Bonnie Buratti, Planetary Scientist

As Senior Research Scientist, JPL Fellow, and Section Manager for the Planetary Sciences Section, Bonnie Buratti operates at the heart of some of the most critical and longstanding work at the Jet Propulsion Laboratory, which Caltech manages for NASA. Buratti is a leading scholar on understanding the composition planetary surfaces, and she has served in key research roles for numerous NASA missions, including Cassini, Deep Space and New Horizons.

Born in Pennsylvania, Buratti excelled in school and went to MIT for college. At Cornell she worked with Carl Sagan just as planetary science was becoming a mature and discrete field. Her dissertation on the photometric properties of Europa and the icy satellites of Saturn relied on Voyager data, and her research ever since continues both to drive new missions, and to sort out what the data tells us about our solar system and beyond. She is particularly excited about current opportunities in exoplanet research.

Buratti is the author of "Worlds Fantastic, Worlds Familiar" (Cambridge, 2017) which brings a specialist's view of the solar system to a broad audience. She has served in key leadership roles for the American Astronomical Society and the American Geophysical Union. Her many recognitions include the Carl Sagan Medal for Excellence in Public Communication in Planetary Science, the NASA Exceptional Achievement and Exceptional Public Service Medals, the JPL People Leadership Award, and the Magellan Award.

DAVID ZIERLER: This is David Zierler, Director of the Caltech Heritage Project. It is Friday, January 18, 2022. I am delighted to be here with Dr. Bonnie Buratti. Bonnie, it's great to be with you. Thank you for joining me.

BONNIE BURATTI: Thank you for having me.

ZIERLER: To start, would you tell me your current title and institutional affiliation?

BURATTI: Well, I'm an employee of the Jet Propulsion Lab, which is an operating arm of Caltech. I'm a Senior Research Scientist, I'm a JPL Fellow, and I'm also currently serving as the Section Manager for the Planetary Sciences Section.

ZIERLER: There's so much there. What does it mean to be a JPL fellow?

BURATTI: There are a small number of people at JPL who have given advice and have done work at the level expected of the ideal JPL employee for a number of years. I think there are about 60 of us who've been named JPL Fellows, which indicates that you've exhibited traits we expect of JPL employees such as teamwork, honesty, openness, mentoring, the kinds of qualities that make successful planetary science missions.

ZIERLER: To get a sense of the hierarchy, the administrative structure at JPL, as section manager, who reports to you, and who do you report to?

BURATTI: I report to the science division manager. My direct reports are all supervisors. Section management is a mid-level management job. It's a service job I'm doing for a few years. I've done other things, mainly mission management, mission scientific contributions, and research. But right now, I'm doing service work because it was my time. It's fun, you really get to mentor and reward people, do that kind of nitty-gritty of figuring out salaries, promotions, all that kind of good stuff.

ZIERLER: On the research side, for you or in your group, what are you working on currently? What's exciting at JPL?

BURATTI: My area is asteroids, comets, and moons, including the Earth's Moon. I'm interested in their surfaces, what they're made of, their structures. If you were standing there, what they would look like I'm an astronomer by background, and my little area of expertise is photometry, which is the quantitative measurement of reflected light from the surface of the body. That's kind of what I'm working on. The missions I'm currently working on are New Horizons, which is actually not a JPL mission, it's run out of APL (Applied Physics Lab) .I'm also working on the DART, the Double Asteroid Redirection Test program. That is also run out of APL. I'm also working on the NEOSurveyor. This is a mission, which hasn't been launched or even built yet, to track asteroids, potentially hazardous asteroids, that might be on a trajectory toward earth. In my section, a lot of people are working on Europa Clipper, which is a flagship mission, a big Cadillac mission, to go visit Europa, which is an ocean world. It has a mantle of water underneath the crust that and may harbor primitive life. It has all the conditions. We don't know, we're going to find out. A lot of people are also working on the Mars Rovers missions, Perseverance, andCuriosity. And there are some small missions, like Discovery Mission Veritas, a Mission to Venus, which is going to a metallic asteroid. There's a lot of activity going on.

ZIERLER: I'm curious if the recently released decadal report from the National Academy, Astro 2020, if you saw any specific takeaways there that are important for your research and your groups.

BURATTI: Now, that was astrophysics. The planetary science one is going to be released later, probably in March, maybe a little bit later. The main recommendation there was that we shouldn't be working on one thing at a time. As you know, the James Webb Telescope, as awesome as it is, did have a lot of delays and cost overruns. What the Decadal said was, we're working on a few things at once, something falls behind, you pull up something else. It sounds good, but one of the things we spend a lot of time doing, and we look at it as wasted time, is competed missions, writing proposals that don't get accepted–we'll have to see how it works out. I think don't put all your eggs in one basket was the main takeaway there.

ZIERLER: In light of the fact that you've been at JPL for so long, you have so much institutional knowledge, as you well know, JPL is in a moment of transition with new leadership. When the new JPL director is named, what are the most important things for him or her to think about in their era of effective leadership?

New Directions for JPL

BURATTI: For starters, I think JPL can do a lot better in diversity and inclusion. Caltech has really led the way there. I think Caltech, under the leadership of President Rosenbaum, has really opened up both the student body and the faculty to more diverse voices, trying to get a more diverse student body and faculty. Some of that has rubbed off on JPL, but not enough. We've recently hired a person to head up that. The other thing is, I think we really have to be worried about our upcoming business in the outer planets region.

The planetary sciences decadal is probably going to name an ice giants mission as the next flagship Cadillac-level mission for the outer solar system, and I'm concerned that JPL, which has always managed the missions in the outer solar system, starting with Voyager and even earlier, now Europa Clipper, is not going to capture that flagship mission. I think the director is going to have to focus on building up the team at JPL, lobbying headquarters because all the people working on Europa Clipper have to have something to graduate to. The ice giants mission to Uranus or Neptune would be the perfect thing. I think those are the two big things, diversity/inclusion/equity and maintaining our leadership in the outer solar system.

ZIERLER: I wonder if you can explain, perhaps even on a technical level, why you see the ice giants mission as a steppingstone, a graduating step.

BURATTI: The Decadal is several panels of distinguished scientists, and in order to put priorities on missions, the first thing they look at is the science. Ice giants are important for a number of a reasons. First of all, their cores are kind of little Earths.. They're almost terrestrial planets with a lot of gas and ice around them. But the thing that makes them most interesting, other than the fact that they're unique in the solar system, is that we haven't really visited one, except during the fly-bys of Voyager. Also, it looks like a lot of exoplanets, planets outside our solar system, are ice giants. They seem to be very common in the exoplanet world. If we study our own ice giants – either Uranus or Neptune - we can study planets as a whole in other solar systems. The other thing is, they have all these interesting moons around them. There's Triton, which is another ocean world, may have a liquid ocean, has active volcanoes, and seasonal transport of volatiles. There are all these other moons around Uranus that look like they were active in the past. They have dust on them that may be organic, prebiotic material. They're treasure troves waiting to be explored.

ZIERLER: For you, as an astronomer, your degrees are in earth and planetary sciences and then astronomy and space sciences. But at the end of the day, you call yourself an astronomer and not a space scientist or a planetary scientist.

BURATTI: If I were going to describe myself, it would probably be planetary astronomer. At one time, planetary astronomy and astronomy was kind of one and the same. All the astronomers looked at everything. Then they separated. With missions, planetary sciences got more dominated by geologists because you're there on the ground, you have boots on the ground, as it were, with the rover. But now, the fields are being brought back together because of exoplanets. We can really teach a lot of what we've learned about the evolution of planets in the solar system to the planets and moons that are being discovered in other solar systems.

ZIERLER: In terms of the technology, let's start first with observation. What are the most important observational missions that are key for your research and the questions you're after?

