Copyright Interesting Engineering
The human body was never designed for space travel. On Earth, we rely on gravity to shape our bones, an atmosphere to shield us from radiation, and a planet full of living systems that sustain us. Take those away, and survival becomes a daily struggle. Yet, that’s exactly what humanity is preparing to attempt with a multi-year journey to Mars, where evacuation is impossible, communication is slow, and help from Earth is not weeks but months away. Health in space isn’t just about staying fit. It’s about finding ways to maintain stability in the body, mind, and environment in a place that naturally lacks these qualities. The International Space Station (ISS) has served as a test bed for two decades, orbiting approximately 400 kilometers above Earth. But Mars lies about 225 million kilometers away. A distance that turns every routine medical, psychological, and logistical challenge into a formidable one. In one of our previous articles, we examined how space dismantles the human body. Shrinking hearts, dissolving bones, and rewriting DNA. This continuation shifts from damage to endurance, exploring how we prepare to sustain human life through years of radiation, isolation, and the long silence between worlds. A one-way challenge A trip to Mars with current technology would take approximately seven to nine months each way, and the mission as a whole could last up to three years. Unlike the ISS, where astronauts can return to Earth within hours, there will be no emergency exits on a Mars journey. Every crew member must be prepared to live, work, and survive with no immediate support from Earth. Astronauts are already trained to handle every system aboard their spacecraft, from navigation and repairs to life support. But the medical aspect of training is comparatively small. They may have to handle medical emergencies with minimal practice and a long period between their lessons and actual use. The risks range from ordinary illnesses, such as appendicitis or infections, to conditions that have never been experienced before in space. NASA and other agencies are testing systems that combine telemedicine, AI assistance, and portable surgical tools, giving astronauts a digital doctor aboard the spacecraft. Still, surgery remains a last resort. Every decision about what to bring, whether a robot surgeon, extra food, or more radiation shielding, involves trade-offs. Resources are limited, and so are the margins for error. The psychological frontier Even if the body can endure space, the mind may falter. A Mars mission will push human psychology to limits never tested before. Life inside a confined capsule for years means isolation, monotony, and complete dependence on the same small crew. There will be no real-time communication with Earth, no fresh air, and no way to step outside except into a lethal void. On the ISS, astronauts already report stress, disrupted sleep, and mood changes during six-month missions. Multiply that by six, add total isolation, and the challenge becomes clear. Studies simulating Mars missions on Earth, including one that locked volunteers inside a mock spacecraft for over 500 days, revealed sleep issues, emotional instability, and breakdowns in communication. Experts believe success will depend as much on psychology as on technology. Structured routines, clear leadership, and strong interpersonal relationships will be essential. Virtual reality environments are being explored to combat sensory monotony, allowing astronauts to walk through forests or beaches from inside the spacecraft. Music, literature, and creative outlets could serve as powerful tools to maintain morale. In deep space, sanity will be as important as oxygen. The invisible threat Beyond isolation, astronauts must face a far more insidious danger. Cosmic radiation. On Earth, our atmosphere and magnetic field deflect most high-energy particles from the Sun and beyond. In deep space, those protections are no longer effective. Astronauts will be exposed to galactic cosmic rays and solar particles that can slice through tissue, damage DNA, and increase the risk of cancer, heart disease, and neurological disorders. Some astronauts on past missions have even reported seeing flashes of light when their eyes were closed. Radiation passes directly through their retinas. Over the course of a Mars mission, the accumulated exposure could equal thousands of chest X-rays. Engineers are experimenting with various shielding methods. Thicker spacecraft walls lined with hydrogen-rich materials, water tanks placed around crew quarters, and even artificial magnetic fields that mimic Earth’s natural barrier. However, heavy shielding adds weight, which limits the spacecraft’s range and speed. Balancing protection and practicality remains one of the most challenging engineering problems in spaceflight. Food remains the most urgent problem Of all the survival challenges, nutrition may be the most immediate. On the ISS, astronauts receive regular resupply missions carrying fresh fruits and vegetables. On a Mars mission, there will be no resupply for years. Prepackaged food can only last for a limited time, and essential vitamins can degrade over time. Without a reliable source of fresh nutrition, even simple deficiencies could jeopardize the mission. That’s why space agencies consider food production in space to be among their top priorities. The first step was achieved in 2015, when astronauts successfully grew and ate lettuce aboard the ISS. Future missions could take that concept further with compact greenhouses capable of producing vegetables, fruits, and algae-based proteins. These closed-loop ecosystems would recycle air, water, and waste to feed the plants, and in turn, the astronauts. Beyond sustenance, caring for plants also offers psychological comfort. In a sterile, metallic spacecraft, tending to something alive can provide a powerful connection to Earth. Recycling life Nothing can go to waste on a Mars mission. The ISS is capable of recycling up to 98% of its water from sources such as sweat, breath, and even urine, converting it back into clean drinking water. The same process also generates oxygen by splitting water into hydrogen and oxygen, the latter of which is used for breathing. Solid waste is compacted and burned up in reentry vehicles, but future systems will have to go further, converting every output into a usable input. For a three-year Mars journey, life-support systems must be nearly perfect. Engineers are testing ways to reclaim nearly everything the crew produces, including air, water, food, and even energy. Some spacecraft concepts even revisit the idea of artificial gravity, using rotation to simulate gravity through centrifugal force. This could help prevent muscle atrophy and bone loss, two major issues that occur during prolonged stays in microgravity. Lessons from Earth’s extreme environments The closest analogs to space missions can be found here on Earth, in places where isolation, confinement, and extreme environmental conditions push human endurance. Antarctic research bases, for instance, operate for months without resupply or sunlight, mirroring the isolation of deep space. Undersea laboratories and submarines offer similar parallels, where small crews live in closed systems cut off from the outside world. These environments teach valuable lessons about leadership, teamwork, and mental resilience. Not everyone adapts well to monotony or confinement. Careful psychological screening and compatibility testing will be essential to building crews that can withstand years of isolation together. Engineering the future human As the limits of technology are reached, scientists are exploring how biology itself might adapt. One emerging field focuses on engineering microbes that can reside within the human body and produce medicines on demand, thereby reducing the need to carry large quantities of medication. Another explores nanomedicine. Microscopic machines that could detect disease, repair tissues, and monitor astronaut health in real time. Perhaps the most radical concept is cryosleep. Slowing metabolism so astronauts can “hibernate” during long voyages. This would reduce the need for food, oxygen, and mental stimulation, while minimizing the psychological strain of years in transit. Yet another solution may bypass biology altogether. Speed. Advanced propulsion systems, such as nuclear thermal or plasma engines, could reduce the travel time to Mars from nine months to as little as two or three. A faster journey would automatically reduce exposure to radiation, muscle loss, and isolation. In space, speed is survival. Why Mars matters Every challenge faced on the way to Mars, recycling air and water, producing food in closed systems, and managing mental health mirrors problems we face on Earth. Technologies developed for space could help sustain life on a warming, resource-scarce planet. Space farming could improve food security, water recycling could revolutionize conservation, and psychological research could benefit people coping with isolation here at home. While visions of colonizing Mars often dominate the headlines, the true purpose of this endeavor may not be escape, but understanding. In learning how to survive away from Earth, humanity is rediscovering what it truly takes to live on it.
