From Earth orbit to the Moon and Mars, explore the world of human spaceflight with NASA each week on the official podcast of the Johnson Space Center in Houston, Texas. Listen to in-depth conversations with the astronauts, scientists and engineers who make it possible.
On Episode 258, Dr. Anna-Lisa Paul and Dr. Rob Ferl discuss how their latest discovery of plant growth in lunar soil just may change the future of spaceflight as we know it. This episode was recorded on July 18, 2022.
Transcript
Gary Jordan (Host): Houston, we have a podcast! Welcome to the official podcast of the NASA Johnson Space Center, Episode 258, “Moon Farming.” I’m Gary Jordan and I’ll be your host today. On this podcast we bring in the experts, scientists, engineers, and astronauts, all to let you know what’s going on in the world of human spaceflight. As we planned ahead farther into space than any human has ever gone before, one of the key questions is, how will we ensure humans survive. And a component of this question is, what are we going to eat? If you’ve seen the movie “The Martian,” you probably have somewhat of an idea of just how important plants are for the survival of humans on Mars. The extent to which plants can be a key aspect to an astronaut’s diet on a deep space mission depends heavily on the success of growing and sustaining plants in space. Before we jump straight ahead to the Red Planet, scientists took a closer look at the lunar surface and recently, using Moon soil collected during the Apollo missions, successfully grew plants. On this episode, we have two special guests joining us to talk about their recent groundbreaking discovery. First, we have Dr. Rob Ferl from the University of Florida, currently serves as assistant vice president for research and as a distinguished professor. He served as a University of Florida faculty member for over 40 years and has received numerous awards for his research, including the NASA Exceptional Public Service Medal for his contributions to the space community that he received this year. Joining the podcast for a second time we have Dr. Anna-Lisa Paul, who is the director of the Interdisciplinary Center for Biotechnology Research at the University of Florida, and a research professor in the department of horticulture sciences there where she studies the responses of plants to novel environments with a focus on the environments and its impacts on space exploration. She’s performed at least ten experiments in space over the past 20 years, as well as in analog environments on aircraft, suborbital vehicles, and extreme terrestrial environments in the Canadian High Arctic and in Antarctica. In 2019 Paul received the NASA Medal of Honor for Exceptional Scientific Achievement, and she was inducted as a Fellow of the American Society for Gravitational and Space Research. Two exceptional individuals and we’re lucky to have them both on this podcast. With that, let’s get right into it. Enjoy.
[Music]
Host: Anna-Lisa and Rob, thank you so much for coming on Houston We Have a Podcast today.
Anna-Lisa Paul: Wow, thanks for having us. This is great.
Rob Ferl: Yeah, we appreciate being here and the opportunity to talk about our projects just generally is a lot of fun, so thanks for having us.
Host: Yeah, absolutely. And this is coming really on the heels of, I mean, I, I was so excited to see that Web feature come out that it, it, wonderful title, you know, like, we, we grew plants in, in lunar soil. That’s, that’s amazing. I want to, that’s really going to be the, what we’re going to be talking about today is this experiment, what led up to it and everything. But I want to first, by gauging just, you know, how that felt? I, I’m, from what I understand, this was something that was in the works for a long time, and, and that moment, you know, whenever you successfully did it, and then we were able to publicize this to the world, I want to know just your thoughts, just, and, and all the hard work that, that got put into that. Anna-Lisa, we’ll start with you. Just, do you have, did you have any immediate emotion or reaction to the success of the experiment?
Anna-Lisa Paul: Well, yes; yes, of course. It’s one of those things that when Rob and I were looking at the very first of the sprouts coming out, the realization hits you that we are the first people to see terrestrial organisms growing in extraterrestrial soil, extraterrestrial dirt. I mean, how cool is that? So it was an, an incredibly emotional experience. And I know Rob can say more on that subject for sure.
Rob Ferl: One of the things you have to appreciate, and I think most people do appreciate, is that even though we’ve had lunar soil samples for a long, long time — for 50 some years — the, the chance for biologists, true biologists, dirty, plain old stick things in the dirt and let them grow biologists, for us to have an opportunity to work with those precious lunar samples was by itself an amazing thing. And, you know, it, it took literally years for us to be able to get them and a lot of proposalizing and preparation to make it happen. So not only was there the, sort of like the just bald-faced joy of seeing plants growing in extraterrestrial soil and lunar soil, there was also the tremendous release and relief from having worked on something for, you know, 15 years in order to get to that point. So there was, there’s a, there’s a lot involved and a lot that we could unpack about the conduct of science in this business. And really, truly, the fun, the joy of, of doing this kind of science, doing space biology in a way that is so, well, biologically meaningful.
Host: Yeah. And, and that’s exactly that, Rob, is, is what I want to explore, because it truly, from what, from what I understand this really was something that, that took a long time. It was, it was a long time in the making and it all came together. I want to start by exploring your guys’ expertise and relationship, because, you know, this was, from what I could tell to both of you, it was a very meaningful and I know you dedicated much of your career to this pursuit. So, so Anna-Lisa, I’ll start with you, to, give us a sense of, of what your expertise is and give us a hint of how you and Rob came together to start thinking about working on growing plants in, in lunar soil?
