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“Houston We Have a Podcast” is the official podcast of the NASA Johnson Space Center from Houston, Texas, home for NASA’s astronauts and Mission Control Center. Listen to the brightest minds of America’s space agency – astronauts, engineers, scientists and program leaders – discuss exciting topics in engineering, science and technology, sharing their personal stories and expertise on every aspect of human spaceflight. Learn more about how the work being done will help send humans forward to the Moon and on to Mars in the Artemis program.
On Episode 197, Thomas Boothby, assistant professor for the Department of Molecular Biology at the University of Wyoming, teaches us about tardigrades, more commonly known as water bears, that are headed up to the International Space Station for a scientific study to learn how these extremophiles adapt to microgravity. This episode was recorded on May 6, 2021.
Gary Jordon (Host): Houston, we have a podcast. Welcome to the official podcast of the NASA Johnson Space Center, Episode197, “Water Bears in Space.” 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. Water bears are about to head to the International Space Station. If you’re not familiar with water bears, or tardigrades, they are super-tiny animals that are best known for their ability to survive in some of the harshest conditions: extreme heat, extreme cold, bottom of the ocean, near volcanoes, highly radioactive environments, and even the vacuum of space. Exactly how they survive in these conditions is something that Dr. Thomas Boothby has been studying for years. Thomas is an assistant professor at the University of Wyoming Department of Molecular Biology, and he’s taking his research to the International Space Station as the principal investigator for Cell Science-04, which is, you guessed it, sending water bears to space to study how they adapt to microgravity. I got a chance to chat with Thomas about water bears and this investigation that will be making its way to the space station aboard the SpaceX Dragon on the upcoming CRS-22 mission, so let’s get right to it. Enjoy.
Host: Dr. Thomas Boothby, thanks for coming on Houston We Have a Podcast today.
Thomas Boothby:Absolutely, my pleasure to be here.
Host:Hey, this mission that’s going to be carrying your experiment to the International Space Station is right around the corner, about to launch. How are you feeling in anticipation of this, of this launch coming up?
Thomas Boothby:Me, personally, I’m extremely excited. We’ve been working on this since 2015, so a lot of hard work and time has gone into this, and really exciting that the launch is right around the corner.
Host:Well, let’s get right into it, Thomas. We’re going to be talking about water bears today and I got to say, I am a huge fan. I discovered them like a, I think it was back, man, it was a couple years ago. “Animal Planet” did this, did this show called “The Most Extreme,” and they did one on like the most extreme survivors, and that’s where they just went deep into the survivability of a water bear. And I was like absolutely fascinated, I could not believe what these things were capable of surviving in. So, let’s just start there, understanding water bears, tardigrades, because that will sort of help us transition into this specific science investigation that’s going to space station. So, let’s start with Tardigrades 101, Thomas, take us through what these things are.
Thomas Boothby:Well, so, tardigrades, or water bears as they’re sometimes commonly referred to as, are a group of microscopic animals that are capable of surviving some of the harshest conditions that we know of. So, despite being these like teeny, tiny, little microscopic organisms that you need a microscope to see, they’re extremely robust, so they can survive a number of extremes that we typically think of as being restrictive to life. So, some examples of sort of extreme environments or conditions that tardigrades can survive include being dried out to the point where they essentially have no water left inside their body or cells; they can be frozen down to just above absolute zero, they can be heated up, in some cases, past the boiling point of water, they can survive thousands of times as much radiation as you or I could; they can go days or weeks with little or no oxygen, and maybe the sort of most remarkable feat that they’ve been shown to perform is that they can actually survive in the vacuum of outer space. They’re the only animal that we know of that can, that can do this, so they’re really, they’re really quite amazing and unique.
Thomas Boothby:So, if I were to, if you were to have a picture of a tardigrade, how would you, how would you describe sort of what they look like?
Thomas Boothby:Yeah, so, what I tell people is think about the little, like gummy bear candy, and imagine that, but with eight legs instead of four. They look like these kind of chubby, little eight-legged gummy bears. Yeah, I think, you know, they’re pretty adorable. If people have seen pictures of them, they’re pretty charismatic, but that’s usually how I describe them.
Host:Yeah, and they’re, I mean the pictures I’ve seen of them, they kind of look clear, right?
