No doubt you have heard of the forays by private companies like SpaceX and Axiom Space into orbits previously only traversed by government-funded entities such as NASA. Dr. Michael Harrison, an ABPM diplomate certified in Aerospace Medicine, has extensive experience supporting commercial spaceflight crews, and is optimistic about the expanded exploration and innovation that commercial spaceflight promises.

No doubt you have heard of the forays by private companies like SpaceX and Axiom Space into orbits previously only traversed by government-funded entities such as NASA. Dr. Michael Harrison, an ABPM diplomate certified in Aerospace Medicine, has extensive experience supporting commercial spaceflight crews, and is optimistic about the expanded exploration and innovation that commercial spaceflight promises.

Dr. Harrison’s journey to the specialty of Aerospace Medicine “has been long, at times unusual or surprising, and always rewarding.” His career in medicine began with an interest in exercise physiology, in which he earned a Master’s degree and a PhD. “My interest and training in exercise physiology exposed me to what would become my career passion and theme through my experiences – human physiology and performance in extreme environments,” he says. As an instrument-rated pilot and a NITROX-certified rescue diver, he became “fascinated with how changes in temperature, humidity, and other environmental stresses can have big impacts on the expected physiological response and, as a result, have an effect upon performance. More importantly, I was fascinated with how a properly trained professional could mitigate these stresses and the associated challenges.”

He went on to medical school, becoming an emergency and critical care physician, and eventually completing Aerospace Medicine training. “Through more training and personal experience in flight and high-altitude environments, hyperbaric and diving activities, and a medical career in high-acuity clinical settings that eventually led to supporting numerous commercial spaceflight missions across multiple companies, I have been rewarded with a challenging and exciting career path. No two days are alike – there are many days where I am in awe of the people I meet and work with and incredulous that I get paid to do what I do.”

Dr. Harrison has had the unique opportunity to care for astronauts – preparing them before their trip to space, ensuring their safety during their mission, and monitoring their health upon their return to Earth. He served as Axiom Space Chief Medical Officer, where he was responsible for ensuring the health and safety of crew and passengers aboard spaceflight missions, including that of the four Axiom Mission 3 crew members traveling to the International Space Station earlier this year. His involvement in commercial space flight began in 2020 when he took a position as flight surgeon at SpaceX; he has also supported Virgin Galactic spaceflight missions. He is currently an Aerospace Medicine physician at Mayo Clinic.

Commercial space companies expand the possibility of space travel to groups of people to whom space travel was previously inaccessible. This population includes older individuals, people with chronic health conditions, and others who wouldn’t qualify as a traditional astronaut for medical reasons. As Dr. Harrison says, “The dawn of the commercial space era has opened doors for a broader spectrum of astronauts that do not fit the conventional model developed by NASA, the Canadian Space Agency, and the other governmental space agencies. The question used to be ‘How healthy do you have to be to go to space?’ This is somewhat misleading – professional astronauts are human beings and develop medical conditions over the course of their career. These conditions are evaluated, treated, and managed. The associated risk is also quantified and mitigated such that they can continue to fly missions to space. And, more often than not, they do continue to fly. Commercial space[flight] will expand the scope of this established practice – we will soon see astronauts with diabetes, a history of limb amputations, sensory deficits such as color vision deficiency, fly to space. The primary duty of the commercial space flight surgeon is to make sure the question becomes ‘How sick can you be and still go to space safely?’”

Dr. Harrison affirms the preventive aspects of Aerospace Medicine training are critical to ensure the safety of the growing number of people who now can travel to space. “Aerospace Medicine is boarded under the American Board of Preventive Medicine for exactly this reason,” he says. “The vast majority of the medical management and risk mitigation should be completed before an astronaut ever enters a spacesuit on launch day. Planning for the management of an in-flight medical contingency becomes a secondary process with a smaller chance of occurring if the efforts put into those first steps before launch are effective.” While Aerospace Medicine specialists are trained to handle in-flight medical issues, their goal is to prevent such occurrences in the first place – which they have done with much success – aligning the specialty with the core principles of preventive medicine.

Astronauts’ physical health is important, but Dr. Harrison notes that their behavioral health, including both psychiatric and psychological considerations, is also key to a successful mission. “The psychiatric component is evaluated against a set of predefined medical standards and is associated with diagnoses – major depression, bipolar schizophrenia, for example,” Dr. Harrison explains. “These diagnoses can require pharmaceutical treatment and they are often disqualifying; hopefully someday programs such as the FAA’s HIMS program will provide a basis by which commercial customers with psychiatric diagnoses can fly to space but there is work to be done still towards that goal.”

Flight surgeons play a vital role helping astronauts handle the psychological issues specific to space flight. Dr. Harrison explains that the psychological component “captures behaviors that influence crew dynamics, stress management, and other coping strategies. These are non-diagnostic elements of personality and individual quirks.” Anyone living with a roommate can likely relate – although in spaceflight, there is no escape from the idiosyncrasies of a fellow astronaut. Beyond the stress that can arise from spending extended amounts of time in a confined space with crew mates, Dr. Harrison notes, “Spaceflight presents an underappreciated psychological risk in an environment that can amplify stressors – you cannot go outside and feel fresh air on your skin, your food may taste different, your family and loved ones who are still on Earth may get sick, you might miss a milestone in the lives of your children, your mission may get extended, your research payload experiment may not work perfectly, you may not sleep well, etc.”

