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Deep Space Hydration

Season 1Episode 293Jun 16, 2023

Experts at NASA's Johnson Space Center discuss the new potable water dispenser that will soon be tested on the space station for future Artemis missions into deep space. HWHAP Episode 293.

Houston We Have a Podcast: Ep. 293: NASA astronaut and Expedition 69 Flight Engineer Frank Rubio has fun with fluid physics as he observes the behavior of a free-flying water bubble inside the International Space Station's Kibo laboratory module.

Houston We Have a Podcast: Ep. 293: Deep Space Hydration NASA astronaut and Expedition 69 Flight Engineer Frank Rubio has fun with fluid physics as he observes the behavior of a free-flying water bubble on the International Space Station.

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 293, experts at NASA’s Johnson Space Center discuss the new potable water dispenser that will soon be tested on the space station for future Artemis missions into deep space. This episode was recorded on May 10, 2023.

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Gary Jordan (Host): Houston, we have a podcast! Welcome to the official podcast of the NASA Johnson Space Center, Episode 293, “Deep Space Hydration.” 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. Part of what makes human spaceflight as fascinating as it is challenging is the well, human factor. Humans are very needy in space. We need it to be a good pressure, a good temperature. We need sleep, food, air, water, exercise; seems pretty standard for us stuck here on Earth, but for engineers designing human spacecrafts and systems, it’s a huge consideration, especially as we travel farther away from Earth. On the space station, we’ve gotten pretty good at sustaining humans. In fact, we’ve done it for more than 22 years, continuously at this point. One system used on board station literally every day is the potable water dispenser. Exactly what it sounds like. It’s a system that dispenses potable or drinking water. Astronauts use it every day to rehydrate their astronaut food and to drink, and they’ve been using it since it arrived on station on STS-126 in 2008. For Artemis missions, we’re looking into how to make the system even better and making some upgrades on its reliability and functionality. Enter the exploration potable water dispenser, the water dispenser of the future. This facility just recently launched to the station on the Northrop Grumman CRS-19 Cargo Mission because what better way to find out if the system can work in space for a long time than to put it in space for a long time. To walk us through the system’s design and features, as well as the test objectives for the station is Exploration Environmental Control, and Life Support Systems Integration Manager Kate Toon, as well as Exploration Potable Water Dispenser Hardware Manager, Micah Johnson. All right, let’s get started.


Host: Kate and Micah, thank you so much for coming in. Houston We Have a Podcast today.

Kate Toon: Thanks so much for having us.

Micah Johnson: Yes, indeed. Thank you very much.

Host: Took us a bit to, to get here, right?

Kate Toon: Sure did. [Laughter]

Host: It’s a very, very busy time.

Kate Toon: Absolutely.

Host: And it’s raining outside, so we had to hydroplane on the way here, but we got here.

Kate Toon: [Laughter] Yeah. All in the efforts of hydration and water, all the things, right?

Micah Johnson: Oh, yeah.

Host: That’s the theme, yeah.

Kate Toon: We’ve got a great theme to start us off.

Host: All right. Let’s, let’s learn a little bit about both of you, Kate we’ll start with you.

Kate Toon: Sure.

Host: You have a quite a history with the portable water dispenser.

Kate Toon: Absolutely.


Exploration Environmental Control, and Life Support Systems Integration Manager Kate Toon

Kate Toon: Yeah. Potable water dispenser. Yeah. So, first off, you know, how I come into play with my new role with the exploration potable water dispenser is in the exploration ECLS group, which is environmental control life support. Our group is dedicated to the idea of using the International Space Station as a test bed for exploration missions for our role in our group, that means, you know, all of the life support equipment getting us ready for exploration, Mars, beyond. Fixing the things that are maybe not broken, but could be more efficient, more reliable, and, and just in general, better so that we can, you know, make that big hurdle for exploration. And ISS is our test bed for that. You know, you can only do so much on the ground. So, my team of, of people are working on, you know, oxygen generation, potable water generation, even just water processing in general. So we’re just trying to fix all those things to get us to get us ready.

Host: Reliability, efficiency, all of that is absolutely key.

Kate Toon: It’s pretty key, right?

Host: You don’t have a Home Depot on Mars.

Kate Toon: We definitely don’t.

Host: Or the Moon even. It’s just, you need to have things run as efficiently as possible. So…

Kate Toon: Yeah. Exactly.

Host: Now, your history with the potable water dispenser is not very recent, right? Isn’t, you’re not just talking exploration. You, you have a history with even the legacy one…

Kate Toon: Right? Yeah.

Host:…the one, that’s on station now.

Kate Toon: Yeah, right? I, I do. I started my career here at NASA after a three-tour co-op stent with Texas A&M University, and I graduated with a biomedical engineering degree. And once I got there, I put on a lot of variety of life support type of hardware. So, including the potable water dispenser, this is, oh my gosh, I’m going to date myself back in 2007. And I was a part of that original team that worked on the first generation for ISS for the U.S. side. So that team over the course of two years was the first to design that. And I was just a project engineer but worked with the PMs (project manager) and the Jacobs contracts to develop that and deliver that. So, since then, I’ve had a variety of stint of other life support hardware, including the Total Organic Carbon Analyzer, which reads microbial counts in the water, which full circle to the potable water dispenser. You know, we check the water quality via that hardware just to make sure that it’s good for crew use. So, just had several just pieces of hardware through my career and here I am certifying and delivering the exploration PWD (Potable Water Dispenser) as full circle. So…

Host: Awesome.

Kate Toon:…nice to see everything in that, that life cycle.

Host: Yeah. And I can’t wait to get into this new piece of hardware, but Micah, let’s talk about you for a second and your history that led you to where you are.

Micah Johnson: So, I, it’s funny hearing her talk about her education background, because I, too was part of the co-op program out of Texas A&M University.

Host: All right.

Micah Johnson: Biomedical engineer as well, so it’s very funny.

Kate Toon: I don’t know that I knew that. [Laughter]

Micah Johnson: Yeah. Yeah. I know we never really talked about, it’s one of the things we don’t talk about, but anyway.

Kate Toon: There you go.

Exploration Potable Water Dispenser Hardware Manager, Micah Johnson.

Micah Johnson: I was working with Lockheed Martin at the time, and we, I was supporting the human research facility. This was back in 2000. And so, anyway, so that’s kind of how I got my foot in the door. They hired me once I did graduate. And so, I continued with that group as a project engineer, and then worked my way up to lead and project manager over a couple of years and stuff. So I’ve done quite a few different projects across the board. As a contractor, you support your NASA customer, different divisions of NASA, so whatever work projects come out of, you know, that, that customer base, you know, we support. And so, I’ve worked on everything from like, a human mass measurement device, an ultrasound for space station. I’ve worked on Robonaut, I’ve worked on, I’ve developed the ICWCs (Iodine Compatible Water Container), which is a iodine compatible water container. And that’s kind of how I got introduced into a lot of the ECLS subsystems with dealing with water and whatnot. And then, I’m trying to think of what else. A whole bunch of different projects.

