Can humans hibernate their way to Mars?

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Jordan Heath-Rawlings Every New year, reality takes one step closer to science fiction. This doesn’t happen in some TV way, mostly, but as a process. Theories, experiments, research failures. Drawing boards erasers more research. And then somehow, a scientist studying squirrels in Alaska gets a weird idea and tests it. And it works. And we’re one step closer to sending humans to Mars. Okay? So sometimes it is like a movie without giving away too much, this episode is about going to Mars, but it is not about Elon Musk, so don’t worry. It’s about space travel, but it’s about a lot more than that. You see, one of the biggest problems with getting to Mars or anywhere else in space that isn’t the moon is how to keep human beings alive for that long. They need food and water and company and stimulation and exercise and all of that for years and years of a long journey and a tiny spaceship, and they can’t just hibernate. Or can they? What if they could? And if they could, if we could turn human beings not off, but way down, the way bears or foxes or that little squirrel up in the Arctic can, what would that mean for space travel? What would that mean for all of us? I’m Jordan Heath Rawlings. This is The Big Story. Brendan Koerner is a contributing editor at Wired and an author, most recently, of The Skies Belong to US love and Terror in the Golden Age of hijacking. Hey, Brendan.

Brendan Koerner Hey, Jordan. How are you doing?

Jordan I’m doing really well. How are you?

Brendan Koerner I’m doing all right. Thank you.

Jordan Let’s start maybe with the problem that we’re maybe finding a solution to. What are the big challenges posed by sending humans all the way to Mars and back?

Brendan Koerner The biggest one is weight. The fact that of the missions we sent to Mars, these unmanned rovers, really the heaviest thing we’ve gotten onto the surface is about one ton. Getting a crew of like, four or eight humans will be many, many multiples of that, in part because we have to land such some kind of vessel that can support them and so they can live on Mars for a period of time to do experimenting or what have you. And the other part of it is that humans require a lot of sustenance in terms of food and water and oxygen. And all of that is going to mean that we have a vessel that’s maybe going to weigh over 300 tons as it departs the Earth’s atmosphere. And that’s many, many multiples more than anything we’ve previously attempted and ladyling on the fuel necessary to get that vehicle. The math doesn’t really add up very well. It’s almost too much weight for us to have the fuel necessary to get the craft there. So that’s the primary problem. There’s also some secondary problems, and maybe the biggest one is humans really haven’t existed outside of the magnetosphere that protects our planet for very long at all. For example, the International Space Station is within the Earth’s Protective Metosphere and that magnetosphere protects us from radiation that exists in our solar system. So if we’re going to be spending a couple of years going to and from Mars and during at the time in transit, there’s going to be a lot of radiation bombarding the spacecraft. And so we don’t know if that’s going to cause serious health concerns for the humans on that mission. And I think there’s also the psychological elements as well. You’re talking maybe 18 months there 18 months back in the cold blackness of space with no companionship except for the couple of people that you probably grow sick of pretty quickly. It could have some real consequence from mental health and therefore affect the performance of those astronauts once they reach their destinations.

Jordan So it’s an enormously complex problem to get humans all the way to Mars. What could we do?

Brendan Koerner And this is I’m getting at something that’s been around for a while to make human needs less on the journey and on the way back. Well, human needs really come down to human metabolism. It’s our body’s need for sustenance, for oxygen, to emit waste. Those wouldn’t be a problem so much if we could slow down human metabolism or even stop it temporarily altogether. And so for a long time, people who’ve speculated often in science fiction have realized that the answer is for humans to do what a lot of other mammals do, which is to hibernate, which is to slow down our metabolisms, reach the state of torpor where we lower the internal thermostat by quite a great deal. And that really slashes our need for food and for oxygen for weeks or even months at a time. So that’s always been the key, is how do we tweak the human body so we can kind of do what a lot of animals do in cold environments for the winter months. And you make this point in your writing, but anybody who’s seen 2001 a Space Odyssey or several other Sci-Fi films from decades ago is kind of familiar with the concept, at least as like a thought exercise.