Thomas Boothby:Yeah, so depending on what kind of microscope you’re using to look at them, if you’re using like a light microscope, many tardigrades are transparent, so you can, you can see through them. Others aren’t, so different species of tardigrades actually, like morphologically, like how they look, is pretty distinct. You have some that, yeah, as you said, there’s kind of clear. You have others that almost look like they have like armored plates on their backs; they look like little tanks, and those are a little bit harder to see through, but yeah, there’s actually quite a bit of a sort of a morphological diversity within the group of animals.
Host:So, in the beginning of this chat you talked about all of these different, very extreme conditions that the water bears can survive in. So, if I were to go hiking around planet Earth, where could I find them?
Thomas Boothby:So, tardigrades have actually been found almost any, anywhere and everywhere that folks have looked for them. They’ve been found, you know, on the tops of mountains, like in the Himalayas, in the deep ocean, in mud volcanoes, tropical rainforests, in Antarctica, but amazingly, if you just go in your backyard, they’re probably living back there.
Host:Oh, wow, I didn’t realize they were, they were so widespread.
Host:So, really, when it comes to the extreme stuff, right, I guess, my backyard, I wouldn’t really consider that very extreme, but let’s just say, you know, like near a volcano or in like a very high-pressure environment, you know, what are they doing? Are they just sort of swimming around or do they go into some sort of process to help them survive these extreme conditions?
Thomas Boothby:Yeah, so one of, one of the tardigrade’s sort of greatest tricks is this ability to go into an ametabolic state, so a state where, essentially, they shut down all the sort of life processes that are going on inside of them. And when they do this, they pull their eight little legs and head inside their cuticle, that’s sort of like their exoskeleton that surrounds their body. And they curl up in this little ball-like structure known as a tun. So, have you ever seen like one of these little like roly-poly bugs?
Thomas Boothby:They’re kind of like a tiny, little, microscopic version of that, where they curl up in this little ball, they shut down all their life processes that are going on and, you know, for all intents and purposes, you know, they sort of, it’s almost like they’re dead, but they’re in this state, they’re extremely resilient, and they’re able to ride out the, the sort of rough, harsh, extreme conditions. So, you know, if that’s a desiccating environment where water is being lost, you know, they’ll curl up in this little ball-like structure, dry out, and then, you know, when water returns to the environment, they uncurl. They come out of this ball-like structure and within an hour or so, you’ll see them scrambling around, eating, reproducing like nothing happened to them.
Host:Unbelievable. I’m sure you’ve been studying this for a long time, so, you know, you talk about when water is reintroduced to environment, or they’re, you know, they’re in a better environment where they can get out of this tun. How long have you seen some of these water bears in this state, before they return back to, you know, kind of frolicking through, and eating, and reproducing and all that?
Thomas Boothby:Yeah, so, tardigrades are able to enter this ametabolic state, and many species are extremely stable and viable in that, in that state. So, kind of an average would be about a decade or so in this, in this ametabolic state, but there are reports that tardigrades have been shown to survive, you know, for like over a hundred years; these were experiments going into herbariums, where they had preserved plant material, and people gathered tardigrades off that preserved plant material, which, you know, was documented and cataloged, when it was gathered and preserved. And they’ve been able to purportedly revive tardigrades that are, you know, hundreds of years old.
Host:Unbelievable. Now, I mean, it’s, this is a very unique trait for an animal. You know not everyone, not every—everyone—every animal can do this. So, what is it about the tardigrade? What unique quality do they possess to be able to do this sort of thing?