Host: Yeah, I love that.

Micah Johnson:…a lot of projects, it’s a great thing. But anyway, eventually, I’m working under a new contract — cargo mission contract, and they have a small projects office. And one of the projects that came forward to us was this xPWD (Exploration Potable Water Dispenser) project. And since I had history with working with, you know, potable water systems and just ECLS stuff in general, I was slated to work it and I’m glad I did so, because it’s an awesome project.

Host: Yeah. And I can’t wait to get into it. Let’s, let’s talk though about the, the legacy one first.

Kate Toon: Sure.

Host: We keep say, we keep saying potable water dispenser, but let’s just take, you know, high-level, what is that? What does it do? And we can start with some of the older systems, Kate.

Kate Toon: Yeah, sure. So legacy potable water dispenser, when it was delivered originally in, I think it was, it was on ULF2, which was 2008, it accompanied the rest of what we call the region ECLS hardware, which is, the water processor, urine processor, again to become self-reliant— not completely, but as self-reliant as we can with water processing on ISS. But then, not only that, provide crew with, we say potable water. That means drinkable water. Think of your campsite, you know, use the water, don’t drink it kind of thing, you know? This is the cleanest water that you could even compared to the ground, the potable water dispenser’s water is cleaner than really, any water that people on the ground kind of normally get.

Host: Like out of your home faucet or something like that.

Kate Toon: Yeah. Absolutely. But maybe, arguably better…

Micah Johnson: Yeah.

Kate Toon:…just from a water quality perspective.

Host: Cool.

Kate Toon: You know, free of bugs and a lot of contamination, which is just required in our closed loop system on station to remove all that and, make it as clean as possible because, you know, we are obviously a closed loop system on station, even the smallest level of contamination or something goes back into condensate and then back into the system. So no water is officially lost unless we purposely trash it.

Host: So you like it clean a little bit for the people, but really for the system.

Kate Toon: We’re a little selfish for our, some of our beds and our scrubbing processes and our oxygen generation systems. I mean, it’s all full circle one thing, and you mess up the balance, so to speak. You mess up everything. So it ends with the crew, of course. But you know, the systems are affected too. So yeah. So, we, the potable water dispenser on station as it is today, which once we get to exploration PWD, just as a note, this will be both running in tandem. We’ll have both up there running and for crew use. But the legacy PWD as it is today, and we’ll stay there until further notice. It pulls from the potable water bus, which is our water processor. And so, it needs to be De-iodinated for the legacy, PWD, as well as the current exploration PWD. Iodine in that system is our biocide, our active biocide that’s pulled out prior to crew consumption. So legacy PWD, you know, I’m trying to think of anything else…

Host: Well, just let’s talk about iodine.

Kate Toon: Yeah.

Host: Let’s talk like, so why, why can’t we drink it?

Kate Toon: Iodine is a great biocide. The Russians use silver as their biocide, but biocide is just not healthy to regularly drink just from medical standards.

Host: OK.

Kate Toon: It’s, it would mess with your, your system. [Laughter] For lack of better words. It’s just not for ingestion, but…

Host: OK.

Kate Toon:…you know, same thing on the ground. You know, we, we have active biocides and water processing plants and such, but it’s always removed prior to consumption. But it’s a way to keep systems and lines clean while it’s kind of in route and, you know, getting to, to crew. So…

Host: Because you talk, you talk about closed loop, and we can expand on that just a little bit, right? So it’s not just, you know, like we, what we are getting at is you don’t have just a tank of water that you’re pulling from; this whole, like, it is constantly being recycled and worked through other parts of the International Space Station. So it’s not just, it’s not just drinking water, water serves different purposes on ISS.

Kate Toon: Yeah. I mean, the water system, you know, we pull, like I said, you know, even humidity and water generation from systems, you know, so if we got running components and from that you get condensation. You know that water is reclaimed back into the atmosphere, which then goes back into the water processor. The urine from the crew also gets processed in the urine processor that goes back into the water processor, which becomes, yes, today’s coffee. So, but regardless, it’s not just a tank of water that’s sustained and maintained. It’s ever moving system. And that, and that flow of the water on station is very important to, you know, to keep things moving, prevents microbial growth and film, biofilm growth. So, which will be a key component when we talk about for exploration PWD as well as legacy PWD. Just the ever-running nature, lack of stagnation to try and prevent those kinds of issues. But…

Host: OK. Still, still on the legacy for just a second…

Kate Toon: Yeah.

Host:…because just to, to get a sense, right, because if you’re on the ground, you think of a, a water dispenser as maybe like a water cooler, but in terms of the microgravity design of how to get water from a system and into a little pouch, so you can actually drink it or you could rehydrate food, just very high-level, what are like the key components that make the potable water system, you know, microgravity friendly?

Kate Toon: Yeah, I mean, it’s interesting. We utilize on legacy PWD, the water bus pressure to get water into the system. And we regulate via valves and check valves, solenoid valves to push and monitor water into food packages. On the front of legacy, PWD, but also exploration PWD, which we’ll get to, there’s incremental amounts depending on what food you’re rehydrating. And also heated water. Heated, heated, basically inside the legacy and exploration PWD, we’ve got coils that gradually heat the water so that you can have warm water or something warm for whatever you’re rehydrating as well. The coils act as a really good, you know, way to slowly but surely heat the water through the, the lines there. And that’s worked in both designs so far. So Anything to add, Micah?

Micah Johnson: No, I mean, that’s about, basically about it. I would say that predominantly though, you know, the water systems, when you say microgravity friendly…

Host: Yeah.

Micah Johnson:…I mean, we rely on a pumps…

Kate Toon: Yeah, exactly.

Micah Johnson:…to generate a pressure head…

Host: Yeah.

Micah Johnson:…to push the water through. So there is no gravity, so you can’t rely on height. You know, like, you know, you see driving around here, you see the big water towers where you’re using the, you know, the height component to generate your Delta P…

Host: Yeah.

Micah Johnson:…pressure gradient. Here we have to rely on pumps.

Host: OK.

Micah Johnson: So, and I, I will say, that we are not the, the PWD and the xPWD do not have pumps installed. They are upstream of us.

Kate Toon: Right?

Micah Johnson: So there is a, there is a, when she said potable water bus pressure, there are other systems upstream of us that provide that pressure head to us to, so really, truly all we are doing is opening valves to allow the water to flow through. So…

Host: OK.

Micah Johnson:…now, you know, that doesn’t mean in the future for other missions, you know, where maybe there isn’t a, a great pressure head up upstream, but we would have to. But so far, we rely on a pump system to generate a pressure head that then, you know, allows the water to flow through the systems. So…

Host: OK.

