A journey to Mars, or space in general, presents an inexhaustible list of complexities and hazards that could endanger both the mission and the astronauts on board. As humans set their sights on Mars and the narrative of colonising it shifted from fiction to fact, NASA established the Human Research Program (HRP). The HRP takes a stepping-stone approach to studying the health effects of human spaceflight, using Earth-based analogues, experiments on the International Space Station, and lunar missions under the agency’s Artemis program (a program designed to take humans back to the moon).

The purpose of this programme is to ensure that space exploration is safe and to better understand the impacts that extended periods of time in space and on different planets might have. The Hazards of space exploration are diverse and the list is, in a way, inexhaustible. However, research being done to understand these risks and develop countermeasures is important if we are to make it all the way to Mars. Imagine it: humans walking the red planet. How exciting!

NASA’s Human Research Program conducts research and develops countermeasures for the major risks attributed to the exploration of Mars and spaceflight more generally. The hazards astronauts will encounter have been classified into five major categories, which are outlined below. Pooling the challenges faced by astronauts allows for an organised effort to understand and overcome these obstacles. It is important to acknowledge that these hazards do not exist in isolation. Rather, they feed off one another and exacerbate the effects on the human body and mind. By understanding these risks more clearly, collecting data, and developing new technologies and methods, NASA can accumulate knowledge that will apply to multi-year interplanetary missions. The five major risk categories are:

Radiation:

The first hazard of human missions to Mars is the most difficult to visualise because it is invisible to the human eye. Radiation is considered to be the most menacing of the five hazards and has the potential to cause the most damage. To better understand the impacts of radiation, NASA teamed up with the U.S. Department of Energy to unpack the effects of cosmic radiation on the human body. The results showed that without Earth’s natural protection, radiation exposure increases the risk of cancer, damages the central nervous system, and can impact both the cognitive and motor functions of astronauts. To mitigate this risk, deep space vehicles will have significant protective shielding, and research is being done into medical countermeasures such as pharmaceuticals to help defend against radiation.

Isolation and confinement:

Behavioral issues among groups of people stuck in a small space over a long period of time will be inevitable. This is one of the challenges a group of astronauts will undoubtedly face on a multi-year mission to Mars. While crews will be carefully chosen and trained, it will be important to equip these explorers with strategies to work together for months or years. While on Earth, we are able to maintain important human connections or escape difficult situations. However, on a trip to Mars, astronauts will be isolated from their families, friends and confined in smaller spaces than we can imagine. These issues will be compounded by sleep loss and work overload, and may have adverse health outcomes, compromising the mission to Mars. Various studies have been conducted to understand the effects of isolation on human behaviour, and these learnings will be used to develop techniques and tactics to maintain – well – sanity.

Distance from Earth:

The third major obstacle for astronauts on a mission to Mars is the distance away from Earth. Mars is more or less 140 million miles (240 000 000 km) away from Earth. In comparison to a three-day trip to the moon, astronauts going to Mars will embark on a six-month trip and three-year stay on the red planet. The consequence of this is that it is a logistical feat, more so than the logistics of the F1, Global summits or trips to the international space station. Space station expeditions have the benefit of being close enough for supplies to be restocked, or, where there is a medical emergency, an astronaut can return to Earth for assistance. These options are not available for Mars exploration. Once the engines for Mars are burned, there is no turning back and no way to resupply the mission. Enabling astronauts to be self-sufficient through extensive planning is essential for a successful Mars mission. Further, astronauts will face a 20-minute communication delay one way, which means they would have to confront emergencies without support from their team on Earth. Talk about loneliness!

Lack of gravity:

The fourth major hazard astronauts will experience is the variance in gravity. On Mars, astronauts will live and work in threeeighths of Earth’s gravitational pull for two to three years. Further, on the six-month trip to Mars from Earth, astronauts will be completely weightless. When astronauts do finally return to Earth, they will need to readjust many of the systems in their bodies to Earth’s gravity. Bones, muscles, and cardiovascular systems will all have been impacted by years without standard gravity. Currently, research is being conducted to ensure that astronauts stay healthy before, during, and after their mission to Mars. NASA has successfully identified how current and future, FDA-approved osteoporosis treatments, and the optimal timing for such therapies, could be employed to mitigate the risk of astronauts developing premature osteoporosis. Further, adaptability programs are being studied in order to mitigate balance control issues. Research is ongoing to develop optimal exercise prescriptions for astronauts, as well as understand the impact on metabolic functions.

Hostile/closed environments:

The vehicle astronauts will spend a lot of their time in is an ecosystem that will play a big role in the astronauts’ everyday life while traveling to and living on Mars. Important habitability factors include temperature, pressure, lighting, noise and quantity of space. It is also essential that astronauts get the requisite food, sleep, and exercise needed to stay healthy and happy. Technology will play an important role in creating a habitable environment for these explorers. Everything in the spacecraft will be monitored from air quality to possible microbial inhabitants. Microorganisms that naturally live on our bodies will be transferred more easily from one person to another in closed environments, so it is important to monitor and understand their impact in space. Astronauts will be prompted regularly to give feedback on their environment, supply urine samples, and communicate possible stressors.

It is clear that there are many, interconnected, hazards associated with traveling to Mars and for space exploration more generally. Luckily, however, there has been a concerted effort to understand these risks, categorise them into groups for further research and resources have been deployed to understand and develop possible solutions to enable travel to Mars. Stick around for further deep dives into the research being done on each of the five hazards explored above.