...who drives a Mars rover?

Ever Wonder? / February 17, 2021
Hallie Abarca next to R2D2
Image attribution
Courtesy of Hallie Abarca

When this episode airs, NASA will be just one day away from landing another rover on Mars. On February 18, the Perseverance rover will reach the surface of the Red Planet, capping off a journey that started with a rocket launch last July.

In an earlier episode, we talked with Matthew Frost about Perseverance’s robot arm, and how it works to collect samples from the Martian surface. But that robot arm becomes a lot more useful when you can drive it around Mars. And that takes a whole team of dedicated rover drivers back here on Earth.

Do you ever wonder who drives a Mars rover?

We were lucky to chat with Hallie Abarca, a former Mars rover driver and software engineer on the Perseverance rover at NASA JPL. She talks about what it was like to drive other Mars rovers, working on “Mars time,” and a new JPL website where you can virtually drive across the surface of Mars from your home.

Have a question you've been wondering about? Email the podcast team to tell us what you'd like to hear in future episodes.

Subscribe to our show on Apple Podcasts, Spotify, or Google Podcasts. To see a full list of episodes, visit our show’s webpage.


Perry Roth-Johnson (00:06):

Hello! This is Ever Wonder? from the California Science Center. I'm Perry Roth-Johnson. When we publish this episode, NASA will be just one day away from landing yet another rover on Mars. On February 18, the Perseverance rover will reach the surface of the Red Planet, capping off a journey that started with a rocket launch last July. In an earlier episode, which we rebroadcasted last week, we talked with Matthew Frost about Perseverance's robot arm and how it works to collect samples from the martian surface. But that robot arm becomes a lot more useful when you can drive it around Mars. And that takes a whole team of dedicated rover drivers back here on Earth. Do you ever wonder who drives a Mars rover? We were so lucky to chat with Hallie Abarca, a former Mars rover driver, and now software engineer on the Perseverance rover at NASA JPL. She talks about what it was like to drive other Mars rovers working on quote unquote "Mars time," and a new JPL website where you can virtually drive across the surface of Mars from your home. It's a fascinating look behind the scenes of space exploration. Let's get into it. Hallie Abarca, you are a former Mars rover driver and software engineer at the NASA Jet Propulsion Laboratory. Welcome to the show!

Hallie Abarca (01:29):

Thank you for having me.

Perry Roth-Johnson (01:31):

Yeah, and Devin Waller, my co-host from the California Science Center is also here today. Hi Devin!

Devin Waller (01:36):

Hey Perry. Thanks for having me on and hi Hallie. Thanks for coming on the show.

Hallie Abarca (01:41):

Absolutely. This is super exciting for me.

Devin Waller (01:43):

So, for the past decade, you've worked on multiple Mars missions at NASA's jet propulsion laboratory, and currently you're working on the Mars 2020 Rover mission. Super exciting. What's your role on Mars 2020 and what are your daily operations?

Hallie Abarca (01:59):

That is a great question. So, the main thing that I'm doing right now on Mars 2020 is leading the image and data processing team. So, we're right now getting ready for our operations on Mars, this coming February and the day to day operations right now is practicing with the different, uh, JPL testbeds. We have as well as data coming down from the actual Rover, sending out what we call cruise check-out data. So, instrument data that we're already receiving from the rover, getting ready for landing. So, it's very exciting right now. Uh, we're all getting ready for the big show coming up.

Perry Roth-Johnson (02:34):

Are the nerves starting to build up as the landing date approaches?

Hallie Abarca (02:38):

Yeah, there’s every time I talk to somebody and we start talking about like how many days are left until landing and that number just keeps decreasing. Once we dipped below a hundred, it starts getting really exciting and really nerve-wracking, but exciting.

Perry Roth-Johnson (02:51):

Well, we wish you the best of luck and hope it all goes well. So, you have a lot of titles. I mean, we introduced you as, Um, a software engineer, but you've, you've worked on multiple Mars missions like Devin mentioned, and, um, you have a couple titles under your belt. Uh, one is a cognizant engineer, um, for a project on Perseverance, which is the name for the Mars 2020 Rover. Can you explain like what a cognizant engineer is?

Hallie Abarca (03:21):

Yeah, so a cognitive engineer at JPL is a term we use for the person responsible for the design and development of a piece of software or a piece of hardware. So, it can be somebody who is in charge of, um, the design and build of a robotic system, or in my case, I was the cognitive engineer for a targeting tool. So, it's the software that the science and engineering team is going to use to decide where we actually want to collect samples or where we want to image or place the, maybe the robotic arm on the surface of Mars when we get there.