Thomas Boothby:Well, that’s a really excellent question, and that’s something that my lab and other labs are trying to uncover. We’ve found some hints and clues, but certainly there’s a lot more to learn. But one of the really interesting features of tardigrades that we found was, that when they start to dry out or enter these sorts of extreme environments, they start to produce a very special class of protein. And this is actually a type of protein that is unique to tardigrades. So, so no other organisms that we’ve, that we’ve looked at possess similar, similar proteins. And what these proteins do is something very interesting: they build up in their concentration. So, the tardigrades just start making more and more and more of these things. And what these proteins seem to do is they make the environment inside the tardigrade, so like inside the tardigrade cells, really, really viscous. So, imagine, you know, as opposed to water, which is very liquid, imagine it more like becoming like honey, where it’s very sort of gooey and viscous. And what this sort of increased viscosity does is it slows down all the bad things that are happening. So, you know, parts of cells start to break down, or unfold, or fuse together, normally, when a cell is drying out, but in this sort of super-viscous environment all those things are still happening, they’re just happening very, very slowly. And when this super, sort of super-viscous environment gets even drier, it, what it does is it forms a glass, so like glass in a windowpane, and this is really important because glass has a very different molecular makeup than say something like a crystal. So, if tardigrades made something that filled their cells with crystals, that would be really bad because crystals are very sharp and pointy, they can puncture cells or crush, you know, sensitive material inside of the tardigrade cells, but these glasses are much smoother and sort of more amorphous, and they’re actually able to encapsulate these sensitive molecules inside of tardigrade cells, and actually preserve them within this sort of glass-like matrix or structure. And what’s really amazing is, when water returns to the system, when you rehydrate a tardigrade, that glassy material just kind of melts away, and it goes back into solution, it dissolves into the, into the water, and it releases all those sensitive molecules that were stabilized inside of it back into the tardigrade cell, where they can perform their normal biological functions.
Host:Thomas, this is, this is amazing. I mean, I, my next question I feel like is a genuine one, but I feel like just everything you’ve just described sort of answers it for me, just how interesting this is, but what got you interested in this fascinating world of researching tardigrades?
Thomas Boothby:Yeah, that’s a great question. So, so besides tardigrades just being, you know, at least to me, like really fascinating, you know, wanting to understand kind of the, the outliers in biology, right, like, you know, tardigrade biology is quite unique, and in my opinion, understudied, and so, you know, just from a purely, from a place of pure intellectual curiosity, understanding how these little creatures are able to do something that, you know, for us, would be so sort of mind-bogglingly impossible to achieve is, was really, really of interest to me. And then, beyond sort of the fundamental biology of tardigrades, I was really attracted to studying them because of some of the potential applications, you know: what we could do in terms of taking the fundamental biological findings that we made studying tardigrades, and sort of the promise of applying that knowledge to trying to solve real world problems was really, really sort of attractive to me.
Host:So, tell me about, you’re, you’re at the University of Wyoming, right? So, you sort of went and described a little bit more about this protein, and you mentioned that you’re still doing a lot more research to figure out exactly what’s going on to allow the tardigrade to have this sort of unique process. So, tell me about some of your research that you’re doing over there.
Thomas Boothby:Absolutely. So, we’ve got, we’ve got quite a bit of sort of diverse research going on here. On sort of the fundamental biological side, we’re really interested in understanding how these tardigrade proteins are working. So, like, what are the building blocks that make up these proteins that make them so special and so protective? We’re also really interested in understanding whether or not these proteins and other tricks that tardigrades use to, say, survive when they dry out, we’re really interested to know if those are the same tricks that tardigrades use when they’re faced with other extremes, like freezing, for example. So, do tardigrades have sort of one, one way of surviving many different extremes or do they have many different tricks for surviving all these different extremes? And then on the more applied side, we’re really interested in how we can take that knowledge and adapt it to addressing real world problems, like stabilizing pharmaceuticals, or developing crops that are more resistant to extreme environments, so that’s kind of our research, in a nutshell.
Host:So I imagine, you mentioned there are tardigrades all over the world and you want to understand more about the, some of these different processes, or at least when they hibernate, or I guess, go into this, you said, I forget the exact state, something about metabolism, but essentially, into this state, and in this tun, do you get to travel to some of those locations as part of your research, like to, you know, volcanoes, or to whatever, deep sea, and understand, like pressure, or are you bringing them to the lab and doing everything in the, at your university?
Thomas Boothby:Yeah, so, so a little bit of both. So, a couple years ago, as part of a NSF (National Science Foundation) training, training grant, I was able to go down to Antarctica, and we were finding tardigrades down there, along with doing some experiments. One of the reasons that our lab located to Wyoming was to be closer to some of these extreme environments that we study organisms from. So, Wyoming has a number of really diverse extreme environments. You know, people typically think of, you know, sort of the hot springs out in Yellowstone, but then there’s also Wyoming’s Red Desert, which is an immense, high-elevation desert, so, so very cold and very dry, with sort of Martian-like environments. And then, of course, you have the Bighorn Mountains, the Snowy Range Mountains, so, you know, we kind of have all different types of environments out here in Wyoming where we go in and collect organisms from.