BURATTI: I think JWST is really important. I don't have plans to observe on it myself, but other people in our section are looking at the ice giants, characterizing the atmospheres of exoplanets, to search for chemical markers of life and to try to envision or detect things like moons, atmospheres, all sorts of goodies that are around these solar systems. Also, to look at the solar system, just basic stuff. Cloud motions on Jupiter, Saturn, that sort of thing. The other thing I am involved in is large telescopes on the Earth. I observe at Mount Palomar. There's an adaptive optics system up there, where you can look at cloud motions on the ice giants. I have a project to do that now, looking at what the weather is like on Uranus and Neptune, looking for the transport of frosts on some of these outer objects, including Pluto. We're looking at that, and Then there are these there giant telescopes like Gemini with large apertures, where you can get more light-gathering power. So those are the two things, JWST and the large telescopes on Earth.

ZIERLER: The US ELT program, if it comes to fruition, which is very much a question mark right now, both with the GMT and the TMT, are these projects that would be important for your research as well?

BURATTI: Absolutely, for the same reason. Light-gathering power is increased, and you can get better resolution. You can do things like track patches of ices on moons in the outer solar system. You can study the weather on Titan, which is another ocean world around Saturn, and you can study the evolution of clouds on the ice giants and the gas giants.

ZIERLER: Because Caltech has such an interest in seeing the TMT get built, I wonder if you've been following this story or see any ways that JPL has helped Caltech achieve this mission.

BURATTI: I think we've contributed people on the technology side of it. I think the big issues, of course, are the political and cultural issues that have to be addressed. Those are kind of beyond the canon of the scientists. But we work together. In fact, I had a guy when I was a group supervisor who actually went and worked on the TMT. I think he's now working on it full-time. There's collaboration there.

ZIERLER: On the instrumentation side, have you been involved at all with samples being brought back to JPL and analyzing them?

BURATTI: No, I haven't, but members of my section have. First of all, when I was a group supervisor, members of my group worked on Stardust, which is a mission that captured some particles in the coma of a comet, and then returned the samples to Earth. For the Mars 2020 Perseverance Rover caching of samples, which of course will be returned later, the project scientist is Ken Farley from Caltech. The deputy project scientist, Katie Stack Morgan, is in my section, and a lot of people in my section are working on sample-gathering and analysis. And we're in the process of building up a sample lab at JPL. Caltech already has one, but we're trying to cooperate and get some unique capabilities on sample curation and analysis up at JPL.

ZIERLER: Finally, on the technology side, what about computation? In what ways has the fantastic growth in computational power, data analysis, simulation, modeling, been useful for your work?

BURATTI: It's been very useful. First of all, the amount of data we gather is immense. When I was working on Cassini, we would gather four gigabytes of data every day and had to downlink it to the earth. It's awesome. You have to have computational power. But I think the real power comes in the so-called data science and artificial intelligence, where you can teach machines to look at data in a way where they can be taught to find and analyze patterns. There are initiatives at JPL–in fact, there was a strategic initiative to expand that to a number of fields that JPL people work in.

ZIERLER: I know so well from Caltech professors how the affiliation with JPL has been so important for their research. I wonder, for you and your peers at JPL, if it goes the other way, if having that connection to JPL really furthers the research.

BURATTI: I think it does. A number of our colleagues on Cassini, such as Andy Ingersoll, and a lot of the mentors and leaders of the mission come from Caltech. We've collaborated with people like Mike Brown and other people on campus. Then, of course, there's this program, I think Mark Simons set it up, called JROC–I haven't done it myself, but many people here have–where you work at Caltech one day a week with a professor and a graduate student. Of course, we have a lot of graduate students. Then, there's the SURF program, where we have literally hundreds of students from Caltech and other universities working at JPL to help us with our research. I sent around an email to people in my Section about a year ago, where I asked them, "How many papers have you written in the last five years with student coauthors?" I expected maybe I'd get a dozen. I got 105. And these are just the ones who responded. There are probably others who didn't get around to answering my email. 105 papers with student coauthors, largely from Caltech, over just the last five years. The collaborations are really pretty immense.

ZIERLER: Now, can you serve on graduate committees? Can you teach courses? How does that work with Caltech?

BURATTI: Yeah, you can. In fact, there used to be a visiting position down there. Bruce Murray asked me to teach some of his classes. There are some people who have joint appointments and teach classes. You can also serve on graduate committees, and we have a program at JPL where graduate students can come on, so yes to all those things.

ZIERLER: A very current question, one we're all dealing with. How has work been from home over this seemingly unending pandemic? In what ways has it allowed you to focus more on projects that might've otherwise been a bit neglected, and in what ways is it difficult not being physically with your colleagues?

BURATTI: I think the last thing you mentioned, that you're not physically with your colleagues, is hard because a lot of ideas are just these conversations in the hallway, where you say, "Hey, have you thought of this?" Or you walk into somebody's office and say, "I want to run this idea by you. What do you think of this? Is it crazy?" Those sorts of interactions. There are two other things that I have found as a manager. First of all, there's an administrative load with COVID. Things like informing your groups and people about what's going on. For a while we had to get permission to go into the lab. Now, you have to get permission, but it's all automated. Also, I've noticed there's this huge amount of burnout. I think that people are sick of this, and I've just noticed that people are not stepping up to do stuff because they're overwhelmed. It's been really tough on people. A couple people have really cratered. A couple people had to move home to live with their parents. The ones who did that, it actually worked out all right. There's a lot of suffering. I see it as a manager.

ZIERLER: Perhaps in happier times, Bonnie, let's take it all the way back to the beginning. Let's start, first, with your parents. Tell me a little bit about them.

BURATTI: My dad was an industrial engineer who worked for Bethlehem Steel. I'm a proud native of Pennsylvania. I was born in the armpit of the Rust Belt, Bethlehem. My mother was primarily a homemaker, but she did some work teaching physical education and that sort of thing. They were both college graduates, which back then was kind of unusual. My mother graduated from the University of Wisconsin, my dad from Rutgers, which is the state university of New Jersey. I would say they're middle-class, working-class people, upwardly mobile. The thing I most appreciate them is that they really put a high value on education.

That was the number-one thing in our family, we constantly were reminded they sacrificed for our education. [Laugh] My brother and sister are both college graduates. I got a PhD, my sister has a master's degree. My mother said that her grandfather told her, "Nobody can ever take your education away. It's something you have that is with you forever." And it's so true. As my brother used to say in another way, there's no cure for stupid. [Laugh] It's kind of the same idea. He was a newspaper reporter, so he had all sorts of pithy expressions. He's still alive. My parents have both passed away, but they instilled a lot of values in me that I think are lasting. I'm grateful for that.

ZIERLER: Were you always interested in science? And as a girl, were you encouraged in those directions?

BURATTI: I was always interested. As a little kid, I loved to tinker and build stuff, always built my brother's erector sets. He wasn't interested, but I was. And I always wanted to work on the car with my dad. But quite frankly, girls didn't do that stuff back then. I had to take home economics, I couldn't take shop. I wouldn't say I was encouraged. But later on, my parents did kind of encourage me a little. It just wasn't acceptable back then. It was unfeminine or something. But I persisted.

ZIERLER: Were you paying attention to the space race, the Apollo mission?

BURATTI: Oh, yeah. I was definitely a child of Sputnik, no doubt about that. I still remember the day in 1965 when Mariner IV took its first pictures of Mars. I was really captivated. Of course, I was reading science fiction, too. I was really fascinated by Mars, life on Mars. Seeing those first images from Mariner IV that basically showed a cratered world, I remember being so disappointed in seeing that.

ZIERLER: What were you hoping for?

BURATTI: Oh, forests, something verdant. We knew that didn't exist, but there's always that fantasy. As an undergraduate, I went to MIT.

From Pennsylvania to MIT

ZIERLER: Were you tops in your class to have gotten into MIT?