Devin Waller (03:55):

And you also mentioned the data visualization. How does that relate to rover driving? What is, what's the connection?

Hallie Abarca (04:03):

Yeah, so I've kind of zigzagged at JPL doing both robotics as like on the uplink side, as well as actually processing data on the downlink side. Um, there's this really cool connection that you can't drive a rover or do anything if you don't have data to plan that on. So, for instance, if you don't have a, you know, terrain model, you don't, you only, don't just blindly drive rovers on Mars. Um, you know, it's always the joke to drive it off a cliff into a crater or into a rock. You need these models that you can basically load into software and basically plan out the route of where you actually want to drive the rover. Um, it's so interdependent that you need the rover to take the data and then you need the data to be able to continue operations. Um, so I've kind of always kind of blended those two things together in the last 10 years at JPL working on image processing on MER, Curiosity, Insight, and now Perseverance. I always keep coming back to the image processing and started it back on, um, in college, working on the lunar reconnaissance orbiter cameras.

Perry Roth-Johnson (05:03):

So, how did you become a Mars rover driver? Was that like the job you applied for when you applied at JPL or...

Devin Waller (05:11):

Yeah. What was that job description like?

Hallie Abarca (05:13):

Definitely not, yeah. Um, I kind of feel like I've, I've been really lucky and been able to fall into a lot of the jobs that I've had at JPL. Um, I was a summer intern at JPL and, um, was able to actually get a job during that summer. And I was hired to do image processing for Curiosity and Opportunity rover. Um, when I started at JPL then because you're in the image processing side of things, you're working with the rover drivers every single day, making suggestions or helping them, you know, so constantly working with the rover planners, I was always sitting in the room and also thinking about new ways as an engineer. You're always trying to think of new ways to solve problems and problems that people don't even necessarily know are problems yet are kind of sometimes the most exciting when you start to think like, Hmm, I wonder if there's a way to make this better. Um, and constantly being a part of that process. Finally, some of the rover planners actually asked me, they said, you know, you seem to be really interested in this and I feel like you get it. Would you be interested in starting to train to be a rover driver, which is such a weird question where like, yes, you just say, yes, I didn't really understood that that entailed like, Hey, you now have to go off and learn robotics. Um, so my evenings were then filled with, you know, DIY, learn it yourself, robotics and motors and all these things that I had never really encountered or experienced before. Um, so after about a year and a half, I became certified as a senior rover driver on a MER.

Devin Waller (06:45):

So, on that point, can you compare rover driving? So, say to what engineers do when they program self-driving cars. I know there's some difference between them, but you both have to program and operate this massive machine and you're not there to see it actually operate in real time. So, is that a good analogy or how, how would you describe it?

Hallie Abarca (07:10):

So, yeah, so the way we actually, um, command these rovers is we have an operations team and it takes people from all over the world. We have science and engineers. Um, you have engineers at JPL, and then we have a science team that is literally all over the world on these missions. So, each day it's like a, you know, eight to five job on MER where you'd come in in the morning, you'd get a new data from the rover overnight. And then you basically have that day to come up with like a list of commands that the rover was gonna do. And then at the end of the day, that gets sent back to the rover and the rover then would do its operations overnight. So, during that day, it actually takes a whole team of people to have each one of their own jobs. So, as a rover driver, we were responsible for commanding the mobility systems. So, driving, and then the robotic arm, somebody else is responsible for, you know, commanding the different instruments or, you know, the cameras. We know that the rover is going to drive a certain direction and the next day we know that we're going to want to turn and drive this other direction. So there's the engineering camera, um, uplink lead, who is responsible for then making sure that they take all of the imagery that we need to do our jobs the next day to be able to drive further, or if we're going to do robotic arm, make sure that we have high resolution imaging right in the front of the rover, in the workspace so that we could place that robotic arm. Cause if you mess that up, that's a day you lose on Mars and you can't just lose days on Mars because of commanding errors, right? Like we, everyone has to, double-check everybody. We actually, at the end of the day, read through all of the commands and double-check everybody. So even the rover drivers are sitting there reading through our commands and other people can poke and ask questions. Well, did you of this? You know, this happened the other day. What about that? And it's kind of this cool atmosphere that you're welcoming suggestions and that, you know, feedback to basically make sure that everyone is on top of it. Um, it was a really cool experience doing that.

