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 287, a NASA expert details an upcoming space station study conducted during a spacewalk to better understand potential contaminants for future human exploration of the Moon and Mars.This episode was recorded on February 16, 2023.
Transcript
Gary Jordan (Host): Houston, we have a podcast! Welcome to the official podcast of the NASA Johnson Space Center, Episode 287, “Science in a Spacesuit.” 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 and more. If you’re an active listener of this podcast, hopefully you’re familiar with spacewalking; but if not, in short, this is where astronauts put on those puffy, white spacesuits so they can work on the outside of a spacecraft. Most recently, we see these a lot aboard the International Space Station for maintenance and upgrade tasks like swapping out batteries and installing new solar arrays. But not very often do astronauts go outside in a spacesuit to conduct science, and that activity is coming up soon. Scientists have been preparing for an extravehicular science activity called the International Space Station External Microorganism study. During a spacewalk with other maintenance and upgrade tasks, spacewalkers will dedicate some time to conducting a scientific activity to understand more about the microbial environment on the outside of the International Space Station that could help us to better understand likely contaminants for when we’re exploring the Moon and other planets. This study has been a long time in the making and is about to launch to the International Space Station on Northrop Grumman’s CRS-19 cargo mission. We’re lucky enough to bring in the project lead, Dr. Aaron Regberg, who’s also a geomicrobiologist and a planetary protection lead. He’s coming on the podcast to help us describe what this experiment is all about. So let’s get right into it. Enjoy.
[Music]
Host: Aaron Regberg, thank you so much for coming on Houston We Have a Podcast.
Aaron Regberg: Thanks. I’m excited to be here.
Host: All right. Well, we’re going to be talking about this project that you’ve been working on for quite some time. But I know you have a very interesting, I want to stop, start with your job title, actually, because it’s so interesting when, when you, when you sent the email and we were going back and forth talking about this, it said, it said Dr. Aaron Regberg, geomicrobiologist and planetary protection lead. So what, what’s, what exactly does that mean? What, what’s your role here at Johnson [Space Center]?
Aaron Regberg: So, I, I kind of have a couple different hats that I wear here. My, my primary job is as a astromaterials curator, so that’s one of the scientists that helps to take care of all of the extraterrestrial samples that we’ve collected. And I am the one that tries to keep the clean rooms microbially clean, and worries about, you know, terrestrial microbes altering our samples. And then in addition to that, I am sort of the planetary protection point of contact for the space center. And planetary protection is like this kind of weird discipline that sits at the edge of science and engineering, kind of at the boundary of the two, and our job is to make sure that we don’t inadvertently contaminate other planets — so take Earth bacteria to Mars, for example, and, and then when we’re trying to look for life on Mars all we find is the bacteria that we brought with us. But it’s also about making sure that we don’t accidentally bring anything scary or dangerous back from other planets. So, you know, back in Apollo times, for the first couple of Apollo missions, they were really worried about, you know, dangerous microbes from the Moon and everything was quarantined: the astronauts, the samples. That was sort of proto-planetary protection on the, on the backwards side.
Host: OK. All right. So you’re not like commander-in-chief for alien invasions.
Aaron Regberg: Absolutely not. No. [Laughter]
Host: OK. All right. It sounds like a cool title.
Aaron Regberg: And even, and even if I was, there’s, there’s somebody at [NASA] Headquarters who is theplanetary protection officer…
Host: Thinking about exactly that, yeah.
Aaron Regberg:…and they’re, they’re in charge. Yeah.
Host: [Laughter] OK. All right. Well, still that’s, that, that’s a good description for exactly what we’re going to be talking about today, which is this, this, this project that’s happening on the International Space Station. But it’s, it, just on this background, this geomicrobiologist and, and you have that day-to-day job of just making sure the, the, the, the materials that we have in our curation facility are protected as well, and you’re, you’re thinking about the contamination for our planet and for others. I wonder what got you to where you are? How’d you, how’d you kind of go down the path to get you where you are today?
Aaron Regberg: Yeah, it’s, it’s a, it’s a good question and one I get a lot, and I don’t think I have a particularly, like, standard or normal career path.