Kate Toon: That’s a good add.

Host: OK. Now, if, if still looking at the — the legacy one, when it comes to, just because you, you talked about Kate that, you know, we’ve been working on this since 2007, 2008 kind of timeframe. That’s a long time that it’s been operating in microgravity…

Micah Johnson: Absolutely.

Host:…just, just taking that, taking the operation over more than a decade, how did it do?

Kate Toon: Yeah. You know, so like any good piece of ISS hardware, there is a learning curve with it. What you think it’s going to do on, on the ground and what its requirements were set out to do and what it does on orbit? You know, I would say, you know, ISS legacy PWD had a, a bit of a learning curve when we started up; when we delivered in 2008, the unit sat, one of the biggest lessons learned, I would say at the beginning, and that feeds into exploration PWD, is, you know, the stagnation of the water inside of the unit once we got it up there in 2008 to check it out, which what I mean by that is, you know, flow through it, get the water out of it, but then check water quality with the total organic carbon analyzer as I referenced earlier.

Host: Yeah.

Kate Toon: Which measures total organic carbon in the water, which is, effectively, I don’t, bacteria for…

Host: Bacteria.

Kate Toon:…well, food for bacteria. And so, from that, you know, that you probably have a bacterial source, so…

Host: If there’s food, there might be bacteria.

Kate Toon: Exactly. So, that’s how we check water quality on station today and to ensure it’s good for drinking amongst also, of course, checking constituents in the water for water quality, like for the chemical constituents of water. But we, sorry, getting back to point, you know, we checked it out and immediately we saw the total organic carbon, and an elevated quantity and knew we had to remediate the system before crew could actually start drinking off of it and using it or eating, for the, eating food packages with the water.

Host: Sure.

Kate Toon: So we weren’t anticipating that. And it was, as I said, with the rest of the region ECLS hardware on station that was just delivered on ULF2 as well. PWD kind of became the focal point from a center director perspective of trying to get it up and running ASAP because it was preventing other emission goals of checkouts. So my team of like three at the time, quickly worked with the amazing water quality lab here on-site to develop, basically a, you know, material cert[ification] only set of packages of Teflon bags, small, water iodinated bags, 40 ppm of iodine – iodide [Laughter]…

Host: Parts per million.

Kate Toon:…yes, and so, and we sent up a series of six Teflon bags, sizes of, you know, maybe seven inches by, you know, three inches long, you know, small Teflon bags. And we sent them up on the next flight to inject into the system to flush it out and remediate it, so that we could get it into a drinkable status. That was — say again?

Micah Johnson: Yeah, I was going to say a shock kit, essentially.

Kate Toon: A shock kit, that’s what we called it.

Micah Johnson: Normal station, iodine levels, we’re talking like three ppm.

Kate Toon: Yeah.

Host: Oh.

Micah Johnson: This is 40. So you’re ten times order of magnitude.

Kate Toon: Exactly.

Micah Johnson: And the whole point is to, you want to, it’s shocking it. It’s just like at a pool at your house, you know, normally you have your normal chlorine generation going on, but every once in a while, you got shock it with that shock bag, which is much higher.

Host: Yes. When you pour the stuff in…

Micah Johnson: This, that’s the analog to it.

Kate Toon: Exactly.

Host: Oh, OK.

Kate Toon: Yeah. And so, we, my team, yeah, again, full circle of 2008 timeframe, and near and dear of things that we considered for the exploration PWD here now, and 2022, 2023, when we delivered. Yeah. So we, we sent it and it was successful. We remediated the system with the shock kit, as we called it at the time, and injected the 40 ppm of iodine into the system, remediated it, checked it out with the water quality system on station, and recovered it. So, but, but from there, yeah, I mean, there was other little things that we learned, crew use and how, how we insert the packages into what we call the beverage adapter. There were some things about the design of that in microgravity and the needle design that wasn’t quite right with the flow of water and how it hit angles within the needle, for example. And then sometimes backing out the water back into the adapter where you put the packages. So, yeah, I mean, a lot of little lessons learned. Once we had our kind of six to months to a year of checkout of use, you know, we really got into a rhythm with legacy PWD. And it, to your original question, it took us a while to get back to it, but it’s been functioning great, you know, and we’ve learned things, you know, here and there things, but overall, I think the crew, you know, loves their rehydration station. I mean, food’s a big component of the psychology of spaceflight. So…

Host: Yeah.

Kate Toon:…giving that to them is a very important attribute of spaceflight.

Host: Yeah. And that’s exactly what I wanted to sort of set the tone for with that, with understanding the, the, the legacy system is, you know, it’s been operating for a long time. That’s great. It means that the design of operating for a long time in space, like we can have a lot of confidence in that, but what you guys are doing is just taking it one step further with reliability, with some of the functionality, right? We’re going to talk about getting, you know, making the water safer and stuff like that for…

Kate Toon: Absolutely.

Host:…for exploration. And so, so let’s get into that.

Kate Toon: Yeah.

Host: So what, what you’re saying, Kate with a lot of the, a lot of those little things that we can learn from, from the legacy system, very much are going to lead into what we’re going to talk about for the exploration…

Kate Toon: Absolutely.

Host:…potable water dispense- dispenser, there’s a lot of cool functions in this that make it just that much better. Micah, we’ll go to you. So what talks about the design of exploration potable water dispenser, what are those core functions? What are those nice little extra features that make it the next generation?

Micah Johnson: Sure. So in, in all these spaceflight, you know, projects for ISS and beyond, let’s start with, there’s a lot of requirements that drive your design in terms of things that you have to deal with in terms of power, how much power you consume or utilize in space, how much you weigh, you know? Things like that. So…

Host: Not a lot and not a lot. [Laughter]

Micah Johnson: You know.

Kate Toon: So do more with less.

Host: Do more with less.

Micah Johnson: Exactly. So, you know, coming to a design for xPWD, we, you know, you have to take all those considerations, you know, things into consideration.

Host: Yeah.

Micah Johnson: But you also rely on because we did have legacy PWD, PWD to look back to, to say, OK, hey, here’s what it is. There are, you know, certainly there are features that are the same. I mean, at the heart of it, it’s dispensing water to the, you know, to food or drink bag. And so, and there were some key requirements that we wanted to maintain, you know, in terms of like how the crew interacts with it. So one of the, we wanted to keep it similar to, in terms of human factors and crew interfaces in terms of, you know, knobs they switch, buttons they press.

Host: OK.