BURATTI: I was close. My school did not have class rank. Pennsylvania is, I think, kind of based on the Quaker philosophy. We didn't have gifted programs or class rank. I don't know if I was in the upper, but I was definitely upper 10%.

ZIERLER: With MIT, did you specifically know you wanted a more science and technology kind of education?

BURATTI: Yeah, I wanted a more science and technology education, but I also wanted a school that was good in liberal arts because I was really also into that as well, not just interested in science. By the way, Caltech didn't take girls back then, so I couldn't have applied. I picked MIT because it was really good in science, but it also was really good in languages. You could take Russian, cross-register at Harvard and take some exotic language if you wanted to. I also visited it and liked the culture, felt like I fit in really well.

ZIERLER: What year did you arrive in Cambridge?

BURATTI: 1970.

ZIERLER: The 60s were going pretty strong at that point still.

BURATTI: Yeah, there were a lot of student protests, which I was involved in, a lot of antiwar activities, antiwar research. I remember there was a Save the Whales initiative, a lot of socially conscious stuff. Student anti-Apartheid movements. It was very active politically at that time. I remember the day that J. Edgar Hoover died in 1972, spontaneously, on the great court of MIT, a pot party erupted. Every year on the day that J. Edgar Hoover died, there was always a smoke-in on the great court until one day, the school administration said, "You've got to stop, students," so it stopped. But for several years, this continued.

ZIERLER: How many women were in the science classes with you at MIT?

BURATTI: When I first enrolled, my class was only about 10% women. And it did vary upon the major. You'd see more women in certain majors such as biology. Engineering had the lowest number of women. Women tend to gravitate to areas they see other women. By the time I graduated, the incoming freshman class was about 25%, and it's close to half now. It gradually went up.

ZIERLER: That department, was it part of physics, or it was its own department, Earth and Planetary Sciences?

BURATTI: It was its own department. Now, it's called Earth, Planetary, and Atmospheric Sciences. EAPS. atmospheres.

ZIERLER: What were some of the courses or professors that inspired you to focus on this program in particular?

BURATTI: I had a bunch of charismatic professors. There was Bill Pinson who taught astronomy, Chuck Counselman, who taught celestial dynamics, and Irwin Shapiro, who was very encouraging as a mentor. I also had Ray Weiss. You have to take a lab. I took physics lab, which was really hard, but Ray Weiss was my professor, and he was just awesome. He's won the Nobel Prize. He came by and visited me in my office at JPL a couple times to see how I was doing. All these things he said about error analysis and plotting your data as you get it still echo in my head. He's really a character.

ZIERLER: Was there a senior thesis or any lab work that was really important for you?

BURATTI: I did research at that time. In the summer, I worked at an MIT spinoff called American Science and Engineering. It was put together, I think, by two MIT professors and an MIT grad. I did research on x-ray astronomy over the summer, and I also did some observing at Wallace Observatory. I did a little bit of work for Tom McCord, who was another great mentor, and I took his planetary astronomy course He was a professor at MIT, and I still work with him, hosting him at JPL as a Distinguished Visiting Scientist.

ZIERLER: What kinds of graduate programs were you interested in applying to, and what kind of advice might you have gotten about that?

BURATTI: I knew I wanted to do astronomy, so I applied to various schools. The number-one thing I wanted to do was apply to a program that was very broad because I wasn't sure what field I wanted to go into. The program also had to have planetary astronomy in the astronomy department rather than the geology department. Because geology kind of scared me. I was scared of field work, first of all. It was all these big beer-drinking guys in flannel shirts, lots of terminology. I wanted to take it from an astronomy point of view, so that basically meant Cornell because they have a very broad program, and they had all these larger-than-life people there: Tommy Gold, Carl Sagan, Frank Drake. That's where I decided to go to graduate school.

ZIERLER: Cornell was considered a real leader at this point.

BURATTI: Yes, it was. It leading physics and astronomy departments. The astronomy department split off, I think, due to some political disagreement before I got there, a turf thing. But it was closely allied with the physics department and was great in so many areas: infrared astronomy, planetary astronomy, radar astronomy - it was big in that with Frank Drake - and astrophysics.

Carl Sagan and Planetary Science

ZIERLER: Did you have a good sense of who you wanted to work with who would be your graduate advisor, even before you got to Cornell?

BURATTI: No, I was totally open to it. I got assigned to Carl Sagan because he was a planetary astronomer, and he was my first advisor. Of course, he's a fount of ideas. But the problem was, I felt I needed more supervision. I was a teaching assistant for Joe Veverka, who was another planetary astronomer. I really liked his style. I switched over to him and did my thesis with him. He retired a few years ago from Cornell.

ZIERLER: What was Carl Sagan like? Was he so famous and such a media figure at this point that it was hard to engage with him? Was he available?

BURATTI: He was available if you needed him. I have a funny story to tell. This was when he was putting his TV program, Cosmos, together. I was supposed to meet him at some point, and he kept putting it off and putting it off. Finally, we were going to meet on Memorial Day. I said, "I'm going to be in Toronto on Memorial Day." He said, "That's OK, I'll call you." He was supposed to call me but got delayed, and delayed, and delayed. Finally, I received a call from him while I was in the Toronto Zoo on a payphone. That was my meeting with Carl Sagan. He really pointed students in the right direction, had a lot of good ideas, was really an awesome scientist, but I needed more day-to-day supervision, which Joe Veverka was really able to provide. My first meeting with him, he produced an outline of my thesis. He gave that kind of guidance, which I needed. Some people, like Chris Chyba and Pascal Lee, students who came after me, were able to work successfully with Carl because they were so much more independent than I was.

ZIERLER: Why do you think that was? Your style was you needed closer mentorship?

BURATTI: Yeah. I just wasn't as mature. I needed to be walked through a research project from beginning to end to be able to be independent, whereas some students come into graduate school and seem to know how to do that already.

ZIERLER: How did you square that circle? What was the solution for you then?

BURATTI: I think Joe Veverka simply walked me through my project. We would meet every week, he told me exactly what to do, he set out problems for me, basically had me outline my thesis and write little parts.

ZIERLER: What was his research at that point?

BURATTI: He was on the Voyager team, and he was doing a lot of work on the photometric properties, of the moons of the outer giant planets, which became my area of expertise. But he was also doing a little bit of work on Mars concerning eolain dust-borne processes. He was ending that as well as ground-based observations. He used to observe at Mauna Kea, but he got out of that altogether and focused entirely on spacecraft observations.

ZIERLER: What was the project that he envisioned for you? What ultimately became your thesis research?

BURATTI: It was photometric properties of Europa and the icy satellites of Saturn. It was basically looking at Voyager data and figuring out how these objects scattered light, what that told us about their surfaces, the morphology of the surface, and their evolution.

ZIERLER: How would the data come to you?

BURATTI: Since he was a team member, he had immediate access to the data. It was downloaded from the DSN, the Deep Space Network, and put on a computer at Cornell that I could access.

ZIERLER: Were there any theories at this point that served as a guidepost for the way to analyze all of this data?

BURATTI: Not really. I think my thesis showed that some of these icy objects have unusual textures. This was one of the first clues that gave us a hint that Europa was an unusual world, an ocean world. Later on, Galileo, based on magnetic properties, discovered a subsurface ocean. But my thesis showed that its texture was very unusual, maybe plume deposits or outgassing of some sort. It gave me the first hint, I think, that this was a unique world that needed to be explored further.

ZIERLER: What were some of the conclusions of your thesis?

BURATTI: That was one of them. The other major conclusion was, I looked at an object called Enceladus, which is another ocean world, a moon of Saturn. There are areas on the moon that that are very old based on counting the number of craters, but there are also relatively recent areas based on the fact that there are no craters. I found that the moon is totally coated with this layer of essentially freshly fallen snow.. That was one of the first hints that there was activity on this moon. Of course, Cassini discovered that there's a gigantic geyser-like structure on the south pole. That was the reason for this coating. But this work I did in my thesis was one of the first hints that there's activity on Enceladus, outgassing, layering on the surface by ejected ice particles from this volcano.

