Physics is the road to Mars—or to economics: An interview with scientist Rob Lillis

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Rob Lillis is a scientist who studies how planets and their climates evolve. Mars is his first love and main squeeze, but he’s also dabbled with Mercury, Venus, the moon, and Europa.

Karin Hauck is Communications Manager for the Multiverse education and outreach group at the Space Sciences Lab.

Rob, hiking in Arches National Park

Karin: Hi Rob! Where did you grow up?

Rob: I grew up mostly in Ireland. I was there until I was six, but then I spent four years in New Jersey until I was 10, then Ireland again until I was 22. So I had a transatlantic upbringing, if you will. Plenty of influences from both sides, so it was pretty easy coming to the US after grad school because of my time in America when I was a child. 

Karin: Interesting, so you spent your whole adolescence there? 

Rob: Yeah, exactly, and that’s the time in your life when you figure out who you are in relation to the rest of the world, so I’m very much still culturally Irish. All my family’s Irish, and I’ve been here 20 years as a US citizen, but I still don’t feel terribly American. I guess it’d be nice if I could pick and choose which parts of America to identify with, but you have to take it all and own it, so that’s also been a process.

Karin: Were your parents scientists of any kind?

Rob: Nope, there are zero scientists in my extended family, but my dad was always interested in science.  He would buy books that he would start and then never get more than a few pages into, then he would leave them on the coffee table, and it was discovering one of these books that led me to want to be a scientist. It was Was Einstein Right? by Clifford Will, and I read it when I was about 15. I don’t think it even had any equations, but lots of cool thought experiments about all the different ways that Einstein’s general theory of relativity was tested, and other theories that were considered and then tossed out in favor of Einstein’s one. It was basically about the process of how scientific theories are tested, and it really attracted me to the whole idea of the scientific endeavor as a career.

Karin: So the books inspired…?

I’m anticipating a follow-up question here by saying that the reason I actually became a scientist was not just those books, it was also that I had a guidance counselor in high school who told me that if I wanted to go into finance, economics, business or anything like that, and I got a degree in physics, then whatever company I worked for could just teach me all that other stuff within six months on the job. Whereas, if I did a degree in business and wanted to become a scientist later, I’d have to go back to square one and start again. 

Karin: I’ve not heard that before about pursuing a physics degree.

Rob: Every time I give a careers talk to college kids or high school kids, I really hammer this home. Even if you don’t think you want to be a scientist as a kid, if you have an aptitude in that direction, you’re much better off getting a degree in science or engineering or something with numbers and critical thinking in it because you can learn all the other business stuff later. So then it was an easy decision to get a degree in physics and maths. 

Karin: And you were in Ireland then?

Rob: It was in high school that I met the guidance counselor who convinced me to pick an undergraduate degree in physics and maths. Then I did a couple of summer internships in the United States, one at Notre Dame and one at the University of Illinois at Chicago—both in physics but different areas of physics. That was how I knew I wanted to get a PhD in the US, and that summer after my junior year in in Ireland, I visited a few different places: University of Chicago, Caltech, Berkeley, Stanford, etc. That fall, I was well-informed enough to apply for grad school, and ended up going to Berkeley and doing a PhD with Bob Lin. 

Karin: Bob Lin is definitely a key person in our SSL story.

Rob: Bob was my advisor. I graduated in 2006, and I’ve been at the lab ever since. That’s another story as to how and why that happened. 

Karin: First, I might backtrack a little to childhood again. Other than these books that your dad had, did you also like nature or science or simply making observations of the outside world?   

Rob: I think I enjoyed nature more for its beauty and the serenity of being outside. I spent a lot of time during my summers as a kid in my dad’s hometown on the west coast of Ireland. That part of Ireland is very windswept and wild. There are no trees within 20 miles of the coast, so it’s a very stark landscape with a lot of cliffs and wind. Being near the ocean was always something that gave me a lot of peace. I mean, I was always interested in why things are the way they are, such as why the tides happen, and any book that could teach me that was always something I gravitated towards. 

Karin: So you were a big reader? 

Rob: Exactly, and not just science books. I loved reading science fiction, but also Stephen King’s horror stories. 

