Transcript

MIC CAVAZZINI: Welcome back to Pomegranate Health, this is part 2 of our story on space medicine. I’m Mic Cavazzini for the Royal Australasian College of Physicians and here’s a quick reintroduction to my expert guests.

GORDON CABLE:              My name is Professor Gordon Cable. I'm an Honorary Professor also at the Australian National University. Currently working with my own company, Human Aerospace, on to work with them on space life sciences projects.

ALICIA TUCKER: So, Alicia Tucker. I work as an emergency physician. I practice down at the Royal Hobart Hospital. I’ve subsequently branched out into being a Fellow with the Academy of Wilderness Medicine. as well as I actively work as a diving and hyperbaric physician.

JOHN CHERRY:   So, my name's Dr John Cherry. I'm the Deputy Chief Medical Officer at the Australian Antarctic Division, a rural generalist, GP-anaesthetist, and emergency physician, and sit as the space analogue representative for the international collaboration of various National Antarctic Programs from around the world.

Let’s go back now to that image we started the story with of the enfeebled NASA astronauts Sunita Williams and Butch Wilmore being carried out of the re-entry capsule on a stretcher. The reason for this is that without having to work against the usual gravitational force of 9.8 metres per second squared, astronauts get more than a little deconditioned. Muscle atrophy in weight-bearing muscles is significant, especially in the calves, back and neck, and later we’ll hear about the cardiovascular effects.

But let’s talk about the serious loss of bone mass that accompanies long-term space travel. There are a dozen studies on weightlessness-associated demineralization that went into a 2021 systematic review. This showed that astronauts experience a 1 to 2 per cent loss of bone density per month in space. In a study published in 2022 in Nature Scientific Reports, researchers likened the effects of 4-7 months on the ISS to a decade of age-related bone density loss on earth.

They used high-resolution peripheral quantitative CT to examine the associated microstructural changes. With age-related effects, the cortical bone tissue is demineralized more quickly than trabecular bone, but in microgravity it’s the other way around. In fact, there are parallels with what’s seen in patients recovering from severe knee injuries who spend a few months on crutches without weight bearing.

For the endocrinologist on my review group, I will also mention that bone demineralization is a symptom of primary hyperparathyroidism. Severe cases are treated surgically, and parathyroidectomy is associated with a rapid normalization of bone turnover markers and recovery of bone mass within a couple of years. As Professor Cable explains, the effects of microgravity on bone mass and microarchitecture appear to be much more persistent. The follow up questions come from Dr Chris Leung, a gastroenterologist in Melbourne who also sits on the podcast editorial group.

GORDON CABLE: It's probably very well recognized that the musculoskeletal system is one of the most profoundly affected part from the cardiovascular system when it comes to microgravity and the bones sort of feature amongst that. It's because of the unloading, it's really a gravity dependent process. Bones mineralize when they're loaded. There are certain biochemical, physiological, cellular signalling mechanisms that respond to load, which get the osteoblasts and osteoclasts doing their thing, remodeling and building. And if you take that away, then the degradation of bone takes precedence and bone, because it's not used, it starts to be degraded. So, calcium is leached out of the bones over time, which happens, well, pretty much straight away. As soon as you go to microgravity, is an uptick in the urinary excretion of calcium, for example, that you can see over the first day or two of being on orbit. And that just increases progressively.

So, the degradation of bone does happen, and you're right about the architecture. So, there's increasing trabecular spacing, there is trabecular thinning, there is modelled load fractures, which can be done using computer-based models, and they show that the fracture load for the bones is weakened. The calcium loss also happens from cortical bone that is a dose-dependent process. So, the longer you are in space, the worse it gets and the longer the recovery is. In fact, there've been some papers suggesting that the recovery of the normal pre-flight architecture, it might never be recovered, even after years. I mean, it can take a year or more for the bone to mostly recover, but in some cases that may never occur fully back to baseline.

