Planetary Radio: Space Exploration, Astronomy and Science - 3 Billion Years Ago: Was Mars Alive?

Episode Date: July 15, 2020

Perseverance, NASA’s 2020 rover, leaves for the Red Planet in just days. Deputy project scientist Ken Williford tells us how it will look for signs of past life where there was once a Martian lake. He’ll also take us through his Jet Propulsion Lab facility where scientists are learning how to recognize the evidence of long ago biology here on Earth. Comet NEOWISE is still lighting up the northern hemisphere sky. Bruce Betts knows where to find it. We’ve also got great new prizes for the space trivia contest. Learn more at https://www.planetary.org/multimedia/planetary-radio/show/2020/0715-2020-ken-williford-perseverance.htmlSee omnystudio.com/listener for privacy information.See omnystudio.com/listener for privacy information.

How Perseverance Will Look for Life on Mars, this week on Planetary Radio. Welcome, I'm Matt Kaplan of the Planetary Society, with more of the human adventure across our solar system and beyond. Strictly speaking, I should have said how Perseverance will look for past life on the Red Planet. Perseverance will look for past life on the Red Planet. There's so much more to this story, though, including how the study of ancient life on Earth is preparing us for the quest on Mars. Ken Williford is Deputy Project Scientist for the rover mission that is now set to launch on or shortly after July 30th. He'll take us inside Perseverance and into his fantastic JPL lab. We've also got two contests to finish this week, along with your opportunity to win one of two ultra-cool New Planetary Society T-shirts.

Bruce Betts will also tell you how to see Comet NEOWISE. With so much going on, we'll make this week's dip into the downlink very brief. Want to see how astronauts on the International Space Station caught the comet? That's the lead image in the July 9 edition. It's followed by headlines about the ongoing troubles of the mole on the Mars inside lander, the next road trip for the Curiosity rover in Mars' Gale Crater, and new findings of more metal on the Moon than was thought to reside there. You'll find lots of links to learn more about these and many other stories at planetary.org

slash downlink. Here's the word of the week. Astrobiogeochemistry, or if you want to save time, ABC. It's the field and the opportunity that brought Ken Williford to the Jet Propulsion Lab a few years ago, and it helped prepare him to help lead all science activity that will be conducted by Perseverance. That science will include the collection of samples for eventual return to earthly laboratories, even as the big rover conducts its own analyses. As you'll hear from Ken, Perseverance also carries instruments and experiments that will bring humans one step closer to visiting the red planet themselves. Get ready for an absolutely fascinating exploration of this mission and the search for ancient life that it will undertake.

Ken and I talked online a few days ago. Ken, it is an honor to welcome you to Planetary Radio, especially now when we are days or at most a couple of weeks away from the launch of Perseverance toward the Red Planet. Thanks for joining us. Yeah, it's good to be with you, Matt. It is a very exciting time. Let's start with the obvious. What's the current status of the spacecraft and that Atlas 5 rocket that is supposed to get its on its way toward Mars? I mean, the delay was from the rocket, right? Nothing to do with Perseverance. That's right. There were a few issues with the, we call it the launch vehicle, but yeah, with the Atlas V rocket and associated equipment. But everything I've heard

so far suggests that the issues are under control and everything has a solution and we're on track for a July 30th launch. So I just saw a little bit ago, someone sent me a picture in an email from down in Cape Canaveral, a nighttime shot of our spacecraft all buttoned up inside the fairing, being rolled out to the pad and ready to go up on top of that big rocket. Does this mean that RTG, that hot radioactive package, is it already installed in Perseverance so it's ready to power up when the time comes? Actually, that's a good question. I believe it is not.

And I can't tell you actually all the details just because I don't know of the exact step-by-step sequence to getting everything ready for launch. But I did hear today our project manager talking about a dress rehearsal with the RTG. our project manager talking about a dress rehearsal with the RTG. And so I believe that must either be done sort of before they lift it up and put it on the rocket, or even after it's already up there, they put the RTG in last. If I remember correctly, with curiosity, it was not installed until very shortly before launch. So I bet you're right about that. installed until very shortly before launch. So I bet you're right about that. Before we talk more about Perseverance and what its job will be on Mars, I noted that you lead a lab at JPL that I'm embarrassed to say I'd never heard of until I started to do research for this conversation.

Even though its name is as simple as ABC, what is the Astro Biogeochemistry or ABC Lab that you lead at the Jet Propulsion Lab? Yeah, well, you have to run in certain circles to have heard of the ABC Lab, I guess. But yeah, we do have a lot of collaborators around the world, but they tend to be organic and isotope geochemists doing similar kinds of work. But our mission really in the lab at JPL is to study the processes of formation, preservation, and then the detection of signs of life and planetary evolution in geologic materials, and planetary evolution in geologic materials, if that sounds like a mission statement. It is, and it aligns. So it's what I came to JPL to do originally, now going on about almost eight years ago.