Micah Johnson: Things like that. So, because, you know, you don’t want to have to teach, they’ve been using it for many, many years. You don’t want to have to teach them a whole new thing in the system when it’s doing the same function in terms of dispensing water, but moving beyond those similarities, you know, some of the technologies that we’ve incorporated in things that we went after, you have your first, you know, is like technology changes over the years, obviously. So you’re talking something from 2008 to something 2020. So, you know, there are just upgrades in terms of electronics, you know, and things that parts…

Kate Toon: Inherent reliability that you get…

Micah Johnson:…parts obsolescence that, you know, you have to make those changes. Those are like at circuit-board level, you know, changes like that.

Host: OK.

Micah Johnson: But then, so, but then you go into more of, I guess, some of the functionality in terms of, well, let’s start with addressing some of the issues that came up for, oh, sorry.

Kate Toon: No, go —

Micah Johnson: xPWD. So, one or, or one of the big things that she’s talked about, Kate talked about was about the stagnation issue. So, when we talk about stagnation in a water system, that is an area where the water flow is not, it’s not flowing through all the time. Or you get, like, eddy currents, little whirlpools. And what happens is, is biofilm tends to grow in those areas. So when I say biofilm, we’re talking the, the bugs, you know, whatever it is, microbes, you know? And, and so, a goal of our design was to make it a streamlined system where you have what we call dead legs. We wanted to eliminate that from the design. So in the original PWD, there were areas where you would have stagnation points to where water would sit and not get touched through long durations of time. And or even when you were flowing through water, you, water wasn’t circulating in those areas and stuff. They had accumulators where water would just sit because they had to accommodate for thermal expansion. And, and just some of those design aspects were creating this problem of biofilm generation. And so, what we wanted to do was take a look at that and say, OK, why did they do that in their design? All right. Can we change it? Can we improve upon that? And so that’s, you know, what we did. And so, it, the first thing that we did was a new plumbing layout. And so…

Host: Yeah.

Micah Johnson:…from entrance of the water, from a, you know, upstream QD (quick disconnect) to the output, you know, we wanted to streamline that plumbing design to allow where all water is, is constantly flowing, all surfaces. And you’re not having, you know, obviously it’s going to sit when you’re not dispensing, but even when you’re dispensing, you want that water to go through, pass through everything, and touch every surface, because friction that is generated from that water flowing over the surfaces is what’s going to remove the biofilm and prevent it from growing.

Host: Interesting.

The new potable water dispenser that will soon be tested on the space station for future Artemis missions into deep space. This new system will work in tandem with the existing potable water dispenser that is currently on the station.

Kate Toon: Yeah. And, and so that’s, you know, one of the original, you know, why it came to our group and our team of you for our exploration ECLS group; environmental control life support is, you know, this idea that legacy PWD doesn’t do well in long, long term stagnation, even going into dormancy, which for exploration missions, we, we need to consider as a reality of how the systems will have to function. And so, like Micah was saying, you know, this, you know, basically the, the top three things we were looking at for exploration PWD wasn’t so much like, I know you were asking the question of like, crew usability.

Host: Yeah.

Kate Toon: How did it influence the design now, you know? Yes, they were here and there, like, oh, the lights and the push buttons and, you know, the adapter for the packages, they were improved. And we, we did definitely send crew feedback, of course. But the real, you know, core of what exploration PWD was providing us was this new layout in plumbing to remove, to remove stagnant legs, to enable dormancy for the system, you know, and the ability to use new technology for the UV (ultraviolet) disinfection.

Micah Johnson: Yeah. I’ll get to that in a second.

Kate Toon: Yeah. And so, just back to legacy for a second, how we, we say disinfect the water, as I already alluded to, we use basically the iodine from the potable bus that gets flowed into the system, but we remove that via something we call an ACTEX (Activated Carbon Ion Exchange). Don’t ask me the full acronym right now.

Micah Johnson: I don’t know, I don’t know what it is…

Kate Toon: [Laughter] But it removes the iodine force, but then the important part is at, it goes to a 0.2-micron filter. And that is like a point of use filter from, for microbial growth. How exploration PWD is different is it uses UV disinfection, basically LED (light emitting diode) bulbs to sterilize the water at the point of use. UV disinfections a huge key core technology we’re trying to demonstrate because 0.2-micron filters is a, a mass hit, right? For exploration, you’d have to continue, we’d have to continue to replace that as like a orbital replacement unit.

Host: Oh.

Kate Toon: ORU.

Host: You have to fly spares.

Micah Johnson: Yeah.

Kate Toon: You have to fly spares.

Micah Johnson: Yeah. The 0.2 micron has like a shelf life of, you know, once it’s wedded, like six months or a year, something like that.

Host: So quite a bit of space.

Micah Johnson: Yeah. Versus, you know UV…

Kate Toon: the UV disinfection…

Micah Johnson:…which is, is hours based, it’s LED, you know, it’s a UV LED…

Kate Toon: Power…

Micah Johnson:…and technology.

Kate Toon: And it’s so, so again, you know, high-level, the big three things for exploration PWD was enabling dormancy, utilizing new technology to reduce mass, which is the UV light technology for sterilization and removing dead legs, which Micah already alluded to, you know? This dormancy getting into, in and out of dormancy, this continuous flow don’t have stagnant paths. These are all things we needed for our exploration missions. So…

Host: I can see that being like a really fun project to just, to look at the path and just, it’s like, where’s the stagnation? And look at literally every nook and cranny of that and just…

Kate Toon: Yeah. Actually, that’s a great. I’m just going to insert another story of lessons learned.

Host: Yeah.

Kate Toon: So we also, upon delivery of, you know, when we said that we had that microbial event, we, we were like, well, is it just the stagnation? Is there something in the design? And we found corrugated tubing that we decided to design with one of the lines within the legacy PWD.

Micah Johnson: Yes.

Kate Toon: And I say corrugated tubing, it’s like little, has little ridges and nooks and crannies, the epitome of like, we shouldn’t have done that. [Laughter]

Micah Johnson: Yeah.

Kate Toon: And so, so much so that within the year, we also replaced it with smooth wall tubing, just, just for that. And we still had, of course, all the dead legs in the system, but at least we had smooth walls. [Laughter]

Micah Johnson: Yeah.

Kate Toon: And so that, and it, you know, from a design perspective, we put it the corrugated tubing in at the time with, you know, little thought there, but you know, just to create more space in the system, right? You’re like, oh, it’s corrugated so, I can move it around the system and make it into the box that you need, right? And so, it had its design reason, but — practicality of it all, and that the, the little ebbs between all of the, you know, the corrugated line just was just a home for bacterial growth. Just another lesson learned. All smooth walls. [Laughter]

Micah Johnson: Yeah.

Kate Toon: As much as you can anyway.

Micah Johnson: Yeah. I know. I mean, going into that, I mean, because it is very important that, you know, what she’s talking about, the smooth walls and stuff like that. But…

Host: Right?