Host: I don’t think any of us do. [laughter]
Aaron Regberg: Oh, yeah. So I studied geology in, in college, and then when I went to get my Ph.D. I was really interested in how the microbiological world affects geology. And so I studied for my Ph.D. bacteria that dissolve rocks and the way that they dissolve rocks, they’re actually metabolically, they’re, they’re breathing them, so they don’t breathe oxygen, they, they sort of breath iron oxides, and, and reduce those iron oxides and make them soluble. All of that work ended up leading me to a job in industry for a while, actually. So I was doing research for an oil company, studying bacteria that lived in oil reservoirs and how they were altering the physical properties of the rocks underground and the chemical properties of the oil, and then trying to use all of that information to see if we could look for more oil, because that’s primarily what oil companies are interested in.
Host: Sure.
Aaron Regberg: And after, after being there for about five years, I kind of realized it wasn’t, wasn’t a great fit for me culturally. And I just, happened that this position that I have now in the curation office at NASA was being advertised right as I was kind of looking around and, and thinking about wanting to do something else. And I was, I was qualified for it in part because of the, the work and the things that I had learned at the oil company.
Host: OK.
Aaron Regberg: So I, I know people want to ask that question and have like a path that they can replicate, but the advice that I always try to give people is just follow things that look interesting to you, because you’ll, it’s hard to predict where, where it’s going to end up.
Host: That’s, yeah, that’s really good advice because look where you are now, and now you get to work on this fantastic project, and that’s sort of what I want to get into. So it’s extra, or external microorganisms on the International Space Station. So, at first glance, right, it kind of sounds like there’s these creepy crawlies around the outside of the space station, but I know it’s more complicated than that. Just, what in general is this study and what, what are we exactly looking for as part of this?
Aaron Regberg: So, so we’re looking for evidence that, that microbes, bacteria, and fungi from the inside of space station are leaking out of space station and surviving in a way where either, either because they’re dormant or because they’re actually growing, which is less likely, but surviving in a way that we can detect them by, by going out and sampling the outside of space station. And the reason we’re trying to do this is, is directly tied into the planetary protection stuff that we were talking about a minute ago. The systems that are used on the International Space Station and for our spacesuits today are likely very similar to the systems that we want to use to, to get people to Mars and to land on Mars and to have habitats on Mars. All of the, all of the vents and ports on the outside of space station are unfiltered currently. So whatever is inside is just being shot out into space. And that’s totally fine for low-Earth orbit. We’re not worried about contaminating low-Earth orbit with stuff from Earth.
Host: Yeah.
Aaron Regberg: But it could be a problem for Mars: if we’re going to send humans to Mars and we want them to look for signs of life and they’re living in this habitat that is just, you know, venting gas and, and maybe leaking a little bit of water out onto the surface, we could be creating our own contaminated zone around the, around the habitat. So, you know, as a scientist I’m like, OK, well put some filters on those vents, like go off, do it, it’ll be fine. Like, here’s the size filter. But when you talk to engineers, they want to know, well, OK, well how, what’s the threshold of leakage that’s acceptable? What’s, you know, how many microbes is too many and how many microbes are we leaking now? And we have no idea because we’ve never measured it. So the, the, like, really big picture idea for this experiment is just to kind of gather that sort of data so that we can go back to the engineers and say, OK, here are the specifications for the system we want you to design.
Host: Oh, wow. This, so this is, I mean, this experiment is huge. It’s going to potentially inform the design for the vents and filters on Mars landers and stuff.
Aaron Regberg: We, we hope so. Yeah.
Host: Wow.
Aaron Regberg: That, that’s the, the goal is to start gathering that data to close that knowledge gap.
Host: The idea of contamination, like what this, the, the concern in the first place: is it, is it more so that the microbes are being shot out and we could potentially like misidentify and just you could say, oh, there’s life on Mars, but actually it’s the stuff that we’ve been shooting out, or is it, does it sort of maybe ruin the science for, you know, what, describe what, what exactly contamination means?
Aaron Regberg: It’s kind of both. I, I think it’s, it, you know, one concern is that we could mistake terrestrial microbes for native Martian life, or wherever we’re going. The other concern, and maybe this is more likely, is that the terrestrial microbes would grow and proliferate on the surface of Mars and would, would cover up any evidence of indigenous life. So it would be like, you know, introducing a, a non-native species somewhere on Earth, like the, the cane toads in Australia, and they just sort of proliferate and get out of control and then we can’t find what we’re looking for because all we’re able to see is the, is the stuff that we brought with us.
Host: OK. All right. That makes sense. Now, in terms of this, this study, right, I think, I think you mentioned that, you know, you’re trying to come up with, you know, the engineers are asking for specifications on how much you’re leaking, but you mentioned we don’t know. So is this study truly novel in that we have, we really haven’t had a chance yet to go out and swab an external environment in, you know, an external space environment? We have, there’s no, is there any history here that we can learn from? There is.