And it was always with an eye towards supporting Mars sample return, and what we call typically return sample science. And so that's the type of science you do on Earth, eventually with samples that are returned from other worlds. In this case, the work in my lab is very specifically dedicated to preparing us to work on samples from Mars that we hope one day will come back. And we're most interested

in looking for signs of life. In this case, it's ancient life in generally very old rocks. So rocks that are most typically in my lab, hundreds of millions of years to several billion years old. And some of them are the oldest sedimentary rocks that we have on Earth. And we're studying some of the earliest Earth environments, some of the earliest evidence for life on Earth. But then another theme is looking at the interactions of living organisms on planet Earth and the non-living systems, the geologic systems, looking at the co-evolution of those things, especially at times of great change. So we're interested in studying mass extinction events and other things like that in the lab. But generally, everything we do is with an eye toward refining the techniques. We call them

the interpretive contexts, or just building the scientific contexts necessary to understand all the great data that we hope to extract from samples that come back from Mars one day. When you look back at the most ancient era of life on Earth, when life began, or at least not long after, my understanding is you don't see a lot of fossils. Are we learning to detect the past presence of life in other ways, which are probably going to be useful on Mars, or we hope will be? Yeah, that's right. There are fossils, I would say, going back, extending back to as far as the good, I would say, conclusive record of life extends on Earth, which in my personal view is to about three and a half billion years ago. There are signs of life that have been reported in rocks older than that, back to about 3.8

billion years ago or potentially older, depending who you believe. But everything older than about three and a half billion years is generally quite controversial and plagued by a lot of ambiguity because the rocks have been so heavily altered at that age by the forces of tectonics on Earth. But we have this record starting at about 3.5 billion years ago, expressed best in Western Australia, a place called the Pilbara, but also some places in South Africa. We do in fact see fossils all the way back and they are not the kinds of fossils that most people are used to thinking about. Certainly nothing like a dinosaur bone, but not even a trilobite if you're familiar with that, or any kind of clam fossil. This is a long time before the evolution of animals and even plants.

This was a time, and in fact, most of Earth history, the vast majority of Earth history, really, the entire planet was populated only by microscopic microorganisms. Now, sometimes those microscopic organisms, so these are bacteria and similar organisms called archaea, so single-celled organisms that sometimes group together in colonies. You know, most people would be used to seeing pond scum, this sort of bright green stuff at the edge of a pond. And that's exactly the kind of stuff we see preserved in rocks. You know, the fossil versions of pond scum are what we see preserved as the earliest best evidence for life on earth in these three

and a half billion year old rocks in the Pilbara in Western Australia. We call these things stromatolites. Imagine a gooey layer of pond scum, and then you have some mud and silt and sand flowing in, covering that gooey layer, getting trapped in that gooey layer of bacteria. And then the bacteria grow up and over that layer of mud and sand. And the whole process repeats over and over and over again, until you build up this wrinkly layered structure that then gets buried and turned into a fossil. You know, a long time later, some geologist comes around and digs it up. And that's the kind of thing, honestly, that that's sort of the holy grail of what we've got

our eyes peeled for with Mars 2020. That's the kind of thing that could be detectable with our rover. And we are certainly going to explore the environments in Jezero Crater, where if that ancient lake was inhabited, and if it was capable of producing pond scum, we are going to go to the rocks, particularly on the edge of that lake, where that stuff would have concentrated and fossilized if that lake was inhabited. So that's one of the types of things we're most excited about for March 2020. I want to mention that I watched most of your fascinating 2017 von Karman lecture at JPL about perseverance. fascinating 2017 von Karman lecture at JPL about Perseverance. But in that, you had an image of a section of stromatolite. We'll link to that lecture, of course, from this week's show page at planetary.org slash radio. How big a dance would you do, will you do, if Perseverance finds stromatolite in Jezero Crater?

Oh, it will be quite a dance. I'm picturing the Michael Jackson thriller video or Saturday Night Fever combined on steroids. That would be a very happy day if we see anything that looks like those stromatolites in Australia. Of course, that said, when the dancing subsides, we will all get to the task of making sure we can confirm a shape like that is actually something important and was actually produced by life. And it's a very tall order. So even with the oldest evidence for life on earth, the scientific community finds it challenging to come to strong agreement. When any new paper is

published, pushing back the record of life and putting a case together that life emerged maybe earlier than we thought, it's hard to get agreement. And usually it takes years, sometimes decades, where many different scientists have to go and look at the same rocks with all sorts of different techniques. Sometimes the story changes over the years as we learn more and different things. And even more so, as you can imagine, for Mars. So it's such an extraordinary claim. you can imagine for Mars. So that's, it's such an extraordinary claim. It would be such an extraordinary claim that life once existed on Mars, that it will certainly require extraordinary evidence. And that's why we think it's, it'll be critical to get those samples back to analyze them no matter what we see really on the surface of Mars with 2020. Well, thank you for paraphrasing that quote from our co-founder, Carl Sagan. You have made me

think back to a time when I did a little dance. Not too many years ago, I got to hold a tiny fragment of that famous piece of Mars known as Allen Hills 84001. I remember when the announcement came, I was so thrilled that when NASA announced that microfossils had been found in this meteorite from Mars, I had to pull my car over to the side of the road and get out and do a little dance. Wasn't long before that conclusion was called into doubt. You know, good science can be so disappointing sometimes. What have we learned since then?

How will we avoid getting it wrong this time? Or did we even get it wrong that time? Well, I think it's a great example, the Allen Hills meteorite. And in a sense, I might not be where I am, having made it through grad school funded by the NASA Astrobiology Institute, largely working on a Mars rover mission at JPL, had it not been for that work on Alan Hills. As much as we point to it as an example of, you know, jumping to conclusions or maybe getting something wrong, really, if people, I really encourage people to go back to that paper or go to the paper, the McKay 1996, McKay et al. 1996 paper that was the original report. And there is a lot of good work to be found in that paper. And often that study is used, I think, oversimplified. And we look at those images that are pretty famous of these sort of worm-shaped features in the rock. But the study was about much more than that.

