What if one person’s journey could challenge how we define capability, not just in space but here on Earth?
The European Space Agency’s groundbreaking para-astronaut initiative set out to find out, and John McFall was chosen to test just that.
Somewhere high above Earth, McFall ran in zero gravity. Strapped into a harness on a treadmill bolted to the floor of a parabolic flight, an aircraft that simulates weightlessness in short bursts, McFall sprinted for 22 seconds at a time; 30 times per flight. Three days of running. One prosthetic leg. In free fall.
He wasn’t running for sport. He was running to prove someone like him, a lower-limb amputee, could meet the same physical demands as any other astronaut.
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The ESA’s initiative set out to challenge assumptions about disability and space. McFall’s journey illustrates what can happen when those assumptions are tested and overcome.
A practising orthopaedic surgeon and former British paralympian, McFall hadn’t always dreamed of becoming an astronaut. But in 2022 he was selected by the ESA to take part in a bold experiment: to determine whether someone with a lower-limb amputation could meet the physical, technical and psychological demands of human space flight. It was the first initiative of its kind and McFall was the first to take it on.
In 2021, the ESA wanted to explore a long-overdue question: why have people with physical disabilities been excluded from human space flight? Their para-astronaut feasibility project aimed to determine whether candidates with lower-limb differences could safely live and work aboard the International Space Station (ISS). McFall was selected to test that idea and, ultimately, to help rewrite the playbook.
“We’re not changing the requirements,” McFall explains. “We’re seeing if it’s still feasible for someone with a disability like mine to meet those requirements.”
McFall was one of 257 people who responded to ESA’s call for candidates with specific physical disabilities, including lower-limb amputations, congenital limb differences or individuals shorter than 130cm. Only 27 progressed to the second stage.
Long before he became a paralympian or a doctor, McFall was already driven. “If you don’t prepare, you fail. You can’t just be a passenger in life,” he says. “Put in the effort, that’s how you move forward.”
Growing up in Hampshire, England, McFall was a talented athlete with a flair for track and field. Sport was a huge part of his identity and he was competing at a national level in sprinting and hurdles as a teenager. He was also academically gifted, with plans to pursue higher education at the university level.
But at 19 a motorbike accident changed everything. He lost the lower half of his right leg. “It was difficult at times to pick myself up and change direction,” McFall recalls. “In the early days I didn’t know what I was capable of. I didn’t know what life as an amputee was going to be like. There was so much uncertainty.”
What he did know was that he couldn’t sit still. “For me it was a question of refocusing: what is it that I enjoy in life? Being busy. Physical exercise. Challenge.”
He flew parabolic flights, aircraft that simulate short bursts of weightlessness by flying in a steep arc, while performing CPR on a training mannequin. He travelled to SpaceX headquarters in California to test extravehicular activity procedures – the technical term for space walks, essentially – practising emergency drills with and without his prosthesis
McFall got back on a mountain bike. He taught himself to run again. He tried surfing, hiking and even snowboarding. Slowly, a new vision of himself began to form. “I realised my disability didn’t matter that much. I was still getting what I wanted out of life.”
He went on to win bronze in the 100m sprint at the 2008 Beijing Paralympics. After retiring from athletics, he trained as a doctor, specialising in orthopaedics, a discipline where his own use of prosthetics gave him a unique insight.
The ESA Fly! feasibility study began in late 2022 and lasted two years. Its purpose was to assess whether someone such as McFall could carry out all the functions required for a six-month ISS mission. More than specific considerations were tested across five domains: astronaut training, spacecraft operations, ISS operations, medical scenarios and crew support.
“Can I perform cardiopulmonary resuscitation [CPR] in microgravity? Use the treadmill? Escape the capsule in an emergency?” McFall adds. “We didn’t know, so we tested everything.”
He flew parabolic flights, aircraft that simulate short bursts of weightlessness by flying in a steep arc, while performing CPR on a training mannequin. He travelled to SpaceX headquarters in California to test extravehicular activity procedures – the technical term for spacewalks, essentially – practising emergency drills with and without his prosthesis. Could he get in and out of the capsule in the required time? Did the suit fit? Would the prosthesis interfere with system interfaces?
“Can I use the strength training machine? The exercise bike?” McFall says. “Can I stabilise and move around inside the ISS? We looked at everything very systematically.”
The treadmill tests were part of a wider suite of parabolic flight experiments, simulating microgravity in short bursts. “For three days I ran for 22 seconds, 30 times per flight with different set-ups of the treadmill and my prosthesis,” McFall adds. “It wasn’t just to show I could run, it was to optimise the hardware I’d need in space.”
By end of 2024, the results were clear. The ESA found no medical or technical barriers to McFall’s completion of a long-duration ISS mission. His performance was submitted to the Multilateral Space Medicine Board, a panel of flight surgeons and medical experts from international space agencies, responsible for certifying astronaut health and readiness. The board granted McFall the highest level of medical clearance. This was a world first for someone with a lower-limb amputation.
One term continued to trouble him: “para-astronaut”. The ESA had introduced the label as a practical way to define a role that hadn’t existed before. But now that he has met every benchmark required of a standard astronaut, McFall questions whether the qualifier should still apply.
“Why am I a para-astronaut? I’m not a para-surgeon. I’m just a surgeon,” he says. “It’s catchy, maybe. But I’m not sure it’s necessary.”
He recognises the importance of initiating conversations. “You’ve just got to nudge people’s perceptions a little. Get on their radar and say: ‘I’m a normal guy too’.” However, he also sees the danger of labels becoming invisible fences, boundaries that may persist even after the barriers are removed.
McFall hopes for a future where astronaut candidates are evaluated on their capability, not assumptions.
He is now in the ESA’s “Fly! Mission ready” phase, having met every benchmark in the feasibility study. He officially sits among ESA’s newest astronaut class, awaiting a potential assignment, something which is already shifting conversations within the ESA and beyond.
Ask McFall why space matters and he doesn’t talk about rockets or milestones. He talks about wonder. “We know so little about the universe. For me, I’d be hugely proud to be just a tiny part of that.”
McFall’s story is not just about exploration. It’s also about equity.
By proving a lower-limb amputee can meet the same standards as any other astronaut, McFall has helped expand the horizon of who can imagine themselves in space, and who might one day get to go.
“I’ve never let my disability define me,” he says. “I’ve always tried to focus on what I can do and what’s possible.”
Space flight offers a rare opportunity to see Earth from above, known as the “overview effect”. Astronauts often describe it as a shift in perception: a sudden awareness that Earth is a tiny, fragile, living ball suspended in the vastness of space, shielded only by a paper-thin atmosphere. From orbit there are no borders, no divisions, only the imperative to protect our shared home.
For McFall that perceptual shift runs deeper still. His work challenges not only how we perceive the planet, but also how we perceive one another. His story isn’t just about changing perceptions: it’s about what we value, what we assume and how much more is possible when we challenge our perception of a boundary.
And perhaps one day soon John McFall will once again run on a treadmill in zero gravity, only this time it won’t be a test. It will be a mission.