Despite challenges, commercial spaceflight offers exciting opportunities. For example, the lessons gleaned from caring for crew or passengers can have practical applications for caring for patients on Earth. “As commercial space expands the breadth and scope of novel medical conditions that can be supported for an orbital spaceflight mission, the benefits will most definitely translate to terrestrial populations and uses,” Dr. Harrison says. “The act of passively monitoring a crew member who might have a suddenly incapacitating medical event and providing actionable data to the terrestrial flight surgeon and flight control team who are supporting the mission on console translates to numerous conditions. For example, the capability of detecting a seizure in an astronaut sleeping in their berth and waking up other crewmembers to provide medical care may provide technologies and capabilities to allow older adults to continue to live safely in their own homes instead of transitioning to an assisted living environment. Or, the ability to detect an early change in health status in a crewmember with diabetes or other chronic medical conditions may influence a clinical action that saves a spaceflight mission; on Earth, that same information may prevent a hospitalization or a transfer to an intensive care unit.” The Earthly application of commercial spaceflight lessons, and medical and scientific advancements that result from space research, are “truly limitless,” says. Dr. Harrison.

Dr. Harrison affirms that Aerospace Medicine specialists are uniquely qualified to lead the care of those traveling to space – both astronauts and commercial space passengers. “Formal training in Aerospace Medicine at an accredited program should not be treated as a luxury or a ‘nice to have’ for any medical practitioner who is offering services to support human spaceflight,” he says. “The saying ‘you don’t know what you don’t know’ applies to this field just as it applies to any other field of medicine.”

While other specialists contribute as part of the team providing medical care to spaceflight crews, Aerospace Medicine specialists alone have the full spectrum of knowledge, training, and skills to provide comprehensive care. Efforts by physicians to assume the role of an Aerospace Medicine specialist without completing accredited training culminating in board certification in the specialty are “professionally inappropriate… The field of medicine has a long-standing duty to do no harm to our patients and the commercial space industry has a duty to ensure its customers are not being misled or exposed to any additional medical risk at any point along the course of the mission.”

Commitment to this duty has driven Aerospace Medicine specialists to successfully mitigate medical risks since the inception of space travel. “There is a publicly available list – if you know where to look – that summarizes the medical conditions that have flown to space in NASA astronauts. This list includes cardiac conditions such as arrhythmias, ophthalmological conditions such as retinal detachment, cerebrovascular events such as strokes. Despite all of these serious medical conditions, NASA is able to boast that they have never had to bring a crew home early due to a medical emergency,” Dr. Harrison notes. “Significant chronic health conditions can be managed and optimized to support crewmembers who are going to space for long-duration missions and this is a direct result of the skill, knowledge, and expertise of the Aerospace Medicine specialists who have supported spaceflight missions since the beginning with the Mercury missions. As the flight surgeons supporting commercial spaceflight missions, we have an even greater challenge in front of us – we cannot down-select to a handful of customers out of a pool of thousands and expect our companies and industry to be profitable. We also cannot expose customers to undue risk and expect the same success across the industry. We must be held accountable and practice within our scope. Board certification in Aerospace Medicine remains the gold standard in supporting the goals of expanding human spaceflight to all.”

This statement underpins Dr. Harrison’s advice to physicians and medical students who would like to pursue a career in Aerospace Medicine. He says, “One of my mentors in Aerospace Medicine was fond of saying, ‘careers are long.’ What they meant by this piece of sage advice was that our training in the early stages of our careers as physicians forms the basis for the rest of the career. A broad foundation – taught by experts and experienced practitioners in the field to meet the milestones and standards of a nationally recognized accreditation body – should not be sacrificed for anything if the ultimate goal is a long career in the field that does not have a self-imposed ceiling,” he says. “Board certification opens many doors and does not close any. If something is worth doing, it is worth doing right and this is true for any medical field. I would urge trainees to be looking at and considering the big picture of their career and the needs of their patients rather than being lured by an easier path.”

Aerospace Medicine physicians have a tall order: Dr. Harrison describes their practice as “sitting on a trap door. We send humans to a very austere and inhospitable environment and, with commercial spaceflight, we are doing so with increasing frequency.”

However, when Aerospace Medicine is done right, by qualified and well-trained specialists, the rewards are astronomical. “Optimal medical management, from a preventive health perspective, is what keeps that trap door from swinging open. If we do our jobs well with our entire team – crewmembers, systems engineers, medical team members, etc. – we will reduce the risk of having that sudden surprise of the floor falling out from beneath us in the form of a medical emergency,” Dr. Harrison says. “The reward will be supporting a crew that has gone to space to perform the next steps in research that may cure cancer, grow food in a novel manner, or provide other benefits to humanity at large over the course of their mission and then welcoming them back home safely at its completion.”

Dr. Harrison is optimistic about the future of commercial spaceflight and the boundless opportunities it provides. “Have fun. Be creative. Think critically,” he advises. “This is a new page in the human history book and there are numerous stories within the commercial space industry where novel solutions to old problems have been identified and employed. Many of them – like a lot of good ideas – are elegant in their simplicity and leave one amazed that we hadn’t thought of it sooner. We are paving the way for future generations to fly to space with the same casual frequency that we board commercial planes to go on vacation. I have three children that I would very much like to see have experiences … that are the result of the work we are doing now in supporting commercial spaceflight.”