Now this again operationally is the significance here as John was talking about with the eyes, same with the bones. You know, if we are exploring planetary surfaces and we have bones that are weakened and we're now moving about ambulating in even partial gravity environments and doing fairly dangerous work on a planetary surface there's an increased risk of trauma. And you know we really don't know what that risk will be, but we certainly don't know for example how bones may heal differently in a low-gravity, partial-gravity environment compared to a one-gravity environment. And of course, we need to have all the mechanisms in place to be able to treat, to immobilize, treat and look after a patient in that environment if they break a bone.

So, it's a significant issue. I mean that's the basis of the physiology. But we do know that the countermeasures that have been used on the International Space Station have been very effective in mitigating this loss to as much an extent as possible, largely brought about by the use of exercise. So, using equipment such as the ARED exercise equipment on the ISS, which is the Advanced Resistive Exercise Device. But also using bisphosphonates, know, supplementing vitamin D, using not only resistive exercise but aerobic exercise and impact loading with treadmills that vibrational impact loading is actually very good for the creation of bone, so that's done as well. And we know that with that sort of approach to countermeasures that you can almost pretty much maintain the baseline calcification of the major load-bearing bones of the lower limb which would be mainly the hip, the trochanters, the femur, so you can maintain the mineralization of that area pretty close to baseline by the time they come back.

But the concern is going to Mars, going deeper into space, can we use the same techniques? I mean certainly we can use the pharmacology but can we use the physical exercise devices that we use now? The answer to that is probably no because as John alluded to earlier with talking about radiation, it comes down to mass and volume and what we can actually pack onto a spacecraft that's likely to be much, much smaller than the International Space Station.

CHRIS LEUNG:   The advanced resistive exercise device sounds fascinating. Can you describe what this actually involves and how intensive the training needs to be to maintain that prerequisite stimuli and conditioning?

GORDON CABLE: Yeah, it's about the size of gym equipment. It's a very big device actually, but it's all vacuum tube driven. I mean, obviously there's not, you can't take weights to space. They don't have weight, right? So, you can't lift weight in space as such, but you know, it's pushing against resistance using a vacuum tube mechanism. I think that you can do, pretty much every upper body, lower body exercise that you would do in any gym. It has to be vibration isolated from the station because as you're lifting weights, as it were, you know, the movement, the accelerations that you generate, generate vibrations which can be transmitted to the station, which can affect sensitive instruments and can affect the gyroscopes. And I mean, a whole bunch of stuff can happen as a secondary effect. So, all the equipment that they use like that has to be vibration isolated using damping systems to keep them separate from the spacecraft structure.

So, it's this very large device and it has to be, you have to learn to do it, you can't take your technique from a normal gym and just sit on an ARED in space and start doing it because microgravity changes your biodynamics. You know, microgravity will change the curvature of your lumbar spine, for example. So, when you lift weights, when you push against resistance, you have to do it in certain ways guided by physios on earth, so you actually don't injure yourself because of the way that your body structure changes in microgravity.

So, astronauts will do probably an hour of that plus an hour of aerobic exercise every day except Sunday, so six days a week, two hours of exercise. But then of course you've got time for hygiene and you can't have a shower in space so, you know, the shared funk you have to sort of towel yourself down and get ready for the next round of work.

CHRIS LEUNG:   There's no Tai Chi in space.

ALICIA TUCKER: No. And then the other consequence of that demineralization, even though we're doing those intensive exercises, you still get calceria and increased risk of kidney stones. Kidney stones are challenging at the best of times, but then put an astronaut without any ability to have any intervention—we don't have a spare urologist to do a quick bit of lithotripsy or go and snare a stone. But although we haven't had a whole heap of people in space with kidney stones on the International Space Station you know crying in pain we don't know who's going to be the person that gets that. Do we need to be measuring calcium levels in urine as a proxy to preventing the formation of calcium pyrophosphate in their nephrons and institute some sort of intervention early on. So, you've kind of got all of these extra issues that comes from just the one physiologic driver.