Karin: I love those, Stephen King is definitely the only person who’s ever been able to make me literally jump while reading The Shining. He has this ability to make mundane things seem so creepy.

Rob: I guess I enjoy being scared without it freaking me out, like I’d never get nightmares because of horror. I’m just lucky that I could compartmentalize my mind like that. I love horror movies today, the scarier the better. 

Karin: Growing up, were you able to see stars and constellations? 

Rob: You know, it’s funny, I can recognize the planets and a couple of the popular constellations but I never really got into astronomy, to be perfectly honest, I was more just into physics The planets and stars interested me from a scientific perspective, but the night sky—other than it just being pretty, like I watched a couple of meteor showers when I was a kid, but I wasn’t one of those people who owned a telescope. I’m sure if I’d really wanted one I could have got one, but staring at the night sky wasn’t my thing, compared to just doing the physics. 

Karin: We talked about mentors, any other mentors or teachers that you particularly want to give props to? 

Rob: I would say, funnily enough, I don’t think I had. I mean, obviously Bob Lin was a very influential mentor, but he also didn’t really get involved in the details of my work, he was so busy doing all the other things that he did. It was great sharing a big result with him, but I didn’t really honestly have any people I would call close mentors. I was always somewhat independent. One thing I do like about SSL is that people here are very helpful if you ask for help, but advisors don’t micromanage, in general. They kind of let you sink or swim and it’s up to you to ask for help if you need it. That suits some people, it certainly suited me, although I’ve talked to other people who say that they actually didn’t like it, that it was a bit unstructured, and those people left SSL, so it’s a bit of a cultural thing. 

Karin: And a personality thing. 

Rob: Yeah, but it worked for me obviously—I’m still here after 20 years.

Karin: It sounds like once you committed to your path of physics, your progress was pretty straightforward—you didn’t really deviate or play around with other very different ideas.  

Rob: Yeah, I mean there were a couple of times when a recruiter from some company would reach out and I’d briefly entertain the idea of doing something ten times more boring for twice the money or even three times the money, but I never seriously considered it. I think I was lucky in that sense, because if I was coming up as a postdoc now and I was thinking about staying at a place like SSL and I saw the cost of housing in the Bay Area, I think I would go to either Silicon Valley or leave the area because it’s simply impossible, unless you have a very high earning spouse, to consider it here. Now, we at SSL are working on that, we have a plan to get the scientists salaries raised significantly. That’s the only place I have any control over, but right now that’s a big problem in terms of people staying.

Karin: That’s a lot to figure out there. So how did you actually end up at SSL? 

Rob: Great question. So I had applied for grad school at a few different places like I mentioned earlier and I talked to Bob Lin—not in person, when I visited because he was out of town, but I emailed with him—and there was a good opportunity, it was the RHESSI mission, which at that point was called HESSI—the High Energy Solar Spectroscopic Imager. Bob had mentioned some student positions that were available to work on HESSI and that it had not yet launched when I got to grad school in July of 2001. SSL seemed like an interesting place with a lot of exciting projects in space. I had already spent two summers doing other kinds of physics after my sophomore year. That was in foam physics, so-called foam rheology and bubbles, and that was interesting but it wasn’t really cool like space is cool. Then I spent another summer doing work on one of these particle accelerators. I was at Chicago but it was on Long Island (NY) and that was interesting too, but it seemed like in those projects there were a thousand people working on one experiment. It was a little too anonymous and a little too abstract. SSL had a lot of different projects and it seemed like an interesting place, and so that’s how I ended up working at SSL with Bob my first year grad school.

Karin: What is the most interesting or mysterious unanswered question in your field?