And it was actually, I think, a pretty nice template for the kind of approach that we take today, where we look for combinations of lifelike shapes. Sometimes in geology, we call them textures or morphologies, but basically lifelike shapes in a rock that are combined with or co-occur with in space, lifelike compositions. So chemical compositions, these can be the elements that are the chemical elements that are important to biology. So there's this sort of super important short list that we often call schnapps, C-H-N-O-P-S. But there are certainly quite a few other elements that are important to life. And then biologically important minerals, you know, the seashells around us are made of calcite or aragonite, our teeth and bones have

apatite, hydroxyapatite, phosphate minerals, carbonate minerals, sulfide minerals, iron oxides, and so forth. Minerals that tend to hang out in the presence of life, they do so often because they represent metabolic substrates. So all animals, ourselves included, use one very specific type of metabolism, aerobic respiration, where we take in organic matter, breathe in oxygen, and harness that energy, that very energetic metabolism. But basically, any chemical reaction that you can imagine that involves what we call redox chemistry,

oxidation reduction chemistry, and rusting is a great example of that, turning iron into iron oxide. Any chemical reaction like that, there's some microbe living off of it. So there are so many different types of metabolisms. And those different metabolisms, when they're expressed in the environment, lead to the precipitation of different minerals that can be preserved for billions of years. So that's important. We look for those. And then we look for lifelike compositions in terms of molecules, the organic molecules. So all life that we know of is carbon-based. We'll often hear about, yeah, but what about silicon-based life or other possibilities? And there are all kinds of possibilities. But when we talk about looking for ancient life on Mars, we're looking first,

at least, for life mostly as we know it. So for carbon-based life that would be built of organic molecules and use liquid water. And so this, going back to that original Alan Hills study, if you take a look at that paper again, you'll find that they were using a bunch of different cutting edge techniques to look at those concentrations of elements and minerals, and in some cases, molecules that co-occurred in shapes that were interesting. So it's actually not all that different, the approach we use today. Now that said, you're right that I think the consensus view is that the interpretation that that represents evidence of ancient life on Mars is not really there in the scientific community today. But it launched that study and similar things around the same time, launched a whole new conversation about astrobiology and the search for life on other planets. The NASA Astrobiology Institute

was founded not long after that. And again, like I said, that paid for a lot of my PhD and put me where I am today. So I certainly look at that study as a really critical step along the way to where we are today. It just reminds me that even when science may have a disappointing result, it often leads to terrific progress. You're talking about that paper from 24 years ago. You look back 44 years to Viking and its first attempt to find biological activity on the red planet. We have learned an awful lot since then, right? I mean, including about the sorts of, yes, life as we know it, but still extreme life as we know it, those so-called extremophiles. That's right. Clearly Viking, and you mentioned Carl Sagan earlier, those heady days

around the time that I was born, actually. And Carl Sagan has long been one of my scientific heroes. And I remember watching the entire Cosmos series in high school and just being so inspired. Yeah, Viking was a huge step. But again, as you said, we have come a long way. And so I often say that Mars 2020, with our core objective to directly seek the signs of life, is doing something in astrobiology that I think has not been done this seriously since Viking, really. So after Viking, with largely negative results from the biology experiment. You and your audience will be aware that there was one part of the biology experiment that produced some ambiguous results that even some folks today think might have pointed to life. But again, the consensus is not there. And generally, people think the biology results from Viking were negative. There was a real lull in Martian surface science after that

until Pathfinder and kind of the era that we're in now of the Mars rovers. But there was this stepwise approach starting with follow the water with MER to MSL, which so brilliantly kind of took a more nuanced approach to habitability, finding evidence for habitable environments that went beyond the sort of binary presence or absence of water. And again, they did that beautifully to now what we're doing, which we'll follow in those footsteps. And of course, we'll be following the water all the way to this lake, ancient lake in Jezero crater. We'll be using a lot of what we've learned from the approach that MSL and Curiosity took to understand the habitability of that environment. But then we'll take that next

logical step, which is to directly seek the signs of ancient life in a way that I don't feel was at least as explicitly done by past missions. Now, that links us to Viking. But of course, we have to understand there's a very important distinction between our mission and the Viking mission. And that is that Viking was primarily looking for evidence of extant life. So those biology experiments were looking for life that was alive at that time or had recently deceased, you know, in the Martian soil or the Martian regolith. Our mission is to look for signs of life in rocks that are very, very old. So in rocks that are older than the ones that I talked about earlier, where the oldest evidence for life on earth is. So these are between 3 and 4 billion years old, closer to 4 billion years old.

So these are very old rocks deposited at a time when Mars was much more Earth-like than it is today and where we have excellent geologic evidence that there was abundant liquid water on the surface, which tells us that the atmosphere must have been very different, much thicker. We believe there was probably a magnetic field and that the planet was much more active and dynamic than it is today. And so we're taking the approach of looking through that window, which is three and a half billion years old, to see if we can determine whether life existed back at that time. Though I imagine you wouldn't, you and the rest of the science team wouldn't complain if one of those cores that you'll be pulling up,

if something tiny crawled out of it, within view of one of the cameras on Perseverance. True, true enough. That would be exciting indeed. And while I say that's clearly not part of our mission is to, you know, if you wanted to design a mission to look for extant life on Mars, and it's a great thing to think about. It's certainly not impossible that life currently exists on Mars, but it's almost certainly, if it does, it's almost certainly in the deep subsurface. And so it's a very different set of instruments and set of technologies that you would send to Mars if that was your goal. And so that is not our goal. But that said, when these samples come back someday, clearly one of the most important things that will happen

