’re not working on them, you probably hear about it when it launches. Then years later, maybe you hear about it when it reaches its destination. But the whole process starts probably decades before even the launch. So, you guys have been watching Cassini for decades.

How does it feel at the beginning looking forward, being excited about the science that this is going to provide for you, but knowing you’re going to have to wait years and years and years? What does it feel when you launch, not when you launch the spacecraft, but when the project gets going?

Jeff Cuzzi: It was a great feeling of excitement, of mutual commitment to a goal, a fantastic goal. Those first PSG meetings were terrific. Even before, the planning stage, like you said, went on for years, went on for 10 years really before it was approved by congress in 1990. Our first big meetings were in 1991. It’s just this great feeling of lots of potential. And then you work through it all, and there’s all the arguments and disagreements that come along the way, and you work through all those. At the end, there’s this great feeling, at least in the case of Cassini, of satisfaction, of fulfillment. Cassini has fulfilled its promise, in my mind anyway. It’s just been a tremendous success. So, you look back on that with great satisfaction.

Host: Right. I can imagine. Yeah.

Chris McKay:I got involved in Cassini after it had already gone through probably about a third of its early history. When I arrived at Ames and started working on this project, there had already been a lot of effort put in in making this mission happen. It got selected soon after I got involved in it. And then I was able to watch it for 20 years or more as the data came in.

To me, there was 2 lessons in that. One is it takes a long time to do the outer Solar System, and the other is that it is multigenerational. That I as a young scientist benefitted from a lot of work that would have been done in the decade before I even came to Ames, before I even knew what was going on.

Host: Right.

Chris McKay: And now, as Cassini ends and we think about what future missions go, I’m doing a lot of that work now for future missions that I know will fly and return their data long after I’m doing something else.

Host: Yeah. You’re retired.

Chris McKay: Or worse.

Host: Right.

Chris McKay: But I like that. I like that idea of projects that are so big and so long that they require us to think intergenerationally.

Host: Yeah.

Chris McKay: And the outer Solar System does that. Cassini was my first experience in it, and now I’m participating in it on the other end following along from what Cassini had done.

Host: That’s awesome. It’s like it’s bigger than any of us. Right?

Dale Cruikshank: I think a point that has interested me over the years, too, is the fact that we started working with a lot of people we already knew from our rather small profession. These people have been working together for three decades on this. This has engendered great friendships and great collegial relationships. Some of them, of course, die off during the long process and new students come in, touching on the intergenerational point that Chris just made. But these are fantastically talented people who are giving of their time and talent to make a complex mission like this a success.

Host: Yeah.

Dale Cruikshank: It is just a tremendous pleasure to work with people of that quality and that degree of devotion and dedication.

Host: That sounds so satisfying.

Dale Cruikshank: Very.

Host: Which is exciting to hear, because my initial thought was “Man, how do you wait that long?”

Jeff Cuzzi: You’re busy. There’s a lot of time that you’re doing a lot of planning.

Host: Yep, yep.

Chris McKay: And working on other missions, too.

Host: Right.

Dale Cruikshank: Yeah. I’ve been working on the New Horizons mission to Pluto for a comparable amount of time.

Host: Cool.

Dale Cruikshank: We’ve had tremendous success flying by Pluto two years ago, and we have another target in view. But that took nine and a half years from launch on a sprint to get all the way out to Pluto.

Host:Right.

Dale Cruikshank: But tremendously successful, satisfying, and it interleaved nicely with the long period that I’ve been involved in with Cassini as well.

Host: That’s also interesting that all of these missions, many of them overlap and are interwoven, as you say. The knowledge we gain from one place feeds into another.

Jeff Cuzzi: Voyager was still flying when Cassini was almost ready to be approved.

Host: Okay.

Jeff Cuzzi: It was very much overlapped.

Host: Yeah, I see. And then this intergenerational point is really nice because that always comes up at NASA. We need to inspire the next generation, train the next generation, so they can take over when you guys hang up your hats and move on after Cassini.