Rob: That’s an easy one for me because I’ve spent the vast majority of my career working on Mars, but I think every single first-author paper I’ve written has been on Mars. So, as is well known in the public domain, the question of Mars’ climate history is the major one: Where did the atmosphere go? Where did the water go? What role did the magnetic field and its disappearance play in that? What role did gravity play? What role did the planetary interior play? Mars is just one gigantic interesting physics problem that mixes space plasma physics, aeronomy, atmospheric chemistry, geochemistry, volcanology, and interior dynamics tectonics; it’s everything from the core of the planet all the way out to the solar wind, and it’s inherently interdisciplinary. We’re going to be working on understanding this for hundreds of years to come. It’s been really a privilege to work on—for example, the MAVEN mission, which has been examining a lot of those atmospheric escape processes for quite a long time. Also I’ve been fortunate enough to have my science path involve a fair bit of work on the surface of Mars, the impact craters and the volcanoes. So I’m more plugged into the planetary geology community and the work that people have done to understand things like the water or CO2 content of the volcanic emissions, and how that plays into the climate history problem. And that work goes alongside with the results that MAVEN has collected and enabled. There’s been a great interdisciplinary approach because no one thinks they’re the expert. The egos are quite a bit smaller in planetary science than they are in some other areas of science because no one knows everything or can possibly know everything. You don’t get the kind of big personalities which have in some areas dominated things and have led in some cases to a toxic work culture. That tends to not happen in planetary science nearly as much. 

Karin: I guess it’s humbling to not be able to know everything.

Rob: Yeah, no one can possibly be an expert in all those things, you have to rely on your colleagues. Unlike, for example, atomic and molecular optics, where you can you can build a lab for two or three million dollars, you can do your experiments and there’s no particular pressure for you to be a nice person, because with your lab and your students, you can do excellent work. Whereas, if you want to understand how the atmosphere is escaping from Mars, you have to spend years lobbying NASA, building a coalition, constructing a team, writing a proposal and working closely with these people for years and years and years. If you’re a jerk, nobody’s going to want to work with you. And so that has led to a more welcoming, less arrogant, better sort of environment to work in. So that’s part of the reason I really have enjoyed planetary science. I think it has some of its cultural roots in geology because a fair amount of the planetary science field is planetary geology and geophysics. The geology culture is less about “you know I’m smarter than you”—which often comes through in physics—but much more about field trips, you know, sitting around the campfire working—

Karin: “Look at this neat rock—“ 

Rob: Yeah, exactly. I’m not saying there’s no academic snobbery, of course there is, but it’s much better than some other fields are. That really has kept me here all this time. Also, it has a decent component of what I would just call exploration, as opposed to rigorous testing of theories. We try to do that, too, of course, but our field— including space plasma physics—that a lot of us at SSL do, it’s inherently observational. It’s not experimental, per se, you can’t control the boundary conditions or the conditions of the experiment. You have to just put your spacecraft up there and see whatever nature throws at you. So, you have that kind of observational science coupled with something that’s very interdisciplinary. No one is sure they have the answer, everyone’s working together, and there’s far more data than there are people to analyze them, so there isn’t much competition for the best results because there’s plenty to go around for everybody. That also leads to just a healthier working atmosphere. 

Karin: Sounds like people respect their teams.  

Rob: Have you read any books about NASA mission teams? By now there have been a couple written. One was about the original Mars Rovers back in 2003/2004. There have been some written about [the] kind of the personalities in solar system exploration. As someone who works alongside scientists, I think you’d like those. 

Karin: Sounds like an interesting psychological angle. I’ve read books about scientists and communication and there’s probably some overlap with the points you make, some folks wanting to be the big voice, versus explaining things in a way that actually brings people in.

Rob: Right, if the person doesn’t understand you, that’s your problem, not theirs. Right, I’ve had a lot of that. 

Karin: Can you describe some of the high points and low points of working on your project(s)? 

Rob: There are two different kinds of high points in careers like ours. When I say crossovers, I mean people who work in space science but who also work at an institution that actually runs missions— and instruments, as well—as SSL does. SSL, LASP (Laboratory for Atmospheric and Space Physics), to some degree both of the Arizona schools…you know there’s only a handful, or probably less than ten. In fact, if you only count labs that don’t do any other DOD sort of work and [those] that can actually manage a whole mission from start to finish, it really is just SSL and LASP. 

