Crafting “a New Song” for Mars and Beyond
As governments and private entities prepare to send humans to Mars, the mission brings significant environmental challenges. While the logistics of sustaining life on the Red Planet have been studied extensively, there's a notable gap regarding the impact of chemicals and materials used during human exploration.
Signs of material pollution on Mars from the Mars 2020 Perseverance mission
In a recent peer-reviewed opinion article in Proceedings of the National Academy of Sciences, researchers from the Department of Environmental Science, Stockholm University, and a colleague at the Research Center for Astrobiology, Spain, and Cornell University, USA, call for extending planetary protection guidelines to address chemical and material pollution.
The aspiration to land humans on Mars has captivated the world's imagination, but it comes with a set of profound environmental concerns. On Earth, human activities have led to the release of chemicals and materials into the environment, causing harm to living organisms and disrupting natural processes.
As John Hader, former PhD student at the Department of Environmental Science (currently at Empa – Swiss Federal Laboratories for Material Science and Technology) and main author, aptly puts it: "Humanity's relationship with chemicals on Earth has been like a bad song stuck on replay: develop a new chemical that doesn't seem to be harmful, use it and release it into the environment, and then discover a few decades later that it actually is harmful."
Drawing Lessons from Earth
This is indeed a familiar situation. Many chemicals used on Earth have had unintended consequences when released into the environment. For example, per- and polyfluoroalkyl substances (PFAS), common in various products, have caused environmental contamination and adverse effects on ecosystems. Similarly, chlorofluorocarbons (CFCs), once prevalent in aerosol sprays and refrigerants, led to ozone layer depletion.
To mitigate such risks, international agreements have been forged to restrict the use of certain chemicals and materials, aiming to prevent environmental damage on Earth. But potential pollution of Mars presents new challenges. Matthew MacLeod, Professor at the Department of Environmental Science and co-author, highlights the fundamental difference: "Our human-made pollution is a unique concern on Mars and other extra-terrestrial bodies because we don't understand how their biogeochemistry and possible extant life could be affected."
Mars Already Touched by Contamination
Mars, though largely untouched by Earth's influences, bears the marks of our presence, as MacLeod explains: "Material pollution is visibly obvious in the form of parachutes and ropes from landing systems, discarded heat shields, and even rovers and scientific instruments themselves. And, every surface mission to Mars also introduces invisible chemical pollutants that escape from materials used in the landing systems and equipment."
The Outer Space Treaty's Shortcomings
The Outer Space Treaty (OST) is the cornerstone of space exploration regulations. A legally-binding accord signed by 114 nations, it serves as a framework for preventing "harmful contamination" that could disrupt the exploration of celestial bodies. However, its focus primarily centers on biological contamination rather than the potential threat posed by novel chemicals and materials. As Alberto Fairén, Research Full Professor at the Research Centre for Astrobiology, Spain/Visiting Scientist at the Department of Astronomy, Cornell University, and co-author, points out: "As currently implemented, the OST fails to address the potential contamination of our neighborhood planets by anthropogenic novel chemicals and materials," he explains.
Beyond contamination concerns, it's crucial to consider sustainability and ethics, and as such, Fairén raises a critical concern: "We need to start debating about sustainability in the exploration of Mars right away, to predict and mitigate the problems we may have in the future."
As plans for endeavours like launching the first rocket from another planet take shape, the potential for a significant chemical imprint in the Martian atmosphere and debris littering the surface looms large. In addition, Fairén emphasizes that sustainability discussions should extend to future plans for permanent colonies on Mars, such as those dedicated to mining activities. The magnitude of potential environmental impact amplifies the importance of proactive measures.
In light of these challenges, the authors are rallying for collaborative research efforts to assess the impact of anthropogenic pollution on Mars. They argue that understanding the possible risks associated with these chemicals and materials is paramount for developing effective planetary protection guidelines. An interdisciplinary approach combining environmental chemistry, planetary science, and engineering is deemed essential to provide comprehensive insights.
The Future of Responsible Space Exploration
Yet, time may not be on the side of the scientists. Amidst the excitement surrounding Mars exploration and the race to send humans to the Red Planet, Fairén questions the rush to land living beings on Mars: “The current rush to send living beings to Mars lacks a well-founded motivation beyond the desire to be the first or the quickest. It is not a sufficiently reasoned approach, as it poses an imminent risk of inevitable biological contamination, potentially hindering our quest to explore Martian life forever.” In a similar fashion, contamination from chemicals and materials can also pose risks to Martian life and disrupt scientific investigations. All three authors agree that understanding the impact of chemical and material pollution on other planets is essential to ensure responsible and sustainable space exploration.
While the challenge may seem formidable, John Hader remains hopeful, stating: "Right now, Mars is a mostly pristine environment, so we have a unique opportunity to write a new song in how we deal with chemicals at an interplanetary level." He adds: "I am optimistic that the environmental chemistry, astrobiology, and planetary protection communities can join forces to write this new song together."
The United Nations Outer Space Treaty
The Committee on Space Research (COSPAR) Planetary Protection Policy
NASA's "Humans to Mars" website
Last updated: October 16, 2023
Source: Department of Environmental Science