Host:That’s pretty cool. Yeah, you got to enjoy those kinds of trips then, you got to enjoy the harsh environments.
Thomas Boothby:Absolutely. Yeah, it helps, it helps to be a little bit tough if you want to go and study these little critters out there.
Host:Well, look, the space station is only 250 miles from Wyoming, you just got to go straight up. So, how did it happen where you were looking at all these different extreme environments and you thought, ah, you know, where we should go is the space station?
Thomas Boothby:Yeah, so, you know, how that kind of came about was, I was just really curious in this observation that tardigrades actually survive a number of extremes that they would never have been exposed to, so it’s kind of this perplexing question of, you know, how could an organism evolve to tolerate a condition that it, it didn’t evolve in? And spaceflight and space environments are probably some of the sort of most foreign or alien environments that you can think of for an organism that evolved on Earth. And so, there have been some space studies using tardigrades before. In particular there was a, there was a Russian capsule that went up in 2007, which actually exposed tardigrades to the vacuum of space, and they were left out there for about ten days in low-Earth orbit, and they were shown to be viable after that exposure. There was another mission involving some Italian scientists, which showed that tardigrades could survive and reproduce without any negative effects during spaceflight. And so, yeah, I got really interested in trying to understand how, right, not just, can they do this, but how are they able to do this? And so, that’s really, kind of the, kind of main driving scientific question for Cell Science-04 mission, is understanding how tardigrades adapt to being exposed to outer space, or to space conditions, rather. And then under those prolonged spaceflight conditions, how do they change and adapt after that initial exposure, you know, say over multiple generations?
Host:So, let’s get into it, let’s get into the experiment that’s going on the International Space Station, you called it Cell Science-04. So, what’s the, what’s this experiment that’s going up?
Thomas Boothby:Yeah, so what we’re really interested in doing is looking at what the initial changes in gene expression, so, so how tardigrades are adapting to spaceflight environments, is initially, and then how that changes over multiple generations. So, essentially, what we’re going to be doing is sending tardigrades up from the Kennedy Space Center to the ISS, and we’re going to basically have two different pools of tardigrades. One pool is going to be our sort of founding generation, where after a week of being in space, we’re going to preserve them in a special chemical preservative, but then the second pool we’re going to let culture, and grow, and reproduce for two months, and that’ll represent about four generations of tardigrades. So, they’ll have time to reproduce, and their offspring will reproduce, and so on, and so forth, for four generations. And then we’re going to preserve those multigenerational tardigrades. And when we get these preserved tardigrades back to our lab here in Wyoming, what we do is we extract a certain molecule called RNA, and this is kind of an intermediate molecule between the tardigrade’s DNA, their genes, and the final products that those genes are sort of the blueprint to make. And so, by looking at these molecules that we can extract, we can tell what changes in gene expression tardigrades are inducing when they’re exposed to space initially, and when they’re exposed to spaceflight conditions over the long term. And our hope is that by understanding how these tough little organisms are able to survive spaceflight conditions, that this will give us hints and clues into, you know, how we might safeguard astronauts during prolonged space missions.
Host:See, that’s going to be a big deal, especially for NASA’s plans to go to the Moon and Mars, just one extra step to help out in that process, very, very fascinating stuff.
Host:I’m curious to hear about how you’ve been preparing to get this experiment going. You know, you, I guess had to start with the initial process of figuring out how to get the tardigrades into space, but what’s been the process from the initial concept, to getting everything packed, and basically, ready to go on a rocket?
