人類は火星への旅に耐えられるのか？――『Are We Ready for Mars?』著者に聞く

Are humans really ready to go to Mars? You'll listen to Are We There Yet, the radio show exploring space exploration. Hi, I'm Brendan Byrne. Humans are venturing into deep space farther than ever before. NASA plans to return astronauts to the lunar surface in 2028, and the agency has its sights set on Mars next. Mars is much farther from Earth than the Moon, which makes it a lot harder to get there and survive. You're on your own. No such thing as an evacuation. No such thing as coming home early in an emergency. No such thing as emergency resupply. Mark Shellhammer is a medical researcher at Johns Hopkins University in Baltimore. He's also the author of the new book, Are We Ready for Mars?, which investigates the challenges that would come with missions to the Red Planet and asks if humans are up to the task. A conversation with Shellhammer about future Mars missions. That's ahead on Are We There Yet? Before we jump into this show, have you checked out our other show?

When We Find Them is a new limited podcast series from Central Florida Public Media. All episodes from Season 1 are out now. What happens to a society when scientists discover signs of life in the universe? When We Find Them takes a deep dive into that day and what might come after. You can get When We Find Them wherever you get your podcasts. Mars has been a subject of curiosity for centuries. Recently, we've sent robotic explorers to the surface like NASA's Curiosity and Perseverance rovers. NASA wants to send humans next, but that's a tough task. The agency is planning to send humans to the moon in 2028. A mission to the moon takes just days to get there. A Mars trip is measured in months. So are humans ready? Well, that idea is explored in a new book, Are We Ready for Mars? Here to talk more about the book is its author, Mark Shellhammer, a medical researcher at Johns Hopkins School of Medicine in Baltimore.

Mark, welcome to Are We There Yet? Thank you. Glad to be here. So, Mark, when we started this podcast some 10 years ago, the framing was when it comes to putting humans on Mars, are we there yet? We quickly learned that there were a lot of challenges when it comes to putting people on Mars. Your new book, Are We Ready for Mars?, answers that question. So are we? I wouldn't say it answers the question exactly yet, except maybe it does. The answer would be not yet. So there you go. Now you don't have to read the book. And we can keep the podcast going. But what really we're getting at is what it takes to answer the question. And the answer will be affirmative. We will eventually be ready for Mars. I wouldn't want to see people try to go now. Wouldn't be pretty. We're just not there yet. What are some of the challenges then, Mark, that we still need to overcome to get us ready for that? I guess your audience probably knows the context of Mars, right?

Really far away. Takes about six to nine months to current planning, technology propulsion, six to nine months to get there. Say I'm on the way back. You've got to hang out there until the planets realign to come back. Three-year mission, most likely, really far away, autonomous from Earth. Now, this starts getting into the really serious human aspects of it. The crew will be autonomous from Earth. Assuming they can communicate, you know, they're not in conjunction, at opposite sides of the sun, communication delay can be 22 minutes one way. So, you've got an emergency, you're on your own. No such thing as an evacuation, no such thing as coming home early in an emergency, no such thing as emergency resupply. So the idea of autonomy is one of the major issues, and autonomy brings with it what I've been calling resilience, not just personal resilience, but mission resilience in the sense that we have to design the mission so that it can withstand

encounters with the unknown. What are the things that we have to figure out? What are the things that we don't know. I could list the major changes in the body that take place during extended duration spaceflight. But basically all the body systems, right? Bones, muscles, cardiovascular system, they start to deteriorate because they don't have to work against gravity. The immune system changes. There's a chronic shifting of fluids from the lower to the upper body that seeming to possibly have some neural effects, reversible so far, maybe not after a three-year mission. There's all of those things. We kind of are getting a handle on many of them, especially thanks to a lot of research that's been going on on the International Space Station for decades, and that's what the Human Research Program does. But still, we are regularly taken by surprise in space. First ever medical evacuation from the space station earlier this year.