ZIERLER: What kind of excitement was there at this point about finding life in some of these sea worlds?

BURATTI: I remember Steve Squyres was also one of Joe's students, and I worked a lot with him. He was the first one who mentioned that Europa might be habitable. It was at a meeting, I think a Division of Planetary Sciences meeting around 1985 or ‘85. He got up and said, "Look, Europa probably has an ocean underneath." We didn't know it at the time. The theoretical models suggested it. It was only Galileo that answered that question for sure. "There's some source of heat, otherwise it wouldn't be liquid. And there's some sort of probably biotic material down there. Why not life? Maybe there's some kind of primitive bacterial stuff there." He did mention the work that I did suggesting there was outgassing activity on Europa. Since then, this whole idea of habitable worlds in ocean worlds has really taken off.

The other thing that happened at the same time that led us to believe in life on ocean worlds was that our ideas on how life evolved on earth were also evolving. When I was in graduate school, it was the Miller-Urey Experiment, where you had this shallow sea zapped by lightning, and voila, there were these amino acids. It hand-waving. Later on, by the time I graduated from graduate school, the canonical explanation, which is accepted by the majority or not all scientists, is that these thermal vents in the deep oceans, sometimes called smokers, are teeming with primitive bacteria. Similar structures may exist on the floors of these ocean worlds and may be the habitable zones where life arises on these bodies.

ZIERLER: Because you can't prove a negative, just to fast forward to today, how much more advanced are we in our knowledge of the possibility of life in these ocean worlds?

BURATTI: Not a whole lot. In fact, scientists have moved away from talking about life's origins to speaking about habitable zones. I know that a lot of people, including my colleagues at JPL, people in my section, like Laurie Barge, are looking at the chemical gradients and environments of these thermal vents, trying to figure out how they could lead to life arising. There's some of that, but we're more focusing on searching for habitable zones and areas rather than trying to explain how life rose because we just don't really know.

ZIERLER: What about missions beyond Voyager to these similar places? What were the prospects at that point?

BURATTI: Cassini, of course, was the follow-on to Voyager. I got involved in that pretty early, both as a team member of the Visual Infrared Mapping Spectrometer and as the lead for the icy satellite fly-bys, leading the team to plan these events. There was Galileo also, which was before Cassini, for which the high-gain antenna never deployed, so the data rate was pretty low. It was only a fraction of what we expected. But it still discovered a liquid mantle on Europa, which led to this idea of the ocean world being developed even further. Then, Cassini, of course, discovered the plumes, the geysers on Europa as well as a whole lot of other mysterious stuff we still don't understand. One thing I find intriguing is, my colleague, Paul Schenk, found these strange reddish streaks on Tethys, and we're just not sure what they are. It looks like maybe outgassing of organic materials from possibly an ocean below the surface. Then, Europa Clipper is the next mission to be launched in a few years, which will go back to Europa and try to explore it in detail.

ZIERLER: Was JPL on your radar even as a graduate student? Did you think about this being a possibly great place to work and build a career?

BURATTI: Yeah, because my advisor, Joe Veverka, and Carl Sagan, too, spent a lot of time at JPL. They were always going there, going to Voyager team meetings, meeting people from JPL, so it was on my radar.

ZIERLER: Were you thinking about academic positions as well, being a professor of astronomy?

BURATTI: I was. I think that was my preferred path. And I did actually get some offers, but I just felt that JPL offered a lot more freedom to explore. You can also educate, you can have students at JPL. I think it was one or the other, but I ended up staying at JPL.

ZIERLER: The initial appointment there as a resident research associate, was that basically JPL's version of a post-doc?

BURATTI: Yeah. In fact, that was a post-doc position that was funded by NASA. It's now called the NASA Postdoctoral Program. You weren't a JPL employee; you were an affiliate employee.

ZIERLER: It was the National Research Council. Was that who funded the program?

BURATTI: It was actually funded by NASA. The NRC may have kicked in a little bit of money, but they're the ones who did the selection. You had to write a proposal, then get selected by peer review. The National Research Council, which is part of the National Academy of Sciences, ran it back then, but now a consortium that runs it.

ZIERLER: Do you have a clear memory of your first impression when you arrived at JPL?

BURATTI: Yeah. I was just totally overwhelmed. A university is kind of small, you're a member of your department, and you know everybody, but JPL was just so immense. It's mainly non-science, engineering, technology, administrative. I just found it completely overwhelming.

ZIERLER: Did you have a clear idea of what you wanted to work on? How much latitude did you have to choose your own projects?

BURATTI: Well, I was working with Torrence Johnson. He was my advisor. I had a specific project to do with him, which was to come up with a better calibration for the Voyager cameras, and I did do that. But he was really good in letting me do pretty much whatever I wanted to do. I was able to, first of all, make sure all the papers for my thesis were written. I hadn't finished all my papers. Then, I collaborated with a bunch of other people, did some observing, and some other research projects. You were pretty free to do what you wanted to do as a post-doc.

ZIERLER: What was the process like transitioning from post-doc to a full-time member of JPL?

BURATTI: First of all, you had to make sure that A, it was a good fit for you, and B, that people at JPL wanted to include you on the staff. After I made sure that both those were true, it had to be an open competition, so I had to actually apply for a job. But you know how these jobs are, it's kind of wired because no one else has the expertise of the job you're applying for, which is your job. And we still do that today. That's the bad news. The good news is, sometimes people apply for the job you want to hire anyway. There have been situations where we've put in a job for someone, but this other great person applies, and we hire them, too. It's not totally bogus.

ZIERLER: In the mid-1980s, what were the big missions at JPL? What were you working on at that point?

BURATTI: Voyager was still going strong, and I was working on it. The last encounter was in 1989 at Neptune, so I was mainly working on that. And then, Galileo came along, and I wasn't involved in that. Not sure why, just the timing was off. Cassini was the next big mission, but I was involved in a lot of little missions along the way, mainly to asteroids and comets.

ZIERLER: Were you involved even from the beginning of really conceptualizing what the missions would be? In other words, was there a culture at JPL where seniority was not so important, and when good ideas happened, even from junior people, it was appreciated, you could move on that?

BURATTI: Yeah, I think you've put it very well. I wasn't involved from the beginning of Voyager, but for Cassini, I was. I was involved formulating a lot of the ideas about scientific strategy, what we should observe. The instruments are usually thought out before the mission is selected. There's not a whole lot of input there. But putting specific requirements on the instruments is there. The place we're able to truly be creative was on the mission design: how many times we should fly by the moons, how close we should get, what we should look at. All those questions are things that were really in the hands of the scientists. By then, I was a mid-career person, but we had a lot of input from junior people as well as seasoned people.

ZIERLER: Obviously, it's a different part of NASA, but the Challenger disaster in 1986, what impact did that have at JPL?

BURATTI: I think the major impact was that we couldn't launch Galileo on the Space Shuttle. Because of that, we had to totally redesign the mission. If you launched on the Space Shuttle, you could move directly to Jupiter. Instead, we had to do this convoluted orbiting around the inner solar system, a VEEGA (Venus-Earth-Earth Gravity Assist) trajectory, involving a gravity assist from Venus and then twice at Earth, which flings you out to Jupiter. I think that was the major effect. Of course, we were just devastated by the whole tragedy, that's the first thing. As I recall, there was a safety issue because there was a lot of fuel in the fuel cells of Galileo, so it couldn't be safely put in the bay area of the Shuttle. We had to launch it on an expendable rocket.

ZIERLER: When did the first discussions that would lead to Cassini happen?

