A new NASA experiment shows finding the building blocks for life on other planets may not require much digging

Even if you’re not a space geek, you may have heard of the moons Europa and Enceladus, both which orbit Jupiter and Saturn respectively. They’re famous for their potential ability to host the building blocks of life beyond Earth. Well, new research from NASA shows that those building blocks may not be hard to find were we ever to send a probe to do some digging around on those moons. Alexander Pavlov is a NASA Space Scientist who led this research, and he joins Federal News Network Executive producer Eric White on the Federal Drive with Tom Temin.

Interview transcript: 

Eric White  Alex Pavlov is a NASA space scientist who led this research, and he joins me now. Mr. Pavlov, thank you so much for taking the time.

Alex Pavlov  Thank you for this opportunity.

Eric White  Absolutely. So what can you tell me about this research? How did this all come about? And what exactly were you all looking for when it started out?

Alex Pavlov  Well, as you stated, the Enceladus and Europa, they’re airless bodies, and if you have air this body, then you have to be concerned about the radiation of the surface. So, we are taking samples from the surface of either Europa or Enceladus, we want to make sure that any type of potential biomolecules are not completely reworked by radiation, you know. So our experimental study was essentially to simulate effects of the ionizing radiation is on this to icy moons and determine how long will it take, if life is there? Or if vertical biomolecules will end up on the surface of those moons, how long will it take for them to completely be destroyed? Or how long will it take to survive for a significant fraction of them, because that will be very important for future missions to Enceladus and Europa whenever they will be.

Eric White  Okay. And so you were trying to figure out just how long those building blocks and we should specify those are amino acids, a bunch of other good stuff that really started things off around here. And you wanted to see how long they could survive in the harsh environment that those planets’ atmospheres create, before they were destroyed? Are they buried underneath the ice? Because those are ice planets, right?

Alex Pavlov  Yeah, so it’s important, these icy moons don’t have really the atmosphere, that’s why amassing radiation is so concerning. You know, like on earth we are doubly protected from radiation because we have thick atmosphere, and we have magnetic field. That’s not the case there. So, we have to pay attention to this. And yeah, we simulated with the samples, the ice samples, we dissolved amino acids, and dead microorganisms in those ices and exposing to gamma radiation, which is a proxy for the ionizing radiation would be expected on those moons. And then, you know, calculated the dosage and see how long, like what dosage, they still be recognizable, the significant fraction of this amino acids will be recognized, which we can tell us that, hey, originally, there was life there, you know, and turned out to be that time take to destroy this isn’t quite long. It takes on Enceladus in particular, it takes 100 million years to wipe it out even very close to the surface. So, that means that the ice on Enceladus will have a time to turn around. So, will become a new ice before the amino acids can be destroyed. So, that’s why a future lander, whenever that might be, will land on Enceladus, it’ll have a good chance to detect amino acids from the interior of the planet. And so there is life, we will be able to see that. On Europa, the situation will be a little bit more hotter because radiation levels are higher. There’s no questions about it. But there are still spots on Europa. And highlighted here is when if you just dig by basically 20 centimeters, which is 10 inches, 15 inches, something like that, there’s still enough thickness to protect those molecules from complete destruction. So there are certainly locations in the Europa where you still can don’t have to depend, still will be able to see biomolecules.

Eric White  We’re speaking with Alex Pavlov. He’s a space scientist with NASA. So, that’s fascinating how resilient these amino acids and molecules are just from a little bit of protection from some of the ice. What is it about the ice that shields it from the radiation that is constantly being blasted at it from space?

Alex Pavlov  But it’s not as much ice as much as temperature helps. First of all, you know, the goal of the temperature is better to please in terms of preservation, right. So if you break the molecules, they are not as subject to that tax by oxidative radicals, you know which radiation is by using because nothing is mobile in the ices at this temperatures. That’s one fact. And the other one, as I mentioned, we didn’t just look at the amino acids from dead microorganisms. So, our logic was, right, let’s just suppose the cells out there right? Suppose life is in the ocean. It might incorporate these amino acids. This is often water but it might incorporate as the cell, right. It’s this chunk of organic matter. So, in some of our samples, there was pieces of E. coli, for example, right. Dead E. coli. And we found out that amino acids in those chunks in those organic shells, they degrade much slower than individual amino acids. Right? They’re kind of because of their guidance errors around them. Again, oxidative radicals, which produced by radiation, have troubles to get to them, you know, and that overall means that the amino acids, the biomolecules, the tracers of life, will withstand for a longer period of time. So, that’s kind of what our findings were.

Eric White  Just a curiosity question about how the research was conducted. You said you were able to calculate, you obviously didn’t watch these for hundreds of millions of years. What goes into the calculations of determining, oh, okay, you know, this much happened in a day and you just kind of multiply that, is it that simple? Or is it a lot more complicated?