Anna-Lisa Paul: Well, I am a plant molecular biologist, but I also have a strong background in biology and also physiological ecology. So in other words, how, how do plants respond to the environments in which they live and, and how do they garner the resources to give to the rest of us in those environments. And so, for me, I was really always very interested in, in how plants work and how plants do the things they do in extraordinary situations and things. And the notion of how plants respond to novel environments is extraordinarily appealing because it’s outside their evolutionary experience. And so working in some kind of environment that they have never seen, like spaceflight, is then sort of the next ultimate kind of step, and that’s where, that’s where the expertise comes together in the kind of work that Rob and I have, have done both in spaceflight but also in what we would call exploration environments like in the Antarctic or in the, in the High Canadian Arctic, and learning to apply some of our different perspectives is what really made for a great team.
Host: So you’re no stranger to adventure, Anna-Lisa, and this just happened to be the next frontier for you.
Anna-Lisa Paul: That’s well said.
Host: [Laughter] Now, now Rob, you, you share this, this passion for pursuing, you know, this, the — other worlds and, and, and, you know, working with Anna-Lisa, how’d you guys end up on this same project?
Rob Ferl: We, we share a number of, of interests, including basically what happens to organisms when they experience strange and novel environments. I’m a, I’m a geneticist by training, I, I grew up in the era of understanding what DNA does and how genes work and how, how the internal metabolic toolbox of organisms allows them to grow, survive, become different things and, and make decisions about their life’s trajectory. And in fact I, I, I grew most of my scientific teeth by trying to understand inside the nucleus of a cell how a gene works and what makes it work and why it’s important that genes work, and it, you know, that’s led us to this collaboration where Anna-Lisa knows a lot more about plants than I do and I know a little bit more about DNA, maybe, than she does. But, but what I have is also a sort of this, sort of engineering adventure sense that, that I share with Anna-Lisa with regards to doing stuff that’s not easy. Part of, part of what creates a lot of the fun in our science is doing the stuff, doing spaceflight stuff, doing, you know, survival stuff is by nature difficult. How you get a hold of stuff like lunar soil is not for everybody, it’s hard to figure out. How you grow plants in space doesn’t just mean sending some seeds up and saying, OK do it. There’s a, there’s a lot of sort of non-scientific engineering technology think, there’s a lot of sort of outside your swim lane thinking that goes on, and part of that, I have to say is, is the opportunity to participate, to be, to be a, to be an active member, to be, for example, talking with the astronauts, being able to go to Antarctica and not just ask somebody to analyze your plants there but do the analysis yourself. So the experiential part of, of our kind of science is, again, I think something that we share as a team and our various, sort of educational upbringings allow us to contribute different perspectives to these kinds of projects. And, and this is one very good one where, one very good example of that, where, where sort of our collective expertise was able to draw upon things like geology, technology, the history of spaceflight, the Apollo era, the interest in Moon landings: all of that stuff came together in a very nice way here.
Host: Yeah, it seems that way. And, and I do want to explore all those, those aspects of that, but, Rob, I’m locking onto one thing you said in just the challenges of, of — it’s hard to do something like this. And Anna-Lisa, you might have a, a little bit more insight into this because from what I understand, you know, this is not the first really attempt to try to use lunar soil to, to grow something. From, from what I understand this is, scientists were attempting this back when we first retrieved the Apollo samples and the, the lunar regolith back in the, in the 60s and 70s. And so, I wonder if we can start with a little history lesson by, by exploring what had been done in the past that maybe we learned from that, that that was applied to this particular experiment?
Anna-Lisa Paul: Absolutely. And so, one of the things is that, actually, plants never have been grown in lunar regolith before. This is the very first. Back in the day, and Rob and I talked with Charles Walkinshaw, who’s one of the scientists who worked back in the lunar receiving facility back in the day, in the Apollo era. They introduced lunar regolith to plants; they, they rubbed their leaves with it, they sprinkled it gently on top of them as the plants were growing in normal terrestrial materials. But primarily it was just to test as to whether there was anything deadly, anything infectious that could be transferred from the lunar regolith to biological organisms, to terrestrial organisms. And so while plants were very important to the, the, the processes of understanding the, the dangers of lunar regolith, they were never actually grown in it with the notion of it could be a support matrix for growing them like you would grow in, in regular soil. And, and we’ve done a lot of research when we first started looking into what it would be like to try to do this, including going to the old archives, the, the hard copy archives in, in Houston, and, and, and Rob can tell you a little more about that story, which is really pretty fascinating.