Aaron Regberg: There is.
Host: OK.
Aaron Regberg: Yeah. So the, the, the Russian cosmonauts have actually gone out and tried to collect these samples from portions of the Russian segments of ISS. And they were really focused on trying to cultivate and grow any microorganisms that they collected, and they were able to do that. So that is some sort of preliminary evidence that there may actually be living organisms on the outside of station. There are some, you know, anytime you do an experiment there, you always look at it afterwards and you’re like, oh, I could have done this better, or I could have improved that. And so there are some things like that with the Russian experiment. And so what we’re trying to do is to replicate their experiment and do a couple of things a, a little bit differently to try to, to make the data more robust. We’re also not focused on trying to grow anything. We’re going to bring, we’re going to freeze the samples and bring them back and just sequence any DNA (deoxyribonucleic acid) we can find. Part of the reason for doing that is that we think that’s more similar to the kind of measurements people might want to make on other planets. It’s unlikely that we’re going to fly a bunch of, you know, petri dishes and stuff all the way to Mars. It’s a lot of mass and…
Host: I see.
Aaron Regberg:…for other reasons. So that’s, that’s kind of what we’re doing.
Host: You mentioned the kit and I definitely want to understand, like, the experiment just as a whole, but just the beginnings of this, right? Whenever you were having these conversations about filters and stuff, when you started having the conversation with engineers to, well, where can we, what can we do to get the data we need to inform the engineers about filters, how did you eventually make your way from that conversation to, let’s get in a spacesuit and swab the filters? So how did, how did that journey happen?
Aaron Regberg: A lot of that conversation I think actually started even before I got to NASA. This was sort of an idea that people had, on, on day one when I showed up, and they had already built a prototype kit and they were testing it on the ground and in analog environments. And it was primarily an engineering-led effort as I, as I understand it. And the engineers were having a little bit of trouble keeping things sterile. So they were getting some contamination in their controls. And so, I think what happened is they said, oh, there’s this new guy that showed up and he’s like half a microbiologist and half a geologist, and he’s, maybe he has some ideas about things that we can do differently to try to cut down on the, on the contamination.
Host: So you got pulled in. That’s…
Aaron Regberg: So I got pulled in.
Host: I see.
Aaron Regberg: Yeah. And then, you know how things kind of go at NASA, people move on to other positions or get pulled into other projects, and sort of all of a sudden I found myself writing the, writing the proposal to try to get more funding to actually get it up onto ISS because the people who had pulled me in had been themselves pulled into, you know, other, other activities.
Host: Kind of worked out in your favor though, because you became the lead of that.
Aaron Regberg: I did. Yeah. It is, it’s, it’s, it’s really exciting actually.
Host: Yeah. That’s really cool. So you, you mentioned, I don’t, I don’t think we, we addressed when you came to NASA.
Aaron Regberg: So I started at NASA in 2017.
Host: 2017; OK, relatively recently.
Aaron Regberg: Relatively recently.
Host: So past couple years you guys have been working on something like this. OK. So you wrote the proposal, and, and now it’s going to be flying. Just, OK, let’s, let’s get into exactly what it is. You are the guy they pulled in and said, hey, we are having some trouble with contamination; how did you solve that? How did you solve the techniques to make sure you were minimizing contamination?
Aaron Regberg: A lot of it was just it, so the tool that they had was already well-suited, the prototype was already well-suited to sort of keep things clean and sterile. A lot of it was just sort of sterile technique or aseptic technique when, when thinking about cleaning it and putting it back together, and keeping, trying to minimize, you know, contamination from, from the people working with the tool. So we started cleaning it in the precision cleaning facilities at the, inside the astromaterials curation building, which are a little bit more specialized than I think the, the, the other ones on center. And so that helped, and then when we, we did all of the assembly after we cleaned and sterilized everything, we worked inside what’s called a biosafety cabinet, but it’s a, it looks kind of like a chemical fume hood, but it’s specifically for trying to work as, as aseptically or sterilely as possible. So working inside that cabinet helped us to, to eliminate or minimize any concerns about contamination.
Host: When, when the astronauts would be doing it in the spacesuits, is the environment itself, just being in the vacuum of space, kind of working in your favor in terms of minimizing contamination?
Aaron Regberg: It might. But that’s, yeah, that’s a question that we kind, kind of open question that we have, but what we’re going to have them do…
Host: It’s part of the experiment, yeah.