Alex Pavlov  So, we know the fluxes of ionizing radiation and the icy moons, right? You know, they’re partially they’re mortal, partially they’re observed. And we can calculate about the dosages that those straits at what how radiation accumulation dosage per second, if you wish, and then we’ll say, well, all right, you know, so you know, the ice is about, you know, up to 100 million years old, what will be the total cumulative dosage those ices would accumulate? Having this dosage in mind, we’ll go to our usual facilities here on Earth. So obviously, we will have to radiate, we can’t wait 400 million years, we’ll have to blast them out at a much faster rate, right.? And so we went to the nuclear reactor at Penn State, and we blasted it with gamma radiation there to accumulate the total dosages. We did experimental a couple months, but obviously, so it won’t be much faster radiation rate, but the total dosage which they would receive there would be the same and based on those dosages we can calculate well, okay, so amino acid decays about at that rate, you know, different kinds, you know. I never see E. coli, it decays slower, you know, so that in mind, you know, having this reduces constants, which is essentially efficiency, how they decaying, we can then extrapolate the what’s happening on these icy moons, and make, you know, okay, on the same surface of Europa, not so well, you know, but some location 20 centimeters deep, that’s okay. You know, and some of this looks like everything is peachy. And so wherever you land, you know, you just can just go ahead and scratch the surface, like, a couple millimeters, and you’re in business.

Eric White  Enceladus sounds lovely, which is interesting, because you had always heard, you know, it had always been about Europa, from, you know, just what I hear in passing from space coverage. But so yeah, let’s talk any future visits that the agency or anybody else really has in mind. You know, you had mentioned that if we were to send a probe to either of those two spots, and just, you know, do some light digging, we could potentially find these amino acids and protein builders and things like that. What would be the significance of that? You know, obviously, people think we discover life, you know, we’re looking for even micro organisms moving around, but just finding those building blocks, what would that significance mean for finding extraterrestrial life or even just the beginnings of it?

Alex Pavlov  Well, obviously, we relate to it from our perspective, right? You know, our perspective is all life as we know, it is based on amino acids, and nucleic acids. So, there’s very few biomolecules which are present. And what we also know about amino acids that they also chiral, they have left handedness, right. And so all life favors the L amino acids, left handed so-called amino acids. So, and when you will find any amino acids in the university meteorites, the abiotic amino acids, there is a little bit access, but it’s both left hand and right hand that present. So imagine if you landed on Enceladus, or at the high latitudes of Europa, and after digging, you find out the amino acids, which are all right handed or left handed, based on life, as we know it, that will certainly be very strong indicative that’s life, you know, that this is not equal proportion of findings, left handed and right by them, you know, so that, you know, not it’s not a sell, per se, you know, but, you know, we do not know, in nature, the processes, which will have 99 percentage of left handed versus right handed. So, that’s a tremendous motivation to go and dig below the ice eventually.

Eric White  Well, until that point, what’s the next idea that you got for testing out just how sustainable the environments on both those moons are? Obviously, you’ve thrown radiation at these molecules. What else are you going to do to make life tough for them?

Alex Pavlov  To make life tough on them? Well, being in terms of the older chemical components, they are there on both icy moons, and so, the important things to test is, of course, to test it, well, variety of things. Well, one thing is to test, you know, for different types of molecules, right? You know, we tested amino acids, we didn’t test nucleic acids, right. The other thing is, there’s different types of radiation. We tested using gamma radiation. On Europa is mostly energetic electrons. On Enceladus, is mostly energetic products. So, it’s a proxy. So, the dosage of radiation is the same, but the type of radiation which inflicting the damage is what is different. So there are things like this. And of course, the most surprising discovery probably which we had this was to look at different types of dead microorganisms, we’ll look at E. coli. But another type of microorganism, AUD, for example, show the step function decay. So, instead of a gradual decay, with dosage, there was an initial drop, and then just stick it out. And also, which, which would be great for Europa, and because all of a sudden, if say you drop 40% of the initial abundances by molecules after that, if they’re not changing or changing very, very slowly. That’s great news. You know, that means, okay, you don’t have 100%. But you know, if you have 60% of the original biomolecules, that’s great, you know, so, obviously, it needs to be tested on different microorganisms, see if this is indeed the pattern that not only the degradation is slow, but it slows down with the dosage. That’s something very interesting to test.

Eric White  And if you don’t mind, why this particular area of work? That’s always a question I have for folks that haven’t been on something so specific, because there is such a vast array of studies that are available in this realm. You know, what made you want to look into this?

Alex Pavlov  Well, as a planetary scientist, I have several projects, and this is only one of them, but it’s obviously a fascinating, you know, searching for alien life anywhere within our own solar system. I don’t know what can be cool for planetary science to be honest. You know, seriously. And so, and I come from Mars research, I do a lot of Mars studies. But from the standpoint of pure astrobiology, just availability of water flicked with water, this liquid oceans with all the chemistry in it makes us do, you know, those icy moons, just trying target. You know, Mars will be my first love, but you know, Enceladus is very tempting.

Eric White  It’s so bad, it’s your secondary school, right? Alex Pavlov is a space scientist with NASA. Thank you so much for joining us and telling us about this research.

Alex Pavlov  Thank you.

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