How space is changing what we know about health – The Irish Times

It began with a conversation at a party. Dr Lisa McNamee, now one of Ireland’s most active contributors to the emerging field of space medicine, hadn’t planned on becoming a doctor, let alone advising on astronaut health.

At the time, she had an arts degree and was toying with postgraduate options in business or languages. But something about that chat, about how straightforward it could be to register for a medical entrance exam, nudged her in a new direction. “At the end of the day,” the woman told her, “if you fail, sure no one will know. You don’t have to tell anyone.”

Years later, McNamee holds the rank of commandant in the Defence Forces, has trained with the European Space Agency (ESA) and the University of Texas, and is a co-founder of Space Medicine Ireland. She now advises on space-flight health countermeasures, lectures in clinical innovation and works with both Irish and European partners to translate knowledge from orbit to Earth.

Space medicine is an emerging field that blends emergency care, physiology, psychology and toxicology to help astronauts manage the health challenges of space flight. Once focused mainly on military and aerospace contexts, it is now gaining wider relevance as human missions venture further from Earth.

A key focus is understanding how the body responds in the absence of gravity. On Earth, gravity helps regulate everything from circulation to muscle tone and bone density.

In space, astronauts live in microgravity, a state of near weightlessness caused by continuous free fall while orbiting the planet. Although gravity is still present, its effects are greatly diminished. Fluids move upward, muscles weaken and bones lose mass. These changes can disrupt normal body function in ways that are still being studied.

“Microgravity is not an environment we evolved for,” McNamee says. “It acts like a stress test on the body, and that tells us things about human physiology that we’d never discover in a lab.”

“Preventative medicine is everything in space flight,” she adds. “You can’t rely on a full medical team. Even medicines can degrade faster in microgravity, so you need to stop problems before they start.”

Other risks include radiation, pressure changes, disrupted sleep cycles, lunar dust and g-forces. These forces, caused by changes in acceleration, can place added strain on the body. As missions extend beyond low Earth orbit, the ability to manage health autonomously becomes critical.

“If something goes wrong on the International Space Station, you can still get someone home in hours,” McNamee says. “But on missions to the moon or Mars, evacuation isn’t an option. You have to treat everything on the spot, sometimes for months. That changes everything.”

The field has its roots in aviation medicine, which advanced during the second World War to keep pilots fit for high-risk flights. The same goal of protecting human performance in extreme conditions now applies to space flight. But in space, even minor issues can quickly escalate. “You’re constantly trying to de-risk,” McNamee adds. “Not just for the individual, but for the whole mission.”

Astronauts often experience bone loss, muscle wasting, disrupted immune responses and altered vision during even relatively short missions. But some changes are less expected.

In Nasa’s well-known twin study, where astronaut Scott Kelly spent nearly a year in space while his identical twin, Mark, stayed on Earth, researchers observed something strange: Scott’s telomeres, the protective caps on the ends of chromosomes, lengthened in space. “That was the opposite of what everyone predicted,” McNamee says. “We thought they’d shorten, as they do with ageing and stress. It completely inverted our understanding.”

These physiological puzzles are more than academic curiosities. They are increasingly being translated into breakthroughs for Earth-based medicine. Take the gut microbiome, a rapidly evolving area of research in cancer care.

An ESA-supported study, Radiobiome, led by Dr Nicholas Brereton at UCD, is exploring how radiation exposure in space affects gut bacteria. “Some patients tolerate radiotherapy very poorly,” explains McNamee, who is not directly involved in the project but follows it closely. “This research could help us understand why, and potentially tailor treatment or even develop microbial transplants to improve outcomes.”

McNamee also advises on a biotech project with Irish firm Aquila Biosciences, developing a “biological Velcro” pad to remove pathogens from skin and surfaces. The idea emerged from concerns about how space flight weakens the immune system and alters how microbes behave.

“It’s non-corrosive and nature-inspired,” she says. “ESA is interested in using it as a decontamination solution for astronauts. But it could also be used in hospitals or disaster zones on Earth.”

If this sounds more like science fiction than healthcare, that’s not far from how McNamee first approached the field. “I loved stargazing and sci-fi as a kid,” she says. “But I never imagined I’d end up working in anything remotely like this.”

Her commitment deepened during a training programme run by ESA during the pandemic. “We had lectures from ESA flight surgeons and astronauts. I learned about space sickness, the impact of radiation, the psychological pressure of being monitored 24/7. It was fascinating. It gave me an entirely new lens on medicine.”

One of the most pressing questions in space medicine is how to keep astronauts safe as missions move beyond low Earth orbit. The moon’s surface, for example, introduces its own dangers. “Lunar dust is incredibly sharp, clingy and toxic,” McNamee explains. “Apollo astronauts reported hay fever-like symptoms after exposure, even inside their suits. If we’re planning to live and work on the moon long term, we need to develop serious mitigation strategies.”

The risks multiply on missions to Mars, where communication delays and total isolation demand even more self-reliant medical care. “When you’re that far out, there’s no evacuation,” says Mark Hannaford, founder of World Extreme Medicine (WEM), a training and research organisation that brings together medics from warzones, polar outposts, disaster areas and, increasingly, space flight.

“You’re in a pressurised capsule, thousands of kilometres from help. That’s the same mindset needed when you’re overwintering in Antarctica or deep in the field in Ukraine,” he adds.

For Hannaford, the crossover between space and extreme medicine is natural. “It’s all austere environments,” he says. “The medicine stays the same. But the setting changes everything, how you improvise, how you lead, how you deal with trauma and uncertainty.”

Nasa has sent representatives to WEM’s conferences for more than a decade, not just to share but to learn. “They told us they get a lot out of hearing how medics in low-resource settings innovate,” Hannaford says. “When you can’t rely on hospital infrastructure, you have to return to core diagnostic skills, listening, touching, observing. And that’s as true on the ISS as it is in a jungle clinic.”

This feedback loop, where space medicine informs Earth-based practice and vice versa, is only growing stronger.

In Ireland, McNamee has helped introduce space medicine as a challenge topic at the Royal College of Surgeons in Ireland’s (RCSI) medical innovation programme. Students were recently asked to design solutions under microgravity constraints. “They blew us away,” she says. “It’s exciting to see how quickly the field is expanding.”

That expansion is also changing the face of the profession. Women, historically underrepresented in both medicine and space, are now entering these areas in greater numbers. “We still know less about how female bodies respond to space flight than we do men’s,” says Hannaford. “That’s changing. And it’s vital, because if we’re serious about long-term human exploration, we need data that reflects the whole population.”

McNamee points to figures like Dr Nina Purvis, the UK medical doctor selected by ESA to work on Concordia Station in Antarctica, where she is performing biomedical research to help shape medical considerations for future Mars missions. “She’s phenomenal,” McNamee says. “She’s running hyperbaric experiments and doing medical training in incredibly isolated conditions. These environments teach you not only clinical skills, but also how to manage uncertainty, how to work in a team and how to keep functioning in high-stress situations.”

That, in the end, may be the greatest gift of space medicine. It’s not just about helping us survive future missions, but about making our healthcare systems here on Earth more adaptable, more inventive and more human.

“What space teaches you, over and over,” McNamee says, “is how little we actually know about the body. But it also shows you how much we’re capable of learning if we’re willing to look in the right places.”