MIC CAVAZZINI:                There was a study I came across, 17 astronauts on mission of four to five months. Seven were given the biphosphonate medication, alendronate. And over this mission, they showed no elevation of bone resorption markers in urine, which the control group did have, and slightly lower excretion of calcium. So, biphosphonate could deal with both of those things.

GORDON CABLE: It's a holistic approach, I guess. I've mean Human Aerospace, the suits that we've developed are gravity loading skin suits which try to prevent bone and muscle loss, also supporting the cardiovascular system through thigh cuff technologies. I mean, you have to look at all aspects and support all aspects. So, it's not just about exercise. It's about the macronutrients, the micronutrients. It's about the fact you don't have UV exposure and suppose you have to take vitamin D to supplement that, you know, all these interactive factors. It's about supporting the immune system, supporting psychology, which we know through cortisol has an important impact on immunity and other aspects of physiology. So, it's not only multidisciplinary, but it's a holistic approach looking at all aspects of trying to maintain astronaut health.

MIC CAVAZZINI: And you already alluded to when astronauts land, the reason we see astronauts getting carried out of the capsules is obviously reduced bone density. What are the other issues that astronauts arriving on Mars would face without the support of a ground crew.    .

JOHN CHERRY: So, if you look at an astronaut landing in Kazakhstan now, or soon to be much more frequent landing around the US, you've got a large support crew that's supporting those astronauts when they return. You know they're supported to get out of the capsule and move to a like a medical tent before then being flown to their home territory wherever they may be heading back to. They've then got a recovery and rehabilitation period that goes from days to weeks to months depending on how long their mission has been.

If we now transport a crew to Mars and we land them on the surface of Mars, we're now telling them that you have to be responsible for extricating yourself from the seat, getting around the vehicle and then getting to a point where you're able to mobilize outside the vehicle to undertake the reason you've gone to Mars. You've gone to Mars to undertake some really important science that can be done on the ground. At the moment, it's not entirely clear how we're going to get to that point.

There are cases where astronauts have landed, due to challenging re-entries, in different regions to where they were planned to land, particularly around Kazakhstan. And there was one case in particular where there were some fires that were encroaching close to where the vehicle landed and they couldn't get the support crew there quickly. The astronauts weren't able to get more than a few metres away from their vehicle over several hours. So, it’s a really significant challenge.

ALICIA TUCKER: One of the other reasons astronauts get carried out is the vestibular side effects of going to space. One of the very substantial issues as well as the fluid shifts when you arrive in space is that firstly the otoliths are all lifting up so your body goes, “Oh my goodness, you know, you're in a potentially vulnerable place I'm going to make you feel like rubbish so that you'll stop moving and therefore you will not hurt yourself”. And then you've got the other mind muddle, is suddenly your environment goes from being up and down to being 360, so you've got this bizarre visual reference change and you're not touching things to move necessarily, so you've also got a change in your proprioception. And they can cause significant nausea and at least 70 to 75 per cent of astronauts will get that, and it's not predictable.

Certainly, Promethazine is a very effective tool, but you have to counter the sedative effects of that with caffeine. And as a commercial astronaut, a non- “Right Stuff,” I've got a lot of money not necessarily health, astronaut, you may not be able to use those medications because of other underlying health issues. With the government astronauts it's a bit like getting your sea legs but just like when you return to land after a long time at sea, when you return to earth, all of a sudden those otoliths are just almost slamming down in your semicircular canals and then all of a sudden you have this massive bit of information—

So, if you are in a flight to Mars, you have a six month transit, and then your bone demineralisation, you've got cardiovascular deconditioning, you get sphericalisation of the heart, your effective plasma reduction is about 20 per cent, so it's almost at that kind critical level that would make any trauma surgeon feel a bit anxious, and then you ask them to walk down proudly down off the off that very precarious ladder out of that lander, and they've got brittle bones, they feel like crap, you’ve put them in an environment which is on the other side of the solar system and then all of a sudden it's like, “Oh.”