Karin: And then operate those satellites… 

That’s right. So back to the two different kinds of high points. One is a scientific high point. I had a paper in 2008 [in which] I put a date for when Mars lost its magnetic field, and that was the first time that had been sort of rigorously shown. Of all the papers I’ve written, it’s gotten by far the most citations. So that was kind of cool to discover something like that. That’s on the science side, but on the mission side, definitely the MAVEN launch was a high point in terms of a sense of achievement. Because you work on something for many, many years — and I actually built part of MAVEN, some of it literally with my own hands–and the energetic particle detector, I worked with Davin Larson on that —and so when you’re part of a team that builds something and works for years to do it…when it comes time to launch it and it’s sitting on top of a rocket, it’s sitting on 300 tons of high explosives a few miles away, and you know there’s a two or three percent chance it all explodes and years of your work and a couple of hundred other people’s work could all just explode before your eyes, it really heightens the sense of importance of what you’re doing. So when it’s successful, it’s very emotional and very satisfying.

Karin: I get that.

Then obviously when MAVEN successfully got to Mars and we started getting data, that was really great, too. The last big high point is becoming the leader of your own mission. I’m the PI for the ESCAPADE mission, which is a twin spacecraft follow-on to MAVEN. When ESCAPADE was selected, that was a huge high point, and then just [recently] when ESCAPADE passed its PDR (preliminary design review) that was a really big, big moment as well, because it was not guaranteed that we were going to pass PDR  at all. It’s a very low-cost mission and we were being very ambitious pushing the envelope. NASA is allergic to risk, even when they say they’re supposed to not be. Because if you’re going to send two spacecraft to Mars for one-tenth the cost of MAVEN, it’s going to be riskier, it just is, and NASA knows that. But when NASA reviewers look at a project they only know how to read risks one way and so it was quite a struggle to do our homework enough to convince the review board that we should be confirmed to proceed to flight. The official confirmation isn’t until august 17th.

Karin: Good luck! 

Rob: It’s basically a done deal now. That was really great to lead the whole thing, from just a thought in one’s head, through the initial concept development, through to the major proposal, through the Phase A and the Phase B. And having to make difficult decisions and trying to do the things you’re meant to do as a leader, but also listening to people and giving them a voice. I’m sure I’m not doing all that perfectly, but it’s been a really rewarding journey. And then when that launches, I hope that’ll be that’ll be pretty great, too. 

Karin: Congratulations, it’s pretty exciting. What about low points?

Not too many low points. It’s always disappointing when a major proposal you’re involved in doesn’t get selected—and I’ve definitely had a couple of those—because you’ve put a lot of work in. I think I’ve had three major proposals I worked on that didn’t get selected, but I’ve also been very, very fortunate because MAVEN was the first big proposal I was involved in. I was still in grad school when it went in and it got picked the first time—most mission ideas have to go through a few different rounds before they end up flying. And same with ESCAPADE, it was proposed once, and we won it the first time, so I think I’ve been pretty lucky.

I haven’t had anything fail on me in space, either. I know some of the older folks have definitely experienced that. CLUSTER 1, Mars Observer, those both exploded, and I can’t imagine that sense of loss. I mean it’s not like losing a family member but it’s got to be really, really tough.

Karin: To see all those years of work just like go up in flames, literally.

Rob: Both of Europe’s attempts to land on Mars have ended in failure, as well, so, yeah, it’s definitely a high-risk field to be in, you have to be willing to accept some serious disappointment, but—knock on wood—I haven’t had disappointment in that sense, like an actual active mission do anything bad. With this new higher-risk-tolerance/lower-cost paradigm—I mean NASA picked three missions, one of which was mine, but between these three missions, we’ll see whether they all succeed or not. NASA is conducting an experiment to see whether missions with slightly higher risk tolerance but much lower price tags can actually do good science. They’ve said that they are nominally accepting 80 success probability, not the usual in 97 or 98. (When you go through this review process, they give you a numerical score of what they think, they give you a probability of staying under your cost limit and staying on schedule.) ESCAPADE received two different scores on staying under cost, one was 48 and one was 78. The 48 included a hibernation period of undetermined length. That was not of our doing, it’s because we haven’t got a launch [window] yet because NASA hasn’t given it to us. When you take that out, we had a close to an 80 probability. 

Karin: When might you launch ESCAPADE?