Jeff Cuzzi: We’ve got some great young people already involved. Right.

Host: That’s outstanding. Maybe one final topic could be — I know we discussed that this is not the end of Cassini. But I was thinking of asking you for a eulogy for Cassini. If you had to reflect on its contributions scientifically and also for the public, to society, in terms of getting people excited about space. Everybody loves the rings of Saturn. People are loving the photos coming back. What, for you, are the biggest impacts or the ones that really captured your minds?

Jeff Cuzzi: Since you mentioned the rings of Saturn, let me say a few things about what we have learned. Saturn’s rings are really like a vast dynamical laboratory. It’s a big, giant particle disk where the particles interact like molecules in a fluid. So, we treat it like a fluid, collisions and such. So, it’s a great way to understand the processes by which our planet formed from the disk of particles and gas that originally surrounded our sun. It’s a laboratory for us to study that. All those processes in the rings probably happened in one way or another in our own forming solar system and in other forming solar systems where we see all these thousands of exoplanets.

Host: Okay. Right. Saturn tells us about Earth potentially and then beyond.

Jeff Cuzzi: And beyond, no doubt.

Host: Wow.

Jeff Cuzzi: The other thing we learned was that Saturn’s rings are changing before our eyes. This fluid flops around and moves and changes. We see things colliding and recreating as we watch. That’s been fascinating. In fact, the whole origin of Saturn’s rings, we think, it’s whether they formed in the last couple hundred million years is a hot topic these days. That is around the age of the fish on Earth or more recently.

Host: Interesting.

Jeff Cuzzi: There are things that are still being worked. So, we can’t answer that question right now. There’s data being taken right now by Cassini that we’ll hear about in two weeks, and this work will go on. But this is a very hot subject right now about Saturn’s rings. This whole concept of impermanence and change applied to this vast structure has been something we’ve really learned very well through Cassini.

That’s very cool Yeah. Because we don’t think about the outer Solar System transforming and going through long term change.

Jeff Cuzzi:Exactly.

Host: We don’t get the chance to see that, normally.

Jeff Cuzzi: That’s right.

Host: Yeah. Neat. That’s a good takeaway. How about Dale or Chris?

Chris McKay: My farewell to Cassini would be, “Thank you for the revelations of Titan’s liquid methane lakes, and even more so for the organic-rich geysers on Enceladus,” because that’s given us astrobiologists a clear direction on what to do next, and we’re doing it.

Host: Awesome. Awesome. We look forward to that next chapter, clearly. Dale?

Dale Cruikshank:I see two things. One is that the things we’ve been finding with Cassini in the Saturn system give us ideas for the use of the James Webb Space Telescope, which will be an enormously powerful facility to be launched in about two years from now.

Host: Right.

Dale Cruikshank:The other thing that comes to mind is that Cassini, with so many of the other things that NASA does, is most often the best news you ever get. And in a world where the media are jammed with not-so-good news. Almost everything you hear from NASA is good news and stimulating.

Host: It is.

Dale Cruikshank:I think that this is a tremendous gift to not only the American public, but to humanity, that NASA has these lofty goals and has found ways to achieve them, and with a cadre of talented, anxious, and vigorous young people to carry these missions out. We are often the best news you’ll ever get.

Host: Absolutely. I couldn’t have said it better myself. That’s so true. You feel that around NASA Ames. People are just so delighted to be here. People out there across the country, across the world, love what you do. Thank you, guys, so much for joining me today.

For our listeners, if you have any questions for these NASA Ames researchers who were part of the very original Cassini science team, you can get in touch with us. We are @NASAAmes online, and we’re using the #NASASiliconValley. You can send us your questions and we will get them to Jeff, Dale, and Chris, and get back to you. So, thanks again for joining us. This was wonderful.

Jeff Cuzzi: Pleasure.

[End]