MIC CAVAZZINI: That extended space flight of Sunita Williams and Butch Wilmore we started the series with is actually only the sixth longest for NASA. And the all-time record is held by physician cosmonaut Valeri Polyakov. Back in 1994-95, he spent 437 days on the Mir space station, making 7000 orbits around the earth in those 14 months. Polyakov had an uncomfortable ride back to Earth because he had outgrown by 4 centimetres the very precisely customised descent module.

But the cosmonaut had worked out religiously for the entire mission and after his capsule parachuted to the steppes of Kazakhstan he made a point of walking from it relatively unassisted to sit on one on a chair in front of the awaiting media. For extra nonchalance he even took a drag from a mate’s cigarette and a sip of brandy. In a later interview he explained that this show of independence had been one of the main objectives of the marathon flight, with the understanding that walking proudly onto the Martian surface might be easier given it only has 37 percent the gravitational force that Earth does.

It’s been suggested that more intense deadlift training and the introduction of high-impact, jumping movements could promote greater osteogenesis, but as already mentioned, the real-estate on a space-craft is somewhat limited. The International Space Station is made up of 16 pressurised modules that combine to a habitable volume of about 1000 cubic metres. That’s a fraction bigger than a modern Boeing 747 passenger jet, but the plane doesn’t need to fit in labs and control rooms, let alone a gymnasium.

The Starship vehicles that Elon Musk plans on sending to Mars will have living space of just 600 cubic metres and the moon-bound Orion capsules are no bigger than a skip bin. We don’t yet have those giant spinning gravity centrifuges we were promised in films like a Space Odyssey or Interstellar. Although in a news story dated December 24, I learned that a Russian rocket company has secured a patent for such a design. With a diameter of 80 metres spinning at 5 revolutions per minute, it would theoretically achieve an artificial gravity of 0.5G.

As already alluded to, loss of bone and muscle is not the only issue. Many astronauts describe feeling clumsy once back on earth as their nervous system has to recalibrate postural control and proprioception. In one account I'll link in the podcast transcript one describes the mess he made in trying to leave a bottle of juice hanging in air so he could float it over to a friend. But it’s not just behavioural adaptation, there are some as yet poorly understood changes to the autonomous nervous system too.

Some reviewers have termed the adaptive plasticity of the vestibular and sensorimotor networks Spaceflight Perturbation Adaptation Coupled with Dysfunction or SPACeD, and this may even correlate to changes seen on functional MRI. In a brain imaging study of long-haul cosmonauts from 2019, researchers observed disrupted connectivity underlying the plantar reflex. There’s actually a research group in Canberra trying to address this known impairment with a textured sock that would increase tactile stimulation.

And you’ve already heard mention of orthostatic tachycardia, or fainting astronaut syndrome. I’ll share some footage of US astronaut Heidemarie Stefanyshyn-Piper addressing a press conference in 2006 just a couple of days after landing from a two week space flight. Mid-sentence she glazes over and is caught by colleagues before falling to the ground. This would not be ideal after first setting foot on the red dust of a hostile planet.

The reviews in this area present a shopping list of changes to the cardiovascular system that occur in response to microgravity. The haemopoetic system downregulates in the first few hours of spaceflight, and so-called space anaemia can persist even a year after landing back on earth. Over months of space travel with less loaded circulation, researchers have variously observed a reduction in left ventricular mass, increased volume of the left atrium, and reduced cardiac contractility.

Another study from the ISS described an ultrasound investigation of blood flow in the internal jugular veins. The outcomes, published in JAMA Network Open, showed stagnant or even retrograde flow in the left IJV in 6 of the 11 participating astronauts as well as significant distention of the veins.

But, even before the crew had returned from the station an alarming incidental finding was made. Two months into a six-month mission, an obstructive thrombosis of the internal jugular vein was found in at least one individual. The anonymised case report was published in the New England Journal in January 2020 but from a later review it seems that the astronaut was a woman in her 40s with no personal or family history of venous thromboembolism. I’ll let Gordon Cable walk through how this triage level 3 was handled, 400km above the surface of the earth.

GORDON CABLE: So yeah, was a study that was being done on the ISS looking at both the venous flow and the internal surface area of the vein to see what was happening, if it was stretching, collapsing, what the flow was doing. And they were using ultrasound on themselves and measuring it sequentially over time.

