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Life on Mars: the ethics of space exploration

Image of Mars taken by the Hubble Space Telescope. Source.

In Episode Five of the popular television series Cosmos: A Personal Voyage (1980), entitled “Blues for a Red Planet,” astronomer Carl Sagan gave his audience a tour of the Red Planet, Mars, as scientists of the time understood it. He talked about the Viking missions, launched by NASA in the mid-1970s and carrying experiments designed to test for the presence of microbial life. The results of those experiments proved controversial, and are still the subject of debate. Is there life on Mars? The question remains unanswered.

Current missions look to change that. NASA’s Perseverance Rover carries the first life-detecting experiments on the Red Planet since Viking. The China National Space Administration’s (CNSA) Zhurong rover explores the planet’s surface, collecting data on temperature, atmospheric pressure, and notable features including possible mud volcanoes. These robotic “astronauts” are, according to NASA, laying the groundwork for future human exploration. NASA plans to land humans on the Moon by 2024 and use lunar exploration as a stepping-stone to send astronauts to Mars. The Artemis Moon missions will give scientists a chance to refine technologies needed for long-term, sustainable human habitation in space.

If, one day, humans have the technology to terraform the Red Planet, remaking Mars in Earth’s image, should we? This is one of the questions the field of space ethics attempts to answer. Scientists and scholars questioned the plausibility and the ethical implications of terraforming as early as the 1980s. The mere presence of humans and human-made objects in extraterrestrial environments means there will be changes to those environments, be they intentional or unintentional. NASA already takes precautions before launching its rovers and landers, constructing the spacecraft in a sterile environment, but introducing humans adds a series of new challenges.

People leave traces of their presence, like the golf balls, tools, and spacecraft parts from the Apollo missions that remain on the surface of the Moon. Both government agencies and private companies want to launch further missions, which means further changes to the existing environment. The human-made change is key here. Do we as a species have the right to irrevocably change another planet’s environment to suit our own needs? If we terraform Mars, there is no reversing the process. In making Mars more Earth-like, we may erase traces of the planet’s past, and thus opportunities to understand its history.

If either robotic or human visitors do find life on Mars, what happens next? Carl Sagan, again in Cosmos, wrote, “If there is life on Mars, I believe we should do nothing with Mars. Mars then belongs to the Martians, even if they are only microbes.” In his view, life had value for its own sake, and humans did not have the right to interfere with it. Later scholars expanded on these ideas. In 2017, the Committee on Space Research (COSPAR) released the results of a workshop on ethical considerations in space exploration, recommending the preservation of a “second Genesis” (life with no evolutionary link to that of Earth) on both ethical and scientific grounds. A recent article in Scientific American emphasizes the potential for harm, both to existing life and to the ecosystem as a whole, with the arrival of humans. “Human exploration has led to many extraordinary new discoveries,” author Nicholas Dirks writes, “but it has also led inexorably to the appropriation and exploitation of natural as well as human resources.” He advises us to be wary of defining “life” based solely on an Earthly perspective. In other words, we do not know what we do not know, and acting based on incomplete information could have unforeseen consequences.

Humanity’s next steps in space have the potential to expand our horizons, but we must take those steps carefully. As space ethicists James S. J. Schwartz and Tony Milligan wrote, asking the often-tough questions about what we can and what we should do in space helps us make more informed decisions about our future beyond Earth.