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NASA's Mars Mission Goal: Find Evidence Of Past Life On The Red Planet

NOEL KING, HOST:

It took seven months for NASA's rover Perseverance to make it to Mars. It'll collect samples that could tell us whether there was ever life there. And I have been told not to overstate the situation, but Perseverance could help us learn whether there might be life there again - human colonists, for example. I talked to two people responsible for the success of this mission.

Nina Lanza is a geologist at the Los Alamos National Laboratory, and Adam Steltzner is the chief engineer of NASA's Mars 2020 mission.

NINA LANZA: We can learn so much from literally any sample from Mars because we've never actually brought them back. But what I'm really hoping for and what one of the biggest goals of our mission is, is to find signs of biosignatures, so evidence that there was life in the past on Mars, which would be incredible.

KING: So when you say life in the past on Mars, I am no expert at all. And so I think, like, oh, fossils or, like, a footprint in a stone (laughter). Is it that or is it something much more subtle?

LANZA: Well, certainly I would not say no to a fossil from Mars, but what's probably more likely is that we're going to see chemical or mineralogical signs that life was there. So ancient microbial life on Earth has actually left us changes in chemistry in our rocks that we can actually still see today that are preserved - because they're little bodies, you know. They may not be fossilized. And, you know, we don't necessarily see the outline even of those microbial bodies. But what we can see is the way that they changed the chemistry and the mineralogy of the rocks.

KING: How does the rover determine, this is a good rock to bring back, and this one is boring, there's nothing there? Are you, like, watching through a camera?

LANZA: We have a lot of cameras. So, yes, we are definitely watching through a camera. But we have a lot of great instruments that are not just cameras. We can get chemistry. We can get mineralogy. We can get morphology. We can get all kinds of information from our rover instruments that we can then use to make decisions about which rocks are exciting enough to actually put in our sample tubes.

KING: What is the timeline like here? When do I get to call you guys back up shrieking that you did it or commiserating that you didn't do it? Like, when will we know something?

ADAM STELTZNER: Well, you have to be patient. It's going to be...

KING: Ah (laughter).

STELTZNER: ...A bit. Getting the samples and carefully sealing them in hyper-sterile and clean vessels on the surface of Mars for eventual return to Earth will happen in the next few years. But the act of bringing those samples home is a little bit of a challenge and is a - currently slated to launch in 2026, maybe 2028 - if we...

KING: Wow.

STELTZNER: ...Fail at that, will be in the early '30s. So it's not a task for the impatient.

KING: OK, fair enough, fair enough. I would be in that group of the impatient, so I'm just going to have to distract myself with other things for a decade. Let me ask you both a big philosophical question. Let's say Perseverance does find a signature of life. What is the most conservative thought that your mind has immediately? And then what is the most out-there thought that your mind has? Let me start with you, Nina.

LANZA: Well, my first thought is going to be, how can this be abiological? That is, how could this be made by something that's not life? Because to have defined life would be incredible. But a big claim like that requires big proof. And so we have to be careful not to be too premature with our declaration that we've done it because we want to be right.

So that's my first thought. OK, how can we be wrong about this? My crazy brain is like, oh, my gosh. Like, maybe there's life on Mars now - because why not? If it could live in that environment in the past, why couldn't it still be there today? That is something that we are not actually going to be able to test with our Perseverance payload instruments. So if we found something that was sort of suggestive of possibly current life, we'd probably have to send another mission.

KING: Adam, what do you think?

STELTZNER: Assuming that all of those things corroborate and we come away with the idea that Mars, at least at one point, had life, that would tell me that life is a fairly common outgrowth of habitable environments because we know 3 or so billion years ago that Mars was habitable for life when life was just getting started here on Earth. So the idea that life is common would be a tremendous relief for me.

KING: Why?

STELTZNER: Well, when I watch the way we careen towards the edge of the precipice occasionally as a species and here on this beautiful globe, I would be terribly frightened if we were the pinnacle of what the universe had to offer. Boy, that would be sad.

KING: NASA's goal, as I understand it, is to have humans walk on the surface of Mars in the future. How does this mission, how does Perseverance contribute to that ultimate goal, if at all?

LANZA: Well, there are actually several ways. I think, first of all, we're going to much better understand the Martian environment as it is today. We do have information from other missions like Curiosity. But it's really helpful to get more data points from different places on the planet. So we need more data.

We're also going to be testing different technologies that may be able to help our future astronauts. A really important one is the instrument MOXIE which is going to be taking Mars air and making oxygen both for the astronauts to breathe and also for them to have fuel to come back home 'cause we don't want to leave them there.

KING: Adam, what do you think?

STELTZNER: Yeah, humans to Mars - humans are a bit of a challenge. They are a lot more delicate than robots.

KING: (Laughter).

STELTZNER: They're cranky and consumptive. They need water and food, and they want the temperature to be right. And they would vastly prefer a lower radiation dose than the average robot.

KING: (Laughter).

KING: So there's a lot of work to get humans to the surface of Mars. But as a robot-builder, I believe that when we do this exploration, we're actually expressing our humanity, our fundamental drive to reach out, understand our universe and our place in it. And so it makes perfect sense to me that that exploration should also involve - physically involve human beings. And so I look forward to someday seeing boot prints on the surface of Mars.

KING: Adam and Nina, thank you so much.

STELTZNER: Thank you.

LANZA: Thank you.

KING: Adam Steltzner is the chief engineer of NASA's Mars 2020 mission. Nina Lanza is a geologist and the team lead for space and planetary exploration at the U.S. Department of Energy's Los Alamos National Laboratory and part of the science team for Perseverance's SuperCam instrument.

(SOUNDBITE OF JACOO'S “CROSSING WINDS”) Transcript provided by NPR, Copyright NPR.