Jordan But for most of that time, how feasible has that idea even been?

Brendan Koerner Not terribly feasible.

Jordan And you mentioned 2001 a Space Odyssey. And in the movie version of that you have four of the six crew members going to Jupiter are in these hibernation pods. And they talk about the details in the movie saying that they’re going to have these dreamless sleep and their bodies are down to 37 degrees Fahrenheit, so extremely cold, on the edge of freezing. And we have gotten nowhere near there in terms of freezing the body and having it still be healthy. So although this has been something that science fiction writers like Arthur C. Clark have speculated on and I think scientists have toyed with the concepts for a very long time. It’s really been a tough challenge for scientists to crack. Speaking of scientists toying with the concept, there is something that’s at least a little bit similar to it. Maybe you can explain what is therapeutic hypothermia, and why would or wouldn’t it work for sending astronauts through space?

Brendan Koerner Yeah. So therapeutic hypothermia is one thing we’ve attempted that kind of at least approximates hibernation of mammals in cold environments. What this is is typically when people suffer cardiac arrest, in particular, doctors will lower their internal temperatures, often using an intravenous cooling fluid, and this will get their temperatures down to just shy of 89, 88 degrees Fahrenheit, which is pretty darn cold for a human being. And what this does is this reduces the metabolism and really reduces blood flow and all those things by about 50%. And that’s great for a body that’s trying to heal itself that, you know, you want as much energy from the body dedicated to healing as you can and not be concerned with things like feeding and inhaling oxygen and all those sorts of things. There’s a big problem with this, though, is that our bodies are primed. When you lower the internal thermostat, we react by shivering. And that makes things really difficult for a physician trying to heal somebody. So they need to administer sedatives and anesthetics to people in therapeutic hypothermia, which means they can’t breathe on their owns. They need to be intubated and need to be closely monitored. So it’s very tough medically. And for a space mission, a mission to Mars, the last thing you want to do is have really in depth, intricate medical procedures being administered by people who are not physicians, who are astronauts, and have people with tubes stuck down their throats and all those complicated things you really only want in a hospital setting. You don’t want that on a cramped spacecraft for months at a time.

Jordan So now we’re getting to more authentic hibernation, and this is where your piece and the research itself gets really fascinating. So tell me about Kelly Drew and the Arctic ground squirrel. Who is she, and what makes this creature so fascinating?

Brendan Koerner Sure. So, Kelly Drew is a neuropharmacologist, and she’s a native of Alaska, or at least grew up there, talked the University of Alaska in Fairbanks into giving her some lab space. And she was working there one day, working on salmon brains. She’d gotten a small grant to analyze the brains of cohost salmon, a very Alaskan project. And one of the professors at the university walked in and went up to her and said, I have a surprise for you. I want to show you something. Hold out your hands. And she held them out and closed her eyes, and she felt this hard, furry lump being deposited in her hands. And she opened them up, and it was this little furry rodent curled up in the fetal position felt like an ice cube in her hands, wasn’t moving at all. And she assumed, well, this just must be a dead something he put in my hands, I don’t know what. And the professor explained, no, this is actually an Arctic ground squirrel. And what they do is they hibernate for eight months out of every year and they’re the most extreme hibernator on the planet. They get their internal thermostat, so their normal operating temperature is the same as ours, 98.6 degrees Fahrenheit. They get it down to 27 degrees Fahrenheit, so literally below the freezing point and exists like that for two thirds of every year. And she immediately thought, well, this is fascinating.

Jordan What’s going on in this little critter’s brain that makes it able to survive in this extremely harsh condition where literally it’s colder than ice inside this thing’s body? And that question in her mind, that curiosity about what’s happening in this creature’s brain changed the course of her life. How old is this kind of research into how animals hibernate and why and when did it start?