Rob: We’re going to be ready to launch on January 1st 2024, but the launch could be anytime in 2024, and in order to stay under budget, we’ll have to figure out something else for a whole bunch of people to do for a month, up to as many as nine months. That can be really tough because what if there’s nothing for them to do? You’ve still got to pay them because you need them, what if they do something else but they get so wrapped up in it, they’re not available to come back to you? NASA sees the risk, but it’s a risk that happens when you don’t provide a set launch date for a mission. But, it’s also exciting to be part of a new way of doing space missions, to see how this can work. It’s been such a risk-averse industry, but now with reusable rockets, the cost of launching has come down. For example, if it always cost 150 million dollars to launch something into space, you’re not going to send a gadget up there that only costs 50K because you’re gonna spend like 10 times that, or 100 times that, to make sure it works the first time. So, there was a very risk-averse posture they have had, now they’re trying to figure out where the sweet spot lies in terms of tolerating more risk, as we pay less and less for launches. I think what they’re calling “Space 3.0” has not been going for too many years yet, and it’s just going to be expanding. It’s a really exciting time to be in the industry and see where it ends up going, like with humans going to Mars, and just a lot more stuff going into space, in general.

Karin: Do you think there was much influence from commercial space flight?

 Yeah, for sure, it did influence this idea of approving more things to go into space. It was driven by two major developments. One was the CubeSat revolution that started at Cal Poly and also Moorehead State and now Utah State, as well, where students are building these little CubeSats. They don’t always work, but they’re a great learning experience and that has also led to more risk tolerance.  And then Elon Musk has changed the paradigm by bringing the cost of launch down by 10 or 20 or even 50 times by having reusable rockets, instead of instead of building a 100 million dollar machine and destroying it on purpose every time—imagine if you built a brand new jetliner and crashed it on purpose as soon as the first flight was over, that’s how inefficient the launch industry has been up until now. So it really opens up huge new avenues for space exploration, so it’s a cool time to be in in this field. Also cultural things like that movie The Martian with Matt Damon— I honestly think that movie really did move the public in a perceptible way in terms of interest in space. 

Karin: Oh yeah, that was such a good movie!

Rob: It was, it was entertaining and it was scientifically 99% correct. I think that got a lot of people  on board. Of course, some highly improbable things happen, but it’s a movie, right?

Karin: Do you have hobbies or interests outside of work that might surprise people? or how do you like to spend your spare time? 

Rob: I do a lot of running and hiking, that’s really most of the sort of activities I do. I try to go for a major hiking trip once or twice a year with my brother or with other friends. Sometimes I go with people from SSL. In March of this year, several of us rented a house up in the eastern Sierra and we spent the weekend snowshoeing. I had never been snowshoeing before and that was a lot of fun. My favorite sport to follow is definitely rugby. I played rugby for many years in high school and still I’m an avid follower. I’ll go to games here and I’ll wake up early and get on a VPN to watch to watch a match in Europe. I’m still definitely connected to Ireland in that sense as well. It’s been tough not going back to Ireland for nearly two years, so I’m going to be going back in in August for a couple of weeks.

Karin: You wanted to talk about mentoring students?

Rob: Yes, it’s something I really like doing. I have three students this summer, the most I’ve ever had at once. It’s really great just walking them through the why of what we do. Obviously people who get in contact with us for that kind of thing are already huge space fans, so it isn’t difficult to get them motivated. This is something in general about the work environment at a place like SSL: almost everyone who works here thinks space is cool. As a PI, it’s not hard to motivate people because they like what they do, and that’s definitely true for the students. Seeing several of the students I’ve worked with over the years go on to grad school and to have successful careers, either in or not in science, it’s been pretty rewarding.

Karin: It’s great to work with students, for sure, and see them succeed. Are your students from Cal?

Rob: It’s been a mix. I’ve had five now from Cal and then I’ve had another six from the United Arab Emirates (UAE). With the Emirates Mars Mission (EMM), that was part of deal, that we mentor students. Matt Fillingim and I mentor one student each summer. We did it 2015-16-17-18-19. They would come to Berkeley for the summer. It didn’t happen in 2020 obviously, and in 2021, we’re doing it remotely which would have been fine, but remotely along with a 10- or 11-hour time difference has been really hard.

Karin: It’s hard enough sometimes to schedule work with a three-hour time difference between US coasts, let alone a time difference like that.

