Mars: who will be able to fly to the red planet and what medical challenges await
Sarah Jane Pell dives with a spacesuit, in 2016 in Marseille, France, simulating lunar conditions. | Alexis Rosenfeld/Getty Images
In the future, Mars could become a home for humans, but we face the challenge of transforming the Red Planet into a habitable environment. However, one significant problem arises: most people cannot safely reach space, complicating plans for Mars colonization amidst global challenges such as climate change.
As of today, the pathway to becoming an astronaut is "lit with hopes and dreams of those who have not passed the medical selection," said Shona Pandya, an astronaut researcher at the International Institute of Aerospace Sciences (IIAS). "Once, children diagnosed with type 1 diabetes would hear from their doctor: 'Well, you can be anything you want, except an astronaut.'
Reasons for Medical Selection
Here are some of the most common reasons for selecting astronaut candidates medically:
- Smoking
- Autoimmune diseases
- Temporomandibular joint disorders (TMJ)
- Obstructive sleep apnea syndrome
- Asthma
- Hypertension
- Migraine
- Anxiety and depression
Astronauts typically do not represent the general population, as they are selected based on physical health. Life in microgravity on the International Space Station (ISS) is a significant stress for the human body, leading to risks of osteoporosis, insulin resistance, and muscle mass loss. Space agencies choose individuals with more resilient bodies who can perform tasks without significant medical interventions.
According to Haig Aintablian, director of UCLA's Space Medicine Program, "Just as pregnancy causes complex and unique changes in the body, space flight leads to distinct physiological changes." Specialized fields focused on space issues are already emerging in medical practice.
The Future of Mars Research
NASA aims for Mars exploration and plans to send people to the planet as early as the 2030s. Mars, being the planet most similar to Earth in the solar system, could one day support life.
A few decades ago, discussions about colonizing Mars were considered extreme for several reasons, including insufficient technical preparedness and the desire to allocate scientific resources to solving problems on Earth. However, Elon Musk, founder of SpaceX, has been a proponent of Mars colonization since the early 2000s and continues these plans, asserting that he wants to build a city on Mars with one million people by 2050.
Now Musk is not alone in his ambitions. NASA experts, biologists, academics, and doctors are seriously considering the possibility of transforming humanity into an interplanetary species.
“The biggest problem humanity needs to solve is the guaranteed survival of our species, which is a logical response to becoming interplanetary,” Aintablian said. “I don’t think there’s a better option than Mars.”
While we have some understanding of health effects associated with staying on the ISS, we cannot precisely replicate the effects of radiation exposure on Mars. Kelly Weinersmith, a biologist and co-author of the book A City on Mars: Can We Settle Space, Should We Settle Space, and Have We Really Thought This Through, believes that Musk's vision of Mars colonization could lead to catastrophe.
However, many advocates for Mars colonization are showing impatience. The only safe path to get there is through significant advancements in space medicine, which has only been developing over the past 75 years.
“Nothing humanity has done that was worthwhile has been easy,” Aintablian told me. “Much of our development as a civilization has been difficult, and the reason we can live so comfortably now is due to incredibly hard challenges that humanity had to solve in the past.”
Human Health Knowledge on Mars
Since very few people go into space, researchers studying how to improve health in space have a limited sample for research. Yuri Gagarin became the first human in space in 1961, and over 600 astronauts have followed him.
NASA researchers have identified several key ways in which Time in space can affect human health - radiation exposure, isolation, distance from Earth, altered gravity, and environmental impacts, such as immune system disruption. But we still lack many specific examples of how these factors affect reality.
One of the most significant studies is NASA's twin study conducted in 2019. The twin study allows researchers to separate the effects of genetic predispositions from environmental factors on health outcomes. NASA compared the health of identical twins Scott and Mark Kelly over the course of a year. Scott was in orbit on the ISS, while Mark remained on Earth.
The study found some new sudden differences between the two men. Scott's telomeres, parts of DNA at the ends of our chromosomes, elongated in space and (for the most part) returned to normal after returning to Earth, which may indicate DNA damage due to radiation and a possible increased cancer risk. Scott also lost body mass, exhibited cardiovascular signs that Mark did not experience, and felt transient cognitive changes after returning to Earth.
If the best of the best face challenges, what can be said of the rest of us? We are gradually gaining some insights in this area. With the development of space tourism, astronauts are no longer the only people traveling to space: wealthy non-astronauts like Jeff Bezos and Katy Perry recently made short trips to space through Bezos's Blue Origin space company.
Aintablian is very interested in the prospect that access to space for civilians will increase, which will also mean that people with medical issues will also be able to travel. This is a huge opportunity for scientists to study medical management for a wider range of diseases.