But what they found incidentally, accidentally was that two of the astronauts, in fact, ended up with thrombosis in the internal jugular vein on one side. And one of them, actually, it was a complete occlusion, no flow at all. So, that obviously caused enormous concern around, you know, how do we treat it? Do we bring them home? What do we do with it? And it had never been seen before. Now, whether or not it had occurred before, we don't know because we weren't looking for it.

What actually happened was that they obviously had some very significant medical conferences with the ground and the ground with the ISS. They decided to treat in-location, They did have clexane, or they had some sort of low molecular weight heparin in the medical kit on the ISS. So, they started treatment. They started with an anticoagulant injectable and they decided on the next cargo mission, which I think was an ESA vehicle coming up, they put some apixaban on the cargo vessel. So, they decided to swap over to a NOAC and treat on-orbit and serially again monitor the progression of the clot to see what would happen.

The clot started to resolve, the flow started to come back after about three months. It got to the point where they felt reasonably comfortable that they could put the astronaut in a Soyuz and bring them home. But they were very concerned, obviously, with all the acceleration forces on re-entry, which are fairly significant. We're talking, you 4 to 6G that there may be some dislodgement of the clot, which would cause other problems. Anyway, none of that happened. They were fine. They got home. They had follow-up scans, and the clot was eventually fully resolved.

But a very interesting finding, and it raises the whole question, what is it about the spaceflight environment that might predispose to venous thrombosis that we didn't know about? If you think of Virchow's triad, clearly we have the loss of plasma volume, the increased viscosity, which also goes along with spaceflight anaemia. But then, you know, you've got the stasis problem as well with the reduced blood flow in the venous system because of the head would shift. In fact, not only was there stasis, there was reversal of flow in some of the scans that were done. There's hypotheses about how ionizing radiation may affect the endothelium.

So, there are many, many theories as to why that's happening but it does raise some interesting problems for the future because we need to potentially do a coagulation screen on astronauts pre-flight. We need to potentially revisit the issue of using hormonal therapies for female astronauts to control or suppress menstruation on-orbit. So, there's a number of really interesting questions that flow out of this and whether this is an unusual finding or is it something that we are really going have to worry about with further longer duration deep space missions and should we be screening for it routinely? So that's the potted summary of the case, but it was a fascinating finding and one of these curveball that comes at you and leads to some really interesting questions of physiology.

MIC CAVAZZINI:                John, this case study that occurred on the ISS, it's a parallel, let's say, of a remote medicine environment that many listeners will be familiar with. The ISS is in a Lower Earth orbit at about 400 Ks above the Earth's surface. Now that's only the distance from Dubbo to Sydney or from Mildura to Adelaide, although the equipment and the expertise on board is more typical of a country emergency room. Tell us what a flight medic would—what diagnostics would they have and what sort of responsibilities would they have? How does this parallel your role on an Antarctic base and then, you know, getting into the comms delays and that kind of thing.

JOHN CHERRY:   Yeah, sure. That's a great question. And quite a, I could speak at length on that for a long time, but I'll try and give it a crack now. A space analogue is an environment that occurs on Earth that shares many of the same challenges and complexities as astronauts will experience in flight. So, Antarctica is the most established space analogue because we have small teams operating in isolation within the Australian Antarctic Program, physical isolation for nine months of the year, they have chronic low-grade stress, they're dependent on technology for survival, they have changes to their circadian rhythms—absence of sunlight during periods of winter or reduced sunlight during periods of winter,             many of these challenges are very similar to space flight, from a physiological point of view but also from a psychological point of view as well and from an operational point of view.

We at the Australian Antarctic Program and with the Polar Medicine Unit have worked with NASA since 1992 providing medical support and medical research opportunities to support long-duration space flight. One of the reasons that NASA works with us is because we have an extremely advanced medical model compared to many of our other Antarctic partner nations and we really do lead internationally when it comes to our capabilities down south. And when I say capabilities I don't just mean physical infrastructure, I also mean the systems we work within, the training processes, the recruitment processes, both for our doctors and our support teams as well.