Aaron Regberg:…is, yeah, so in the kit we have, we have eight sort of swabs and we’re going to have them use six of them to swab surfaces.
Host: OK.
Aaron Regberg: And then we’re going to have them take a seventh one and just open it up and kind of hold it out for 30 seconds or a minute and then put it back without touching anything.
Host: As like a control?
Aaron Regberg: As a control.
Host: OK.
Aaron Regberg: Yeah. And then the eighth one will be another control or a blank where it never gets opened. So we, we did all the assembly, we put it together, and so if we find something in that sample, we know it’s something that we accidentally introduced.
Host: OK. OK. So the kit that they’re going to be bringing out with them, right, I think, is the idea here that they do this job as one of the many activities in a six-and-a half-hour EVA (extravehicular activity), right? It’s not, it’s not a dedicated swab EVA, right?
Aaron Regberg: No, no, no.
Host: Yeah.
Aaron Regberg: Absolutely not.
Host: Right.
Aaron Regberg: No. In, in fact, we’re probably going to be what’s called a, a get-ahead task.
Host: Oh, you don’t even get on the timeline. Oh, man.
Aaron Regberg: Well, it’s all in flux. The number…
Host: I see.
Aaron Regberg:…you know, at the, the way they schedule EVAs is, I’m learning a lot about it right now.
Host: Yeah. It’s, it’s tight. A lot of people want to do a lot of things.
Aaron Regberg: But it’s, yeah, it’s really tight. And so the, the latest, greatest plan that I’m aware of is it we’ll be sort of the last, the last task at the end of the EVA…
Host: OK.
Aaron Regberg:…and it’ll, where, where we get samples from and how many samples we get will in some part depend on, you know, how the rest of the EVA went and how much time they have at the end.
Host:Yeah. So what are the locations that were most interesting, the ones you identified, because you’re not just be swabbing random areas on the outside, right?
Aaron Regberg: No, no. So we’ve identified some of these venting locations near the airlock. One of them is a, is a location that is used to vent carbon dioxide from inside station, so they have carbon dioxide removal systems that scrub CO2 out of the atmosphere to keep it safe and appropriate for the astronauts, and then that CO2 gets vented out into space.
Host: OK.
Aaron Regberg: So we think maybe there are microbes, you know, hitching a ride in that, in that gas stream. The other locations will be around the airlock. So the airlock, you can kind of think of it like a big vent, right?
Host: That makes sense.
Aaron Regberg: Every time you open the door, you get a, you know, they pull vacuum but you get a little puff of gas and whatever is on the astronaut suits is going out, out. And then the, the other location, the other vents, we’re still kind of talking about. One idea is there are some vents that are releasing hydrogen. That, there’s a, so there’s a machine on the inside a station that produces oxygen from, by splitting water, so the hydrogen is a byproduct and that just gets vented…
Host: OK.
Aaron Regberg:…out into space. And then there are some other, I guess, CO2 scrubbing systems that we might try to go sample. Again, some of it is going to depend on how much time the astronauts have, so we’re sort of trying to, right now we’re having this discussion, we’re trying to generate like a priority list. Like, OK, if you have the full amount of time that we asked for, go do this and this and this and this, and if we only have 15 minutes maybe we’ll just collect six samples right around the airlock…
Host: Right.
Aaron Regberg:…without going anywhere and we’ll look at that data and then try to make a case for, for more time on a different EVA.
Host: Which would be convenient. The airlock would be convenient because they start and end the spacewalk there, right? But I guess what you’re evaluating is, are these other places, could they potentially have more or less microbes? Or that is, are you evaluating that the microbial environment?
Aaron Regberg: That’s right.
Host: I see.
Aaron Regberg: Yeah. And so, the, the vents actually have these little covers on them, I think to protect them from micrometeorite damage, and so we’ve gotten permission to be, for the astronauts to actually peel back that little cover and, and swab underneath. And so if you kind of think about areas where microbes like to survive, there’s this kind of, you know, shielded area around that vent, there’s little spurts of gas coming out every now and then, it might be a little bit warmer or a little bit more humid than just a random surface on the outside of station. So we really think that if we’re going to find anything anywhere, that those kind of locations are where, where we think we might find them, it’s like – like, where you kind of have to think about like where…
Host: Like mold forms in your house?
Aaron Regberg:…where mold would grow in your house, yeah.
Host: Yeah, yeah.
Aaron Regberg: It’s the warm dark kind of places…
Host: That’s what I’m thinking.