BURATTI: I wasn't involved in those. I came in later than that. But I think it was really back in the late 80s, even while Voyager was still going on, when the first science working groups were put together.

ZIERLER: What were some of the main scientific objectives of Cassini?

BURATTI: The main objectives were to understand the composition of the moons, to understand the size, rotation state, weather, and dynamics on Saturn, to understand the ring structure and its dynamics, the interactions between the rings and the inner moons, to discover new moons, which Cassini did, and also to understand the origin of the dark material on Iapetus. This is a strange moon of Saturn, where one side is literally as black as coal tar, and the other side is, like bright ice. It's now pretty well established that the low albedo, the dark material, is very rich in organics. In fact, this might be the prebiotic material that was brought to the Earth on comets. That was one of the major questions, the origin and makeup of this mysterious dark material in the outer solar system.

ZIERLER: When did you actually get involved yourself?

BURATTI: I think I got involved in the early 90s.

ZIERLER: Did you contribute at all to Magellan?

BURATTI: No, that was radar. That was Venus. That's outside of my wheelhouse because A, it's radar, and B, it's a terrestrial planet. Mercury, Venus, Mars, Earth, sometimes the Moon are the terrestrial planets. I've done some work on the Moon, and I was on the Mars Observer team, but my instrument was canceled. Of course, later, the mission failed, so maybe it was a blessing in disguise, I was also on another mission that got canceled. That's something I should bring up. I had a lot of disappointments early in my career. One was the Comet Rendezvous Asteroid Flyby (CRAF), I was selected for the imaging team on that mission, and it got canceled, and then I was on the Visual Infrared Mapping Spectrometer team of Mars Observer, and the instrument was deleted from the payload. Two of my early missions got canceled, but I followed what my mentor, Joe Veverka taught: just press on regardless. Whatever you've learned from these failures, just keep on, never give up. That's what I did.

ZIERLER: When did you get on a path of managerial responsibilities? When did that start in your career?

BURATTI: I was a group supervisor for about ten years, and I never really consciously went on a managerial path. The position of section manager came up, and it is a service job. I felt I should serve, at least for some portion of my career at JPL because JPL's been good to me, so I should give back. That's basically what I decided. It wasn't a conscious decision. I think probably pretty soon, I'm going to look for something back in the technical arena. I've been section manager for three and a half years, and I think three to four years is the ideal amount of time.

ZIERLER: The idea is that there's a set amount of time to do your service, then you can go back to the research more.

BURATTI: That's the way I feel. A lot of people do go into it as a career, but I can't see that, really.

ZIERLER: Is JPL small enough so that when there's a change of leadership, like Ed Stone in the 1990s and Charles Elachi in the new century, did you feel those changes at your level?

BURATTI: Absolutely, yes. Each director has kind of a culture that they bring to the lab. I think that that has happened each time we get a new director. As I said before, I'm really looking forward to some diversity. Inclusion, equity, and diversity are important, and I do hope the new director–and I think he or she will because Tom Rosenbaum spoke to JPL employees about his vision for the director, and he mentioned that specifically. I think that's one thing that will be very welcome in the culture. And there are other things, like effectiveness at interacting with the eastern power establishment, and I think that's really essential because as I said before, we need to capture future missions, , and that is going to involve some discussions. I'm pretty positive about what's coming up.

ZIERLER: Tell me about the VIMS instrument on Cassini. How did that get started?

BURATTI: Actually, I was on the original Mars Observer VIMS, Visual Infrared Mapping Spectrometer team. As I said, the instrument got deselected. Then, it reappeared on Cassini. It is an instrument for obtaining the spectra of moons, Saturn, and the rings between 0.35 and 5.2 microns. It's got three octaves of spectral range, and it's medium resolution.,. I think it was 11 to 6 nanometers if I remember correctly. I led the team that discovered carbon dioxide on Iapetus, this strange moon. Other members of the team, Roger Clark, Dale Cruikshank and the Team Lead Bob Brown discovered organic materials. We're not sure whether we discovered ammonia. That's still up in the air.

But we did identify polycyclic aromatic hydrocarbons (PAHS), which are complex organic molecules, in some of this dark material. We also drew a connection between the inner moons of Saturn and the rings. Also, discovered a bunch of organic prebiotic material in addition to PAHs. We looked at water ice and contaminants on Enceladus, and detected some organic materials in the plume. It really was an incredibly powerful instrument. It was so sad to see Cassini's entry into Saturn at the end of the mission. I had this fantasy of, "Maybe our little instrument will survive." Saturn doesn't really have a surface, but, "Maybe it'll kind of just stay there." But it's all disintegrated now.

ZIERLER: The discovery of carbon dioxide, what questions did that resolve, and what new questions did it raise?

BURATTI: It gave an indication of the temperature conditions. You only get it when it's really cold. It did suggest that Iapetus formed in this cold region of the solar system, probably in place. The spectral line that indicates it is carbon dioxide seemed to be switched a little bit, so it looked like it was combined with maybe organic materials, showing that it might act as a substrate for causing organics to become more complex. It seems to combine with other molecules. Subsequent to that, we actually found carbon dioxide on all the moons we were able to see it on. Some of the moons, we weren't able to detect it because we didn't get close enough or couldn't get accurate enough signal. It seems to be ubiquitous on these moons' surfaces, which we didn't really expect.

ZIERLER: Finding carbon dioxide and seeing also that there are organic materials, how much of a leap is it to saying that there might be plant life that would be respirating this carbon dioxide?

BURATTI: I think that's a pretty big leap because first of all, it's solid CO2, ice, not a gas. But if we're looking at life, I think we'd have to look at primitive life in a subsurface ocean. That's probably where it exists. I think plant life as we know it–it's just too inclement. It's cold, there's no atmosphere, none of the things that we associate with plant life on the Earth are there. The CO2 there is probably not biotic, it came out of the cloud of dust and gas from which the planets formed and combined with other chemicals.

ZIERLER: Is there any collaboration with the European Space Agency on Cassini?

BURATTI: A lot. There was a lot. The Europeans built the antenna. In fact, on our instrument, VIMS, they built the visible channel. We had numerous European members on our team.

ZIERLER: The European members mostly traveled to JPL? Did you ever go to Europe for this work?

BURATTI: We switched on and off. We had team meetings in Italy and in France. I think we met in England once. But we had quite a few team meetings in Europe. The other thing is, we had not only VIMS meetings, but we had project science group meetings where the whole project got together. We had two in the US and one every year in Europe.

New Horizons and the Deep Space Network

ZIERLER: Tell me about the origins of the New Horizons probe. Were you there for the beginning of that?

BURATTI: Yeah. That has a colorful origin. And Alan Stern, who's the PI of that mission, gives this dramatic little talk on its origins. Actually, JPL and Applied Physics Lab were in competition for capturing that mission. I wasn't actually on either team at the beginning. Then, after APL won the competition, Alan Stern put me on his team right away. He realized he couldn't ask me to be on the team at first because JPL was competing. But it's not a Cadillac mission, it's, like, the second tier of NASA missions called New Frontiers, which are billion-dollar missions, between $1 and $1.5 billion.

ZIERLER: Is this part of the Faster, Better, Cheaper framework?

BURATTI: Yeah. That's, in fact, how it started. Rob Staehle, who was a JPL employee, had a discussion with the director of NASA at the time, the administrator of NASA, whose name was Dan Goldin, and talked about Faster, Better, Cheaper. Rob convinced him we could go to Pluto for cheap. NASA decided to have this competition because it was the only planet that we hadn't visited. There was a competition, and APL won out, developed a mission, and has really done a good job at it. It was the first time they'd done a mission of this size. They've since captured Dragonfly, which is a mission to Titan and also has JPL people on the team. But New Horizons was their first opportunity to show that they could do an outer solar system mission.

ZIERLER: What were some of the technical challenges from the beginning with New Horizons?