Micah Johnson:…you know, again, going back to this plumbing enhancement, it is a big deal. And in terms of what we did, and so, even so much like we had to, we had an innovation that we incorporated in our design with our thermal expansion device. We call it the TED. But so a lot of your thermal expansion devices — revolve around bellows or reservoirs to, so, let me describe thermal expansion real quick. So when you have temperature gradients in a closed system, you’re going to get the water is, well, not even closed, but in general, water expands or contracts. So as you get water gets warmer, it expands, just like air expands, like in your balloon, you know, that, and you get hotter out that your balloon gets bigger when it gets cold, it shrinks. Same thing. Water behaves the same way. It’s a fluid. And so, because of that, in your closed loop system where you’re, you’re shut off from any, you know, upstream or downstream, you can create high pressure gradients because of thermal expansion, because we do have a heater, and we have, and the waters coming in can be up as low as 65 degrees. And you’re heating water to nearly 200 degrees. That’s a huge thermal gradient. So you can generate really high pressure, so you need something to accommodate this thermal expansion. But, and so in the legacy PWD, they utilized an accumulator, basically, or a reservoir, a secondary like tank holding. So — as it expanded, water would come into it, and then it, and then when it would, you’d dispense it, you would kind of get it out. But that was a major source of stagnation problem. So in our design, we, like I said, one of a technology innovation that we incorporate, we, this TED (Thermal Expansion Device) device. So it, we developed it, it took a little while to design and stuff, and it, it basically it allows for the fluid can pass through it fully, so it’s not holding water. It has a, a particular design that allows — you know, fluid flow to go through it, touch all surfaces. So you’re not getting film development, but it has these diaphragm, titanium diaphragm plates that, you know, by, you know, I guess geometry and, and just, you know, mechanical properties, they flex when the pressure goes up. So it allows for a volume to expand, and then when it cools it can contract and stuff. And we had to do, we also did computational fluid dynamics analysis of it to make sure that the water flowing through our system is touching all the surfaces, engineering enough friction and all that stuff. And then for this device, you know, we did fatigue analysis, which we, because they are flexing, you want to make sure that they’re not going to break…

Host: Expand, contract, expand, contract. Yeah. Yeah.

Micah Johnson: Yeah. And you’re, and you’re experiencing these upwards of, you know, 150, 200 degrees swings of, you know, we had to make sure that it would survive that. And, you know, we, so we did lots of analysis, but it was an interesting and neat design to work on and to incorporate and stuff like that.

Host: Yeah.

Micah Johnson: But, you know, things like that, you know, it’s, you know, it seems small because it’s just one little component in our stream, but it’s a very important element of the design to make sure that we’re eliminating these…

Host: Right?

Micah Johnson:…you know, these dead legs and whatnot. So…

Kate Toon: Yeah, I just, no, and I just, I, this is, that’s good. And I was just going to say, you know, when we were coming into this podcast, you know, you had asked, you know, you know, that idea of, you know, what crew feedback was such, you made the system, you know, the way it is today?

Micah Johnson: Yeah.

Kate Toon: And those little features and things that we did definitely enabled it. But like I said, you know, for exploration, it’s kind of like we had mission success goals for the next generation, less of crew feedback on functionality. We had some core goals that we needed to, to iron out with this next unit. And then just the obvious, you know, station, the folks we have on station is growing, right? So having a second water source for rehydration was also another big benefit to station. Not just for our exploration goals, but…

Host: Yeah.

Kate Toon:…you know, not creating a line at the kitchen, so to speak. So that everybody has a chance to get their food as we ever increase our crew size and compliment. So I’m sure it’ll be desired…

Host: Right?

Kate Toon:…here shortly.

Micah Johnson: More upgrades.

Host: More upgrades. So let’s talk about them.

Micah Johnson: So another big delta that we incorporated in xPWD is, we made it kind of smart in the sense of…

Kate Toon: Absolutely.

Micah Johnson:…we add, so one of the requirements that, that NASA wanted us to incorporate is the ability to get data, telemetry data from the unit on orbit. So this is like information on, you know, how sensors are behaving, you know, current levels of, you know, voltage levels of life of the filter, the, or excuse me, the UV reactor. Things like, you know, all this type of information. You know, they wanted to have more insight into its performance. And so…

Kate Toon: Yeah. Legacy PWD, that’s a great add, you know?

Micah Johnson: Yeah.

Kate Toon: Legacy PWD didn’t have any really telemetry on the system. And so, this was, yeah, like Micah is saying is a huge add.

Micah Johnson: A new capability, I guess. So, and with that, you know, we had some new technology that we included in its design. A, we, you know, we call it the brains of the system, but…

Host: Yeah.

Micah Johnson:…it’s a, a programmable automated controller unit that basically talks and tells, you know, tells like when the valves to open or it, it tells when the heaters to turn on and off. It, it tells, you know when the UV reactor should turn on and off. It’s, so, and…

Kate Toon: And so, in practicality, why that’s important or how that’s been important in the lessons we’ve learned from legacy is, you know, over time, valves and tolerances of these, you know, water dispense in, on station vary and it will vary, and it has varied. And so having this insight into, you know, how valves are reacting, and the power draws and, and how the system’s performing, you know, we can by telemetry adjust. So like, let’s say 25 MLs (milliliters) isn’t quite 25 MLs anymore, when you want to dispense, if we have to adjust, now we have the hard telemetry to get, you know, exploration PWD to adjust based on system performance.

Micah Johnson: Yeah. You can command.

Kate Toon: And you can, we can command.

Micah Johnson: xPWD from the ground to tell it to do stuff.

Kate Toon: So much so, right?

Host: That’s great.

Kate Toon: So we have two unique settings on exploration PWD. So we have basically dispense, hard dispenses with a knob on the front, which is similar to legacy 25 ML to 250, but we also have two customizable settings. We call it custom one, two.

Micah Johnson: Yeah. Yeah.

Kate Toon: And if it’s a preference, you know, say that crew compliment really likes, I don’t know, fajitas or something, you know, and that as always, a certain quantity, you know, that can be customized for that crew. And again, adjusted on the ground to, to make that a custom setting. So when it goes to that turn and that knob for custom one, it’ll always dispense at whatever you want versus just the gradient of 25 to 250 and a circular knob as it clicks over.

Host: Wow, that’s cool.

Micah Johnson: Yeah. If you want 27 milliliters or 57, some weird number, you can make it do it. [Laughter] So…

Kate Toon: Yeah. You know, and that’s been something that crew has feed, fed back on. You know, the, the food lab here is awesome on-site. I don’t know if anybody’s had a chance to go there, but it’s pretty awesome. But, you know, they have a set standard for how much things should be rehydrated, right? This requires this.

Host: Sure.