Rob Ferl: So if, if you, for those of us that are old enough and can think back to the Apollo era, we all have to remember that the return of lunar samples was for that era generating a lot of the discussion that we might be hearing and have heard a little bit about with regard to bringing Martian soil, Martian samples, back to Earth now. In other words, will we be introducing extraterrestrial harmful organisms into our terrestrial environment? The movie “The Andromeda Strain” was coming out at the same time as the Apollo landings were taking place, and NASA was very serious about what’s called backward containment. In other words, they didn’t want the lunar soil samples to negatively impact the terrestrial biology. That’s why the astronauts were, were quarantined inside of a trailer for a few weeks, and that’s why up and through Apollo 14 the astronauts, their samples, their soils, their, their, even their spacecraft were, were quarantined just in case there was a bad bug that would come back from the Moon. Plants, animals, fungi at the Lunar Receiving Laboratory, there was an entire army of scientists dedicated from, say, 1960…something they built the Lunar Receiving Lab, all the way through the early 70s: a lot of science was done where lunar samples were rubbed on to terrestrial organisms to see if any bacteria or viruses would transmit from the Moon to the Earth. That didn’t happen. Lunar soil, lunar rocks were all deemed to be safe with no biotoxic organisms in them. But after that, the samples were locked down, they were made pristine, kept pristine, so that geology and the main goal of lunar science — in other words, understanding the Moon — was the top priority. Interactions with biology went into the background at that point.
Host: So then, when you guys were thinking about, you know, you know, you spent some time looking at plants in microgravity and in the space environment; I guess I’ll direct this to Anna-Lisa: what, what made you think that, that sort of now, or, or whenever you started the experiment if you can give us an insight into that, that it was the right, the right time to, to attempt this particular experiment?
Anna-Lisa Paul: Well, I think that every, everybody has this notion that eventually we’re going to be going back to the Moon, going to explore past our, our corner of the solar system, take our plants off Earth. And when you think about it, plants are really what enable us to be true explorers, to be able to explore past the limits of what you can just bring with you in terms of supplies. And so, we knew, we, meaning me and Rob, but we, meaning also the community, that if we’re going to understand how to use in situ resources, resources that would be available to us on the surface of the Moon or the surface of Mars, in a greenhouse, for instance, we have to do a lot of homework to understand what that looks like first. And so, back ten, 15 years ago now, we started doing those experiments with simulants. And so, we used a, Johnson Space Center simulants that are supposed to be very akin to what you would find on the surface of the Moon, at least in some of the, the areas. And could you grow plants in that? And a lot of people have done that, that work of looking at how could simulants be used to at least practice what it would be like to grow plants in a lunar greenhouse losing, using that kind of regolith. And we found very quickly that it’s not as easy as just putting some in a pot and plopping in a seed. And so we spent a number of years, first of all, figuring out how could you do it really well with the simulants, and then the next step of course, was how would you do it with the real stuff? So about ten years ago, we put in our first proposal, and as Rob sort of mentioned earlier the, the, the folks at the lunar Allocation Analysis Review Board looked at it and said, yeah, you know, these biologists: they’ll get it all messy, you know, it won’t be pristine anymore. We, we can’t have that. Why would they think that that would be a good idea? Now, of course, they didn’t say any of those things, they were just very polite and saying, yeah, well, thanks for applying, but, you know. So to make a long story short, we, we’ve applied a few more times and each iteration we learned more and more about how doing it well with the simulants, how to do it in smaller and smaller amounts, and so, at the end of the day in 2019, we applied very precisely for a particular type of material, we asked for materials from Apollo 17 that were sort of all jumbled together, stuff that Harrison Schmitt scooped out of the fender of the rover, and so we thought, nah, you know, no self-respecting geologist would really want to play with that stuff anyway, so they could give it to us. And so, the proposal was, and now in 2019, very well-received because not only was it the time, we’re going now back to the Moon as, as a peoples, right, and so the, the pristine materials that we’re collecting from the Apollo era, there’s end in sight to think two things. One is that, well, yeah, maybe we really do need to understand how plants can grow, but also we are probably going to be able to get more. And so it’s not quite so scary to give some to a biologist to get all, to get all messy. And at this point, I should hand it over to Rob for the rest of the story.
Host:Yeah. Yeah. Rob, you talked about the difficulties of acquiring the samples.
Rob Ferl: Yeah. So the, the, the spirit of everything Anna-Lisa has, has nicely laid out for you, there’s, there’s some additional things though that, that are, that are worth considering when we talk about, well, why, why was now a good time. And, and it is a sort of a pretty complex, I think, set of societal and scientific reasons why, why it came to happen. First off is, yeah, we got, we got better at our proposals in using smaller amounts and our research ideas got increasingly compelling, just like what would happen in any scientific proposal endeavor. But I have to tell you also that, that groups like the Lunar Exploration Analysis Group, it began about 15 years ago to talk about biology on the Moon as well, and that was at the, at the beginnings of the inklings that yes, science and people were going to go back to the Moon. So the community began waking up to the idea of biology going back to the Moon and us needing to understand what would happen to biology when it came in contact with the Moon. The community it, sort of writ large, began to think about that seriously about, about 15, 18 years ago. And certainly by 12 years ago, as Anna-Lisa mentioned, when, when we went to do some serious background work on what was accomplished in the Lunar Receiving Lab — in other words, to truly understand whether or not, well, to understand deeply what happened to plants as they came in contact with bits of lunar samples — first off, I had a break off here for a quick second to say, you know, that was just a blast. Literally, the people that are the archivists there were just wonderful to us. They actually found film for us that was frozen, and they unfroze the film, they digitized it for us so that we could have, we could have first real glimpse of what was happening to the plants and the plant scientists inside the Lunar Receiving Lab back in 1969, ’70, ’71. So we, we got to, almost 50 years later, 40 years later at that point, we got to unpack the science that was done and then sort of largely forgotten about. So we got to unpack all that right during this time in this era when, when lunar science, sort of largely speaking, was waking up to the idea that, yeah, we need to, we the collective, we need to understand what happens to biology on the Moon. So the community was waking up, the science was sort of being reinvigorated and, I think Anna-Lisa hit it on the head when she said as soon as, as soon as there was a larger commitment to the Artemis program when we would be going back, the, the ability to relinquish some of those samples for biological purposes began to make a lot of sense. And we just happened to be there at the right time. Maybe not “happened to be there,” we planned to be there at the right time. But basically it was a nice confluence of, of us maturing our science ideas, the Artemis program, with the promise of replacing anything that we might ruin in terms of, in terms of lunar samples, and the need to understand what happens to biology if we’re going to the Moon for longer periods of time.