Thomas Boothby:Yeah. So, so initially, kind of the biggest consideration was just trying to figure out how we’re going to grow these little animals in space. So, in the lab, we normally grow them in these sorts of big glass petri dishes filled with a liquid medium, but in space that wouldn’t work so much because the, in microgravity the liquid media that the tardigrades grow in would just sort of float away. So, yeah, initially, it was validating a bioculture system that had been developed by some NASA engineers and adapted to this project. And then, it was really just going through a number of sort of dry runs and seeing, you know, in ground-based experiments, how our experimental plan for the actual flight experiment went. You know, it was a lot of optimizing things that don’t sound very exciting, like how fast a pump moves water through the system, or how much oxygen we need to deliver to the media. But, you know, all that sort of nitty-gritty detail has been worked out and we’re now, actually, this, just this week, in the process of prepping our samples that will go up to the ISS, so that basically involves loading the tardigrades into syringes that will be frozen and can be stored frozen and delivered to the ISS in this sort of inactive state. And then along with that we’re packaging up a lot of the food that the tardigrades eat because, over multiple generations, they’re going to need to be fed a couple times to stay healthy. So, the species of tardigrade that we use, they eat unicellular algae, so little, little algal cells, so we’re also getting those loaded into syringes, and ready to be sent up to the space station.
Host:So, actually, running the experiment on station, it sounds like this, whatever setup you have is going to be installed on a facility on space station, and every once in a while, is it going to require astronaut interaction to go ahead and use this syringe and feed the water bears, over generations?
Thomas Boothby:Absolutely. So, yup, when the, when our samples get up to the space station, they’ll be in syringes, and the astronauts will need to thaw out the tardigrades to sort of reactivate them, and then inject them into this bioculture system. Once they’re in the bioculture system, it’s pretty hands-off. We have telemetry, so we can sort of monitor the temperature and the flow rates and everything, inside the bioculture system. But then, yeah, you’re exactly right, at sort of two-week intervals an astronaut is going to need to attach an algal syringe to the bioculture system and inject fresh algae into it for the, for the tardigrades to eat, but, and then, and then at the end of the experiment they’re going to need to essentially sort of dismantle a portion of that bioculture system, which will be frozen and stored until we can get it back at our lab in Wyoming. So, there will definitely be some astronaut interaction with this, with this experiment, but there are also sort of large portions that are, that are automated.
Host:Yeah. Honestly, it sounds pretty easy in terms of the astronaut crew time needed, just, you know, feed it, it sounds like not even that often. You said once every two weeks was the feeding schedule?
Host:Yeah, see, it’s not even that bad. When it comes to measuring though, you said you’re going to, it is going to return, that’s part of the plan is it returns back to Earth, you go to the lab, and you have a number of things that you’re going to be looking at. Is there anything on orbit that will be, that you have in terms of measuring tools? It sounds like you have the, in the facility, you have the ability to control climate and watch all data coming in, but are you going to be doing any data gathering from the facility while it’s in orbit?
Thomas Boothby:So, the only sort of measurements that we’re making on orbit are environmental measurements. So, you know, what the, what the environment that the bioculture system is in. And we’re going to be using that telemetry, so, you know, the temperature, and whatnot, to replicate those experiments back here on Earth, and so we call those our near-synchronous ground controls. So we’re basically going to be doing the exact same experiment, but here on Earth, almost in real time with the, with the flight mission. But yeah, all the, all the sort of biological data that will be gathered is going to be done once we get the samples back from the space station, then we’ll process them here, here in the lab in Wyoming.
Host:So, you said — you said we, right? So, it’s not just, it’s not just you sending the water bears up and looking at everything. It sounds like you got, you got a decent support team that’s helping to bring all of this together.
Thomas Boothby:Yeah, absolutely. And yeah, it’s really great that you bring that up because, you know, I’m just one person in a team of really amazing folks. So, here, in the lab, in Wyoming, specifically, we have Cherie Hesgrove and Ryan Bettcher are working on this project. But then, on the NASA and the KBR side of things, we have a lot of people who really, sort of deserve some credit. So, specifically, Medaya Torres is our CS-04 mission scientist, Natayla Dvorochkin is our contract support scientist, and then on the KBR side there’s a bunch of people that I’d just like to acknowledge really quickly: Daniel Nolan, Kevin Sims, Oscar Roque, Christina Lim, Crystal Kumar, Kris Vogelsong, Brandon Schmitt, and Jamie Bales, Susan Markey, Meghan Feldman. And then on the NASA engineering side, Peter Zell and David Pletcher. And I’m sure I’m forgetting some other folks, but it’s been a, it’s been a huge team and group effort to get to this point, and yeah, I think it’s worth taking a couple minutes just to acknowledge all these folks.