Aaron Regberg:…that you don’t, that you don’t go that often.
Host: And it, does the Sun have anything to do with it, because I like, I’m, I’m assuming like, in these areas the Sun wouldn’t shine, so would that be favorable to microbes to grow?
Aaron Regberg: Yeah, so ultraviolet radiation from the Sun is a, is pretty good at, at sterilizing and killing a lot of microbes in space. So yeah, anywhere where we can find some, some sort of shady spots and protected spots are, are more likely to, to have microbial populations.
Host: OK. All right. So in terms of the, the full kit, the, the actual pieces of scientific hardware and, and tools that they’re actually going to bring out to this vent when they, when they bring it out, what exactly, you mentioned some swab kits, you mentioned all of that, but what exactly is, is going to be part of their bag that they’re taking out to the work site?
Aaron Regberg: So, it’s, it’s this box, basically, and it’s got canisters kind of set into it, and the box is — I always tell people it’s about the size of a breadbox, but I know that’s not a great reference anymore — but it’s, it’s like, you know, kind of a foot by six inches.
Host: OK.
Aaron Regberg: And there are these metal canisters inset in it and, and each inside, each canister is a swab that kind of looks like a giant version of the swabs that we’ve all been sticking up our nose for, for COVID tests for the past few years.
Host: [laughter] OK.
Aaron Regberg: It’s a, it’s actually a commercially-available swab that’s designed to take a sample from the inside of your cheek.
Host: Interesting.
Aaron Regberg: So the head of the swab is about the size of a nickel.
Host: Oh, OK. That’s a little bigger than the stuff they put up your nose for COVID.
Aaron Regberg: Yeah, yeah. A little bigger because, and that’s, so it’s easier for the astronauts to work with in the spacesuit gloves because those are kind of clunky and hard to manipulate things.
Host: OK. So that, that was probably a huge consideration, what, like, make sure it’s not terribly fine where they would have…
Aaron Regberg: Yeah.
Host:…to really strain their fingers to do it.
Aaron Regberg: Yeah. And so they have a big a big handle that is actually a, a repurposed piece of equipment that was used to repair tiles on the space shuttle if they needed to.
Host: Oh, OK.
Aaron Regberg: And so, you plug that handle into one of the canisters and you pull out the swab and you take your, you know, you swab your surface, just like they do on the inside of space station or just like you would use a Q-tip to kind of clean a little corner in your bathroom or something, and then you pop that swab back into the canister and the canister has a, a hermetic seal at the top. And at the bottom there’s a, a filter and the, the filter is made out of Teflon and the, the pore sizes are smaller than most of the bacteria that we find on Earth. That, the pore size is 0.2 microns. And that filter is really important because the canister has to be able to equalize pressure with the outside environment, so it has to be able to go to vacuum.
Host: Oh yeah.
Aaron Regberg: If it was, if it was completely sealed up and there was no vent on it, you would take it outside and you would open it and there would be this little, you know, puff of gas. And that’s a safety concern I think, because if you didn’t have it put together correctly, you know, it could pop the top off and things could go floating out into space.
Host:I was going to say, it can compromise the whole canister too, maybe, right?
Aaron Regberg: Yeah, yeah. So we put this filter stack on the bottom.
Host: OK.
Aaron Regberg: And that lets it equalize pressure when we take it out, and it also lets it equalize pressure when we come back in. But it’ll keep whatever microbes that we collected in there: they’ll, they’ll, they won’t make it through the filter. Hopefully they’ll stay stuck to the swab, but if they don’t, they’ll end up on that, on that filter.
Host: OK. Yeah. It’s just for, it’s just for the pressure and no microbes are going to escape it.
Aaron Regberg: Yeah.
Host: OK. That’s a cool design. And I like the handle design too because you don’t have to like pinch that little swab or anything.
Aaron Regberg: Yeah.
Host: You got this big handle to help you maneuver it in a, in a bulky spacesuit. That’s a, that’s a very interesting design.
Aaron Regberg: Yeah. Credit to the tools engineers for that. That’s, they, they came up with that, that idea.
Host: Very cool. OK. So they got the, the handles for each of those, the swabs are actually going to go in the vent. Then you got one that you just stick up into the vacuum of space and put down, and one that you leave, and that’s your eight.
Aaron Regberg: Yep. And that’s all eight. Yep.
Host: All right. And so, yeah, so it’s this big box. OK, so then what happens? After you do your samples, you bring it back in the airlock?