Brendan Koerner Well, you certainly had curiosity about hibernation stretching back many centuries. But I would say that the advent of really serious research into hibernation really dates back to the beginning of the Cold War. And that was a time in the United States particularly, you had a lot of money sloshing around in the pursuit of beating the Russians, beating the Soviets in the space race and this arms race. And so there were some people thinking, well, we haven’t even gotten a satellite up yet, but eventually we’re going to have to go toe to toe with the Soviets and that may include going to Mars and beyond. Let’s look into this hibernation thing. And also there was a military component that there was a lot of interest in saying, well, maybe we can hibernate soldiers in the winter and have them ready to do battle when conditions are harsh. So there was a lot of research going on and a lot of this was going on in Alaska because obviously a lot of the creatures up there do hibernate through the very cold winters. That’s the farthest northern outpost we have in the United States. So you had a lot of scientists up there with tons of funding from this kind of military industrial complex that we’re starting to interrogate. The question of why do certain mammals, including arctic ground squirrels and bears and a variety of others, why are they able to sleep through the winters and then kind of come out of that torpor as if nothing had ever happened? So that’s really where it began. But I would say that there was a lull as the cold War kind of atrophied into Daytone and there was increasingly less interest after the space race matured as well. And it was really kelly Drew and a couple of other researchers starting in the 90s were kind of the renaissance of hibernation research.

Jordan So when Dr. Drew began digging in to the squirrel, how did it go? What kinds of things was she trying to learn? What triggers this and how it might be used on humans, if that’s even what she was looking for.

Brendan Koerner Yeah, so the first thing she did was use a technique called microdialysis to study the brains of these squirrels. This is when you basically stick extraordinarily small tubes into the brains of these hibernating squirrels. So you can extract some chemicals to study extract the neurochemicals. And one thing that surprised her was that when she did this, when she examined the brains afterwards, there was no damage. You couldn’t find where the tubes have been stuck. And that’s very unusual. Usually we do this with other non hibernating creatures. You can see little pieces of scar tissue or what have you, little marks where you did stick the tubes. That wasn’t the case with the ground squirrels. And so she thought, well, hibernation must give them some kind of neural protection, and that could be really useful. Maybe hibernation is this super protected state. And if that’s the case, maybe if we could say hibernate soldiers who’ve been traumatized in battle and are trying to recover from traumatic brain injuries, maybe getting them to reach a kind of hibernating state will help them recover. And so because of that, she was able to get some funding from the Army Research Office, United States, and that was really when things started to take off for her in terms of looking into what are the chemicals that trigger this state and the squirrel, and will those chemicals also be effective in perhaps human beings. And so she actually spent the bulk of the 1990s, the mid to late 1990s investigating a neurotransmitter called GABA. And GABA is really integral to the sleep process, and it makes sense. Hibernation is a cousin of sleep, right? It’s kind of similar. We have a lore metabolism when we’re sleeping. So she figured, well, then it must be a neurotransmitter involved in sleep that’s responsible. So she did all sorts of experiments with Gabba and some related chemicals and kind of got nowhere. It wasn’t until 2005, so this would have been actually 13 years after that frozen ground screw was first placed in her hands. She hired an undergraduate research assistant, and his job was to look through the literature and just find anything that had come out about Hibernation, no matter how tangentially related, hoping they could maybe dig up some leads about what to do next. And he actually came across a Japanese language paper, and he didn’t speak Japanese, but the abstract was in English. And it just briefly mentioned that these researchers in Japan, working with Hamsters, had managed to get Hibernating hamsters to stir out of their torpor by blocking receptor the a one adenosine receptor. This is a part of the cell that responds to chemicals and then emits signals that affect the physical state of an organism. And so this wasn’t really what Kelly Drew was looking to do. She was looking to do the opposite. But he flagged this paper, and they kind of fouled it away on this huge pile of other papers. And actually, two more years passed, and it was not until 2007. Dr. Drew encountered a Japanese speaking researcher at a lab she was visiting. And she asked him, like, hey, I’ve got this Japanese language paper. It’s been sitting in my hard drive for a couple of years. Can you translate this for me? And he did. And she read it in full for the first time, and she thought, well, if blocking these receptors wake up the hamsters, maybe if I stimulate the receptors in my squirrels, that will induce hibernation. And so she found a drug called Cha that does stimulate this particular adenosine receptor. And sure enough, this did induce hibernation in her ground squirrels. So it was a real breakthrough.

