The road behind me is long. It's a journey measured in G-forces, orbital laps, and the slow, quiet hum of life support systems. When I look back, I see a career that was built on a foundation of rigorous training, countless hours in simulators, and the breathtaking privilege of living and working in space. I see the face of our home planet, the magnificent sight of a sunrise from orbit, and the countless small moments of human connection with my crewmates.
But today, I find myself thinking less about the road behind me and more about the road ahead. My time as an active astronaut, flying missions and living on the International Space Station, was an incredible chapter. But I’ve come to realise that my true work is now. It's using every lesson, every experience, and every bit of knowledge I’ve gained to help lay the groundwork for the most ambitious journeys humanity has ever conceived: missions to the Moon and, eventually, to Mars.
My career was, in many ways, an apprenticeship for the future. I was part of the generation that learned how to truly live in space. The International Space Station (ISS) wasn’t just a floating laboratory; it was a school. It was a prototype for a permanent human presence in the cosmos. Every day we spent up there was a lesson, and every challenge we faced was a data point.
We learned firsthand about human physiology in a microgravity environment. We learned how to combat the rapid loss of bone density and muscle mass, and we discovered the strange effects of long-term weightlessness on our eyes and our internal systems. These weren't just medical observations; they were the blueprints for the exercise equipment and countermeasures that would be built into future spacecraft. We proved that with the right tools and the right discipline, the human body is more adaptable and resilient than we ever imagined.
We also learned profound lessons in psychology and teamwork. On a multi-month mission, with no privacy and no escape from your crewmates, a crew’s ability to work together is just as important as the spacecraft's ability to fly. We learned how to manage conflicts, how to maintain morale, and how to find a sense of community in a place that is fundamentally isolating. This knowledge is priceless for a future Mars crew, who will be completely isolated for years, with a communication delay that makes a real-time conversation with Earth impossible.
Our experiences on the ISS taught us the importance of self-sufficiency. We were constantly maintaining and repairing the station, from fixing pumps to troubleshooting computer systems. We learned to be our own mechanics, electricians, and plumbers. This is a crucial skill for future explorers. A mission to Mars can't rely on resupply missions from Earth. The crew will have to be able to fix anything and everything that breaks, a lesson we learned the hard way—and the right way—on the ISS.
All of these lessons form the bedrock for what comes next. The next giant leap for humanity will be a return to the Moon, and it's not a simple repeat of the Apollo missions. The Artemis program is different. This time, we're going back to stay.
The Moon presents a unique set of challenges that are both similar to and different from those we faced on the ISS. Instead of weightlessness, we will have partial gravity—one-sixth of what we feel on Earth. We don't fully understand what a long-term presence in a partial-gravity environment will do to the human body. We'll have to develop new suits and new rovers designed to operate in this new environment. Then there's the lunar surface itself. The fine, abrasive lunar dust, known as regolith, is a major concern. It's incredibly sharp and sticky, and it can damage equipment, get into living spaces, and even cause health issues. We’re working on solutions to this now, using my own astronaut experiences and those of my colleagues to inform the designs of new airlocks and habitats.
But the Moon isn't the final destination; it's the next proving ground. It's where we will refine the technologies and procedures we need for the ultimate goal: a human spaceflight to Mars.
A mission to Mars is a different animal altogether. It’s not a trip; it’s a journey that will take years. A round trip could take up to 30 months. The sheer length of the mission introduces unprecedented challenges. For a Mars crew, the isolation will be absolute. There will be no quick ride home. The communication delay will be significant, up to 20 minutes one way. This means that a Mars crew will have to be empowered to make their own decisions in a crisis. There will be no calling up Mission Control for a quick consultation. My experience on the ISS taught me how to lead and manage a crew under pressure, but a Mars mission will require a level of autonomy that is truly a first for humanity.
Then there's the danger of radiation. Outside of Earth's protective magnetic field and the ISS's orbit, astronauts will be exposed to a constant barrage of galactic cosmic rays. We are studying this extensively now, designing new shields and exploring propulsion technologies that could shorten the transit time.
My ongoing contributions to the future of space exploration aren’t about flying anymore. They're about advising the engineers, the scientists, and the program managers who are designing the next generation of spacecraft and habitats. I sit in meetings and offer a unique perspective: "What is it really like to live there? What does a crew truly need to survive and thrive?" I can tell them that a simple, sturdy handle is sometimes more important than a complex piece of technology. I can remind them that a crew's psychological health is just as critical as the air they breathe.
I also spend a great deal of my time on STEM education, travelling the country and the world to talk to young people. I tell them my story, not as a fairy tale, but as a roadmap. I explain that the next great innovations won't come from a lab at NASA, but from the classrooms where they are learning today. The solutions to the problems of lunar dust, radiation, and Mars habitation will be discovered by the kids who are currently obsessed with video games, robotics, and biology. The future of space colonisation is in their hands.
Looking out at the stars, I don’t see an end to my career. I see a new beginning. I see the Moon and Mars, not as distant, abstract places, but as future homes, future outposts for humanity. My journey to space was a culmination of a lifetime of work, but it was also a single step. The real future of space exploration is a multi-generational project, a collective human effort that will take us to new worlds. It's a journey that began with my generation, but it will be completed by the next. And my most important role now is to help them take the first step.