Aaron Regberg: Yep. We bring it back inside. We have to take, there’s a whole bunch of attachment points on the outside of that box so that, you know, the astronauts have a bunch of different ways to tether it to their suit or attach it to their suit so they have an easy way to work with it. We have to take up, we have to have the astronauts take all those off so that it will fit in the freezer that’s on space station. So we’re going to freeze the entire box at minus 80 Celsius; that’s a temperature that works really well for preserving microbes and preserving DNA.
Host: OK.
Aaron Regberg: And it’s just going to sit in the freezer until we get a ride back on a SpaceX vehicle, and it’ll come back in a special, like a, it’s like a, they call it a cold or a double cold bag. It’s like a really fancy, soft cooler with special ice packs in it so that it stays frozen all the way back to Earth.
Host: OK.
Aaron Regberg: And then we’ll get it back here to JSC and we’ll bring it into our labs, and we will take those, those swabs apart and extract DNA, and then work with some collaborators to, to try to sequence that DNA.
Host: I’m guessing the DNA sequencing process is a little more complicated, which is why you didn’t opt for the on-orbit DNA sequencer.
Aaron Regberg: It is, yeah. One of, actually one of the, one of the problems with the onboard DNA sequencer is we’ve optimized all of our processes to work with those really small swabs…
Host: Yeah.
Aaron Regberg:…that they use inside, and we actually don’t have a procedure for how to get a big swab processed and onto that sequencer.
Host: Interesting.
Aaron Regberg: So that was something where we kind of looked at it and I talked with, with Sarah Wallace, who’s one of the scientists that, that helps to, to design operations for that sequencer on space, and she’s actually on this project as well, and we both kind of decided that it would just be simpler and more effective to try to do it on Earth.
Host: OK.
Aaron Regberg: And the sequencers that we have on Earth, the sequencer that is in space is amazing, but like a lot of things, the sequencers that we have on Earth, the instruments that we have on Earth, are sometimes a little bit more sensitive than what we can afford to fly to space because of mask constraints and, and things like that. So we thought we’d have our best chance of detecting something if we did, at least the first time, all of the work on the ground.
Host: OK.
Aaron Regberg: If we get an opportunity to do this again, and if this becomes part of a sort of routine monitoring package, we will try to figure out how to do the analysis in space.
Host: OK. Yeah. So it’s, it, it definitely goes beyond just swab size as the reason for going to the ground. It’s, you have better instrumentation, you can, you can have a lot more confidence in your scientific results. Yeah. That, that’s what I, that was going to be my next question was the, the repetition of this. Obviously, you’re got, you have the six samples plus the two controls. It’s, you know, that’s, that’s a decent sample size, but it sounds like you, you definitely want more to have the more confidence, right? So…
Aaron Regberg: Yeah, we’d like to replicate the experiment and, and then the sort of long term thought that we have is that this may become part of something that we just ask astronauts to do routinely to verify that all of our equipment is working correctly. So, for example, if you send someone to Mars and you’re worried about contamination and you’ve installed filters or, or whatever, you still need to be able to, to make some measurement to understand that the whole system is working correctly. And so you could, you could use this swab in that situation as well to make sure that you weren’t accidentally leaking microbes out of a, a filtered vent, for example.
Host: OK. That could be part of routine Mars operations.
Aaron Regberg: Routine Mars operations. Yeah. It’s something we’re considering, you know, maybe asking people to try practicing with on, on Artemis.
Host: Oh, yeah. You would, can do the same thing there.
Aaron Regberg: You can do the same thing on the surface of the Moon, just to kind of get people familiar with it. It, it also just helps to understand, you know, as, as a curator, we spend a lot of time thinking about contamination and worrying about contamination, and we do everything to the best of our ability to make sure there is no contamination. That’s kind of an impossible task. There’s always going to be some kind of contamination. So it’s important from a science, a science perspective to try to characterize, you know, you do the best you can to make sure there’s no contamination, but then you try to characterize whatever, whatever gets through your controls anyway so that you, you have a really clear picture of what, you know, what is a real scientific signal that you’re measuring and what is, is maybe from, from a contaminant.
Host: What does sequencing the, the microbes help you to do? Like, you can identify where, where the microbes came from, what are the most, what are the best that could survive very harsh conditions? What are you looking for?