There is a single doctor at each station for each season, other than at Casey Station over summer, where there are two doctors due to an increased operational tempo. All of our stations have a single doctor and they're supported by four lay surgical assistants who are expeditioners who have undertaken two weeks of medical training at the Royal Hobart Hospital. The doctors bring experience in medicine, emergency medicine, surgery, anaesthetics, dentistry and we provide additional training as well as well as in a number of other areas and they're supported by the lay surgical assistants who don't operate independently, they don't act independently, they're under the direct supervision of the doctor at all times but that provides us with a surgical capability and anaesthetic capability which we sometimes have to use.

So, over summer, if we're doing a medical evacuation, it's about two weeks to do that. That's roughly the same as a medical evacuation from the surface of the Moon in the upcoming missions. Over winter, it's nine months of isolation, so nine months for medical evacuation. That's similar to a medical evacuation from Mars. So, the historical experience that we bring, but also the systems and the processes that we bring, are really useful for NASA and for space agencies around the world.

This is actually forming part of my PhD that I'm working on at the moment and some of the challenges around how do we provide a model of care that addresses the needs of the astronaut population in those long-duration space flight settings. It's pretty clear, I think, to most people that there needs to be a physician on those long duration space flights and a physician of appropriate training with appropriate upskilling who's supported within a system be that with AI support or with additional crew training in particular areas to support additional medical capabilities or potentially surgical capabilities depending on the mission format but those things are still in process. You know, when we talk about mass and volume and the challenge of only having a few kilos for a medical kit, selecting what you take which is going to be appropriate for your needs is a real challenge.

When I was working for the European Space Agency we redesigned the medical training curriculum for the European Astronaut Corps around that needs analysis looking at what they could expect to experience, the difficulty of treating it, the mission implications and the likelihood of it occurring. All of those things need to go into the mix to then work out, do you take extra cannulas or do you take extra fluids or do you take an ultrasound? And if so, which one? There's a whole body of work that needs to go into that, but it's fundamentally both a medicine challenge and an engineering challenge at the same time.

MIC CAVAZZINI:                Fantastic, Does Gordon or Alicia want to talk to the telehealth kind of parallels and how long it takes to get a call to a specialist from Mars Orbit?

ALICIA TUCKER: Yeah, I suppose the thing is just in terms of communication is at the moment there's real-time communication on the space station every minute of the day apart from you know a couple of like little windows where there might be say 30 second blackouts. But for all intents and purposes it's almost instantaneous communication so the ability to communicate with the astronauts on the space station is actually probably more robust than trying to get to a similarly extreme environment on Earth like on the Antarctic continent or when you're up at base camp on Everest or in the middle of a desert or a jungle et cetera you know the communications there aren't as instantaneous.

However, when we go beyond low earth orbit it's going to be a little bit more challenging because we don't have the same satellite technology yet. We know that there is going to be those delays. We know there's going to be least a 20 minute delay between asking a question on Mars and then getting the answer another 20 minute delay, let alone if you factor in other environmental issues such as dust storms which could completely and utterly cloud the entire surface of Mars and therefore interfere with your ability to be able to communicate. So, the lessons that we have learned through things like remote health and even in the last five years—COVID made these systems a lot more robust. And I think that the terrestrial applications are not to be underestimated.

JOHN CHERRY:   I think when we think about telehealth, we have to define what we're talking about because telehealth can be as simple as a text conversation. It can be as simple as a phone conversation, be that through a satellite link that we utilise. Or it could be as advanced as us supporting an intra-abdominal operation for an expeditioner at one of our stations with remote monitoring of anaesthetic capabilities in real-time for our generalist doctor on the station, real-time camera support, cameras that can look into the airway, look into the abdomen, as well as a range of other physiological supports and pathology and imaging supports that are integrated into a system.