Rob: It’s kind of amazing that the Emirates Mars Mission has worked as well as it has, given the time difference between here, Colorado and Dubai, but I think everybody was sufficiently motivated and willing to stay up late a couple nights a week, and then the others could stay up another couple nights a week and so you wouldn’t have to. Now I only have evening meetings twice a month, so that’s pretty good.

Karin: When you say evening, what time are you talking about?

Rob: Well, one of the monthly ones goes until about 10:30 at night, but that’s only once a month and for the folks in Colorado, it’s 11:30. That’s the big meeting where the government people from the UAE are on, so it has to be on their time because they’re paying for it, but for a lot of our other meetings, the folks in the UAE are the ones that are staying up late. I do appreciate that.

Karin: Wow, that’s a collaboration. 

Rob: Honestly, the whole UAE mission has been so different than any NASA mission, just how it got going and a lot of the cultural differences. It’s been a real eye-opener in terms of learning about a different culture. I’ve had lots of trips over there, lots of preconceptions I had that were wrong…

Karin: Right what would one of those preconceptions be?

Rob: Well, for example, what percentage of engineers in the UAE do you think are women?

Karin: I bet it’s better than one would think, just because I’ve interacted with some of the students from the REU program, ASSURE, so let me guess, ten percent?

Rob: Seventy percent of engineers who are nationals are women!

Rob at a public outreach event in Mirfa, United Arab Emirates

Karin: Wow, that’s got to be pretty unique among middle eastern countries. Very inspiring.

Rob: Yes, it’s an interesting mixture of the government pursuing progressivism, but also sexism working in the opposite direction. The government pushes women’s education in a really big way. The men are already given a lot of free stuff by the government and have typically  been really coddled by both the government and historically by their families. They’re treated so well and given so much free stuff that they have not felt nearly the same pressure to go get a real career. A lot of Emirati men, when they turn 18, the government gives them a piece of land and will often set them up with some investment company. They’ll just build a hotel or apartment block on your land and you own ten percent of it, just for nothing.

Karin: And women don’t get that kind of help?

So, a lot of women actually pursue real careers now. Of course, there are plenty of very successful male engineers in the UAE, as well, but there are more now who are women. It’s because the men are given all this free stuff, so the government is trying to cut back on that now. They have actually had to work on getting men to go into engineering. And another thing that’s culturally different is that a lot of these very educated women, they still have arranged marriages, because that’s definitely part of the culture. But now there’s been a whole mini-generation of women who are single well into their late 20s, which is completely mind-blowingly unheard of for that part of the world, and it’s because they refuse to marry men without college degrees. So they’re fine with the arranged marriages but they’re not going to marry someone who isn’t similar to them in terms of levels of curiosity and education. So several of our colleagues over there were already married at 22, but many didn’t get married until much closer to 30. And it’s because they just couldn’t find husbands or their families couldn’t find them educated husbands. There’s just a lot of stuff that you wouldn’t think is the case if you read the news concerning the Middle East. And also you see the women wearing the headscarf but they really don’t have to. My student this summer, she never wears her head scarf on Zoom, and there’s another student at Colorado and she wore it for a while, then she decided it was a barrier to her integrating with her American friends, so she stopped wearing it and she didn’t even care when the other folks from the UAE were visiting, and they didn’t care either.

Karin: Interesting.

Rob: It truly is a choice. I initially didn’t quite believe that. You know how people say, “Oh, it’s my choice,” but it’s not really—I truly do believe it is their choice in most of these cases. I’m sure that’s not the case in most countries over there, but the UAE is an exception to many rules. It is simultaneously both very conservative and very progressive, because they only discovered oil in the mid-90s or maybe the 80s, something like that, so in 1980 it was a very poor, extremely conservative, extremely religious place. So a lot of the older folks there, that’s all they know and so they’ve managed that cultural transition pretty admirably. There’s still a lot that’s far from perfect, they’ve been accused of treating their migrant workers poorly, but that’s gotten a lot better, as well, and anyway it’s been quite a good experience working with them. 

Karin: Sounds like great consciousness-raising and wonderful partners to work with. Thanks for talking with me, Rob. 

Rob: Thanks a million, Karin.