Deep fan thrombosis just a few years ago on ISS. These are things that have not happened before. So that's the big issue is something unexpected will happen. It's going to be technological and or medical. Probably it's going to be some combinations of both. And the crew is going to be too far away from Earth to get real-time help or to turn around. In a nutshell, that's the big picture, facing the unknown when you're on your own. From a medical perspective, what are some of the ways that you can overcome that? Is that by sending someone like you on the mission to fix these things? Is it relying on AI? How are we going to be able to send this mission with everything they could possibly need with these challenges that you've outlined? And mind you, this is a very inhospitable environment to begin with. To say the least. I'm not a medical doctor. I'm a PhD, SCD actually.

So I'm on the research side of things, but I'm at a school of medicine. So, you know, some of my best friends are doctors. Okay. So we'll send one of your friends. There you go. But it's a bit of a sideline, but it's an interesting point because the researchers are not the doctors and the doctors are not the researchers. Now, there are doctors who are researchers, of course, especially at a place like Johns Hopkins. That's what it's all about. What I'm getting at is that astronauts are subject to medical privacy protections, just like those of us here on Earth. So the researchers, what we're going to talk about here today, that there could be other things going on in space that we don know about because they so far private medical information And there some communication back and forth but it not what it needs to be That would be one of the answers to your question about like, what can we do? We can start to treat every mission like it's an experiment. We have not been sending people into space that long. We haven't sent that many,

fewer than 700, maybe it's fewer than 800 now. They haven't all been test subjects for experiments, medical experiments. There's a lot we don't know, and I would make the contention that we should treat all of those things as if they are effectively scientific experiments, share the medical data with the researchers more openly. You're listening to Are We There Yet, the radio show exploring space exploration from Central Florida Public Media. I'm Brendan Byrne. We're speaking with Mark Shellhammer, a professor at the Johns Hopkins School of Medicine in Baltimore. We're talking about his new book, Are We Ready for Mars? Well, let me give some other answers to your question. Obviously, the things that have worked so far have been pretty effective. I mean, despite what I said, there are, we are taken by surprise. Astronaut screening, many, many people apply to be astronauts. Very, very few are chosen. And that's largely medical screening, partly medical screening, which has generally been very effective. They stay in really good shape. You know, they're healthy individuals. In order to keep them that way on the flight,

it would be nice to send a doctor. The crew medical officer on a space flight is not always a physician. So usually is not a physician. You would hope that that person is a physician on something like a Mars mission, probably will be. But even if you send a doctor, you know, doctors, Now, Serena Nonchancellor is a friend of mine. She was an astronaut, and she was an engineer before that, and she was a physician after that, before she became an astronaut. And she would say she is not a physician astronaut. She's an astronaut. Yeah, she used to be a doctor, and she could still do some doctor stuff, but the training, the preparation, the skill set for being an astronaut, to some extent doesn't make it possible to be a really good doctor. Good meaning not disparaging their skills, but, you know, they're not current in medical practice. And so there are limits to what you would be willing to have one of those people do,

like you're not going to be doing surgery. The other solution or the other approach to this is what we start to get at in the book. If you're not going to be able to predict everything, to anticipate everything, The NASA approach so far is to mitigate the known risks, right? Muscle atrophy, boom. You have a research program for that. You have an exercise countermeasure. So what's going to come up and kill you, metaphorically, hopefully, is the thing you haven't thought of. So what do you do about that? Not quite sure, except what might probably help is a sufficient level, open to interpretation, a sufficient level of monitoring of the crew, the environment, the spacecraft over the course of a mission so that you can start to detect anomalies early on. Hopefully, you see things happening the day before, a week before, a month before. what would otherwise turn into a medical situation.

I think that kind of thing needs to be done more rigorously on a space flight, not to be big brother, right, not to have mission control watching everything you do, but to give the crew themselves the information so that they can start to track not only their well-being, but how is everybody getting along, and is everybody doing their jobs? It may be a deficiency in performance. like why is it taking you twice as long to do this task, that kind of more extensive monitoring combined with the appropriate processing, artificial intelligence, which is what we started getting into near the end of the book. There's also this idea that sending humans to places like the moon is going to help us prepare for Mars. We've sent the, and I say we collectively, I had nothing to do with the Artemis II mission, but you and I, you know, hit the launch button for Artemis II. But no, the Artemis II astronauts return from the moon. We're learning from them. NASA wants a permanent science base on the surface of the moon.