Devin Waller (09:10):

So, you have two teams that are working, um, from what we understand, you have an uplink team where you mentioned, they send a command from mission control and you guys send it to Mars. And then of course the, the commands that come from the rovers, they get down linked back to, uh, earth where you guys analyze all the data. Um, but then we heard that you guys will work or at least during the beginning of the mission, they would work around the clock on Mars time. What, what is that like? And how, how long were you guys on shift for Mars time?

Hallie Abarca (09:45):

Yeah, so I'm actually really lucky. I've never had to do an uplink Mars time before. Um, I'm getting ready to do my first Mars time for, uh, Perseverance. So, this will be fun. We had like a mini Mars time on insight, but it's not quite the same when you have a lander versus, um, in a smaller team, we did it for about one month versus what we're going in for is three months. Um, so the way Mars time works is, you know, because a martian day is 30 minutes longer. You're marching your day and you're actually working like a 24 and a half hour a day every day. So, you, you, you shift to Mars. So, you're always working when the rover is asleep, when it's nighttime on Mars and then we're working then while it's asleep. And so, you have this time cut off, right? Like we know that we have to send commands by this time, or the rover is not going to get the commands in time. Cause it only has like a window that it's sitting there listening. So you have to have your day done with, you know, a team that's all over the world, coordinate get this plan, all the commands sent at this deadline.

Perry Roth-Johnson (10:48):

Okay. So, you're basically like shifting into being more nocturnal and then shifting out of being more nocturnal as you're marching your day long. Do I have that right?

Hallie Abarca (10:57):

That is correct. Yep.

Perry Roth-Johnson (10:59):

Oh, that sounds stressful.

Hallie Abarca (11:00):


Devin Waller (11:01):

So, having worked on with so many different landers and rovers, uh, you know, you, you know that hardware, you know, those cameras, what are the key differences between the cameras? So, you worked with MER, Spirit and Opportunity. You've worked with Insight lander and Perseverance. Are the cameras similar or are they different?

Hallie Abarca (11:22):

Yeah, so, so the, the cameras are light years ahead of where we have been previously. So, for the cameras that we had on MER, MSL and Insight, they were actually the same cameras on all three of those missions for the engineering cameras. We had different science cameras, each one of those, but the engineering cameras, which is the majority of the images that we take every day to do all of our mobility and, you know, the panoramas that we take daily, um, on Insight, they just change it out. So, it was a color CCD, but the same camera. So now we're going from a one-megapixel camera to a 20-megapixel camera that is full color. Yeah. And we've been doing these really cool experiments where we've been driving out in the Mars yard is kind of the, you know, get practicing and getting ready for all of this. And every once in a while, we'll take like a full resolution, 20-megapixel image and it's just jaw droppingly beautiful. And I can't imagine this is the Mars yard at JPL, which I personally love the Mars yard at JPL. You know, it's a really special place for all of us who work on these rovers, but I can't imagine what this is going to look like, you know, on landing day in that first week, when we start getting all of these images down and have our first panorama down, it's, it's going to be very inspired even for us who work on it and get, you know, jaded by, you know, these really cool things that we do. Um, you know, one thing I think that people don't realize it's, um, I always get a lot of questions like, Oh, is it so cool to see the images first? Um, but something that's funny is we actually release all these images to the public. Usually within about five minutes of the time it hits the ground. So, the minute we're processing those images, they're released to the public five minutes later, if you're a nerd like me and you go on the web, you can kind of figure out when we're getting down links to the DSN pages, that JPL public DSN pages that you can see when we're getting down links from different rovers. If you then start refreshing the raw images page for that particular mission, you're probably going to see the new images a few minutes later. And I think it's so cool that we're always bringing in the public and taking everyone along with us.

Devin Waller (13:23):

I think that's going to bring a lot of excitement to our guests. We have a lot of citizen scientists out there that are probably listening.

Hallie Abarca (13:29):


Perry Roth-Johnson (13:31):

Uh, I want to look ahead a little bit and think about the future of your field. Um, a few years ago, there was some chatter about your team using virtual or augmented reality to help operate the rovers. I know now you're leading, um, a project called ASTRO, which is this big, awesome acronym that JPL likes to use. Uh, tell me if I'm getting it right. Advanced Science Targeting toolkit for Robotic operations. Is that related to the virtual or augmented reality efforts before? And like where are you guys taking it from here?