will be to look for any evidence of extant life that they might contain. And so no doubt there will be work done to determine whether there is evidence of extant life that they might contain. And so no doubt there will be work done to determine whether there is evidence of extant life in our samples. It's just that our strategic approach is not to sort of optimize our capability to answer that question. This question is about how did Mars evolve as a planet? What can we learn about our solar system's evolution broadly, the evolution of terrestrial planets broadly, and then the broader question, was Mars ever inhabited? Ken Williford has much more to share with us as we begin the countdown to the Perseverance Mars rover mission. I'll be

back with him after this break. I want to come back to your lab, or rather your lab's website. I hope that people will take a look at it. It's fascinating. I especially enjoy the little tour of your lab equipment. You've got a lot of cool toys, by the way. What in the world or what in any world is a CEM Mars 6 Microwave Assisted Extraction Digestion System. Right. Yeah. Okay. It's interesting that you found yourself concentrating on that. Yeah, we are extremely fortunate to have some very fun toys to play with. I hesitate to call them toys, lest our funders get angry with us. toys, lest our funders get angry with us. But certainly we relate to them just as an excited kid would on Christmas morning when we get a new one or we get an upgrade. It's just as exciting as I remember the newest transformer being when I was a kid. So the CEM extractor, the Mars 6 device that you talked about, this is a device, it's basically a very fancy microwave. So this is a microwave assisted extraction device. And we primarily use it

to extract organic molecules from rocks. We will take a rock sample from the field. It is say a 2 billion year old, you know, mudstone from an ancient lake, let's say. year old mudstone from an ancient lake, let's say. And we believe it has organic matter in it. And that organic matter consists of the dead bodies of the bacteria that were living in the surface of that lake and fell to the bottom. And then the molecules that they were made of, some of them sort of polymerize into a gooey substance we call kerogen, but some of them remain as something like oil. We would call it in my lab bitumen, but it's basically oil. We study both of those organic substances, kerogen and bitumen. The bitumen often has a lot of great information in it about the original organisms that produced it. So we use an organic solvent, basically,

imagine something like alcohol, we just pour, it's really methanol and dichloromethane into a Teflon tube and seal it up. And inside that tube is also several grams of rock powder of that mudstone. And then we heat it up in the microwave under pressure. And that organic solvent extracts the bitumen, gets that oil into it, and then we filter the whole thing. And now we have our solvent in a vessel, we evaporate away the solvent, leaving behind this sort of oily film. And then we do some chemistry on that. And we eventually put it into our GCMS or our gas chromatograph mass spectrometer, which tells us about its molecular that. And we eventually put it into our GCMS or our gas chromatograph mass spectrometer, which tells us about its molecular composition. So we look at the structure of the

individual molecules that make up that organic matter. Many interesting things are preserved. Some of the typical things we call steranes and hopanes. And these are molecules that are produced. They sit inside the cell membranes of eukaryotes like ourselves, so algae and plants and animals inside every cell membrane. They have these molecules called steranes. We're familiar with cholesterol. That's an example of this. And it regulates membrane rigidity. And so these little membrane building blocks basically are stripped down to their basic organic skeletons, their hydrocarbon skeletons, and then they can be

preserved for billions of years. And then we can measure them in the lab and determine that, hey, look, there was a, you know, some kind of algae here living in this lake. And we make other measurements on those molecules and learn more and more about what types of life was living in those different environments and what sorts of metabolisms they were using. And also you can extract information about what the planet was doing at that time. If you say measure the same thing through a time sequence that's preserved in a long drill core, for example, we can measure the isotopic composition of different molecules and learn something about how the ocean and atmosphere were behaving over time.

It really is utterly fascinating. You make me want to visit and look over the shoulder, your shoulder, shoulder of your colleagues in the lab and watch as this works. But I mean, you'll see where I'm going with this because you have all these wonderful machines and a fair number of human hands to make them all do their work properly. You don't have that luxury on Perseverance. Now, the suite of instruments that it carries is simply awesome. But I mean, if you were to think about what Perseverance is capable of doing on its own, I don't even know if it's fair to ask this, but what percentage of the capabilities of labs back here on Earth, like your own, are going to be carried by Perseverance to the surface of Mars? I expect pretty small.

Yeah, that's right. I mean, I certainly couldn't put a percentage number on it, but I think it's totally fair to say that it's a tiny, tiny fraction of the full capabilities of the laboratories of planet Earth. I mean, there are so many things we can do here on Earth when we don't have to worry about the mass and volume constraints in the harsh environments of space and of the surface of Mars where the temperature swings are enormous and where it's impossible to go and repair these things. I mean, think of a synchrotron. One of the types of instruments that we like best to study the record of ancient life on Earth and plenty of other things, involves putting some type of microscope or spectrometer at the end of a beam line that itself is the product of acceleration

of electrons and production of x-rays in a ring that's the size of a city block or more. And so this synchrotron radiation allows us with different analytical techniques to get an extraordinarily high spatial resolution and signal to noise that we could not otherwise achieve. I will say we will never fly a synchrotron, at least in this form that I'm describing, because you'd never do that. If you were able to do that, you would sooner build a synchrotron on Mars than to fly it there, right? Now, of course, it's possible that we could find some radically new technology that would allow us to do the same thing in a smaller package, but we don't have that yet. And even then, just sort of by

definition, anything you send to another planet, you're always going to be able to get more, have more diverse capabilities if you bring a sample back to, you know, the scientific home of humanity, which is planet Earth. So as you said, yeah, there are extraordinary capabilities that represent pretty major advances in interplanetary science on Perseverance relative to prior missions. It's often asked, do we have to make major sacrifices in instrumentation to do what we're doing to move Mars-SAPL return forward? And it's certainly true that the space that on the Curiosity rover that is taken up by the SAM and KEMN instruments, those large spaces inside the front of the rover where you have these extremely capable analytical laboratories, that space on