Kate Toon: And it’s like basically the instructions on your food package of how much it should rehydrate, but, you know, crew likes it sometimes, you know, a little soupier or, you know, and, and becomes, you know, a crew preference. And so, crew has learned over time, and especially with their extended stays of kind of how they prefer to rehydrate their food. So just get, again, back to the idea of food is comfort on station, something familiar and, comfort item, you know, giving them the ability to adjust that, you know, that’s great.

Host: That customization. That’s really good.

Kate Toon: Yeah.

Host: I think another improvement that I saw on the list for the xPWD is, you know, since we’re on the topic of crew and preference and stuff like that, this might have to do a little bit with crew. This might have to do a little with the ground team, but I know accessibility and maintenance was one thing that you guys…

Kate Toon: Oh, yeah.

Host:…took a look at because if you’ll have to fix or do whatever to the potable water dispenser, you do want to make it as easy as possible. And, and you made some, you made some upgrades to that, right?

Micah Johnson: Yeah. I mean, one of the, the main things that we wanted to go after was this continual maintenance aspect of PWD is the, the exchange of the, the filter. So…

Host: I see.

Micah Johnson:…legacy PWD had a, this ACTEX, this iodine filter removal iodine filter removal media and then they also had this 0.2 micron, and it was in this, they called an ORU, orbital replacement unit, but it was in a nice little package, you know? So PWD had that. And so, but where it was located was on the side of the unit. Sorry, yeah, got thunder there. It was on the side of a unit, and you had to literally pull the, the chassis of the PWD out from its locker, you know? It did have slide rails, but you had to pull it out. So you had to do a lot of activities just to pull out.

Kate Toon: A lot of crew time.

Micah Johnson: Then you had to remove this panel to get to it on the side. And like, if, if your slide rails were buggered up or something, maybe you couldn’t remove it all the way, whatever, you know?

Host: Yeah.

Micah Johnson: And, but it just took some time. And, you know, crew time is a very valuable commodity for, you know, station right now. And anyway, so one of the key things we wanted to do is let’s move it to the front, so they don’t have to pull it out from the drawer and do all this, you know, so let’s simplify its removal. And you know, because this, the old design had a quite complex mechanism that you had to go through, which…

Kate Toon: Latching and unlatching…

Micah Johnson: latching…

Kate Toon:…could pop it out of QDs.

Host: Oh.

Micah Johnson: And so…

Kate Toon: Quick distance.

Micah Johnson:…we, you know, we were like, can we make it more simple? You know, can we make it to where you don’t have to pull it out of the drawer, you can do everything from the front. And so, that was something that we did. So, we were able to relocate essentially where this location was to the front. So now the crew can just undo a couple of screws pulled out, put the new one in, and, you know, it saves quite a bit of time. So they still have to replace it. It is something that does have a lifetime on it. The, the filters, since we went down to just one, to, we still have the ACTEX to remove the iodine. That’s something that we will always, as long as you have iodine as your Biocide as part of your water bus, your potable water on station, you’re going to have to remove it for point of use. And so, we still had to have our iodine filter, and it still has to be replaced and so, but it just, now, it’s easier to do.

Host: Now it’s easier.

Micah Johnson: So, yeah. And they can just do it right there at the front and save some crew time.

Host: Let’s go back to UVs for a second…

Micah Johnson: Yeah. Yeah.

Host:…because definitely it’s related to the filters, right? So just, it sounded like the legacy had multiple filters to get rid of that…

Micah Johnson: Yeah. So for microbial control, specifically, once you removed the iodine, so once you removed the iodine, you no longer had this biocide in your water. So the 0.2 micron filter that was in the PWD design was downstream of this iodine filter. So you remove the iodine, now water’s flowing through un-iodinated, so stuff could grow. So then you have this 0.2 micron filter that was supposed to, you know, remove, you know, if there was anything to potentially grow in between this would remove it on its way out.

Host: One for, one for the iodine, and one for the nasties.

Kate Toon: Right?

Micah Johnson: Yes.

Host: OK.

Kate Toon: Now, whereas UV, right, isn’t a filter anymore.

Micah Johnson: Yeah.

Kate Toon: It’s, you know, it’s the sterilization of water via the, the UV lights…

Host: OK.

Kate Toon:…that are hitting, you know, the surface area of the water. And, you know, legacy PWD, the 0.2-micron filter did do well.

Micah Johnson: Yeah. It works…

Kate Toon: You know, once we had the constant flow, the 0.2 filter did its job and we actually used that kind of 0.2 filter…

Micah Johnson: It’s used all-over.

Kate Toon:…all-over station. It’s not just in the, the potable water dispenser. So, very common so to speak, item on station, but trying to move away from that with the UV lights.

Micah Johnson: Yeah. So because what we’re gaining from this in terms of exploration is, you know, now you’re talking really long-duration type activities. So this has a shelf life. So if you’re talking six months, a year shelf life, that’s not, it’s not going to make it for something where your mission is two years.

Host: Yeah.

Micah Johnson: And so, or three years or whatever. And so, the benefit of the UV reactor is, is it is based on the life of the bulb. I mean, there’s a couple factors that go into it, but one of the main things in terms of its life — what limits its life is the fact of it has this LED and as you know, you know, here in for terrestrial applications, LEDs last pretty long. So…

Host: Yeah.

Micah Johnson:…this thing has upwards to eight-to-ten-thousand hours of operation. And because we only turn it on when we’re using it and every so often we turn it on, you know, you’re not using it constantly. So I mean ours, you know, through our usage assumptions and things like that, this, it should last eight to ten years. And so, I mean, I don’t have to replace a 0.2 micron every year now.

Host: Yeah.

Micah Johnson: So…

Host: Just a little bit more power.

Micah Johnson: Yeah.

Host: And now you can reduce your filtering usage by half or something.

Micah Johnson: Yeah.

Kate Toon: And, and further, you know, what we’ve found through utilizing this technology is that, you know, we, the UV light, like on terrestrial, you know, uses and how these bulbs work, it’s actually an ever-growing market. It’s only improving exponentially almost for UV reactor lights as sterilization. So, you know, there’s even promise perhaps in the future if you can get down to a certain power level usage because you can’t just have these for sterilization everywhere. It would probably be too much power with the technology…

Micah Johnson: Yeah.

Kate Toon:…as it is today. But the market is growing. And so, you know, proving out this technology now just at the fundamental level for other applications on larger scale could be hugely beneficial and kind of a paradigm shift for sterilization on, for water systems in general. So it’s, it’s the beginning to something of this technology usage that I think has a lot of spaceflight applications in the future.

Host: You have to be forward thinking with this kind of stuff.

Kate Toon: That’s, that’s the team, that’s the goal.

Host: Yeah. Yeah.

Kate Toon: I got to think about it. So…

Host: I think we hit a lot of the different functions of xPWD. I think the heater is the one we haven’t touched yet, right? I think that’s been improved.