Aaron Regberg: Potentially, yeah. So at a, at the most basic level, DNA sequencing will help us identify what microbes were present in the sample. So were there bacteria, were there fungi, were there some other kind of organism that we weren’t expecting? If we have enough DNA we can try to sequence not just genes that let us identify who is there, but genes that tell us about what those organisms are capable of metabolically. So can they breathe oxygen or are they like those weird bacteria that I studied in grad[uate] school that can breathe iron and don’t need any oxygen? That requires collecting more biomass usually, so we’re not sure we’re going to be able to do that type of sequencing, but the goal would be to, to paint as clear a picture as possible of what microorganisms were present in the sample and what types of metabolisms they’re capable of employing. So what kind of foods do they like to eat, what kind of things do they need to breathe, things like that, and that would help us understand where they came from. As a sort of first order, we’ll, we’ll compare to what we know is on the inside of space station. So they do microbial monitoring routinely inside station, there have been DNA sequencing experiments that happen in there, so we have a big list and database of, sort of, here are the things that we know are always around inside station. And so if we see those outside, it’s, it’s the most logical explanation is that they came from the inside.
Host: Do you believe that, you know, we’re doing this experiment on the International Space Station, you mentioned that it could help us a lot with exploring other planets, Mars, namely; do you believe it would, the knowledge we gained from this would transfer nice, nicely to the surface of Mars? Meaning, the bacteria that likely grow in the vacuum of space would more or less maybe be the same that would grow on the surface of Mars in a completely different atmosphere and environment? Or is there a possibility that, you know, different things could grow? Does it translate nicely?
Aaron Regberg: It’s not, yeah, that’s a good question; it’s not, it’s not one to one.
Host: OK.
Aaron Regberg: But the things that make it hard to, for bacteria to grow in space, you know, in low-Earth orbit, are not completely different from the things that make it hard for bacteria to grow on the surface of Mars. So in low-Earth orbit, you have a lot of ultraviolet radiation to deal with; that’s also a, a problem on the surface of Mars. You know, in low-Earth orbit you have no oxygen; on the surface of Mars, you have very, very little oxygen. So it’s not exactly the same, but it’s similar. The pressure on the surface of Mars is a lot lower than the pressure on Earth, not as low as vacuum but it’s a lot lower.
Host: OK.
Aaron Regberg: So it’s, it’s similar. So you might expect to see similar types of microorganisms, but you, you know, ones that are adapted to be able to handle not having a lot of water around and exposure to ultraviolet radiation, and, and things like that. You know, big temperature swings; but it’s not, it’s not a given that would be the exact same species.
Host: OK. When the samples go down to the ground, how do you, how do you handle them in terms of your, you have it, you said you met, you have them in this special, I think you said double coldbox, but how, how does, you transfer it, how do you transfer it from the spacecraft and then get it over to a facility and get it into a DNA sequencer? What does that process look like?
Aaron Regberg: I’m learning a little bit about that myself. I’m not…
Host: Cool.
Aaron Regberg:…I’m not entirely sure, but my, my, there’s a whole group at NASA called Cold Stowage, and this is their entire job is to make sure that stuff stays at the right temperature on the way up and on the way down. So they’re, they’re going to be in charge of unpacking the spacecraft and making sure it stays the right temperature until they’re ready to hand it over to us.
Host: OK.
Aaron Regberg: And then when they hand it over to us, we will, it, it, it’s a chemical extraction process and I, and I’m not sure we’ve totally decided yet how, which, which process we’re going to use to get the DNA out. But you basically take that swab and you, you, you peel it off the stick, and put it into a, a, a test tube, and you add different, different compounds and, and heat it up and agitate it to try to break open the cells. And then that DNA goes into the, to the liquid that you’ve added to the test tube. And then there are a bunch more steps to kind of clean that DNA up and get it into the right configuration that you can put it onto the sequencer.
Host: OK. But is there, like, the different techniques, do they have different levels of sensitivity or…
Aaron Regberg: Yeah, that’s, that’s what it is. There are, there are different ways to do it. Some of them are optimized for different types of microorganisms, some of them are, are optimized for different size fragments of DNA, so the length of the DNA that, that comes out at the end of that process. And so we’re going to, we have some ideas about how we want to do that, but we’re going to, we’re going to talk to our collaborators. The DNA sequencing is a really, really rapidly evolving field. So even what we wrote, you know, we submitted this proposal to do this work in 2019, and even the ideas that we had about what we might want to do with the samples in terms of the details of how we were going to extract the DNA and do the sequencing in 2019 are kind of outdated at this point.
Host: Interesting.
