How NASA’s Perseverance Rover Will Look For Life

IRA FLATOW: This is Science Friday. I’m Ira Flatow. Are you tired of staying home? Well, pack your bags, we’re going to Mars. That’s right. The flights are booked, the landing spot is ready. And NASA’s next visitor to the red planet is nestled snugly aboard its Atlas V rocket. And if all goes well at the launch later this summer, Perseverance, the rover formerly known as Mars 2020, will touch down on Mars in February of 2021.

And then, well, it’s going to begin a quest to find signatures of microscopic long dead life, if it is there to be found. Here to join me to talk more about the mission are my guests Katie Stack Morgan, Deputy Project Scientist from Mars 2020 at NASA’s jet propulsion laboratory in Pasadena, and Diana Trujillo, a JPL aerospace engineer and the domain lead for robotic arm science. That’s the one that carries many of Perseverance’s scientific instruments. Welcome to Science Friday.

KATIE STACK MORGAN: Thanks Ira, glad to be here.

DIANA TRUJILLO: Thanks Ira, I’m super excited.

IRA FLATOW: Oh, well we’re excited to have you. Thank you. Katie, we’re sending another robot to Mars. What’s different about this mission? What are we looking for?

KATIE STACK MORGAN: Yeah so this mission, it’s the first mission in a potential Mars sample return campaign. And that’s really what distinguishes Perseverance from previous rovers. Our objective is to collect in cash samples on the surface of Mars for potential return to Earth. And no other Mars mission has done that before.

IRA FLATOW: Now, I know that Curiosity is up there already looking for water, still chugging along. Why can’t that rover help with doing the same stuff?

KATIE STACK MORGAN: That’s right. The main goal for Curiosity has been to search for habitable environments. And it has done that, and it has done that successfully. And Curiosity has helped, in the sense of expanding our understanding of habitable environments on Mars and what Mars was like in the ancient past. And so this mission seeks to build on that. And taking it one step further, knowing that we’re collecting samples with Perseverance to bring back to Earth. We’re really looking for those samples that will give us the best understanding and chance of finding ancient life on Mars.

IRA FLATOW: You mean you are looking for something that shows that Mars life may have happened in that spot?

KATIE STACK MORGAN: That’s exactly right. We look for what’s called biosignatures, which are textures, patterns, or substances that we see in the rock, that could have only formed by life.

IRA FLATOW: Can you be fooled by that? I remember years ago they were looking at samples they thought were made by microbes. Remember that whole fiasco? Yeah?

KATIE STACK MORGAN: Yes, and you know, that’s a really good point, because while we have a sophisticated suite of instruments on Perseverance that I think better enable us to search for biosignatures than any previous rover before, it’s very likely that we’ll have to get those samples back to Earth to say conclusively whether there was ancient life on Mars.

IRA FLATOW: That’s cool, and I can’t wait for that. Diana, what is different about Perseverance as a rover, as an engineering advance?

DIANA TRUJILLO: I think that there’s a lot of things that are different. The robotic arm itself has a much bigger turret. So think about the arm as a shoulder, elbow, wrist, just like yours. But when it gets to the turret where your hand will be, it’s way bigger. It also carries instruments that we didn’t have before, like PIXEL, SHERLOC and SHERLOC which splits into WATSON, which are pretty cool names, I will say myself. And then a drill. And then also a gas removal tool.

Now, I’m very excited, because if you look at the pictures of the drill, it also looks like a massive drill that is going to help us really get under that surface and give her the answers of what she’s looking for, hopefully, and the science team as well.

IRA FLATOW: Now, talk to me as an engineer now. What was the biggest engineering challenge you had to overcome?

DIANA TRUJILLO: The biggest challenge for my team really is the fact that the arm is holding together all of those pieces that I just mentioned, where any of those instruments that need to be pulled out for rework or reinstalled for rework, or do functional testing or any capability, or software update, on any of those things the robotic arm has to be involved.

And it is kind of, you’re building your LEGO set, and every time you think that you’ve got it working perfectly, somebody comes in and just takes that critical part of your LEGO set. And then you have to rethink about everything again to make sure it works perfectly. And you’re doing all of this in the floor, in the clean room, with a bunch of people waiting for you to nail it every time so you don’t take their time for their function.

IRA FLATOW: Diana just mentioned a lot of instruments. WATSON, SHERLOC. What are these instruments doing actually to find traces of life?

KATIE STACK MORGAN: So the PIXEL instrument, I’ll start there. PIXEL uses X-ray spectroscopy to search for chemical elements and to make maps of those chemical elements. And that’s a really important advance that our instruments have that previous instruments haven’t had. We can actually match up in detail a map of the geochemistry, of the composition of the rocks, with the very fine textures that an instrument like WATSON, which is the camera provides.