Jordan What happened after that breakthrough? What happened when her research came out?

Brendan Koerner Yeah. So there was one problem with Cha. So, Cha, it does stimulate this receptor in the brain and starts to lower the temperature of the body, but there’s receptors in your cells, all over your body, right? And so if you inject this drug intravenously and it gets in the bloodstream, it goes to the heart, of course, and it slows down the heart until the heart stops it’s. A really good way to kill an animal is to inject Cha into their bloodstream so that’s so she had to inject it straight into the squirrel’s brains to get the desired effect without killing them. So that’s an advance. But the problem being that you really want to avoid sticking needles into people’s brains whenever possible, and you still don’t want to do it outside of the most controlled, delicate hospital setting, so you can’t do it on a spaceship. And the way she talks about it, she had these posters blown up of the data and to review it before publication, and she had them hung up in the hallway outside her office. And she was looking at them one day, looking at the data, she should have felt great. She was about to publish a really important paper about a breakthrough that had taken her quite a long time. But instead, she felt a little dejected just knowing that, well, you know what? I found this, but I’ve really fallen short of my goal, which is this is not really useful, the applications that are limited because I haven’t cracked the problem of how do I administer this safely and not have to inject it into brains? And she had one of those rare yet splendid eureka moments, and she thought, well, what if I mix this with another drug that would block Cha’s effects everywhere except for the brain? So basically what she needed was a drug that would act on the body and kind of counteract and cancel out the effects of the cha, but would have molecules that were so big they couldn’t cross that barrier that separates the body from the brain. Right. So only the cha would get into the brain. And she found this. It’s actually a drug called 8-Spt. It’s pretty well known. It’s related to one of the active ingredients in black tea. And she made a cocktail of these two drugs, 8-Spt and Cha, and she injected this into the squirrels and also into rats, into lab rats. And it worked exactly as she intended, that it really cooled down and made these rats enter this torpor, but didn’t do what therapeutic hypothermia does, which is caused shivering. It was more of like a natural thing that didn’t require a sedatives or anesthetic, so the rats could breathe on their own. And this was really the breakthrough. And this is the drug cocktail she ended up patenting in 2014. She filed a patent application for it as something that she intended to be used primarily on traumatized soldiers on the battlefield, that you could administer this outside of a hospital setting intravenously, and it would help cool down and help these soldiers, wounded soldiers, enter torpor so their bodies start to heal.

Jordan So that takes us all the way from the 1960s in the space race up to the mid 2010s. Since that happened, how has this picked up steam with regards to its potential use in space travel?

Brendan Koerner I know that things, I guess, started to move kind of rapidly, at least based on the pace of prior progress since then. That’s exactly right. So around, you know, 2010, 2011, NASA was getting more serious about Mars. You know, setting a goal of, we want to get to Mars by 2040 is kind of the the loose goal of the program right now. And so they started getting more serious about investing in ambitious research that would help us accomplish that. And one of the people they enlisted is a man named John Bradford. He’s the head of an engineering firm in Atlanta called Spaceworks that tackles all sorts of kind of ambitious blue sky projects for the military as well as NASA. And he started to get really serious about, well, how can we get astronauts into a torpid state to reduce their metabolisms, reduce weight? He initially looked at therapeutic hypothermia as a potential solution and kind of understood the limitations of that with the shivering and the anesthetic and all that. And then he encountered Kelly Drew’s work when it came out, when it was published. And so she signed on as a consultant. They arranged for her and another researcher to test this cha, eight Spt cocktail on on pigs, which are a little bit closer to humans than than rats. They did that experiment had very good results. And so it was this perfect dovetailing of, you know, NASA’s growing interest in getting us to Mars by 2040. And Dr. Drew’s breakthroughs kind of happened simultaneously and after this began to sort of gather steam. NASA is interested, other organizations are interested.