Micah Johnson: Yeah. So one of the things with the heater that we wanted to address was the ability to make it more efficient. So heat the water faster or, or use less power to do so. So you’re only given so much amount of power, like I talked about in terms of requirements that, you know, and because heaters do take a lot of power to, you know, generate the heat to heat them, you know, we’re not obviously dealing with an open flame and a stove, you know, type of situation. So we’re utilizing an electric heater technology basically. So heater, heater strips around, you know, a piece of metal and then you heat the metal, which then heats the water itself. So…

Host: OK.

Micah Johnson: So, and nothing that, you know, in terms of the PWD, it worked perfectly fine. It, it did its job. We wanted to make it to where it would heat the water a little bit faster, and then when you did heat the water, when you got up to temperatures, you know, that it was supposed to get, we wanted it to use less power in terms of, you know, certain channels could turn on and off and in the, such that maybe you’re only heating this little bit of bit of portion to keep it at temperature as opposed to heating everything constantly. And then it turns off and then it cools and then it all turns on again, you know? And so, these are not a, in both systems, they’re not on demand water heaters, like the new technology craze here on terrestrial applications where you’re, you got to understand that those type of systems require, you know, 10 kilovolts, you know, power. Tons of power.

Host: Yeah.

Micah Johnson: We don’t have that ability. So if you want water on demand where you’re getting, you know, 150 degree, you either got to have tons of power or you got to have a long heat pipe, you know, something that allows you to, you know, and again, so back to our requirements, we don’t have that much power. We don’t have that much space. So there is a, it is function in terms of sort of like your old school where you’re heating a — you know, a tub of water, although ours is not a tub. You’re talking like pipes or in our case, a spiral corkscrew looking apparatus, but you are kind of heating it in that old school way. But we want to do it as efficiently as possible, and we wanted to reduce the amount of power of sustaining that temperature, you know, so when it’s not being used, like I said, you’re not constantly heating it.

Kate Toon: It’s that surface area contact…

Micah Johnson: Yeah.

Kate Toon:…through the system that is heating it and trying to make it the most efficient.

Micah Johnson: And so, we went through a couple of, you know, trade studies, design, you know, early design looks at, you know, different — you know, technologies or different layouts and, you know, and we ultimately, you know, went with the design that we have currently. But it also ties back into this programmable automated controller I talked about earlier, where we have the ability, again, from the ground to, we can also turn on and off certain heater channels. Like maybe we find that, hey, you know, we only need four of them running to get it to temperature fast. You know, like we can reduce the power and we can say, eh, don’t turn those ones on. Or, if maybe one of them is not working, you know, one of the channels is not working for our heater design, it will still run, it will still heat the water. I mean, and, and so, you know, redundancy if you will, that’s, you know, these are some of the, the changes that we incorporate into the heater. So, yeah.

Host: Saving a lot of power. OK. All right. Did we hit all the features of the potable water dispenser?

Kate Toon: I guess?

Micah Johnson: I think so. [Laughter]

Kate Toon: [Laughter] Yeah. I think we covered; we covered a lot. Yeah.

Host: [Laughter] Yeah. We did. Good.

Kate Toon: Yeah. It’s, it’s, yeah, it’s, it’s really, it’s exciting. Yeah. So, you know, it’s supposed to go on NG-19 here coming up.

Micah Johnson: Yeah.

Kate Toon: It was supposed to launch a month ago.

Micah Johnson: Yeah.

Kate Toon: NG-19 slipped out. Right now, we’re looking at July, but the current flight plan may put us a little later. You know, back, back to the, you know, moment of thinking of stagnant systems, I can’t help, you know, back to the point…

Micah Johnson: It’s definitely…

Kate Toon: It’s going to be sitting for a while, you know? If a, minimum, you know, and we’ve acknowledged this as the ISS program; that it’s going to be sitting for longer than we had desired. But you know, something else for ground processing, we’ve done a lot for, you know, upgrading or making our ground sterilization practices, you know, better based on what we learned as well. So we’re hoping those ground improvements prior to delivery have helped us here to maintain even longer, you know, duration stagnation for as before it gets up there. So…

Host: Nice.

Kate Toon: Yeah.

Host: Very cool. So when it gets up there, you said it’s going to be, you’re not going to get rid of the legacy one, we’re going to have two systems running, so that’s going to be nice and convenient.

Kate Toon: Yeah.

Host: Someone’s reheating their food—yeah, I’ll just use the other one. So that’s…

Kate Toon: Yeah. Exactly.

Host:…that’s kind of nice.

Kate Toon: That is a luxury that’s, so the crew has not had as of yet, especially in these high, high crew compliment periods, you know?

Host: Yeah.

Kate Toon: So yeah, definitely. I think, you know, avoiding that line and having to take turns with meal, mealtimes will be great. So…

Host: So you have the, it’s a, this is kind of a technology demonstration is…

Kate Toon: Yes. Absolutely.

Host:…sort of how you’re categorizing it, right?

Kate Toon: Yes.

Host: Four months to a year test cycle, right? So that you at least want to test the performance of it. Is there a possibility you would just leave it there?

Kate Toon: Absolutely.

Host: Or you need to make space? Oh, you, you would maybe leave it…

Kate Toon: Yeah. You know, so for exploration PWD, like a lot of our other exploration, we call them tech demos, the idea is, you know, that they are not, none of our systems are right now for mission success relied upon, and this is an important nuance, is if we didn’t have like my group’s hardware where we’re making things more efficient and lighter and more reliable, or even adding more capability from a, a mission success perspective, it’s not relied upon. So for like, let’s call them orbital replacement units and how we’re managing spares and sustaining of these, these pieces of hardware, they’re not required for ISS to function. It, it in a lot of cases helps. But in some cases, it’s more crew time and, you know, to try and demonstrate the technology. So point being is, is that if we get to the point where exploration PWD is showing its function as reliable and, you know, still good water quality, that extra rehydration station on station, that’s a lot of, that’s mouthful, is, you know, we will keep it…

Host: Cool.

Kate Toon:…and it wouldn’t be just disposed of, you know, it would continue to run as long as it was providing benefit and demonstrating technology for what we’re trying to do for exploration. So, yeah, it’d stay.

Host: That’s fantastic.

Kate Toon: An extra benefit and extra rehydration for the crew. So…

Host: So great. Yeah. It has potentially long-term life and it’s going to be in the lab, right? That’s the plan. So you got one in node one and then, right? Is that right? The other one? No. Wait, where’s the, where’s the…

Micah Johnson: The galley rack?

Kate Toon: Galley racks.

Host: Galley rack. OK.

Micah Johnson: That’s pretty sure, I can’t believe this, but I’m pretty sure it’s node one, so…

Host: OK. Yeah. Yeah.