Perseverance is taken up by what we call the adaptive caching assembly. And it's this sort of robot within a robot that looks like a little bottling plant. And it stores the sample tubes and it processes the sample tubes, etc. But it's also true that out on the end of the arm, we have two very advanced new instrument platforms called Sherlock and Pixel. And these are both spatially resolved instruments of a type that we have never had on a previous space mission. These things both are analogs to instruments that we use, like instruments we might find on a synchrotron or in labs back on Earth, where we can sort of simultaneously extract that spatial information and the compositional information. So we're at the same time, we're looking for lifelike shapes and lifelike compositions. And both instruments raster or move a beam about the diameter of a human hair over an area about the size of a postage stamp, and they create a map of chemical composition. And so you're now resolving spatial information in the compositional

heterogeneity that we were not otherwise able to do in past missions. So whereas the APXS instrument on the Curiosity rover averages the elemental composition over about, say, a square centimeter, PIXL will map that elemental composition over about the same area. So it's a big advance. So it actually creates an image. What is the advantage of having that spatial revolution rather than, as you said, just averaging out what the radioactive activity it finds? Yeah. So we will often talk about in the scientific community, and we deal with it in my lab, the difference between what we call bulk analysis or spatially resolved analysis. And they absolutely both have their strengths.

Bulk analysis is often cheaper and much faster, and you can get a higher throughput measuring those average compositions. And sometimes you actually want to know the average composition because it allows you to sort of not be biased by this or that thing. You really just want to kind of average over a larger area for certain questions. But spatially resolved analysis, which is almost always technologically more difficult, you know, in labs back on earth, sometimes more expensive to do and requires more careful sample preparation often, so it can be slower. But the amount of information, the information density is so much larger in this case.

And the key thing here is spatially resolved analysis, like we will achieve with Pixel and Sherlock on Perseverance, allows us to simultaneously look for lifelike shapes and lifelike compositions. So it's not just, do we see a composition that indicates life? It's, is that composition that indicates life? Is it arranged in a shape that itself indicates life? Another way to say is we're looking for spatially correlated compositional heterogeneities. So some folks say life tends to be clumpy. It has little bits of this over here and little bits of that over there. So those are the types of things we're looking for. In your von Karman lecture, you pointed out, as you zoomed in on a bit of stromatolite,

pointed out, as you zoomed in on a bit of stromatolite, a little wavy, a little bit of filament. And you said this is the kind of thing that gets people like you excited. That's right. Yeah. And that is something that I'm not sure in that case, it is a fossil microbial cell, but it looks very much like what we call microfossils, which in younger rocks, microfossils can include little protists like foraminifera and little sort of single-celled animal-like things. In the much older rocks, certainly that we'll study on Mars and the much older rocks on Earth, these microfossils are even smaller, and these are individual fossilized bacterial cells. And so they're often tiny little spheres or filaments that are one to 10, say,

micrometers in diameter. So very, very, very small. Smaller, in fact, than anything we can resolve with any instrument on perseverance. And so in order to see these things, not only are they smaller than what we can resolve with the instruments that have ever flown, by the way, on any space mission, they require some very careful sample preparation. And the image I was showing you there or showing in the lecture was of what we would call a petrographic section. So it's where

we cut a piece of rock, basically glue it to a glass slide, and then cut away as much of it as we can, and then grind it down until it's thinner than a sheet of paper, and then polish it to a mirror finish. So we can shine light through it and see these little features that are inside of it. So those are the types of techniques we'll be able to do with the samples when they come back from Mars. And it opens up many new analytical possibilities. And again, I'll recommend that listeners check out that lecture that you delivered about three years ago.

It's a great additional background to all of this with the advantage of your great slides. While we're talking about images, Jim Bell was my guest a couple of weeks ago. We talked about how his team's Mastcam-Z will integrate with the other instruments carried by Perseverance, some of which you've been talking about. How important is that imaging on a bigger scale, the kind of stuff that Mastcam-Z can do in the search for past life on Mars that Perseverance will be taking on? It's absolutely critical.

I mean, it's just absolutely fundamental to what we're doing. And the Mars rovers are often described as robotic geologists. More than anything, the Mastcam on Curiosity and Mastcam-Z on Perseverance are like the eyes of that geologist. fairly tall geologists sort of cruising across the surface, looking around and doing that most basic activity that a geologist does in the field, which is to look at the shapes, the colors and the textures and the structures that she sees around her to understand the basic processes of formation and alteration that led to those rocks in the exploration area. So they really are sort of our first weapon there as we explore our environment. Everything that you've been talking about

just is more evidence of what a complicated machine this rover is. You mentioned that sample handling system, which is just a mechanical marvel. I mean, to me, it seems more like robots within robots within a robot, but one more level of complication. Do you ever worry about all those moving parts in that harsh environment? Yeah, you're right. It absolutely, it's sort of robots all the way down, right? A robot within a robot within a robot. And to say nothing about the follow-on missions, I mean, it's a very similar situation there. Just the number of robots involved boggles the mind. But I try not to worry about that. You know, there are certain things that are outside of my control, which is nearly everything. And, you know, I just don't walk down that path of worry in that case. I, you know, instead, I think about my colleagues, the just incredibly talented engineers at JPL and all the other organizations that have supported us to put this thing together and to get it into space. It's been really a highlight of my career to work with the people who are so

creative to come up with these designs, but then to make them happen. I mean, we have this sort of key challenge or key benefit from another point of view of working at JPL is navigating the science engineering language boundary. It often feels like we come from different countries, you know, and it can be frustrating at times. But the beauty of the engineers is they actually get it done. You know, the joke is the scientists are always trying to break it and make it do more than it can, or they always want more. And the engineers are just trying to hold us back.