Host: So Anna-Lisa, I want to further understand, you know, that the timing seemed to work out and there was this, there was this pitch in 2019 where the, the, the lunar folks, the lunar sample curation folks said, hey, it’s, it’s, we’re going to say yes to this, and I wonder, I wonder what was the approach, the design of the experiment itself that, that really sold this community on, on allowing you to, to use the, the lunar soil? Can you talk about the approach that went into how you were going to execute this experiment?
Anna-Lisa Paul: Well, the, the approach was pretty much the same as that we had pitched in the past, in that we, we developed a system, a growth system, that, that was formed on these tiny culture plates that essentially you could use as little as 900 milligrams of material. That’s about a fifth of a teaspoon of lunar regolith that you can grow a single Arabidopsis plant in. And the, the other thing that we did is, is we had a colleague here at the University of Florida, Stephen Elardo, who’s a geologist who has also worked with lunar samples. And so we developed a good proposal on, on how to be good stewards of, of lunar material, how to, to preserve the material the best that we can, as opposed to, you know, just flinging around willy-nilly into the little ceramic pots or something. I mean, we had a very clearly-defined mechanism by which we would use the material, preserve the material, archive the material, and make sure that the regolith that we were entrusted with was, was taken care of very well. And so that was one of the things that we learned in our earlier proposals that was profoundly important to the, to the review board. We also were in a very good position because Rob and I have used Arabidopsis now in a number of different — well at this time, like ten different — spaceflight experiments that we also had very well characterized the responses of Arabidopsis at the molecular level to these other novel environments, and had practiced the basics even in greenhouses in the Arctic at that, at that time using in situ materials up there. So it all came together, I think, very perfectly to, to make the perfect storm of a proposal, to demonstrate that we had all the kinks worked out, we had all the background material as far as plants responding at, at, in spaceflight and other exploration environments, that made the, the, the, the final key piece of information about going back to the Moon was plants was in our hands, and this is the way we had to do it.
Host: So if I’m, if I’m reading that back right, Anna-Lisa, it sounds like the Arabidopsis you had, you had refined techniques for growing in, in, in different, you know, harsher environments, which really helped to say that this is a, this is a plant, from what I understand it’s a, it’s a plant that’s easier to grow in, in, you know, it’s a very robust sort of plant, but then you also had a lot of data it sounds like to compare it to. So it’s not just, it sounds like this experiment goes beyond just, can we do it?
Anna-Lisa Paul: Oh yeah.
Host: Right. You obviously want to, you want to compare it to, to other models. So, so it seemed like that was sort of the, the reason why you picked this plan.
Anna-Lisa Paul: Oh, yeah. That’s very true. Arabidopsis thalianais the model organism for plants. And not only have Rob and I done a ton of, of work with Arabidopsis in spaceflight and other analog environments, so has the rest of the world. And so we could take the, so we use it as a control. We use this JSC-1 stimulant. And so, all of the comparisons, both in growth morphology and also molecular responses, the gene expression patterns, were compared to the, the, the lunar simulant that was growing right beside them in these same, in these same culture plates. And what we could do then is we could take the, the patterns of gene expression that was different between the simulants and each of the different Apollo sites and ask, what does that look like in terms of what we see in terrestrial stresses? And again, Arabidopsis has been used around the world for all manner of different stress responses, and so when we took those abundance of databases of molecular responses to, say, high salt stress, to heavy metal stress, to drought, to anything, because Arabidopsis has been used this way we can say, oh, look at that: you know, half the genes that are being expressed are associated with reactive oxygen species and the other third are associated with heavy metal responses, and so we could use all the data that’s out there for Arabidopsis to compare what’s going on in the samples we were doing.
Host: So Rob, in terms of your, your expertise on the genetic level and looking at the gene expression based on what, what stressors were being introduced by using this particular soil, it sounds like, sounds like you had a lot of, you had your techniques as well pretty refined and you would just use those, you would use that standard, those standard techniques that you used for, for a lot of other experiments and that the community was very used to, and just have this new dataset with what’s happening with lunar soil.