Host:Absolutely. Yeah, and that’s part of the whole deal, right, is it’s not just, you know, it’s not just, “hey, Thomas, let’s get your experiment on the International Space Station,” it does really take a team, not only to get it up there, but to do all the work, to monitor it, make sure it’s working fine, and then of course, what you, what you’re all anticipating is when you get the water bears back from space into the lab in Wyoming and you get to conduct some fascinating research from that, from that group of water bears that went up there.
Host:Yeah. Now, one of the things I’m thinking of, Thomas, is, you know, there’s, well, I think what we’re all anticipating is when you’re starting that research, you know, what are the potential applications that you are thinking of in terms of maybe something we can learn, that we can bring back to benefit us here on Earth, or something that we can use to further space exploration. What are some of the things that you’re looking at that might have potential benefits to this experiment?
Thomas Boothby:Yeah. Well, definitely, part of the sort of stated goal of this mission is, you know, to start to build a foundation for developing therapies or countermeasures that might better safeguard astronauts in the future during prolonged space missions. So, you know, as I sort of mentioned before, spaceflight can be a really challenging sort of environment for organisms, including humans, who have evolved to the conditions on Earth. So, in space, you have much less gravity, you’re in microgravity, and you’re also exposed to a lot more radiation. So, for humans who spend a lot of time in space, you know, there can be detrimental effects to being in these environments. And so, one of the things we’re really keen to do is understand, you know, how are tardigrades surviving and reproducing in these environments, and can we learn anything about the tricks that they’re using that might be adapted to safeguarding astronauts. So, for example, if we see that tardigrades, when exposed to sort of this increased radiation in space, which produces a lot of reactive oxygen species, which are these sort of damaging chemical moieties that are really bad for cells, if tardigrades are producing a lot of reactive oxygen species scavengers, which basically kind of negate those negative effects, then that might be something that we would consider either through, you know, like a dietary supplement, or something like that, providing astronauts with increased antioxidants or reactive oxygen species scavengers. That would just help them stay healthier in space for longer.
Host:See, this makes me think about this experiment and this, like you said, you want to, you want to set a foundation, right, that’s what you were talking about whenever you were thinking of potential application. And I think that’s a very exciting thing to say because what makes me, it makes me think that this is scalable, right? You can continue the research, maybe, maybe bringing next cell science investigations up to the International Space Station. And you were just mentioning the radiation environment, which in low-Earth orbit is a little bit different from say, the Moon. And with the Artemis program, with NASA returning to the Moon, there are potential, there are potential options to have investigations like this, where you can study water bears in an even higher radiation environment and gather even more unique data. So, it, to me it sounds like this is something that you can continue for a while.
Thomas Boothby:Absolutely, we hope so. I think, you know, there’s a lot more to learn about tardigrades and a lot of, you know, continuing potential benefits to society.
Host:And that’s a, that’s such a big deal and it’s all happening on board the International Space Station coming here real soon. So, Dr. Thomas Boothby, thank you again for coming on Houston We Have a Podcast. And really, best of luck to you and your team as you gear up for this launch of a, on a SpaceX Cargo Dragon to the International Space Station. Best of luck to you as your, as your journey just begins for Cell Science-04.
Thomas Boothby:Great. Thanks very much.
Host:Hey, thanks for sticking around. I hope you learned something about water bears and you’re as excited as I am for this launch of CRS-22. You can watch these water bears launch from Florida, travel to the International Space Station. Just check out our website NASA.gov/ntv has the latest on our TV schedule when you can see the launch live. If you like this podcast, we are one of several NASA podcasts across the entire agency; you can check all of them out at NASA.gov/podcasts. We, Houston We Have a Podcast, are on the Johnson Space Center pages of Facebook, and Twitter, and Instagram. So, if you want to talk to us, just use the hashtag #AskNASA on your favorite platform, you can submit an idea or ask us a question, just make sure to mention it’s for us at Houston We Have a Podcast. This episode was recorded on May 6, 2021. Thanks to Alex Perryman, Pat Ryan, Norah Moran, Belinda Pulido, Jennifer Hernandez, Rachel Barry, and the International Space Station Program Research Office for helping to set us up with Thomas. And, of course, thanks again to Dr. Thomas Boothby 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.