BURATTI: First, of course, is power. You have to have nuclear power, an RTG, a radioisotope thermoelectric generator. They decay with time and trying to fit your instrument payload into the constraints of a small energy source is the first technical challenge. The second technical challenge is data volume and data rate. You have to send all this data through space, so you have to use smart ways to narrow it down–you can't use the Deep Space Network (DSN) all the time. You can either compress the data or take less data. Here's a big challenge that came up. Before, when we launched, there was one moon of Pluto, but there were other moons that were discovered later. It looked like there might be a lot of small moons and debris. The question was, are we going to get hit by that debris? Was the spacecraft going to get hit? Mark Showalter came in and did all this dynamical. We finally decided it wasn't a problem, but that was one of the challenging things.

ZIERLER: In what ways was the competition between APL and JPL good for the mission?

BURATTI: I think both teams presented really good proposals. They were both really honorable missions. I think in the case of APL, they knew they had to succeed and do well because this was the first time they were doing a mission of this sort.

ZIERLER: And for JPL, what was good for them having the competition?

BURATTI: I remember there was a lot of bitterness that APL had been selected, to be honest.

ZIERLER: But you remained involved.

BURATTI: Well, yeah, I wasn't involved in either team at the beginning, but shortly after selection, I became a member of the APL team.

ZIERLER: What was that like, working for the other team, so to speak?

BURATTI: I knew all the people. I had worked with Alan Stern, the PI, on a bunch of other stuff, and I knew all the people on the team. In fact, some of them, I had worked with on Cassini, so it really wasn't a problem. We all knew each other.

ZIERLER: What were some of the major research questions that New Horizons was designed to answer?

BURATTI: The first one, really always the big question, what does it look like, and what is it made of? By the way, New Horizons discovered water ice on Pluto. It wasn't discovered before the mission, from the ground. Water is kind of like rock that far out in the solar system. It's so cold, it's frozen solid. All this methane and nitrogen were overlaying the water ice, so you couldn't really see it from Earth, but there were small patches of water ice that New Horizons discovered. The composition is important, but the main thing was morphology. No one expected that the heart of Pluto is a series of glaciers. We haven't seen anything like that before or since. We wanted to see if there were any more moons, if it had rings. We didn't find either. Again, we wanted to know the identity and makeup of this dark material that exists in some patches on Pluto. Again, we found it was very rich in organics. We also tried to understand some of the unusual terrains we discovered on Pluto.

There's one we called the washboard terrain, which we think is composed of these odd structures. On Earth, they're called penitentes, which is Spanish for praying figure. They are spires of ice that form in aa process of sublimation. We also discovered what really looks like an extinct ice volcano, Wright Mons. Then, of course, Charon, the main moon of Pluto, what an oddball that is. I'd say it's about as weird as we expected Pluto to be. It looks like half of it melted and the other half didn't. You can see little pieces of terrain that broke away from the part that didn't melt. It's really interesting. Just an amazing mission.

ZIERLER: What kind of temperatures did New Horizons have to contend with that far out in the solar system?

BURATTI: It's around 40 Kelvins. That's about -400 in Fahrenheit. Pluto has always held a special place in the hearts of the children of the world. Children were really disappointed that it got demoted. I remember having this discussion with my brother about how long it would take you to die if you were standing on Pluto if you were bundled up. We decided it would take about five seconds. We had that discussion. It's pretty cold out there.

ZIERLER: This humorous controversy about Pluto being demoted as the ninth planet, in what ways did New Horizon contribute to those debates?

BURATTI: I think we showed it's a planet. First of all, it has five moons, which weren't discovered by New Horizons. But it's got active geology, it has an atmosphere that changes with the seasons. I personally think it's a planet. In some sense, it doesn't matter what you call it, and we're not obsessed with this, but this thing about it not clearing its orbit, I personally think it's kind of absurd. Has Earth cleared its orbit? There are all these near-Earth asteroids in our vicinity. Clearing its orbit doesn't really mean that much.

ZIERLER: What about size in the way that some people say there are other objects in the solar system that are larger than Pluto, and they're not planets, so why should Pluto be?

BURATTI: Because Pluto orbits the sun. The things that are larger, and I think they're referring to Ganymede and other planetary moons, don't orbit the sun, so they can't be planets. But Pluto does orbit the sun, and it the biggest Kuiper Belt object at least that we've discovered so far.

ZIERLER: For you, the primary characteristic is, it has to orbit the sun.

BURATTI: The three things the International Astronomical Union, which demoted Pluto as a planet, said were: it has to be round, it has to orbit the sun, and it has to clear its orbit. I would say those first two are valid. But this idea about clearing its orbit, I think, is bogus. It's kind of a dynamical definition that doesn't have to do with the planet-ness of something.

ZIERLER: Are you a diehard? Do you support these campaigns to re-promote Pluto to becoming a planet?

BURATTI: The New York Times had a thing today where we were supposed to vote, and I voted for planethood. I would say that I'm not really pushing it, but whenever I'm asked about it, I do say I think we should reinstate it as a planet.

ZIERLER: After New Horizons, what was the next big project for you?

BURATTI: I got involved in NEO Surveyor, which is a telescope that's going to look for more potentially hazardous asteroids. Amy Mainzer is the head of that. Actually, it's going to look for small asteroids down to 140 meters in size. It's going to try to discover about 90% of those. I also worked on this Discovery mission, a small mission called Dawn at Vesta. It visited two asteroids, Vesta and Ceres. I was on the Vesta team.

ZIERLER: With the asteroid work, I can't help but ask, have you had a chance to see Don't Look Up?

BURATTI: I haven't seen it yet. I just haven't had time. Everybody tells me I should watch it. By the way, Amy Mainzer was a technical advisor on that.

ZIERLER: You should definitely check it out, I'd be curious to hear what you think about it. On that point, are there asteroids out there that are of concern right now? What's some of the science that will allow us to adequately prepare for something that might be a danger to us?

BURATTI: There isn't anything that we know of that's projected to hit Earth. There's no immediate danger.

ZIERLER: How do you define immediate? How many years out can you go?

BURATTI: Hundreds of years. Maybe some of them, a thousand. Sometimes it's hard to go out that far because you're not sure of perturbations and things like that. But I would say hundreds of years. There is one, Apophis, that was a concern for a while, but that's been retired. It's going to get about 20,000 miles to Earth, and scientists are gearing up to study it. What do we have to know about asteroids? There are two things. First of all, we have to know the structure of the surface to see how we would attack it. We have to know how fluffy it is, how rough it is. Also, what it's made of because you can tell how friable it is by what it's made of. Understanding the asteroid is the first part. The second part is what we call mitigation.

How are we going to deflect or crush this asteroid? I'm actually involved in another mission now, a participating scientist on DART, Double Asteroid Redirection Test, which is going to go to this binary Earth-approaching asteroid, Didymos and Dimorphos are the names of the primary and companion, crash into the smaller asteroid to see how much it deflects the orbit of the pair. That's one method to impact it. Another method is the gravity tractor, which is to put a mass such as a spacecraft near it and f try to nudge it out of its orbit. Then, there are nuclear weapons, which is a problem because nuclear weapons have been banned from space. Of course, if they're there to save the world, maybe it's OK. But if you have some imminent danger, how are you going to direct that asteroid away from the path towards Earth in time?

Keeping an Open Mind on Life Beyond Earth

ZIERLER: I'm curious if you were following the excitement around Oumuamua a few years ago.

BURATTI: Yeah, I definitely did. Really interested in this idea that Avi Loeb has that it is an extraterrestrial vehicle. First of all, let me say that I think it's OK that he's come out with this idea because this is what drives science. When you have an idea where you're kind of going out on a limb, then other people do work to dispute it. It's not impossible. It's not the likeliest explanation for its accelerating orbit. It could be outgassing, which it probably is because it's coming in from a cold place to a warmer place, so any gasses are going to sublimate. That's probably what's happening. But it's incredibly interesting that something from outside our solar system that is that unusual would come in to visit us.