But the engineers, whereas we dream up every possibility, you know, in the realm of science and come up with all the fun stories, but the engineers make it work, you know? And it's just, I've learned so many times during my experience on this mission, you know, and it's just, I've learned so many times during my experience on this mission, you know, about the kinds of sacrifices that need to be made and, and how it, you don't always get

everything that you want, but it's, it's in the interest of, of getting something, you know, and making it work and solving a problem that is just, you know, absurdly hard if you really think about it, uh, what we're trying to do here. And, and so, you know, absurdly hard if you really think about it, what we're trying to do here. And so, you know, my hat goes off to all of them and I try not to worry. It does seem like you guys on the science team, you discover the miracles and they build them. That's right. Yeah. Yeah. We need each other for sure. Before we leave Perseverance, there are two or each other, for sure. delicate humans to follow the robots to Mars. Can you mention a little bit about that role of Perseverance and how it will be helping to make it a safe place for us men and women?

Yeah, absolutely. I mean, I personally think that's a very important part of what we're doing. I'm a huge fan of human spaceflight, and I'm very inspired by the idea of one day, a human being flying to Mars and standing on the surface, picking up a handful of Martian regolith and grabbing a few rocks and bringing them back to the ship and flying back to Earth to tell us all what that felt like. I mean, that idea really inspires me, and I know it inspires a lot of people in this country and in the world. And so I look forward to when we can one day see that happen. We have the META instrument contributed from Spain, which is a weather station. So measuring the weather conditions is obviously relevant to future human explorers. We have the MOXIE instrument, which converts a carbon dioxide, which is abundant in the Martian atmosphere, into oxygen, which is very rare at Mars, in the atmosphere anyway, but would be vital to human explorers. atmosphere anyway, but would be vital to human explorers. Obviously, human explorers could breathe oxygen, but a critical piece of getting humans home safely is having an oxidizer for the

fuel in the rocket that will get them off the planet's surface and back home. And all the better, so much the better if they don't have to bring all that oxygen with them from Earth and can have it made for them on the surface. And so that's what MOXIE does is to demonstrate on a small scale something that could be scaled up later to support human spaceflight. And then RIMFAX is an instrument that's contributed by Norway, and it's a ground penetrating radar. This technology has been used in the past in orbit and currently in orbit around Mars, but never on the surface. We plan to use RIMFAX mostly to look at geologic structures in the subsurface, but one application for ground-penetrating radar in the future could be to look for ice or water in the subsurface that human explorers could use. So those are the specific

things that we're doing. But in a broader sense, everything we learn about Mars prepares us better, I would say, to send humans there and get them home safely. It is all thrilling. We are all looking forward with such excitement, enthusiasm to that launch. And then out there in February of 2021, those seven minutes of terror that we experienced with curiosity, where are you going to be when perseverance makes that descent down to the surface? Yeah, well, it's an interesting question. Certainly, I will be either at JPL or very close to JPL. I imagine I'll either be on lab, we call it, at JPL. And I really hope there's a way for us to do that safely, to be there together as a team. But as we all know, it's such a strange time in the world right now with the coronavirus.

And so it can be hard to get those groups of people together in a small room that we're all familiar with, jumping up and down and yelling and screaming with joy at a successful landing. I don't know what it my family watching this on the computer. And that'll be okay, too. You know, no matter what, we're going to be together, you know, in spirit, at least. And I'm definitely going to be connected immediately. You know, I'm sure I'll be texting with my best friends on the mission and, you know, in phone calls. and in phone calls and at the very least, celebrating what I hope and expect is just gonna be another one of those great days where we can all be proud of what we've done together.

Well, I'm gonna share that hope with you and I'm gonna go beyond and hope that we are back in a big room full of people, thousands of us who watched curiosity make that descent. And we were jumping up and down and cheering. I'll only say this time, let's hope it's a big room full of vaccinated people. But one way or another, we'll be following along with you, Ken. I got just one other question for you.

And it was obvious from your Von Karman lecture. I think it's obvious from this conversation. You clearly enjoy sharing what our boss, the science guy, calls the passion, beauty, and joy, the PB&J of science. Is this as important to you as it sounds like? Absolutely. Yeah. I mean, I was just talking with some of my colleagues earlier about exactly this question. And I can tell you that for myself, the opportunity to do this kind of thing and to talk about science with other scientists, but especially with non-scientists is as important to me as anything. I love so much being able to talk about these things and

share ideas and communicate. So I appreciate this opportunity and it's great. Look forward to many more. Ken, it really has been a great pleasure. Thank you so much for joining us here on Planetary Radio. Ad Astra, Ad Ares, looking forward to all that great science that Perseverance will start doing in February of next year. Yeah, the pleasure is mine. Thank you so much, Matt, and look forward to talking to you about it again when we're on the surface, maybe. Oh, please count on that. I hope you'll be back.