Rob Ferl: Yeah, yeah, yeah, that’s pretty much exactly true. But it sort of, sort of under, underappreciates the, the entire role of Arabidopsis here. For one thing, Arabidopsis is a very small plant and that’s, that’s one of the reasons why the logic behind using it in spaceflight sort of makes it collinear to the logic of using it for lunar, lunar sample growth. When we fly an experiment to the International Space Station, for example, volume is limited, and in order to have very many plants you are better off having smaller plants that can do a lot of their growth cycle in just a few weeks. And so you can sample a lot of biology, understand a lot of what happens in their metabolic tool chest, on orbit or in a small growth chamber with a little bit of lunar soil to support their growth. So, so the, the notion of Arabidopsis, and the power of Arabidopsis in, in this particular point, is really, is really truly worth appreciating. But getting back to your main point, your question there, yeah, the ability to use widely recognized tools for understanding what genes plants are expressing in a given environment lets us understand what it takes for plants to live in that environment. And that’s why, as Anna-Lisa mentioned, some of the responses we saw in the plants growing in lunar soil, those informants of what their cells, what their nuclei, are doing to allow them to live in that environment — she mentioned heavy metals and metal stresses and salt stresses — these are all hallmarks of certain sort of metabolic responses that we can now seek to understand by comparing them to all the other databases that have already been mentioned. But one thing that’s important to recognize from this is that we, we are informed by all those previous experiments, but it’s important to recognize that nothing’s ever been grown in lunar soil before. So when we interpret those data — oh, we see salt stress it must be a salty environment, or we see metal stress, oh, that must be the nanophase iron in the lunar soils that don’t appear here on Earth — that’s probably too simple of an interpretation, and I think Anna-Lisa would agree that we generally wonder, sort of how does, how does terrestrial biology react in an extraterrestrial environment for which there is no evolutionary preparedness? Would their reactions, would their gene expression patterns, make sense? Would they be somehow differently informed by misinterpreting what’s going on in the environment? For example, the nanophase iron that’s present in lunar samples; does that create an iron reaction in these plants or does it create something different? So we’re at the front edge of really trying to understand what all those gene expression data tell us about the lunar environment, because this is our first encounter with it. And we have to, we have to look at, we have to interpret, we have to wonder, whether all of our data are sort of to be interpreted literally, or do they need to be interpreted as a, as a novel response to a place they’ve never been before?
Host: Interesting. OK. I want to, I want to explore a little bit about, OK, so, so we’re, we’re, we’re getting a better understanding of part of the experiment is, you know, growing these plants in this, in this soil, what, what are the stresses, and using the gene expression maybe to, to identify what those stresses are. And it sounds, you know, it sounds like you guys are going to take a pretty deep dive, but I want to, from my own, you know, I’m, I’m not, definitely not a biologist, but I’m going to go ahead and assume that you’re not just going to put a seed in lunar soil and put a light on it, water it a little bit and see what happens. I think, I would assume there’s a, there’s a, there’s this element of maybe putting in some additives to help it grow, and then I wonder when, when we first started talking about the soil, we talked about these early Apollo experiments where we were rubbing soil on plants to see if there was any bad things in there. And I wonder in this experiment was there any, anything from the soil that you knew was bad and maybe perhaps you removed ahead of time to help it be successful? Anna-Lisa, can you talk about what went into actually helping the, what’d you do to actually grow the plants?
Anna-Lisa Paul: So, so we knew, for instance, that from our experience when growing in, in the simulant, there’s no, or there’s very few nutrients that are available to the plant. And so we knew from our past experience that we’d have to give them a little bit of, I guess what you would call dilute fertilizer in order for them to grow at all. Otherwise, they’re just not going to grow past sort of this, the two-leaf stage, and then they would just die. So we gave everybody, and that includes the, the, the JSC-1 controls and all the, the, the three different lunar sites, a little bit of a nutrient solution just to help them survive on there. Now we knew that there were going to be differences between the, the simulant and the lunar regolith simply because by the nature of it. The lunar regolith has never been, of course, exposed to the wind, to the rain, or any kind of weathering, and so those materials are profoundly sharp and reactive and, and lots of surface areas and, and porous bits and knobs and stuff in that material, that is very, very different than even the harshest volcanic ash that you can find on the surface of the, the Earth. So we knew there were going to be challenges. What we didn’t fully realize is what the extent of those challenges would be, and what kind of strategies that the plants would mount against those impediments. And so, in addition to looking at the, the gene expression patterns of, of how they respond to the, to the different regolith, we also could see when, well, we, we, we grew them in little sets of four, we planted about four seeds on each one of the, the, the replicated samples, and eventually after about a week we wanted to thin them out and to let only one single plant be growing in each one of those little tiny micro pots. And we noticed as we pulled out the, the materials to be thinned, that the roots of the standing plants, the plants that we, we pulled out of the regolith, were sort of shorter and, and stockier, and, and, and they looked like they’d been really struggling to get into the regolith, compared to the relatively long and slender roots that went from the, the, the JSC-1 controls, the terrestrial materials. And so even from the get-go we realized that, that plants were struggling with some of the physical features of the regolith that made it a more of a challenge for them to grow because they, it was just, it was just hard. You know, think about the difference between walking across, you know, sharp stickers versus walking across cool grass.