The data we get from that, is that going to help you answer that question, are we ready for Mars? Not completely. I don't think so. I don't think it's going to be sufficient. This is a tough balancing act. This has always been the case in space flight. Astronauts do not sign up to be professional guinea pigs, right? They realize, and especially as years go on, more and more astronauts even now have medical and scientific backgrounds. They realize the importance of this, but still, you know, nobody likes to be monitored so closely, constantly, especially in the case of medical information. This is the classic, even if they're not pilots, this is the classic kind of military pilot versus flight surgeon mentality, right? The more information on my medical status that I freely share, the more likely somebody's going to find something that will remove me from flight status. Even if it's inconsequential, if it's an anomaly, it just raises eyebrows and you say, well, you know, better safe than sorry. Maybe you want to

and there's history to this. Going back to the Mercury program, they took Deke Slayton off of flight status because of a heart murmur. And it was extremely contentious. So, and this is in the 60s, early 60s. We will see if the longer the moon base is on the moon and up and running, maybe we can increase the level of monitoring. NASA puts out, especially the human research program periodically will put out an RFI request for information from the community, like, hey, we're going to do this. What are we missing? What should we be thinking about? And I believe there was one fairly recently that they requested some information of like, what would you do with the moon base? Or what would you do with extended presence? And so I submitted an answer, and I'm sure I'm not the only one. Let's get more data. NASA does also have, we're saying NASA, right? They're not the only game in town necessarily, but they take the lead on these things. NASA does have a Moon to Mars program office with the intent of doing just what it sounds like,

figuring out what you can do on the moon to prepare to go to Mars. It's technologically oriented, so I don't know if this is in their thinking yet, but hopefully it will be. The answer, just like the answer to are we ready for Mars, the answer is, will we have sufficient data from stays on the moon? Probably not with current planning, but hopefully in the future. That was Mark Shellhammer a medical researcher at Johns Hopkins School of Medicine in Baltimore and the author of the new book Are We Ready for Mars Still to come our conversation continues with a question What if we sent humans to Mars right now? They would get there and they would not have the physical, maybe even mental capacity to do the things for which we're sending them to Mars. You want them to do more than just figuratively plant the flag and be there. How do we get astronauts ready for a mission to Mars? That's the head on Are We There Yet? Thank you.

You're listening to Are We There Yet? from Central Florida Public Media. I'm Brendan Byrne. We're talking about what it takes to send humans to Mars. There's a lot of challenges to do just that. So what are we doing here on Earth to prepare for that day? And what do we still not know about how the human body will handle a trip to the Red Planet? Our conversation continues with Mark Shellhammer, a researcher at John Hopkins School of Medicine in Baltimore and author of the new book, Are We Ready for Mars? The moon, in the grand scheme of things, is much closer, right? Just takes a couple days to get to the moon. Very little communication delay and blackout, as we saw. I mean, we were getting HD video from the Artemis II mission coming back, where Mars would be far different than that. So you're saying there's certainly a challenge in Mars being far more difficult and not having enough data without giving away too much in the book. Are we ready for Mars? Your answer was not yet. Will we ever be ready for Mars? and what do we need to do right now to get to that point?