So, one of the things that is inspiring to me with the work that the Australian Antarctic Programme and the Polar Medicine Unit have done over a long time is they've been at the forefront of telemedicine in Australia and around the world. And one of the big flow-on effects for us is that we've seen technology and systems that we've pioneered then translate into rural and remote settings and provide improved healthcare options to populations in those areas across Australia.

You know, one example that springs to mind is we've recently completed the NASA's largest ever ultrasound study looking at if novice sonographers, so people who've never picked up an ultrasound before, can generate clinically useful images using and following protocols that we've authored with our NASA colleagues. And, you know, that has huge implications for small communities that may have an ultrasound device, but perhaps someone who's never utilized it before. There might be a single practitioner setting or a very experienced nurse who's working in rural or remote Australia. And that decision-making capability where you can generate an image using a protocol that can be stored and forwarded and interpreted off-site can then impact the patient journey and potentially prevent a hundreds of kilometres journey to the nearest tertiary medical centre where those facilities are available. And so that's the sort of things that we're talking about. And, I think, in Australia we lead the world when it comes to rural and remote health care and I think again it's something we should be very proud of as a nation.

MIC CAVAZZINI: I'll let Gordon have the last word. Do you want to say something about wearable data sensors, even ingestibles and implantables? How mature is the technology for monitoring the health of various systems.

GORDON CABLE:              You’re right about the wearables and the importance of them. I mean, the technology is fairly mature. A number of different versions of that have been flown to the ISS. There's a Canadian sort of variety of that, the astroskin suit that can be worn with a number of wearable technologies and of course that's going to become increasingly important as we go further in space. The astronauts themselves have be much, much more autonomous through the use of wearables, through the use of AI, through the use of just-in-time training using virtual reality, all these technologies and robotics.

Don't forget robotics. All of this we need to look at providing them the tools to become more autonomous because if they have a medical emergency or indeed if they have a technological emergency, they need to deal with it. And what NASA is eventually going to hear or the ground control is eventually going to hear is, “We had a problem, we did this, we fixed it, we're in the recovery mode, we're back to situation normal. Thank you very much, it's done”. Unless they can do that, they're really not going to get any help from the ground with a 20 minute one way and 20 minute the other way time delay. So, I think that's the point, I think the further we go, the more difficult that will be the autonomy of astronauts using wearables and technologies like that will become very important.

But just finally, if I could just reiterate the importance of the space to earth link, the fact that we do technology development, we support astronauts in their missions, professional astronauts I'm talking about for these wonderful deep space adventures. But the whole point is that the technology that matures out of these missions can be spun back to earth and can greatly improve the healthcare of patients in Australia and around the world. Not only from a telehealth perspective, but from all the other physiological interventions that we are likely to learn about as we go deeper into space. The radiation argument, I guess coming back full circle by coming up with, for example, pharmacological radiation countermeasures that can be used for astronauts in space, but can also be used for patients receiving radiotherapies and angiography and other radiological imaging techniques that will be a vital spin back.

And I read in a textbook once that for every dollar spent in space, there's $9 of benefit for earth-based economy. So, when people say, go to space? Why waste the money? I mean, there is a really compelling argument, right? There are apart from the existential, we've got to go because we're explorers and we need to see it with our own eyes.

MIC CAVAZZINI: Just I was putting the final edits on this podcast, NASA brought four astronauts home from the International Space Station a month before the end of their mission. The details have, so far, been kept very private, but we do know that one crewmember’s space-walk planned for Jan 8^th had already been cancelled as a medical precaution. While this incident has been touted as NASA's “first medical evacuation in 65 years of human spaceflight” it’s not the first medevac from orbit and far from the first acute illness.  

In a 2018 analysis of Holter monitor recordings form astronauts on the ISS an incidental finding of supraventricular ectopic beats is described. Fortunately, there were no other alarming signs, and with such a small study sample it hasn’t been possible to separate the contribution of individual physiology to this presentation. In 1987, a cosmonaut on the second ever mission aboard the Mir Space station also experienced minor heart irregularities. Aleksandr Laveykin was returned to earth with a visiting Soyuz crew, half-way through what would have at the time been a record ten-months stint on-orbit.