Host: Yeah, that’s, I, I’m, my feet are hurting just thinking about it, so I, I can, I can only imagine what the, what the plants were going through. OK. So, so yeah, you’re going to be, you’re going to be looking at some of that data, of course, and, and, and I wonder, well, let’s, let’s focus on that actually, let’s go back to it, Anna-Lisa. Do you have an early interpretation of, because ultimately, you talked about, we, you know, the, this, this soil, this, this lunar regolith is, is sharp, it’s, it’s, is harsh, but somehow it, it, it worked its way through these stressors and, and we saw Arabidopsis come through. So from your, from your expertise of doing this with different simulants and different harsh environments, what do you, what, what’s your going-in theory and what are, what are you planning on investigate, on, from, from your perspective, from your biological perspective, that will give us a sense of how this is happening?
Anna-Lisa Paul: OK. OK. So there’s two, two parts to that.
Host: OK.
Anna-Lisa: So, for the first part, think about this, how do we, how do we know that they’re harsher? How, how do we know that, that, that, that is some, some aspects are different, more difficult than others? We, in the study we use three different sites: we use Apollo 11, Apollo 12, and Apollo 17, so those are three different areas from the Moon. And those three areas are actually quite different. And so, just to bring it down to, for instance, between Apollo 11 and Apollo 12, Apollo 11 is much older. And so the maturity of those regoliths is how a geologist would call it, those regoliths are more mature: they’ve been exposed to the solar winds, for instance, for almost a billion years longer, and during that time they’ve been more suffused with the, for instance, the nanophase iron, the metallic iron that Rob mentioned earlier. They’ve gotten more sharp, more sharp glasses, more surface area fractures and things, and so those materials should be worse than the Apollo 11 materials, which are much younger, less mature. And in fact that’s what we saw. And so if you look at the plants that grew in Apollo 11 mature, lunar regolith versus the Apollo 12 lunar regolith, the, the plants are happier growing in the Apollo 12, they have fewer genes that are differentially expressed in, as a stress response, and so those data themselves say to us that, that the harshness of the regolith is something that we can both predict and perhaps ameliorate. And that’s one of the things you were asking earlier: so what are you going to do about this stuff, and how are you going to make it less harsh, and what, what do you see for the future? Because yeah, you’re not just going to put a shovel of it into your greenhouse on this lunar surface and, and call it a day. So anytime, the minute that you add water, the minute you add air, you are already starting to change the regolith because the, those edges are getting, going from those sharp, prickly things to getting their edges rounded off a little bit. Anytime you grow something into it, the first generation of plants that grew in that regolith were struggling, but the next generation that grows in it will have had that regolith be conditioned by the plants that grew in it before. And if you’re really planning on growing true crops and things, you’re not going to be limited to doing a very precise, scientific experiment, you’re going to be able to say, dig in organic materials and really stir that stuff up and, and ameliorate some of the sharp surfaces and difficulties that roots will have growing in that because you’ll put additives in it that’ll make it a far more conducive environment for plants to grow. And so that’s going to be the next steps before you actually do this on the surface of a Moon greenhouse.
Host: OK. Very insightful, Anna-Lisa. Thank you. Now, Rob, you mentioned the, you’re at the very beginning of understanding the gene expression and looking into it. Can you tell me some of the next steps that you’re going to be taking and your perspective on what do you hope to find out, what do you hope to investigate over the next couple of months, years, to learn more from this experiment?
Rob Ferl: There are, there are just so many kinds of things and kinds of questions that can be asked and, and it’s, and it is worth, it’s worth investigating some of these just at a very top level. Right now, we have in our laboratory lunar samples that were in the presence of biological species — the Arabidopsis plants — for several weeks. This is the first time biology’s been introduced into lunar soil samples. What, what kind of questions, what kind of changes have occurred in that, in those regolith samples that indicate biology was there? Would, would it not be an interesting astrobiology question to, to simply ask, OK, what sort of signals did biology leave behind? Wouldn’t it be interesting to know whether or not there are biosignatures, clear biosignatures, that are now in that regolith simply because the plants grew there? In a related way, we grew these plants in a laboratory setting here on the Earth that was not biosafety standard, it wasn’t sterile environment by any means. Back in the Lunar Receiving Laboratory, when plants were sort of dusted and sprinkled with lunar soil samples, those, those experiments were done in gloveboxes where human interaction, human microbes, for example, would not contaminate the sample. When we grew these plants we grew them in a shirtsleeve environment that we sort of anticipated would be not unlike the shirtsleeve environment of a lunar laboratory when samples were brought in from the outside. So not only have these lunar samples been in contact with plants, they’ve been also in contact with whatever microbes are floating around in our laboratory or off from our clothes or our skin. And so therefore, again, we have to sort of wonder what’s the bioecology now of those lunar soils? And by the way, now that biology has