Aaron Regberg: It’s like if you, it’s, it’s evolving as fast as, you know, you get new computers, right? So if you, if you had a computer from 2019 today in, in 2023, it’s like, kind of old and slow and not very exciting, and you’d want to do your work on the, you know, play your game or whatever on the, the newest, best machine. And that’s kind of what we want to do here too.
Host: Yeah.
Aaron Regberg: So that’s why, if it sounds like I’m being vague, it’s because we want to take advantage of whatever we think is the best technology available when, when we actually have the sample in our hand to do the work.
Host: That’s, that’s good though that, I mean, you’re, you’re, you’re planning for this, you have techniques down, but it sounds like it, it’s very adaptable in terms of how you can approach the, you know, in actually getting to sequence the, the DNA here. That’s a, that’s a pretty cool experiment, if, if you can just kind of kind of roll with whatever is the latest and greatest.
Aaron Regberg: That’s our hope, yeah.
Host: Yeah. That’s really great. You know, this is, this is just an absolutely fascinating kind of experiment that you, that you guys are doing but, I wonder, you, you mentioned you came from industry and started with the oil and gas and now, you’re, you’re here and working on a mission like this, right, you’re thinking about, you’re working on the International Space Station, you’re thinking about the, you know, the contamination environment for different planets. I just wonder just, you know, looking at your, just your job now and what you’re doing, as a whole, how do you, how do you feel about it?
Aaron Regberg: I mean, I’m, I’m really excited about it. It’s fun to be, it’s fun to be involved in these conversations and there are, it’s a really long time scale. But I don’t know, I, I really like the idea that the work that, that I’m doing and the work that the people I’m, I’m working with are doing is, is setting up other people for success. So if we, if we do a good job of, of minimizing contamination or preventing contamination, it’s going to, it’s going to make it really easy, or hopefully easier, for another scientist to come along after me and look for life on Mars or, you know, understand how the solar system formed because they have these really great samples to work with. And I, I don’t know, I get a lot of personal satisfaction out of that. This is, the work that I’m doing is, is, is setting up the next person to be really successful or to find something cool.
Host: Oh, that’s awesome. Do you see yourself sticking with this kind of project for a while, meaning, you know, it sounds like there’s a chance that this could evolve and you could be doing something very similar with, with different spacecraft that are on and around the Moon, gearing up for, for a Mars mission; do you see yourself sticking with this or do you kind of want to set a good example, pass it on to the next guy, and maybe do try something new?
Aaron Regberg: I don’t know. Yeah, we’ll see. We’ll have to see how it goes.
Host: Yeah. Follow…what was your advice? It was, follow whatever you’re interested in.
Aaron Regberg: Yeah.
Host: Yeah, yeah.
Aaron Regberg: Yeah. I think that’ll, that’ll probably be my strategy.
Host: Whatever comes up. All right. That’s really cool. Well, Aaron, this was an, this was so cool to be able to talk to you and, I know this is going to be launching pretty soon to the International Space Station, so I’m very excited and I really hope the, the timeliners can squeeze it in to the, a very, a spacewalk that’s coming up in the very near future so you can, you can do this sooner rather than later. This is, this is going to be pretty exciting. So, Aaron Regberg, thank you so much for coming on Houston We Have a Podcast. What a pleasure talking to you today.
Aaron Regberg: Thanks a lot. Yeah, this has been really fun.
[Music]
Host: Hey, thanks for sticking around. I hope you learned something today. It was really a pleasure to talk to Dr. Aaron Regberg today. A very interesting experiment coming up, launching aboard Northrop Grumman’s CRS-19 mission. You can always check NASA.gov for the latest experiments that are happening aboard the International Space Station. And also, Aaron is part of the astromaterials research group here at the International, at the Johnson Space Center, and they have a website as well, you can check out some of the great things happening over in his group with astromaterials. If you like podcasts, though, we have a lot of them at NASA. You can go to NASA.gov/podcasts to check out all of them. I know “Curious Universe” launched their latest season, so make sure to go and listen to them. You can also follow us specifically for Houston We Have a Podcast at the Johnson Space Center pages of Facebook, Twitter, and Instagram. And if you use the hashtag #AskNASA, you can ask a question on any one of those platforms, and if you want to make sure you ask a question to us, you can also use that hashtag but make sure to mention it’s for Houston We Have a Podcast. This episode was recorded on February 16, 2023. Thanks to Will Flato, Pat Ryan, Heidi Lavelle, Belinda Pulido, Jaden Jennings, Erin Anthony, and Rachel Barry. And of course, thanks again to Dr. Aaron Regberg 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.