ZIERLER: Do you buy Avi Loeb's argument that Oumuamua did not have characteristics of either a comet or an asteroid?

BURATTI: I don't think that is exactly right. It's different from anything we've seen in our solar system, but it extends what we've seen. The strange shape–it could be a shard of an asteroid or planet where you've just seeing the crust, for example. We know it came from outside the solar system, but outgassing is the Occam's Razor simplest explanation for its odd orbit.

ZIERLER: On a philosophical level, wouldn't it stand to reason that if this is an alien spacecraft, and it came so close to us, why not get a little closer?

BURATTI: I think the reason is because it's gone away. You have this event that's happened, and you have to grab it while you can.

ZIERLER: I meant from the aliens' perspective. If they took all of this trouble to get so close, why not get a little closer?

BURATTI: That's a good point. I hadn't thought about that. I'd say that might be an argument against it being an alien. But they also might be circumspect, that we might send out some nuclear weapons or something. Human beings are pretty crazy.

ZIERLER: Oumuamua or not, if you were a betting person, do you think there's life out there?

BURATTI: I don't know. Science is based on facts and observations, and there's no evidence that there is life elsewhere, but that doesn't mean I don't believe it's there. I just don't know. I have no idea, really.

ZIERLER: Have there been portions of your career where you felt strongly one way or the other based on what you were or were not seeing?

BURATTI: I would say I've always had an open mind. When I was at Cornell, I was fed a steady diet from Frank Drake and Carl Sagan, kind of the fathers of the field of extraterrestrial life, and I then definitely believed the universe was teeming with life. But one book that has shaped my thinking is Rare Earth by Don Brownlee and Peter Ward, which said bacterial life may be common in the universe, but intelligent life is practically nonexistent. Their argument was based on the fact that all the improbable things that make the Earth habitable, clement, non-destructive are so unlikely to happen anywhere that life such as us is rare.

ZIERLER: With the search for exoplanets, do you think that framework will stand the test of history?

BURATTI: I think, again, the same questions arise. Here's this planet in the habitable zone, but how about all these other things? It doesn't have a moon. One of the things that Brownlee and Ward said is that you have to have a large moon because otherwise, the tilt is too great. The moon keeps us from tilting too much. If the tilt is too great, the seasonal changes are too extreme, so it wipes out life. You have to have a giant planet out there to suck in all the asteroids, otherwise there will be many more terrestrial planet-approaching asteroids that will destroy life if it arises on the planet. There are a bunch of other things like that. For example, a planet has to have enough radionuclides in its interior for plate tectonics to occur. Because if you don't have oceans, you're not going to have life arise. Basically, there are so many unlikely things about the Earth that it would be hard to find a planet where all these things occur. I think the same argument would still hold for all these exoplanets.

ZIERLER: Tell me how you got involved in the Rosetta mission.

BURATTI: That was actually through a tragedy. The NASA project scientist was Claudia Alexander, this amazing person, larger-than-life, and she passed away before her time, so I was asked to step in.

ZIERLER: What did they want to find out about the comet? What was the point of the mission?

BURATTI: It was mainly just to see how a comet, Churyumov-Gerasimenko, evolves through a perihelion, as it comes into the sun through one passage, what kinds of changes its surface goes through. The Rosetta mission was commanded by the European Space Agency, but NASA had two and a half instruments, and members of the science team. We watched interesting things like pieces of it breaking off, and lots of jets. There was one case, still haven't quite figured it out, where this boulder looked like it fell uphill a couple hundred feet. We also studied the water production, the gas production, and the composition. Glycine, which is an amino acid, was discovered on the surface of the comet.

ZIERLER: What was NASA's support from a funding perspective for Rosetta?

BURATTI: They supported an infrared instrument, a UV instrument, part of a mass spectrometer, and they supported members of the science teams of those and other instruments. They supported me. We started having team meetings in the US when I took over.

ZIERLER: On the service side, when you're elected to chair the division of Planetary Sciences for the AAS, what were some of the responsibilities you had in that role?

BURATTI: The main responsibility was to run meetings. The DPS has a meeting every year, and quite frankly, it's what the DPS is all about. I had to lead putting together that meeting and run it. There are other things, like leading an award committee. You have to deal with problems. That might be the hardest part. But mainly, it's running meetings.

ZIERLER: From that vantage point, what did you see more broadly as some of the key questions in the field in planetary science at that point?

BURATTI: I really think exoplanets. How many Earth-like planets are there? I think that is one of the big questions. Other big questions are basic things. How did the solar system form? What were the models for formation of e solar systems in general? I think the evolution, we know a little bit more about.

ZIERLER: To what extent does learning more about comets, such as the findings of the Rosetta mission, answer those questions about the origins of the solar system?

BURATTI: It tells us a lot. One of the major things is, it tells us the temperature in the early solar system was cold. That's good for forming organic molecules you need for the evolution of life. One of the things we found on Rosetta were e molecular oxygen and nitrogen. that can only form under really cold temperatures. This comet formed in the Kuiper Belt region, the outer solar system. We're pretty certain of that based on its orbit and dynamics. It must have been really cold there, and that was conducive to the formation of things like amino acids, which were later transported to the inner solar system by comets like Churyumov-Gerasimenko, the Rosetta comment.

ZIERLER: Tell me about the Worlds Fantastic, Worlds Familiar project? How did that get started, and what were your motivations?

BURATTI: I've always had an interest in humanities and outreach. Outreach is really important to me. And I've always wanted to write a popular book. The way to finally get started is to have a contract. You think about it, write a couple chapters. I finally met this guy with Cambridge University Press. I said, "I have this idea." He said, "Send me a couple chapters." He liked them. Once you've got the contract set up, you have to do it. And I want to write some more books, but I think the COVID pandemic has set me back for a while. I have some other book ideas.

ZIERLER: The conceit of the book, the notion of a guided tour, how did you come up with that?

BURATTI: I think my editor came up with that. I think it's kind of a common rubric or expression. I was thinking about the inferno, where Beatrice guides Dante through this tour of purgatory. I think that was an idea I had, actually. [Laugh]

ZIERLER: What were some of the most important things you wanted to convey about the solar system?

BURATTI: I wanted to convey not so much about the content because the book is non-inclusive. It doesn't go through everything in the solar system. It's to convey the enterprise of science. How do scientists discover? How do they operate on a day-to-day basis? People have a misconception of science; they think it's cut and dried. But a lot of it is tenuous, and a lot of the scientific methods is based on hunches.

ZIERLER: The book was so well-received. Was it fun for you when it came out, all the attention you got?

BURATTI: Yeah, I liked going to the book signings and things. Somebody from New York called me up and wanted me to go to the Harvard Club. I really did like it. But I do want to continue writing. That's one thing that's really important to me, and that's something that's stalled.

ZIERLER: A year later, you won the Carl Sagan Medal. Tell me about that.

BURATTI: That was really exciting because first of all, Carl was one of my mentors. We worked together, published a paper together. I think I won it mainly because I taught this teacher's workshop for about 20 years at JPL. I figure it touched 100,000 students. Finally, NASA stopped funding it, so I didn't do it anymore. Then, there was the book, and I like to do public speaking. I think it was a combination of things I've done in outreach that got me this award.

ZIERLER: Moving closer to the present, as you became more senior at JPL and served even in a mentor status to some younger scientists, first, what was interesting to them, a different generation who had decades of future in their career to think about?