Hallie Abarca (14:01):

Yeah. So that was one of the coolest projects I've ever worked on. So, for, um, there was a really cool project called on-site that, uh, JPL collaborated with Microsoft. And so that was a Hollins VR experience where, um, we actually brought that to back to the Curiosity team to basically be able to get the latest data down and then walk around on Mars and have science, collaboration, and discussions, you know, and actually understand the scale of everything around the rover. Um, we take all these images and you kind of forget that these rovers are the size of like a small car. And you know, there's always this common problem where you'll have a science team member saying, Oh, can we, you know, drill or, you know, place the robotic arm on this rock and it you'll get this picture. And, you have to remember, we have like zoom cameras on these rovers.

Devin Waller (14:52):


Hallie Abarca (14:53):

Um, and it'll be like a pebble when you figure out where this image is, it's like, no, you cannot drill or sample on this pebble. It looks really cool, but it turns out it's like two centimeters. Um, so when you're actually walking around on Mars, it gives you so much more understanding of like the size of everything and, and you can make these decisions so much faster. And we had talked about earlier, you know, there's a deadline, you, right? At the end of the day, we have to send something to Mars or we're going to miss our shot to how to do operations that day. And we can't afford to lose a day. And so suddenly if you're having science team members who can collaborate and very quickly make science, um, observations, everyone wins, um, for Mars 2020, we actually basically brought that to the web. So that's how our ASTRO was born is it's now a web-based tool that, you know, you don't necessarily need the, um, you know, VR hardware or AR hardware. You can just jump on your laptop and very quickly understand what the world looks like. And that's something that, you know, really the rover drivers, which goes back to my experience as a rover driver, we're really the only ones who ever understood what the terrain looked like around the rover had, you know, the spacial understanding. And now the idea is you can jump on your laptop and anyone can do that. Um, on the project, there's a new, exciting part of this where we're actually pushing this out to the public from Mars 2020. So, after we get data, we'll actually be able to, you know, anyone on the public will be able to go onto JPL's Mars website and actually experience the terrain around Mars and see the latest images come down.

Perry Roth-Johnson (16:27):

That's so awesome.

Devin Waller (16:28):

That's going to be really exciting.

Perry Roth-Johnson (16:30):

We're definitely going to have to link to that in our show notes.

Devin Waller (16:32):

Yeah, definitely. One question that I always want to ask is, you know, we try to demystify what it takes to get from, you know, to get into certain career paths. And I know a lot of people look at at, you know, jobs like you have, and it's just that they're so amazing. What advice would you give to somebody that wanted to get into something that was similar?

Hallie Abarca (17:00):

Oh, I love this question. Um, so I think a lot of, um, you know, my own personal struggles have been, am I good enough to do this? Um, personally I failed calculus twice and the third time around, I got an A in it. Um, and so I think sometimes you can be very hard on yourself and really think that you're not smart enough. Sometimes it just doesn't click yet. Or, you know, if you keep pushing, eventually you'll get through it. Um, I think there's also so many different parts of the STEM field that, you know, I work with people who were artists in college, who, um, you know, are now rover drivers or, you know, even designing really cool software. I work with all these people in so many different fields, electrical engineers who are doing, you know, commanding the cameras on Curiosity. And I think it's, I think a lot of people think that you have to have this like niche understanding or, you know, um, don't necessarily think that they have the right background to get into something like this. But a lot of it is just getting involved in trying new things and putting yourself out there to, you know, try and internship whether or not you think you're the right person for it, but putting yourself out there and getting that experience is really what, um, really helps people. Um, I have a coworker who, you know, built an R2D2 and it kind of proved that, you know, she could totally be a roboticist and became the rover driver on MER and Curiosity. So that just kind of is like, I think that's the really cool thing about this field is that, you know, by putting yourself out there and trying new things is it's a very welcoming field nowadays to like bring people in with different backgrounds and experience and everyone who has all these different background and experience really brings something to the table and a different perspective.

Perry Roth-Johnson (18:44):

I'm glad you shared this story about, um, you know, not necessarily passing calculus. I mean, that's a story I like to share around with people who are interning with us at the science center too. And they're, they're kind of like, eh, I'm not sure, like I failed multi-variable calculus, you can pick yourself up again.