been in contact with the regolith, I think we can legitimately call it lunar soil. And geologists would have an interesting little discussion about that. So, so very, very sort of specifically, if you turn, just turn it on its head for a little bit, there’s a lot of questions that can be asked about these lunar soils now simply because they were in the presence of plants and terrestrial biology microbes for a few weeks. This, this, this really presents some interesting thoughts from sort of the non-plant biological sciences perspective. But, but back to the, the directionality of your questions, in other words, what are sort of the next steps from, from, from where we are now, there are a number of things that are really interesting to think about. For a while I think we’re going to be limited to growing small plants and probably Arabidopsis. A lot of people would like to see what a radish does, what a corn plant does or something like that. But the, but those seeds and those plants are so much bigger it would take a serious, seriously, large commitment of lunar dirt to make that happen. But what we can do is, what we can do is, is ask what sort of genetic variation would be useful in growing plants in the existing lunar soil. For example, we could take Arabidopsis mutants in various kinds of genes that have to do with getting back to what we’ve learned, salt tolerance or heavy metal tolerance, or other sorts of things that would allow plants by their genetic nature to thrive even better than they did. So that’s, that’s another direction that we could head. But for the, for the time being, the real question is going to be back to Anna-Lisa’s point: if you grow now the next crop and the crop after that, using the same plants, does, does biology condition the soil well enough, better, make it easier for the next generation of plants to go there? And, and before I forget, I just wanted to also mention that sort of a human element here…just, just think for yourself, just anybody think, if you were given the opportunity to do something for the very first time, very first time, what, what would you do? How much nutrients would you add? How, how much light would you use? How much any of these kinds of things would you do? And, and the question is, boy, if we had to do it all over again I’m not sure what we would do different, but there are a few things that we would look at. And some of them have to do with the conditioning of the samples as, as you’ve mentioned. One of the things we found fairly early on was that the different lunar samples that accepted water differently, they wetted differently; I think that’s, that is a really interesting phenomenon that basically would take some physical work to make sure that water interacted well with the samples. So as, as, as the scientific community sort of absorbs what we’ve done so far, I think we’re going to see all sorts of interesting proposals for what to do next.
Host: Very interesting. So on this, on this, this theme of next steps, Anna-Lisa, I’ll go to you: it seems like, is it fair to, to maybe hope that maybe in the near term one of the next steps that, that you can, that you can take is to, to further this experiment by exploring and maybe using those same samples, lunar samples, that you acquired, but just try it again with a different plant or maybe the same plant and see what happens with the reuse of soil? Is that perhaps, maybe a, a near term goal for you to explore beyond just looking at this experiment?
Anna-Lisa Paul: Absolutely.
Host: Very good.
Anna-Lisa: That’s an easy one; in the works.
Host: In the works. Fantastic. That’s really good to hear. Now, now we explored in the beginning of this chat a little bit about the timing of this, you know, like why now? Part of it is really this, the, the Artemis program that’s, that’s right around the corner. We’re going to be launching here soon, Artemis I is, it’s supposed to be a continuing program, and with that, comes regular presence on the lunar surface, where we could potentially and, and very likely, be acquiring more and more samples, which I think is very exciting for the scientific community, and I’m sure, I’m sure from you guys as well. From your perspective, what, and, and from, for your research, what does the Artemis program open up for you in terms of possibilities to, you know, you mentioned already just the differences in some of the lunar samples from these different sites, now we’re talking about future sites, I mean, I think to, to me, I would think that opens up a world of opportunity, but for you guys, but, and Anna-Lisa, I’ll, I’ll go to you first, what, what excites you about the, the opportunities that are presented by, by having this Artemis program and, and, and potentially very soon, getting new samples?
Anna-Lisa Paul: Oh yeah, absolutely. Getting, getting new samples from, from different sites would be amazingly valuable also to add to the, to the data of, of what, what the impact of different types of regolith has on plant growth. But also, from the perspective of, since, since part of the Artemis program is to have a presence on the Moon, that not only bringing back samples but will be extraordinary is taking the seeds to the, the lunar surface itself. And I don’t mean, of course, tossing them outside the airlock but, you know, growing them in a microhabitat inside the lunar habitat that the astronauts will be occupying. And we could very easily, for instance, set up astronauts with the same kind of micro form factor, and you could grow the same experiment, even, almost in the palm of your hand, but using the lunar gravity itself. So there’s a lot of things that can be done now that the Moon is opening up a little bit more to the next generation of scientists. And yeah, we were the first to do this kind of stuff on the Earth, but we certainly won’t be the last and it’s going to be, been taken over by a lot of people who might actually do it on the Moon.