Yeah, I think we will be ready for Mars. We could send people to Mars now, but like I said, it wouldn't be pretty. It would be, you know, and they would get there and they would not have the physical, maybe even mental capacity to do the things for which we're sending them to Mars. You want them to do more than just figuratively plant the flag and be there. Yes, be there and plant the flag and say, thank you. we did our job, we're coming home now because we can't take this anymore. We have nothing to do here. So we can do better. So we need to support more research to do this. We need to change our conceptual approach, which is really what the book is trying to get at. And by that I mean that largely, and again, I'm speaking mainly from my experience with NASA on the NASA side and the human research program. There are other space agencies, and there's commercial space-like companies. Commercial space-like companies, though, while they send people into space,

and they very well send people to the moon and Mars, they are not research agencies. They're not funding, believe me, they are not funding the kinds of research that I do. But they put it on their flights, which is not insignificant. So my experiment has been carried on several SpaceX flights and Axiom as well. So I credit them with that. They don't have to do that. The current approach, which is largely a risk mitigation approach, like I refer to, right? This is what the human research program at NASA does. It's more appropriate to think of it as an applied research agency than a science agency per se. Of course, you have to do science. That's part of applied research. But really, the NASA approach so far is identify a problem. You know, I was talking about this a few minutes ago. Bone loss, immune system changes, you know, what they call behavioral health and performance, psychological issues, mood, motivation, depression.

Identify those problems and then put a research plan into place to mitigate them and hope that you can mitigate them. But mitigate, even mitigating all of them, and they probably won't all be mitigated to the extent that you want them to be, like the radiation problem. Mitigate them to the extent that you can, and then light the fuse and go. And so what's going to happen there? A couple of things. First of all, you may have mitigated individual problems, but you have not mitigated the interactions of multiple problems, which is something that we really are not good at thinking about, not just, you know, NASA, but in general. Science has progressed so far by being reductionist. Remove all the confounds and study this one little thing. You know, space is full of confounds, and what I might consider a confound to my particular body system is your body system that you're interested in studying, right? So in space, it makes this a problem very acute.

You can't break it down and just study and address one body system at a time. If we can figure out how to start approaching that issue, kind of integrative physiology or systems medicine, it's sometimes called, that would have a great potential to help us here on Earth because we don't do this with medicine here on Earth, right? Something happens to you, you go to a series of specialists. Does anyone pull all that information together? Hopefully your primary care physician, if he or she is doing a really good job. But that's, you know, it's extraordinary effort to do that. And then tracking not only the interactions between body systems, but the interactions of the crew with each other and then the crew with the environment and then the crew with the mission in the sense that they have jobs to do. In some sense, that describes our lives here on Earth. Just the Mars mission makes it much more acute. You have to address those issues on a Mars mission, but we're not yet addressing those issues on a Mars mission.

I don't think people understand the magnitude of that. And I can't say for sure that I'm right about this because we haven't been to Mars with people yet. But the history of spaceflight tells us that we can expect some tricky situations and we should be thinking about this differently. We need a different conceptual approach. You're listening to Are We There Yet? The radio show exploring space exploration. I'm Brendan Byrne. We're speaking with Mark Shellhammer, a researcher at Johns Hopkins School of Medicine in Baltimore, about his new book, Are We Ready for Mars? Are we ever going to get to that? I'm thinking of all of these challenges that you're outlining. This is something that's never been done before. It's very difficult to have an analog of this. Not only the long-term deep space travel, but this crew interaction over time, this disconnection from their home planet. Are we ever going to get to a point where there is enough research that we can say confidently yes we ready for Mars Or is this something where you and I just got to get in a capsule and go and see what happens Or astronauts go not you and I

Yes, not you and I. At some point, that will be the case. You do the best you can. The best you can, of course, right, is subject to a lot of interpretation. You do the best you can and then you go. There will be huge uncertainty. Even if we were to go in 100 years, there would still be huge uncertainty because of the fact that you're going to have to go in the face of great uncertainty, which is all the more reason you need what I've been promoting, more monitoring, because you're going to face the unexpected. You want early warning indicators that something is going off the rails because it will go off the rails because you're facing the unexpected. So that, again, feeds into that idea like let's do some more monitoring, medical monitoring, performance monitoring, spacecraft monitoring, and integrate those things into a model of what it looks like for people to adapt to spaceflight over the course of a mission while things are decaying and while the spacecraft itself is undergoing changes as well.