A couple of years prior to that, the Soviets had conducted another medevac from the predecessor to Mir, the humble Salyut 7 space station. In September 1985, three cosmonauts launched for what was to be a six-month mission that would test new technology and procedures, some with military applications. In March of the following year the crew were to be replaced by the first all-female space-flight, on International Women’s Day no less. But this propaganda coup was scuppered thanks to the troublesome prostate of Vladimir Vasyutin. #irony.

Although the embarrassing affair was kept very quiet, it seems that 33 year-old Commander Vasyutin had kept a pre-existing condition hidden from the doctors who cleared him to fly. Once aboard, he was unable to manage the pain and fevers with available medications, forcing him to fess up to his comrades. Mission Control even enlisted the services of a psychic to magic the ailment away, but without success the crew were evacuated just a third of the way through their scheduled mission.

The last space yarn I’ll leave you with dates way back to the Apollo 15 mission of 1971. The 12-day expedition was more focused on science than previous lunar landings and involved multiple EVAs. But Commander David Scott and Lunar Module Pilot James Irwin both experienced severe pain and oedema of the fingertips on moon walks up to 7-hours long. We know now that a lot of astronauts involved in EVAs lose their fingernails because of the pressure and abrasion on their hands caused by the space suit gloves.

Irwin also experienced a bigeminy cardiac arrhythmia and briefly lost consciousness on returning to the command module. The mysterious presentation has been simply dubbed “Apollo 15 space syndrome,” though the suspicion is that with a broken hydration system in their EVA suits, the astronauts may have suffered complex outcomes of extreme dehydration and salt imbalances. Almost two years after returning to earth, Irwin actually experienced a myocardial infarction that may have resulted from endothelial damage.

I hope my scattergun of anecdotes over these two episodes captures the dazzling array of acute and chronic afflictions that can result from space travel, and even more pedestrian conditions that need to be managed in novel ways. According to a discussion in the Conversation the maths suggests that a medical emergency on-orbit would be expected every three years, so you could say we’ve been pretty lucky to date. Let’s hope that luck holds as more and more people visit space with commercial operators, not highly selected and trained heroes, but ordinary punters like you and I.

I am very fortunate, though, to have had Professor Gordon Cable, Dr John Cherry and Dr Alicia Tucker sharing their passion and insights for this episode of Pomegranate Health. They’re actually working to get training in aerospace medicine more formalised and have already established a unit of study in the Healthcare in Remote and Extreme Environments program at the Uni of Tasmania. Also look out for the face-to-face workshops of the Australasian Society of Aerospace Medicine.

In more terrestrial concerns, did you know that you can count time spent listening to this podcast towards your CPD as a Category 1 educational activity. There’s a link in the episode blurb that takes you to a prefilled MyCPD form.

There are heaps more great episodes to browse, so for the full archive go to racp.edu.au/pomegranate. But it’s slightly easier to search and keep up with new releases by subscribing to a podcasting app like Apple Podcasts, Spotify or Castbox. You can even sign up to email alerts at the website. Please send me any suggestions via the address podcast@racp.edu.au

I am very grateful to all the physicians on the podcast editorial group who took time to provide feedback on this story. They include doctors Aidan Tan, Rahul Barmanray, Simeon Wong, Fionnuala Fagan, Maansi Arora, Stephen Bacchi, Jia-Wen Chong, Aafreen Khalid and health informatician space nerd Professor Paul Cooper.

This podcast was produced on the lands of the Gadigal people of the Yura nation. Writing for the Powerhouse Museum, Aunty Joanne Selfe uses the word Warrawal for what we describe as the Milky Way. In different Aboriginal cultures it is described variously as a river, or smoke from the campfires of ancestors. Gamilaraay astrophysicist Karlie Noon goes on to explain how the dark dust lanes and bands in the Milky Way form the shape of the Celestial Emu, Gawarrgay.

I’m Mic Cavazzini, for the Royal Australasian College of Physicians.