BURATTI: First of all, I look at all the papers coming from the section, because as a manager, I have to approve them. The early and mid-career members of the section are sophisticated scientists, their software is so much more sophisticated, all the tools they use, it's way beyond anything I do now. That's one thing that's so impressive. They're also looking at big picture things. A lot of the section is doing work on astrobiology. They look at stuff like what happens if you put more of a certain chemical in a potentially habitable environment. Even though they're specific questions, they really relate to the big picture. You can see that they're working small, but thinking big. I don't think there was so much of that when I was developing my style. We tended to be more isolated. I think the questions now in planetary science about life, about exoplanets, the origin of life, are so much bigger so that when people are working, they connect to the whole much better. That's what I think the biggest change is. And the tools are so much more sophisticated.

ZIERLER: In terms of the sophistication of the tools, do you rely on the younger generation to do those measurements? Or do you make a special effort to stay current with all of the changing technologies?

BURATTI: I follow the academic model where most professors do very little hands-on work. They have graduate students and post-docs. I've more fallen into that model. Otherwise, you can't really conduct research. It's better because you give out all these plum ideas to people. I always keep a couple projects for myself, but mostly I've handed them off to post-docs and students.

ZIERLER: Moving to the future, for the last part of our talk, as you plan to step down from this service role and get back more to the research, what do you want to work on next?

BURATTI: I mentioned I'm on this DART mission, Double Asteroid Redirection Test. I would like to try to understand the changes that are made in the companion asteroid before and after it's blasted with the spacecraft. That's one thing I'm interested in. The other thing is the ice giants, trying to use the Palomar Observatory, the adaptive optics system up there, to understand cloud motions, weather systems, the evolution of Neptune and Uranus through one seasonal cycle. I think those are the two things I'll be working on.

ZIERLER: Some retrospective questions about your career. First, what stands out in your memory as simply having the most fun in science and astronomy?

BURATTI: Actually, to tell you the truth, it was this side project I did, where I and a student were looking at–this man in 1950, amateur astronomer Leon Stuart had observed this flash on the moon. The place where he saw this flash, we observed a fresh crater, so I and my student Lane Johnson wrote a paper on our analysis of this event. Boy, did that get a lot of press attention. I was even interviewed on CNN. It was pretty awesome. I think that was probably the most fun.

ZIERLER: Looking back at some of the fundamental questions going all the way back even to graduate school, what has been resolved in your field, and what remains out there, where the debates remain?

BURATTI: I think the whole question of life elsewhere and the origin of life is still there. We haven't made much progress. But for example, this dark material in the outer solar system I've mentioned - that is prebiotic and essential to the origins of life. We have a pretty good idea what that is made out of. We understand the composition of the moons of the outer planets a lot better than we did. We understand a little bit more about the solar system's origin, at least the conditions such as temperature. There are still competing models about how it formed. But I think those are the main things.

ZIERLER: How has JPL changed culturally over the years?

BURATTI: It's gotten much more formal. When I first came there, it was much more seat-of-the-pants and informal. But a lot of structures have been set up. And I think it's because everything's done on computers now, so you can ask people to do more stuff if they're going to do it by computer.

ZIERLER: What about the budgetary environment? What have been some of the ups and downs in terms of the support it's gotten from NASA?

BURATTI: It does go up and down. NASA isn't terribly political, but the flavor of each administration changes. For example, Obama was more favorable towards climate studies. Before that, I think the near-Earth, potentially hazardous asteroids crashing into Earth were a big factor. Now, the budget has really gone up. Part of it is the coattails with returning to the Moon, but people are supportive, the American public is supportive of NASA and the space program, so we've done pretty well, actually.

ZIERLER: In what ways has the privatization and commercialization of the space exploration through companies like SpaceX or Blue Origin changed JPL for the better or the worse?

BURATTI: The thing I see most is that they're poaching all our employees because they can pay much more. We're losing employees to these organizations. But on the positive side, having launch vehicles is good. Generally, the Air Force would supply our launch vehicles. Of course, the Saturn V was NASA's, but we usually rely on the Air Force. Now, SpaceX can provide them as well. The other thing is, space tourism is something NASA can't and wouldn't do. In terms of exploration and discovery, which is not profitable, that's something only NASA can do. But in terms of space tourism, that's something that SpaceX and Blue Origin would only be able to do. The other thing they're interested is mining. Resource utilization in space involves the mining of metals and rare earth elements on asteroids, and bring it back to earth. They're interested in that.

ZIERLER: What about Caltech's relationship with JPL over the years? How has that change?

BURATTI: I think it's been slightly strengthened because of programs that have been set up, for example, JROC, to collaborate with Caltech scientists. We have a lot of scientific collaborations in the labs on campus. I know many people in my section work down in John Eiler's lab on various things. We have a lot of Caltech grads in our section, and they still collaborate with their professors. If anything, I've seen the relationship strengthened. There are also some people who have dual appointments at Caltech and JPL.

ZIERLER: Finally, some questions looking to the future. If we do get out of COVID, and you feel like that's what will help you with your next book project, what do you want to work on next? What might your next book look like?

BURATTI: I think the book I'd like to write right now is one on Europa, how it's kind of a window to learning everything. That's the book you want to write, the golden notebook, where you get into everything. Also, I'd describe the missions that have explored it.

ZIERLER: Of all the things to write on, what's so compelling or special about Europa that it should receive this star treatment?

Europa is Weird

BURATTI: For me, it's the fact that it was the first weird object I looked at. Here was this moon that looked like a cracked egg. When Voyager went by it, it was the weirdest thing we'd seen. Of course, Io was also weird because it was spewing these sulfur volcanoes. Then, we found it had an ocean, and there may be life there.

ZIERLER: Just an imaginary question. Let's say this was a zero-sum game, and all of astronomy, all of NASA, all of JPL's resources, you had to choose between research within our solar system or research beyond our solar system. Given all that we've done within our solar system, does that tell you that it's more important to continue on that research path? Or have we done so much that if you had to be faced with the choice, we should look beyond our solar system?

BURATTI: I'm of the opinion that looking to exoplanets is the number-one thing we should be doing. If I were earlier in my career, I definitely would've gone into that field. Because there are billions of exoplanets. Just in our own Milky Way Galaxy, there are probably about 100 billion. There's just so much more out there. Exoplanets should be the center of our attention.

ZIERLER: Beyond searching for life, what else will enhanced research and knowledge of exoplanets tell us about earth, about the universe, about the fundamental questions in physics and astronomy?

BURATTI: I think by looking at the whole panoply of exoplanets, we can understand how solar systems form. We look at our own solar system, and it's hard to tell. But if you look at 100 solar systems, or 1,000, maybe we'll know more about how we formed, how the planets condensed, how they got larger, that fundamental question of where we came from. I think by looking at a lot of solar systems, we'll get a better handle on that.

ZIERLER: Based on what we know now, is your inclination more that our solar system is unique or not so much?

BURATTI: It's interesting, but it does seem to be pretty unique. The large planets are kind of out far. But quite frankly, we don't have enough data yet to say that. All these so-called hot Jupiters, all these large planets found near their stars, are the easiest ones to discover. Maybe that's why we found all those. Maybe those are rare. Maybe as we do more and more work, we'll find more solar systems like the Earth's.

ZIERLER: Based on the instrumentation that's available to us and what's coming online, just as a matter of thinking about how life might form, would you be more surprised if we detect bio-signatures first or techno-signatures first?

BURATTI: Techno-signatures. I think that would be a wow. Like it's depicted in ET, the whole world would change.

ZIERLER: Techno-signatures, of course, because that would be a sign not just of life, but of intelligent life.

BURATTI: Right.

ZIERLER: Is it safe to assume, then, for my last question, as long as you're active in the field, that would be the pinnacle for you, to be able to be around for that discovery?

BURATTI: I think so, yeah.

ZIERLER: Bonnie, I'd like to thank you so much for spending this time with me. It's been a wonderful conversation. I'm so glad we were able to do this. Thank you so much.

BURATTI: Thank you, David.

[END]