Devin Waller (19:01):

So it must be a calculus thing because I had to retake it myself. So that was the class I retook in college. It is not easy...

Perry Roth-Johnson (19:08):

Ok, so we're all in the same club.

Devin Waller (19:08):

But you know what we all made it.

Hallie Abarca (19:12):

Yeah. I'm not sure that anyone will, yeah, at JPL want to hear me tell this story, but yeah, so it was calculus three and I literally passed it my last semester at ASU, knowing that I needed to pass this class to get into JPL and start a month later. So, I was so happy that, you know, I ended up walking away with an amazing grade after having, you know, a few episodes of failure.

Perry Roth-Johnson (19:34):

Now you're going to land another Mars rover.

Devin Waller (19:36):

Yeah. Right.

Perry Roth-Johnson (19:38):

No big deal.

Hallie Abarca (19:39):

Yeah, but that's something that's so important is being able to pick yourself back up and put yourself in a situation, even, you know, if it's not the easiest thing that comes to you, is it keep working at it. And I think that applies for all jobs in STEM.

Perry Roth-Johnson (19:52):

You you've worked on Mars for, it seems like almost a decade, uh, at JPL. Is that your favorite planet or do you have a different planet that's your favorite?

Hallie Abarca (20:02):

Ooh, uh, Mars is definitely my favorite work planet. My favorite planet though, I have to admit is definitely Earth. Um, I think it's a really special planet that we have, and I'm very thankful for it. Uh, the more you learn about Mars, the more excited you are about the fact that we have an excellent planet here with beaches and palm trees that you can go to on weekends.

Devin Waller (20:21):

You know, that's a really good point. Has it working, it's giving you, it sounds like it's giving you a new appreciation or deeper appreciation for this planet. Um, is it, is it something that the more you learn about say the differences on Mars, the more that this planet actually shows how truly special it is?

Hallie Abarca (20:42):

Absolutely. I mean, so when I used to, um, be a rover driver on Opportunity, you know, you'd wait to get these images back from, you know, the new place you've been right? Every time you drive a rover, you're in some new location that nobody has probably ever seen at that resolution. Right. We have orbital data for all of these, um, you know, for Mars and the moon, but actually being on the ground and seeing it in high resolution from, you know, centimeters away, um, is really something else that you realize how desolate it is. And it's like, you know, you can go into the desert in California, but there's still so much life and there's still so much happening around you. But when you're looking at these images coming from Mars, it's theirs, it's just desolate. And it's, it's gorgeous. In my opinion, it's like I could paint my walls in images that we've taken from these rovers. And I'd be very happy, but coming home and, and being able to, you know, drive, living in Los Angeles, right. We can go to the mountains and legal live in Pasadena in the foothills. And it's, it's just so gorgeous here. And I, I really am thankful for all the life that we have on this planet.

Perry Roth-Johnson (21:47):

Uh, where can people follow you online and find your work?

Hallie Abarca (21:51):

Ooh. Uh, so, um, you can find me online on the Mars people website. We're getting that set up right now that you can see all the different sorts of people who are working on Mars 2020. Um, it'd be really cool. I think they're putting bios together of all the different teams and seeing, kind of see the breadth of all the different sorts of people all over the world, working on Mars 2020.

Perry Roth-Johnson (22:09):

Awesome. Well, it's been a pleasure talking to you, Hallie. Thanks for taking us through a tour of all the different Mars missions from the start of your career. We wish you all the best with your most recent baby Perseverance when it lands in February. Thanks for joining us on the show.

Hallie Abarca (22:23):

So much for having me. This was a lot of fun.

Devin Waller (22:25):

Thank you so much.

Perry Roth-Johnson (22:27):

Well, that's our show and thanks for listening! Until next time, keep wondering. Ever Wonder? from the California Science Center is produced by me, Perry Roth-Johnson, along with Jennifer Castillo. Liz Roth-Johnson is our editor. Theme music provided by Michael Nickolas and Pond5. Special thanks to Devin Waller for producing and hosting this series. We'll drop new episodes every other Wednesday. If you're a fan of the show, be sure to subscribe and leave us a rating or review or tell a friend about us. Now, our doors may be closed, but our mission to inspire science learning in everyone continues. We're working hard to provide free educational resources online while maintaining essential operations like on-site animal care and preparing for our reopening to the public. Join our mission by making a gift at californiasciencecenter.org/support.