Introduction
Traveling to Mars may sound like an exciting adventure. However, in reality, this journey is a test of survival for the human body. NASA reports that as astronauts leave Earth's magnetic field, they are subjected to a continuous barrage of cosmic radiation. In addition to weakening the immune system and raising the risk of cancer, this radiation damages DNA and may have an impact on the brain system. Besides, spending a month in a zero-gravity environment results in a considerable loss of bone and muscle mass.
"Every journey to Mars is not only a technological (transportation and life support) but also a biological engineering (adaptation to radiation, lower gravity, and a harsh environment) problem," is how NASA characterizes these difficulties. In other words, we need durable bodies, in addition to strong rockets, to reach Mars.
Survivors of the Impossible
Humans are not the only species that struggle to survive in space. Microscopic animals known as tardigrades (water bears) can survive in the most extreme environments, including high pressure, vacuum, temperatures ranging from -200 °C to 150 °C, and even cosmic radiation. According to a 2007 experiment conducted by the European Space Agency (ESA), tardigrades may endure brief exposure to the radiation and vacuum of space (Jönsson et al., Current Biology, 2008). Special proteins that protect DNA, including the DSup protein, (DSup is a DNA-binding protein produced by tardigrades that protects DNA against radiation and other stress factors by binding to nucleosomes), are the foundation of this resilience. Future Mars astronauts may find this biotechnological tool motivating, as it has been demonstrated that DSup lowers DNA damage when introduced to human cells.
Plants also demonstrate an unexpected ability to adapt in space. According to experiments carried out on the ISS, certain plants modify their gene expression to adjust microgravity. Through distinct genetic mechanisms, model plants like Arabidopsis thaliana continue to establish roots in space conditions, according to NASA's Advanced Plant Habitat experiment (Zhou et al., BMC Plant Biology, 2019). This is important for understanding the remarkable adaptability of living things' DNA as well as for future space agriculture.
By changing its genetic code, life can survive in even the most adverse conditions, as demonstrated by these examples. The "library of survival" found in nature may contain genetic techniques that could help humans go to Mars.
Adapting Human DNA for Space
So, is the human body ready for this brave new world? We could even take it further: should we be genetically reprogrammed to go to Mars?
So far, it has been discovered that prolonged exposure to space has serious effects on DNA. According to NASA research (Ghani et al., 2024), microgravity and cosmic radiation can cause DNA damage and chromosomal abnormalities in human stem cells, impairing immune system function and leaving astronauts vulnerable to disease on long missions.
Scientists are working on various genetic interventions to reduce these risks. Tools such as CRISPR-Cas9 offer promising options for strengthening DNA repair genes or creating genetic modifications that provide protection against radiation (Vukmirovic et al., 2020). Furthermore, inspired by organisms that can survive in extreme conditions, ideas are being developed to make human DNA more resilient. For example, the DSup protein found in tardigrades can protect cells from radiation, and theoretically, this property could be transferred to human DNA using CRISPR (Hashimoto et al., 2016). Similarly, some laboratory studies suggest that CRISPR could enhance the capacity to repair DNA damage (Shibata et al., 2017).
Beyond this, genetic interventions not only provide protection but also offer opportunities for adaptation. Modifying genes to reduce muscle and bone loss in microgravity conditions could make astronauts' bodies more suited to the space environment. Although these ideas are still in the laboratory stage and surrounded by ethical debates, they are candidates to become an important part of future space biotechnology.
However, despite promising developments, rewriting the human genome raises serious questions. It remains unclear whether interventions in DNA will increase the risk of cancer or mutation in the long term. Although it has the potential to protect us during a journey to Mars, altering human genetics is a complex area from an ethical, psychological and biological perspective.
Future Directions
Today, thanks to technologies such as CRISPR, rewriting human DNA is no longer purely theoretical; however, creating a genetic profile suitable for Mars remains fraught with many unknowns. Research into radiation resistance, the safe enhancement of DNA repair mechanisms, and the long-term effects of genetic interventions is still in its early stages. Although findings in these areas are promising, even a minor error in the human genome could lead to unexpected mutations or cancer-like permanent effects.
Furthermore, the psychological, ethical, and social consequences of genetically modified astronauts have not yet been fully addressed. As we push the boundaries of human biology engineering, not only technical but also moral questions are increasing.
The first humans to go to Mars will be living examples that redefine humanity's limits. This journey is not just about setting foot on another world; it is also a way to rediscover who we are. As Stephen Hawking said, “Remember to look up at the stars and not down at your feet. Try to make a sense of what you see and wonder about what makes the universe exist.” As long as we continue to look at the stars and wonder, we will continue to discover both the secrets of the universe and the deeper meaning of being human.
Conclusion
In conclusion, gene-editing technologies such as CRISPR are opening the door to a new human form capable of withstanding Mars' harsh conditions. However, rewriting DNA is not merely a biological solution, but also an ethical and existential inquiry. It may be possible to alter our genome to adapt to Mars, but in doing so, we will also need to redefine what it means to be human.
References
Jönsson, K. I., Rabbow, E., Schill, R. O., Harms-Ringdahl, M., et al. (2008). Tardigrades survive exposure to space in low Earth orbit. Current Biology, 18(17), R729–R731. https://doi.org/10.1016/j.cub.2008.06.048
Zhou, M., Sng, N. J., LeFrois, C. E., Paul, A.-L., & Ferl, R. J. (2019). Epigenomics in an extraterrestrial environment: Organ-specific alteration of DNA methylation and gene expression elicited by spaceflight in Arabidopsis thaliana. BMC Genomics, 20(1), 205. https://doi.org/10.1186/s12864-019-5614-6
Ghani, F., & Zubair, A. C. (2024). Discoveries from human stem cell research in space that are relevant to advancing cellular therapies on Earth. npj Microgravity, 10, 88. https://doi.org/10.1038/s41526-024-00488-3
Vukmirovic, D., Seymour, C., et al. (2020). Deciphering and simulating models of radiation genotoxicity with CRISPR/Cas9 systems. Mutation Research/Reviews in Mutation Research, 783, 108298. https://doi.org/10.1016/j.mrrev.2020.108298
Hashimoto, T., Horikawa, D. D., et al. (2016). Extremotolerant tardigrade genome and improved radiotolerance of human cultured cells by tardigrade-unique protein. Nature Communications, 7, 12808. https://doi.org/10.1038/ncomms12808
Shibata, M., Nishimasu, H., et al. (2017). Real-space and real-time dynamics of CRISPR-Cas9 visualized by high-speed atomic force microscopy. Nature Communications, 8, 1430. https://doi.org/10.1038/s41467-017-01466-8