And maybe before then, that's Ken Williford. He serves as the Deputy Project Scientist for the NASA Mars 2020 mission, Mars 2020 rover that we now know as Perseverance. He is also the director of the JPL Astro-Biogeochemistry Laboratory. Bruce Betts joins me next. Greetings, Bill Nye here, CEO of the Planetary Society. Even with everything going on in our world right now, I know that a positive future is ahead of us. Space exploration is an inherently optimistic enterprise. An active

space program raises expectations and fosters collective hope. As part of the Planetary Society team, you can help kickstart the most exciting time for U.S. space exploration since the moon landings. With the upcoming election only months away, our time to act is now. You can make a gift to support our work. Visit planetary.org slash advocacy. Your financial contribution will help us tell the next administration and every member of Congress how the U.S. space program benefits their constituents and the world. Then you can sign the petitions to President Trump and presumptive nominee Biden and let them know that you vote for space exploration. Go to planetary.org slash advocacy today.

Thank you. Let's change the world. Time for What's Up on Planetary Radio. It's the special extended edition of Planetary Radio. We're answering two, count them, two contests today. I know, it's never been heard of before, except maybe once, I think. Anyway, that voice you heard incredulously there was Bruce Betts, the chief scientist of the Planetary Society. Welcome back. Thank you. What? What's up? There's this comet. We talked about it last week. You've been stuck under the fog and clouds, haven't you? I've tried twice.

Socked in, as they say. So Comet NEOWISE has turned out to be pretty groovy, especially for those using binoculars and taking pictures. There's some gorgeous pictures on the web. You can see it naked eye. Don't expect it to look quite as stunning as in the pictures with your eyes, but it's still pretty darn cool. And will depend on how much light pollution you've got as to whether you're able to see how much of the tail you may be able to see, or it may depend for Matt on whether clouds follow him around. And so how do you see it?

It's passing into the evening sky by the time this is coming out. That's the best place to look for it. You, the farther North you are, the better. So in our neck of the woods, Northern U S and Canada will do better than lower, but it's getting higher in the evening sky each night. And if you're in the southern hemisphere, look online for pictures because, sorry, that's all you're going to see. So look to the northwest, low in the northwest over the coming few days, and the comet will be there below the Big Dipper, below Ursa Major. It'll be rising higher in the sky each night, but it'll also be getting dimmer as it gets farther

and farther from the sun. So it's a trade-off. You're going to want to look probably an hour or so after sunset, because that's a trade-off between it being higher in the sky and the brightness of the sun i do encourage you to check find an online finder guide because it is moving from one night to another and it'll help you find it uh it is not streaking across the sky as shown in most cartoons just just a little tip there anyway's up. And if you're looking in the evening sky, look over in the east just a little later, and you'll see bright Jupiter with yellowish Saturn nearby. A couple hours later, middle of the night, Mars coming up. And in the pre-dawn sky, Venus dominating the pre-dawn east, getting higher as time goes along.

Good stuff. If you don't have clouds and if it makes you feel any better, Matt, I'll retell my story. I spent 12 nights on three trips at Palomar Observatory long ago, and every night was cloudy. Wow. I do feel better now. Thank you. Feel my pain. Let it soothe you. Share your pain better now. Thank you. Feel my pain. Let it soothe you.

Share your pain. Yes. Thank you. We move on to this week in space history. It was kind of a big week. First humans walking on another world, Apollo 11. In 1975, Apollo-Soyuz took place with the U.S. and Soviet Union meeting up in space. And then 1994, we watched the first fragments of Comet Shoemaker-Levy 9 slam into Jupiter. 51st anniversary of Apollo 11. Hello to Michael Collins and Buzz Aldrin out there. We move on to random space facts. That's the Kuiper Belt trying to make me feel worse, I think, by hissing at me.

Just for you, Matt, I've got an all-comet show. So comet tails can sometimes be as long as the Earth-Sun distance, as long as 1 AU. Stunning. They always point away from the Sun, even when it's headed away from the Sun. That one I've used long ago, but good to keep in mind. Tails are leading as Comet NEOWISE heads away from the Sun. We move on to the trivia contest where we have not one, not three, but two contest answers. Where shall we start, Matt? Let's start with the joke. So I asked you

all to make up a light sail joke and we would subjectively using all of our wisdom and judgment pick a winner. And I know we did great, Matt, because I've looked at them. Tell me more. I will. I'm just thinking about our judgment and wisdom, which we probably did use 100% of. Between us, we probably have 100%. No wonder my brain is so tired.

All right. So here it is, folks. Thank you to all of you who submitted. You did entertain us, every last one of you, but we don't have time to give everybody.

I'll read a couple of runners up. Robert Johannesson in Norway. Two light sails were crossing the asteroid belt on their way to the outer solar system when one got hit by an asteroid. The other light sail said, chances of you getting hit by an asteroid were more than this joke winning anything.

Turned out to be right. And the other one from Mel Powell in California. He actually submitted a whole bunch, but here's the one that Bruce and I like the most. He said he wanted to come up with something funny about how LightSail 2 changes direction, but all the jokes he thought of were too tacky. Tacky. Tacked like a sailboat. We tack twice in orbit.

He said that's the one that hurts Dr. Betts the most. Sorry. We couldn't really narrow it down to just one. So we have two winners. Oh, such craziness, Matt. Such craziness. They are both going to get Planetary Radio t-shirts that you can find at the Chop Shop store, chopshopstore.com. But guess what?

We're going to throw in two coupons for pints of Ben & Jerry's ice cream. In particular, of course, we hope you can find Boots on the Moon, the flavor that we talked about a few weeks ago, the one they came out with in honor of the appearance of Space Force, the new Netflix TV show with Steve Carell. Well, we have a couple of these left,

and if we get them out quickly, I think they're only good for another couple of weeks, so we'll try to get them right out. Here's the first of our winners, Gene Lewin in the state of Washington. And he also submitted, I think, 10 different jokes. But here's the one we like the most. Why didn't LightSail invite Earth's atmosphere to the party? Why? Because it was such a drag. First atmosphere, it's a drag. It is a drag. No, no, no. If you have to explain it, it's no good.