Micah Johnson: Someone’s going to…

Host: Yeah, I should know too, but, yeah, no, so that’s good. So, so they’ll both be on there. That’s great. And then, what I’m thinking is looking forward, right? So there’s, what we’re thinking now is this, is, we, we’ve talked about all these nice features, we’ve talked about, thinking ahead to the Moon, to Mars and stuff like that. Is that the next step for you guys is thinking about, you know, beyond station, making it even smaller, you know, looking, making it even more reliable? Or are you, are you there yet or are you just like, let’s focus on xPWD first?

Kate Toon: You know, I – you know, I think there is that drive to think, you know, as we, any project finishes up, you know, you think of, well, we are where we are with cost and schedule and you know, where we made benefits and where we made our requirements so that we could improve upon this latest version. You know, there’s always lessons learned and things that you capture through a project, so that can roll into the next version. You know, space exploration doesn’t, you know, end obviously with station. This is just the beginning of you know, trying to demonstrate this type of technology. So, like I even said earlier, you know, UV technology is, you know, that, that field is growing a lot. So application of how to utilize that in our system might even evolve with the technology over time. So, you know, that’s the great thing about it. You know, we’re just trying to keep up with, you know, the, you know, this day and age technology, so to speak, and, and utilize what we can on those lessons learned in space. And surely there’ll be another version. I’ll, I’ll say, I’ll, I’ll be good with just launching on NG-19 and seeing how this performs and…

Host: Yeah.

Kate Toon:…you know, and then we’ll, we’ll see how we can improve for the future. You know, I think inherently with spacecrafts as they are and, or, you know, the Gateways and the, you know, other next, next systems, you know, that come along, you know, lighter, better, more reliable, that’ll always be the name of the game. So they’ll inherently always be room for improvements.

Host: Very good.

Micah Johnson: But there always need to be a potable water dispenser.

Kate Toon: Yeah, if you’ve got crew up there. I hope so.

Micah Johnson: I mean, as long as there’s someone needs to consume something, you know, a drink…

Host: Someone needs to drink.

Kate Toon: Yeah.

Kate Toon: Exactly.

Micah Johnson: There’s going to be a, some form or factor of what, you know, we have developed, you know, with the, you know, whatever modifications in the design to facilitate that vehicle that it’s on and, and…

Kate Toon: Absolutely.

Micah Johnson:…their requirements set. Yeah. You know, requirements drives everything, so…

Host: Sure.

Micah Johnson:…you know, and, in terms of how we design these things. But it’s definitely a good springboard moving forward for those new, new vehicles and new, new missions.

Kate Toon: Yeah, absolutely.

Host: You’ve worked really hard on this and it’s very, you know, it’s, it’s apparent to me that you’re eager for this thing to go out. You’re like, “ah, I’ve worked so hard.” But do you have a sense of satisfaction or, or pride in just all the work, you know, testing the system, improving the stagnation, working on UV technologies? You put a lot of lot of work into this, so like, how do you feel with the product that’s going up? You feel proud of, of everything you’ve done?

Kate Toon: Oh, yeah.

Host: Yeah.

Micah Johnson: Yeah, yeah. Definitely. I mean, it’s, you know, knock on wood in terms of…

Kate Toon: Yeah, all the things. [Laughter]

Micah Johnson:…we’ve actually had, you know, not all, you know, very few problems and, you know, issues that have come up and…

Host: That’s awesome.

Micah Johnson:…and the little ones that have, you know, we were able to identify root cause immediately and, you know, get them, and then fixed up and stuff. So we’ve had a lot of success, you know, first time right out the gate. And that’s, you know, of course, dedication or, you know, thanks to my, the teams involved and all the, all the guys that have worked into development. You know, of course, you know, having a, a good bit of schedule to be able to take time to, you know, work on these aspects and stuff like that. Not, and so, that certainly has helped. But no, it’s, it’s been one of the, a more, I guess, complex project for, at least for me personally in a while. So that’s always fun, you know, as a, as a project manager and working on different projects for ISS, you know, working on something cool and, you know, kind of neat and not, you know, that’s, that’s definitely fulfilling. So, yeah.

Kate Toon: Unique and important.

Micah Johnson: Important. Yes, definitely.

Kate Toon: You know, like we said with the crew, you know, this is such an important feature…

Micah Johnson: Yeah.

Kate Toon:…for, you know, being thrown into a brand new space in, in space, you know, having something familiar like food and, you know, having that comfort I think’s a big deal.

Micah Johnson: Definitely.

Kate Toon: Improving upon that’s important. And yeah, I’m so excited to get it up there. I’m, I’m excited for all the telemetry that we’re going to get…

Micah Johnson: Yeah.

Kate Toon:…because I think, you know, data’s data. I mean, I’m an engineer of course, but you know, we haven’t, like we’ve alluded to, you know, we really haven’t seen system performance for PWD, because we haven’t had the ability to see the telemetry and how, you know, the valves are working and, and correlation with the heater or the dispense cycle. So, you know, having all this data will maybe, like you said earlier, you know, how can we improve upon the system, knowing that now, having the insight into the system now. I think that’s also going to help overall of what we learn about the system and microgravity and fluids and space, so it’s cool.

Host: That’s awesome. And I’m excited, I’m excited for you both and the team that all put it together. So very, very, very exciting times. Thank you so much Kate and Micah for coming on and talking about…

Kate Toon: Thank you having us. It was a great time. Thank you.

Micah Johnson: Very Cool.

Kate Toon: Even through the rain and the thunder throughout the, the podcast here. It’s great.

Host:That’s, well, we, it was raining down and we’re talking about water. We got that water thing.

Kate Toon: We’ve got our water theme for sure.

Host: [Laughter] Awesome. Thank you both.

Kate Toon: Appreciate you guys’ time. Thanks.

Host: Yeah. This was great. Thank you.

Micah Johnson: Thank you.


Host: Hey, thanks for sticking around. Really enjoyed the conversation today with Kate and Micah. Very energetic group. I definitely learned a lot from them both today, and I hope you did too. You could check out for the latest – If you want to know what’s going on board the International Space Station, and all the great technology demonstrations and science aboard. We’re one of many NASA podcasts across the whole agency. And you can check us all out at That’s where you can find us in our full collection of episodes, which you can listen to in no particular order. If you’re on social media, you can talk to us on the NASA Johnson Space Center pages of Facebook, Twitter, and Instagram, and you can even use the hashtag #AskNASA to submit an idea for the show or maybe ask a question. Just make sure to mention it’s for us at Houston We Have a Podcast. This episode was recorded on May 10th, 2023. Thanks to Will Flato, Pat Ryan, Justin Herring, Heidi Lavelle, Belinda Pulido, Jaden Jennings, and Destiny Doran. And of course, thanks again to Kate Toon and Micah Johnson 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.