Host: Well, that’s really exciting. And I feel like, you know, it, it, to me it, it, it kind of continues from there. You’re talking about bringing samples back, you’re talking about growing things on the Moon. I feel, to me, it seems like the, the more that we do this, the more refined our techniques can be until maybe, you know, in a future Artemis mission, you know, if, if you keep trying this, if you keep experimenting, we could be, you know, we could have, like, small farms on the Moon that could supply at least a little bit of nutrients on the Moon. But to me this pursuit really helps us to get to Mars as well. And I feel like the more we do this, the more we try things on the Moon, the more we experiment in these harsh environments, the better equipped we are to create farms for the journey to Mars, on the deep space transport that’s going to, that’s going to carry humans all the way to the Red Planet, and then ultimately on the surface of Mars, dealing with Martian soil and figuring out the challenges there, you know? I know there’s one of the things is like, perchlorates, for example, you have to figure that out. But I feel like if you do it on the lunar soil, you know, it really helps, you have more data that can maybe be applied to growing it successfully on, on Mars. Rob, I’ll go to you first. Do, do you feel the same way? Do you feel like this opens up avenues for deeper and deeper space exploration and, and the more we do it the more, the more science we do in support of growing plants in these harsh environments, the better equipped we are for a journey to Mars?
Rob Ferl: So the simple answer is, yeah, I agree. The, the, the longer answer gets just a little bit complicated and, and nuanced in the way that that Anna-Lisa mentioned, and that is, as we, the collective we, start thinking about bigger, longer operations, we are, we’re talking about humans doing this stuff. It becomes a, a human endeavor. And plants are there, yeah, to provide food, they’re there, yeah, to provide some science there, they’re there, yeah, to renew our oxygen and sort of clean up our water, do all the things they do here on Earth. That’s why it’s important always to remember that, you know, we, wherever we’re going to go we’re going to create some sort of ecosystem and putting plants in that ecosystem to do for us on Mars what they do for us here on the Earth makes abundant sense. But the nuanced part of this is that with humans going and with, going with enough capability, the science that we would like to do can be done on the way, it can be done there, and samples won’t have to come back. You know, the whole “Mark Watney colonizing Mars” thing is way more real than I think people can truly appreciate. The notion that, that we will send plant biologists as well as some seeds when we go to these places is, it’s a very real think. And it’s, it’s, and the, what I celebrate about our current era is that we are talking about sending people, and enough people and for a long enough period of time, so that when we envision in our laboratory what a lunar plant science laboratory might look like, it’s not pure science fiction anymore. It’s, it’s very possible. And when we think about growing plants on the space station as a model for what the transit vehicle plants might look like, it’s not just fiction anymore. It’s, it’s very possible; it’s very real. The kinds of things that we’re doing now will support the scientists, the plant scientists, the people that make these voyages. So yeah, I agree completely, and I think that it’s part of what makes all of this such an enthralling kind of science to do the, the human element.
Host: You’re making it sound very real, Rob. And, and, I think that, I mean, I think that’s your intent is to show, is to share just how, how real this is, and to your point, not just to science fiction. Anna-Lisa, I wonder if you have the same sense. And you know, I, I, I feel like you’d be the perfect person, I’d throw your name in the hat to go to the Moon and try and try some of this, try some, of growing some crops on the Moon yourself. But I wonder if your, if your level of excitement matches Rob’s?
Anna-Lisa Paul: Oh yeah. Unquestionably. I mean this is why we do what we do. I mean, this is, humans are explorers and it’s, it’s an amazing opportunity and privilege to, to be able to make it so.
Host: Yeah. And you, both of you are contributing so much to the scientific community in, in order to do that. It’s, I, I, I’m very excited to be talking with both of you today because you did something brand new, you grew plants in, in lunar soil. And it’s, this has been to me amazingly informative to get to talk to you both and, and talk about what went into it, but not only that and just, just lead to what comes next and it’s, it just sounds so very exciting. So, Anna-Lisa and Rob, thank you so much for coming on Houston We Have a Podcast and, and, and, letting us in on some of the, the efforts that went into your work. Huge congratulations to the both of you for, for the success of the experiment, and it sounds like you’re, you’re not even close to done. Sounds like there’s, there’s a lot more to do. A lot more to find out and, and I think that’s equally exciting. So thanks again to you both.
Anna-Lisa Paul: No, thank you, thank you very much.
Rob Ferl: Yep. It’s been a privilege to be a part. We appreciate it.
[Music]
Host: Hey, thanks for sticking around. I hope you learned something today from Anna-Lisa and Rob, they were both awesome to have on the podcast and the amount of depth they went into their research is fascinating and just the, what is going to come next is just absolutely incredible. So make sure you keep up with the latest at NASA.gov. You can check out the latest research that’s going on with some of the lunar soils, as well as our efforts at the Artemis program, you can go specifically to NASA.gov/artemis. We are, of course, one of many NASA podcasts across the whole agency. You can check any of them out at NASA.gov/podcasts. You can check us out there, Houston We Have a Podcast, our full collection of episodes are there, and you can listen to any of them in no particular order. If you want to talk to us, we’re on the NASA Johnson Space Center pages of Facebook, Twitter, and Instagram, and you can use the hashtag #AskNASA on your favorite platform to submit an idea or ask a question, just make sure to mention it’s for us at Houston We Have a Podcast. This episode was recorded on July 18, 2022. Thanks to Greg Wiseman, Pat Ryan, Heidi Lavelle, Belinda Pulido, and Jaden Jennings. And of course, thanks again to Anna-Lisa Paul and to Rob Ferl for taking the time to come on the show. Give us a rating and feedback on whatever platform you’re listening to us on and tell us what you think of our podcast. We’ll be back next week.