Jordan What comes next? And I guess what I’m trying to get to as we get close to wrapping this up is no progress for a long time, relatively rapid progress in the, in the mid 2010s. And since then, what have we seen and how far away are we still?

Brendan Koerner So there’s a lot of activity on this front right now, and I write about this in my story. NASA’s funding through its Space Medicine Institute down in Texas at Bell University, they’re funding a range of projects that are looking at potential routes towards human hibernation. One researcher I spoke to for the story, a man named Cliff Callaway, who is an emergency medicine physician at University of Pittsburgh. He talked to me about saying, well, I think that the ultimate solution may be partly Dr. Drew’s cocktail and partly some things that I’ve experimented with in the emergency room and maybe another innovation that’s being funded by NASA as well. You probably need a multipronged effort because the human body is so complex. But he is literally right now setting up an experiment where he’s going to make people torpid for like 20 hours at a time and see what the effects are. And he said to me, will we get to what an Arctic ground squirrel is at 27 degrees Fahrenheit below the freezing point for eight months? That’s probably going to be a tough nut to crack, maybe too tough to ever really happen. But look at bears. Bears only get down to like the low eighty s at most, so they’re not really dipping their internal thermostat as much. And we have a lot of genetically similar to them and to a lot of hibernating animals. There are three branches of the mammalian family. There’s osteoplacentals, there’s the marsupials, and there’s a couple of these egg laying mammals as well, like the platypus, all three of those branches have hibernators. And so the logical conclusion is that we have a hibernator as a common ancestor. And so in a lot of ways this capability is inside of us. It’s part of our genetic heritage and we just need to find a way to unlock it. So while I think that the extreme hibernation of the Arctic ground squirrel is going to remain beyond our grasp, but I’m pretty optimistic about our ability to reach some state of torpor that is going to help us make a safe mission to Mars.

Jordan The last thing I want to ask you, we’ve talked a lot about mars and I know that’s the thing that I’m interested in. It’s the primary focus of your piece in terms of how this could help us get there. There’s got to be a lot of other uses for something like this. Soldiers on a battlefield is one example. We going to see billionaires put themselves to sleep and wait with the climate crisis or what?

Brendan Koerner So this is something I maybe had the most fun thinking about when I was trying to think about the long term implications. And there was something kind of appealing about just shutting down and stepping away from the din of my own thoughts for a little while. And the only thing I realized, it’s like kind of a form of time travel. If you can just kind of zip in and out of reality for weeks or months at a time. It’s kind of like maybe the only attainable form of time travel and I think people will be very curious to try it. And like you said, there can be uses to wait out global cataclysms. Obviously you need someone to revive you, so that makes things a little hairier. But I think there are a lot of potentially interesting and maybe ethically thorny implications that we are able to master. This ability to kind of turn ourselves off and on at will.

Jordan It’s a fascinating thing to talk about. Brendan, thank you so much for this.

Brendan Koerner Thank you so much for having me.

Jordan Brendan Koerner writing about Hibernation in Wired. That was the big story. Welcome back. Thank you for joining us for a brand new year. We’ve got a whole lot of things cooked up. We can’t wait to share them with you. And as always, and I know you must be tired of me asking you to do my job for me. We would love to hear what you think we should be talking about this year. What do we not get to last year? What’s going to be a bigger problem this year than it was in 2022? Tell us. We are currently lining up brand new guests and brand new topics, so don’t hesitate to share what you can do with us on Twitter at The Big Story. FPN. You can do it by email. By emailing. Hello at the Big Storypodcast dot CA. And you can do it by calling us and leaving a voicemail 416-935-5935. If you don’t know by now, The Big Story is available in every single podcast player that existed in 2022 and all the ones that will come to exist in 2023, just search for it, subscribe, follow, like rate review, all that good stuff. And you can ask for it on your smart speaker. Just say play the big story podcast. Thanks for listening. Thanks for coming back for another year. I’m Jordan Heath Rawlings. We’ll talk tomorrow.