And then, maybe not surprising, the only one that we teased you with last week, Stephen Trollinger, or Trollinger's joke, we'll repeat it here. Where does the light sail sleep when visiting the photon? Photon, photon. I just have a bad habit of explaining jokes. Sorry. Stephen and Gene, congratulations. We will try to get those right out to you. At least we'll try to get the coupons right out so you can enjoy your Ben and Jerry's. And thank you again, everybody, for entering. We can go on to the other contest. I asked you, what do the following have in common? The Venus atmosphere near the surface

and some coffee decaffeination processes. How did we do, Matt? Sort of a more or less moderate response to this one, respectable, but I think it threw a lot of people. A lot of people talked about how difficult it was to sort of correlate these two things in a Venn diagram of coffee, Java, but they worked it out. Here's a response not from our winner. Sorry, Marine Benz in Washington State. It's a good week for Washington, but still a good way first to get started. Steaming hot Venus and my sad decaf brew possess a common connection known as CO2.

How close is she there? I would have to say that is a correct answer. I was looking for more, but I didn't specify that. So indeed, they both share carbon dioxide, at least one of the decaffeination processes. But what's, I think, super cool, super cool, is that they also share another detail. Did anyone else bring that up? actually. Then we even got some explanations of it from some people. It happens that our winner did not specifically mention it. Is this the super criticality that a lot of people wrote to us about? Wow. I like hearing you say that, Matt. Super criticalofagis ex bialo venus. Yes. The carbon dioxide near the surface and then back to the bottom several kilometers of the Venus atmosphere, pressures and temperatures are so high, the carbon dioxide is supercritical. And this supercritical carbon dioxide is also used in one of the decaffeination processes.

For those who don't know, the supercritical state is when the temperature and pressure are above the so-called critical point where distinct liquid and gas phases do not exist. It's just one supercritical goodness. Thank you for that. I'm still not giving the winner here. We're going to tease it out a little bit longer so I can read this response from David Dearden in Utah. a little bit longer so I can read this response from David Dearden in Utah. Supercritical fluids combine the solvating power of liquids with the low viscosity of gases, but are an in-between state that is neither gas nor liquid, as we just heard from Bruce. Supercritical chromatography was largely developed here at BYU by Dr. Milton Lee. Any ads? Love the show.

Well, thank you, David. Nice work there. Okay, finally, and I think I wasn't just trying to mislead you. I was mistaken. I think I said I referred to our winner as a he. Nope, it's a she. It's faithful listener Laura Dodd up in the far northern reaches of California. She is a past winner, but it has been about two years by my records. She said both the near-surface atmosphere of Venus

and a coffee decaffeination process involve lots of carbon dioxide. The other similarity is that I don't want to go anywhere near either one. Congratulations, Laura. congratulations Laura we're going to give you your choice of either of Jim Bell's most recent new books either Hubble Legacy 30 Years of Discoveries and Images or the Earth Book from the beginning to the end of our planet both of them look great I mean I've actually got the Earth Book and I can definitely vouch for that one. The other one, I can only go by what I've seen online and it seems to be well-loved. We'll check in with you, Laura, see which one you want. I got a couple more for you. Michael Unger in British

Columbia and John Guyton in Australia and others who, kind of like Laura, complained that if you could only get decaf there, they never want to go to Venus. That could be the scariest thing about the Venus surface. Dave Fairchild, our poet laureate, put it a bit more poetically. Pressure down on Venus is an atmospheric stew, mixed sulfuric acid, and a lot of CO2. CO2 will make a decaf sure to leave you placid. Most would say, however, they would rather drink the acid. I like that.

All right. Thank you, everybody. We're now ready to move on. Back to comets. ESA's Rosetta spacecraft was, of course, very successful studying a comet, getting there in 2014. But here's your question. What and when were the, what and when was, what and when was the last flyby encounter of a comet by a NASA spacecraft? Go to planetary.org slash radio contest. You have until Wednesday, July 22nd at 8 a.m. Pacific time to get us this answer and get a load of this brand new prize.

We've never offered either of these before. And if you win, you'll have your choice. It's back to the Planetary Society store. You can get there most easily from planetary.org slash store. It's at chop shop store dot com. That's where all the great stuff is from Chop Shop, but he hosts our merch. You can either get the 40th anniversary t-shirt from the Planetary Society, which shows the actual location of all of the planets at the time. I think it was November or December of 1979,

where all those planets were when our three founders created the Planetary Society. Or if you choose, we have, we're bringing back a classic. It's the original Clipper logo for the Planetary Society that was our logo for so many years. You can have your choice, either the 40th anniversary or the Clipper logo T-shirt that blasts from the past if you win this one. And that's it. We're done. All right, everybody. Go out there.

Look up in the night sky and think about your dogs running with their tails in front of them, just like a comet. Thank you. And good night. That's just too good. Only when they're going away from you, of course. My hat's off to you. Not my tail. My hat's off to you.

That's Bruce Betts. He's the chief scientist for the Planetary Society who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California, and is made possible by its members who know we are the Martians. Join us at planetary.org slash membership. And if you're enjoying the show, tell your friends about us and tell strangers by leaving us a quick rating or review. Thanks.

Mark Hilverde is our associate producer. Josh Doyle composed our theme, which is arranged and performed by Peter Schlosser. Stay safe and well at Astro.