However, 10 or 15 minutes in space is absolutely not comparable to conditions on the ISS. As Mars presents even more dangerous conditions, the time spent far from Earth can have serious consequences. Mars has toxic dust, a lack of vegetation and breathable atmosphere, and gravity is only 40% of Earth's. Earth's global magnetic field protects our planet from harmful radiation, while on Mars it is localized rather than planetary.
NASA's research has shown that the maximum time a person has spent in space continuously is 438 days. But missions with people on Mars will likely take at least nine months just to get to the planet, let alone the time spent on it or returning (which could take up to three years). Mars is usually about 140 million miles from Earth, based on its orbital path around the Sun, with up to a 20-minute communication delay one way. If a medical emergency occurs, astronauts will likely not be able to receive timely telemedicine instructions because there will be no opportunity to turn back for treatment.
Expeditions to Mars will have to take all their supplies with them before leaving Earth. And when the first people take their first step on this planet, they will not receive the same intensive assistance that astronauts receive upon returning to Earth.
New Horizons in Medicine
Reaching Mars is only part of the challenge. We have already reached space, but humanity on this planet is just beginning to explore limitless possibilities. Ongoing research is based on educated assumptions about what the Martian environment is like.
As space medicine develops, new programs are beginning to emerge, determining ways to transport people into space as safely as possible for extended periods, with unqualified medical personnel also involved. UCLA plans to launch a space nursing program and possibly training for space paramedics. SpaceMed is a European master's program focused on human health in space flight and other extreme conditions.
Today, astronauts receive most of their medical services from ground medics known as field surgeons through telemedicine. Aintablian predicts that in the future, medical professionals will accompany astronauts on their expeditions, such as to the Moon or Mars. Artificial intelligence should serve as a resource for field surgeons and help develop other technologies that will bring us closer to Mars.
Technologies are already in development. Google recently collaborated with NASA to create an AI system that could help astronauts diagnose and treat medical conditions arising during flights when there is no access to telemedicine.
However, details play a crucial role, noted Pandya. AI can assist with emergencies and diagnostics, but the necessary data will be enormous. Since very few people travel to space — and mostly it’s men — models may rely on a non-representative sample, which could lead to inaccurate predictions of physiological changes in space. These nuances need to be accounted for.
Currently, there is a gender gap in research - so significant that Weinersmith noted that there is never a line for the women's restroom at space colonization conferences. Human reproduction and development in space are, therefore, critically under-researched.
To date, it is unknown whether any person has ever been in space during pregnancy or whether there are people conceived in space. Research on the first space pregnancy and birth will be crucial for establishing a self-sufficient colony on Mars. (Additionally, space tourism companies plan to build hotels in space, and we know that people engage in such activities there.) Ideally, we would like to know what happens to a person giving birth in space before they encounter it.
“We aim to conduct research to understand these risks before we go there, because if there are enormous risks, there are usually technological solutions for some of them,” Weinersmith said.
NASA will launch a second Crew Health and Performance Exploration Analog experiment this October — a year-long "mission" to Mars in a 3D-printed environment at the Johnson Space Center in Houston, where data on psychological health and the effects of isolation and constraints will be collected. Scientists are conducting bed rest studies that model the physiological effects of altered gravity and weightlessness. In the context of reduced funding, space medical researchers advocate for continued investment in space and biomedical sciences.
Madeh Mozneb, a biomedical engineer and research fellow at Sharma's lab at Cedars-Sinai Medical Center, noted that the ultimate goal is to send "avatars" of astronauts into space, using their stem cells to create 3D tissue cultures that represent different parts of their bodies.
The hope of many space medicine doctors, such as Pandya, is that in the future, space expeditions will include all medical specialties — from neurology to radiology.
Mars and Earth
Research in space medicine is not cheap. “I often get asked: why are you spending money on space health when there are countless problems on Earth?” Pandya says. But thinking this way is incorrect, she points out.
Research conducted in space has already improved health on Earth. Achievements in digital imaging, made during the Apollo 17 mission in 1972, later became crucial for the development of CT and MRI. Remote health monitoring tools developed for astronauts in space are now widely used in hospitals.
Research in space medicine will also enable more people to travel to space. In 2023, Pandya's team demonstrated the safety and functionality of a continuous glucose monitor in a space environment, which could ultimately allow diabetics to check their sugar levels in space. This matters for current astronauts who may develop insulin resistance and prediabetes symptoms during prolonged flights in space.
A child diagnosed with type 1 diabetes who dreams of becoming an astronaut now has a chance to realize their dream, and studying how the body metabolizes glucose in space helps to better understand health on Earth.
There are also diseases that develop over decades. Muscle loss in space can help scientists better understand how to treat conditions like Duchenne muscular dystrophy. Neurological diseases like Alzheimer's on Earth typically do not become apparent until a person is 60 years old.