And it’s by mapping those textures to the composition and the distribution of organic matter, which is what SHERLOC can provide, as well as the minerals that SHERLOC can detect as well, they really give us the best chance of making a case for a potential biosignature. In the past, rovers have analyzed the entire rock all at once. And when you do that, you lose the ability to match the chemical signatures with the very fine textures.

IRA FLATOW: If you map and find something there, will your mission have anything to do with finding the spots for a return sample mission?

KATIE STACK MORGAN: Well, so what we’re going to do is we are going to identify those potential samples that we think have the best chance of giving us evidence of signs of ancient life, as well as telling us about the evolution of Mars as a planet. And so we’re going to drill and collect those samples. And our samples look something like a pencil, or maybe your pinky.

And we’re going to store those samples in tubes that have been engineered to be very clean and very protective, to ensure the scientific integrity of those samples. And then we will either put those samples down on the surface of Mars for the follow on mission to collect, or we’ll keep them in the body of the rover, and we may play a role ourselves in handing them off to the next leg of the mission.

IRA FLATOW: Last time we talked, you had a science team in Australia to study the stromatolites left by ancient bacteria. Useful? Learn something?

KATIE STACK MORGAN: Yes, absolutely. Earth provides a fantastic laboratory and range of experiences for us to explore Mars. Some things about Mars are very similar to Earth, and we can use our experience on Earth to help inform how we study and approach Mars. But some things are very different, and we have to be thinking about that, because there are surprises that Mars throws at us.

Part of our team went out to Australia and we talked about that about a year ago. And we also did another field test in Nevada with our science team this past winter. And that was a really valuable experience for our team. And just prepares us really well for what it’s like to do ops on the surface.

IRA FLATOW: What about the rover itself? How do you test out whether it can traverse the terrain, things like that?

DIANA TRUJILLO: So at JPL we have had representation of how Mars looks with that terrain. We tried to mimic that with the rods, with the sand, with the inclination planes that we put in there to see if the rover can go up and down. So we do a lot of testing there. We also are fortunate to have other labs in where we have, for example, the motors that we will be using for driving, and we exercise how much life those motors have and how much can we drive or for how long.

But the now understanding of how we are going to do all these driving, where Katie still wants us to go, is now an additional lab that we put together within some cases spare parts from the rover that we didn’t use. And we created these additional test bed. We call it the Vehicle System Test Bed. The Vehicle System Test Bed is almost a full replica of what is flying to Mars with [INAUDIBLE] or with engineering models. And then we take it for a drive. We take the cameras. We do the whole end to end, and prove to ourselves that this is going to work.

IRA FLATOW: Have the wheels been upgraded? I know we had problems with some of the wheels in the previous rovers and getting stuck in the sand. Are they upgraded models that maybe the tread is better or the traction?

DIANA TRUJILLO: So a few things there. So yes, the design of the wheels is different. We have also look at the software. As you might remember from Curiosity, when we started to have punctures on the wheels, we also upgraded the software to find ways of how to drive it in a way that we wouldn’t create so much torque that we were puncturing the wheels. And new ideas or strategies about how to drive.

Now, with respect to where we’re driving and getting stuck in sand, this is the beauty now where there’s an intersection in between the engineering team and the science team, where the science team also comes in and helps us with the understanding of what type of terrain we’re about to get into. Is the sand packed? Is this sand loose? And if that is the case, how should we drive it?

IRA FLATOW: What’s it like trying to balance the science and the engineering concerns in this kind of project, Katie? I mean, do you think you can hand it off to Diana and say, it’s all yours, take it away, but watch out for this?

KATIE STACK MORGAN: That’s a great question, and one that I think both Diane and I will have a unique answer to. Of course, as scientists, we want to go to the best rocks that we see. But sometimes it’s hard to get there. Or the slopes are too steep. Or it’ll take too much time on a given day.

And so there are all these trade offs and kind of compromises that you have to make. At the end of the day, we want to try our best not to compromise the science of the mission, but sometimes we have to work with the engineers to figure out how to make that happen. And maybe it’ll take a little bit longer than we had originally hoped it would, or maybe we have to take a different route. But in the end, the engineers are really our partners in helping to accomplish the science mission.

DIANA TRUJILLO: And if I could add to the do the answer that Katie just gave, I will tell you that that’s the fun part of my job, where you actually start thinking about, hey, my job as an engineer is actually to enable this. and not so much drive this. And so coming up with creative solutions to get what the scientists want is the part that makes operations so much more fun, right? Because you need to go back to how did we design this thing, how did we engineer it, what’s the maximum capability that I can squeeze out of the rover, and how creative can I get to get what she’s asking.

IRA FLATOW: I love it. I love it. Let’s talk about the exact spot, Katie. Where’s the exact spot the rover is slated to land and why?

KATIE STACK MORGAN: Yes. So the Perseverance rover is headed to a location on Mars called Jezero Crater. And it’s a crater that’s located on the inner rim of one of the largest and oldest impact basins. You know, life on Earth evolved around 3 and 1/2 billion years ago. And the rocks that we’re going to with Perseverance are also about 3 and 1/2 to 4 billion years old.