But you were talking about analog facilities. You may know that in this community, the human spaceflight community, we generally think of five hazards of long-duration spaceflight. So there's altered gravity, generally zero gravity, but planetary gravity. Space radiation, which is deep space radiation, especially a lot harsher than it is here, low Earth orbit. Distance from Earth, which is the autonomy, remote in this part. You know, you're not going to get a lot of help from them. Isolation and confinement, just what it sounds like. And toxic and closed environment, possibly toxic. So not only the planet, but the spacecraft itself can start to get pretty gamey after a while, right? Because you've got a lot of people living in there for, not a lot, but a small number of people living in there for a long period of time, exercising, eating, using the bathroom. It can get gamey. I like that adjective.

It can get gamey. Yeah, it can gamey, to use the technical term. Really, to your very insightful point that you started with, when people, the community, develop space flight analogs, okay, extended head down bed rest, right? Lay down, head slightly depressed, starts to mimic the fluid shifts, that muscle atrophy because you're confined to bed for possibly months at a time, certainly weeks. All right, that mimics some of the zero gravity effects. Isolation and confinement, put them into chambers of various kinds. NASA has something called Hera. Now they have something called Shapia. I think they have just brought another one online. Or Antarctic winter overs, pretty good. Isolated, confined, dangerous. In a very real sense that you can't ethically mimic in other situations. They know that there is no way out of there if there's an emergency until the spring.

But very much to your point, those are separate analogs. Where's the analog that mimics the zero-G physiological changes at the same time? They don't exist. I don't know if they will ever exist. So because of that, the chances are the first time you're going to see that particular configuration of stressors and body changes and brain changes, you know, mental changes, psychological changes, is going to be on the mission itself. Finally, Mark, I'm going to ask you, I know you are a researcher, so this may be difficult to pull your crystal ball out and speculate, but if a mission to Mars is ever going to happen, when? It will happen. Hopefully, we will live to see it. I hope I live to see it. The standard answer has always been about 20 years, about 20 years from now. That seems to have been the answer for about 30 years, right, for decades or longer. Yes, exactly. And that's the answer that I'm going to give you with a nuance, with a twist.

20 years after we decide that it's the priority, right, because when I was at NASA, I did my time at NASA. It ended about 10 years ago and started about 13 years ago. So I was on a leave of absence for my academic position. And the thinking at the time was, I mean, the current design reference mission was Mars. We are working on sending people to Mars. And, of course, that changed. And now the Artemis program has taken over and the immediate priority is going to the moon. Not that that's a bad thing. That's sufficiently hard, right? Make no mistake. I do not mean to trivialize going back to the moon, but it pushes Mars off again by another decade at least. So I'm going to say, again, about 20 years after we decide that it is really the next priority destination,

can you do that while you're still exploring the moon? of course, but probably takes more resources than are available to us at the moment. So, 2040s. Okay, good news for us. We can get the podcast going until the 2040s. We won't have an answer to, are we there yet? Until then. That's fine. I'll come back then and do it again. I'm sure we'll have you on in the interim while that happens, too. We've been speaking with Mark Shellhammer, a professor at the Johns Hopkins School of Medicine in Baltimore. We've been talking about his new book, Are We Ready for Mars? Mark, thank you so much for your insight. Great conversation. Thank you. Enjoyed being here. Always glad to talk about humans in space, especially Mars. That's going to do it for this week's show. If you're interested in our search for life in the universe, check out our newest podcast, When We Find Them, a limited series that explores the search for life and what happens when we find it. Get it on Apple Podcasts, Spotify, or wherever you get your podcasts. All six episodes of Season 1 are out now. But stay connected with this show, and be sure to follow us on social media. You can find us on Instagram and Facebook.

or at AWTYspace. And if you've got an idea for a future episode of this show, or you want to join as a guest, reach out. Our email is arewetheryet at cfpublic.org. Are We There Yet is a production of Central Florida Public Media. Our producer is Marian Summerall. Editorial guidance comes from LaToya Dennis. Support for Are We There Yet comes from our listeners. Until next time, I'm Brandon Byrne. Thanks for listening. you