So when we think about Mars being different the past than it is today, we’re going to the interval of time when life was developing on Earth. And we think by probing that period of time on Mars, we have a chance to capture that potential evolution of life on Mars as well. And so we have an environment in Jezero that we think was really conducive to the occurrence and preservation of life. We have a delta. And we know that there was an ancient lake there.

We have some very interesting minerals that will really good at preserving signs of ancient life. And we know that from the Earth rock record. And we’re optimistic that we’ll see similar things on Mars.

IRA FLATOW: I mean, you as a geologist, what’s it like when you’re looking at this, and you just, oh, I wish I could take my hammer out and hit it, or pick it up, or something like that? Do you get that feeling sometimes?

KATIE STACK MORGAN: You know, that’s a funny question. And you’re talking to two JPLers. And we do robotic space exploration. But it’s true, you know, as a geologist. Sometimes you look at a rover image. And even if it’s giving you a 360 degree view, or we’re using the most close up camera that we have, it just isn’t a substitute for actually picking up and holding that rock yourself.

And that’s one of the reasons why the Mars community and the scientific community has been so supportive of Mars sample return. Because before we’re ready to send astronauts to Mars, we have the robotic capabilities to bring those samples to us. So we’ll be able to hold those rocks. So even though we can’t be there in person when we get those samples back, we’ll be able to have all of the field notes that our science team has recorded and the data that the Perseverance collected to help us put the samples in context. It’s similar to what geologists do. It’s just broken up into pieces.

IRA FLATOW: Just a quick reminder. I’m Ira Flatow, and this is Science Friday, from WNYC studios. We’re talking about NASA’s Perseverance rover, soon to be launched to Mars. One of the main banes to any mechanical object, wherever it is on Earth, on Mars, is dust. And I remember dust can get in the works of the gears. There were concerns that even on Mars, dust would cover the solar panels and keep some of the rovers from getting recharged. Diana, are we still as worried about dust as we were before? [LAUGHS]

DIANA TRUJILLO: I think that we’re always worried about dust. But I think that the question really is from the designing standpoint, yes, there is concerns that the [INAUDIBLE] needs to be taken into consideration. But when we now transition to actually operations, the operations is actually more manageable in a way, because of the experiences, as you mentioned, from previous rovers.

And the thing that I feel like it makes it very concrete for us is that we start thinking about it in a way as if there was a human on the surface of Mars, and you’re walking towards a dust devil. You’re going to bring your head down. You’re going to cover your eyes. You probably are going to turn around. And we do those sorts of things with the rover.

The science team knows that there is a dust storm coming our direction, and then we command all the cameras to look down, or we turn the rover, or we do things to make sure that the dust is not hitting us on the cameras. It is unfortunate when it hits us on the cameras. But at the same time, we try our best to use gravity to help us, and also cover ourselves by canting the cameras down.

IRA FLATOW: I imagine now your greatest anxiety is you must be getting the butterflies about the launch, right? We’ve worked so hard on this. Let’s just get this launch off the ground, right Diana? You must be just saying, OK.

DIANA TRUJILLO: We’re absolutely excited. I mean, we did every single test we can possibly think of. It’s just incredible to know that now at this point, we’re just thinking about what did we not do, what else can we fit in? We engineers are constantly trying to maximize everything that we can possibly think of. So I feel like at some point it’s just launch, because we will find other ways of continuing to test things, and things that we didn’t do that we could have done, but in reality we don’t need it because we are so ready for this.

IRA FLATOW: Katie, you too, a little bit anxiety?

KATIE STACK MORGAN: Absolutely. Of course, there’s always anxiety, though this is the one part of the mission where it truly does feel like we have to turn the keys over, and there’s really nothing as scientists that we can do at this point. We sit back and we watch it happen. And once we land on the surface, then we come in and we take over, and then it’s our responsibility. So it’s hard. We’re on the edge of our seats.

But it’s also, you recognize that at this point we put up our hands, and we cross our fingers and say, let’s hope that we’ve tested it and we know everything that’s going to happen and it’s going to turn out well. So of course always anxious, but optimistic and hopeful that we’ve done our job.

IRA FLATOW: Well, we’ve been covering 30 years of rover launches on Science Friday. So we want to wish you the best of luck in this one.

KATIE STACK MORGAN: Thank you so much.

DIANA TRUJILLO: Thank you.

IRA FLATOW: You’re welcome. Thank you both for taking time to be with us today. Great conversation. Talked to Katie Stack Morgan, Deputy Project Scientist from Mars 2020 at NASA’s Jet Propulsion Laboratory in Pasadena, and Diana Trujillo, a JPL Aerospace Engineer and the domain lead for robotic arm science. That’s the arm that carries many of Perseverance’s scientific instruments.

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