Life on Mars: The Ethical Implications of Colonizing the Red Planet

It’s a Godawful Small Affair

Human expansion into space is at the periphery of our current, scientific knowledge. There is a long and earnest history of proposals for such a project; it fills canons of science fiction, occupies reams of academic writing, and reposes smiling in the hearts of millions as a hope, and a dream. Today, major institutions, billionaires, and even the nation of Luxembourg are investing in ambitious off-Earth plans. Environmental scientists and economists are proposing ways to use space-based resources to improve life on Earth. Slowly, surely, the idea is making its way into the mainstream.

Wonder if He’ll Ever Know/ He’s in the Best Selling Show

SpaceX’s Falcon Heavy had its maiden flight in February 2017, igniting a firestorm of media coverage, and a flurry of tweets from the company’s CEO, Elon Musk. The massive rocket thundered off its launchpad, while the accompanying corporate webcast blasted David Bowie. In a double act of remarkable precision, the twin side boosters returned to the launch site, blazing triumphantly down to their landing zones. The central core, however, unfortunately slammed into the Atlantic at 480 kilometers per hour. Oops. Well, they’re working on it.

As the largest operational rocket in the world and the cheapest in its class, the Falcon Heavy represents a critical first step towards SpaceX’s stated goal of “enabling people to live on other planets.” Now, in the wake of the first successful flight of the Falcon 9 Block 5, SpaceX is preparing for the radical cost-cutting that will enable its much-hyped journey to Mars. The Falcon 9 and its derivative, the Falcon Heavy, are at last complete, and the design team is now moving on to bigger and better things.

Last year, SpaceX revealed their next-generation launch vehicle, nicknamed BFR, or “Big Falcon Rocket.” Boasting assets like on-orbit refueling capability, precision maneuvering, a unique pair of stubby delta wings, and (at last!) complete reusability, this truly massive booster represents the crux of Musk’s Martian ambitions. Test flights have been optimistically scheduled for late 2019, and demonstration flights to Mars are scheduled for 2022.

SpaceX’s journey from small-launcher corporate maverick to established industrial innovator has spawned a number of imitators, including Jeff Bezos’ Blue Origin and Richard Branson’s Virgin Orbit. These new space firms hope to drop the price of putting objects in orbit (measured in dollars per kilogram) by an order of magnitude within a decade. Vertical boosters and fully reusable spaceplanes are also currently being developed. SpaceX is merely the most visible and successful representative of a larger movement. The company’s meteoric rise has been accompanied by failures, delays, setbacks and (naturally) explosions, but Space X has made the half-century-long dream of rapid and cheap reusable orbital spacecraft into a reality – and its competition isn’t far behind.

No government has taken up the goal of Mars colonization en masse, but the success of commercial space has opened up new possibilities. The cost of settling Mars is no longer, pardon the pun, astronomical. A human presence on Mars seems an ever closer prospect. But, while the economic obstacles to inhabiting the Red Planet have been greatly reduced, a plethora of ethical and physical stumbling blocks remain.

Is There Life on Mars?

When Mariner 4 flew by Mars in 1965, it revealed a cold, arid world, wrapped in a thin atmosphere, where average temperatures rarely climb above freezing. Clearly, this desolate rock was not the Mars of H. G. Wells, or Percival Lowell. But there is something eerily Earthlike about the place. Great channels and river deltas lie alongside impact craters, testifying to a time when Mars had liquid water flowing on its surface. Largely undisturbed for gigayears, Mars provides a window onto the Solar System’s past.

Mars was once hospitable – perhaps more so than Earth. Life, probably microbial in nature, may have existed there in the past. It may still lie hidden in some corner of the planet, or deep underground, unexamined by the robot emissaries that humanity has managed to send thus far. When the Viking landers deployed their life-finding experiments in 1976, some of them came back positive. Despite anomalously low levels of organic molecules, something appeared to be consuming a nutrient solution they had introduced to the Martian soil. Was it life? Probably not. Peroxides or irradiated perchlorates seem to mimic life rather well on the Martian surface. Over a decade ago, the Mars Express orbiter detected methane, a biomarker, and the Curiosity rover recently showed that levels vary seasonally. A handful of hardy organic molecules have been discovered in the Gale Crater, and there appears to be subsurface ice everywhere. Life is consistent with all these signatures – though it’s hardly the simplest explanation. We don’t have enough data to decide with any certainty, but suppose life did exist on Mars. What would this imply for us?

SpaceX’s website proposes terraforming – making Mars more earthlike, with a thicker atmosphere, plants, and even oceans. In this scenario, what would become of these putative Martian microbes? They are adapted to a desiccated world. Radically altering Mars’s environment would prove destructive to them. Do we have a moral obligation to microbes? I would argue that we do. If there is independent life on Mars, then Mars is its inheritance – not ours. To seize an inhabited world and make it our own, eradicating native life in the process, would be immoral. The possibility of panspermia – that any Martian life is Earth life and Earth life Martian, regardless of where it originated – complicates matters, however.

What if there was life on Mars in the past, although there is none today? That would necessitate a moratorium on terraforming. Anthropologists like Michael Oman-Reagan have called for a new “interplanetary environmentalism,” ensuring that at least some vestige of Mars’s past could be effectively preserved. We won’t know enough to make an informed decision about transforming the planet until extensive clarifying work has been done, either by probes or by scientists in person. Failing to analyze any possible Martian life would be a great loss to the store of potential human knowledge. Moreover, terraforming could have globally catastrophic repercussions for the red planet. If we weren’t careful, Martian settlers would end up “living on a collapsing landscape,” as the global permafrost-like soil melted. Settling new worlds must be a scrupulous business. What’s needed is a grace period, during which human specialists and their robotic assistants can establish whether Mars has indigenous life, and determine the best course of action.

Life may be thriving on Mars in just a handful of decades. The question is, what kind?

It’s the Freakiest Show

Long-term exposure to microgravity can have many deleterious effects, including anemia and vision problems. These, however, can be overcome by artificial gravity. But cosmic rays or solar flares outside of Earth’s protective magnetosphere could lead to cancer, blindness, nerve damage, and even death.

Some modicum of healthy gravity might be restored once reaching the surface, but Mars lost its magnetosphere ages ago, and its atmosphere provides little shielding from harmful radiation. The first long-term habitats will have to be underground, or buried in ice and regolith. Growing food sustainably in a contained environment will be a logistical challenge. Venturing outside for routine labor or scientific work will be dangerous. These problems would persist for decades, or even centuries, in such a large-scale, slow project.

Kim Stanley Robinson’s Mars Trilogy, a hard science-fiction series, has long been acclaimed as a roadmap for future colonists. In Robinson’s novels, the colonists’ terraforming efforts prove calamitous. As they reshape the planet’s surface, craters are eroded, valley walls collapse, aquifers burst, and the northern lowlands are turned into an ocean. Yet the trilogy finishes with an environmentalist instigator, reconciled at last to her terraformed planet, walking by the seashore, marvelling at Mars as an example of human flourishing. Children play in the sand, their fists full of basalt and breccia grains shorn from the rocks of an ancient impact basin. On Mars, Robinson’s humans are given a chance to restructure society in a more egalitarian, kinder, more sustainable way. And they ultimately succeed. This is a fantasy, but it is also an example we might learn from.

Life on Mars will be tough. If it’s shared with Martian cousins, our human presence will have to be limited, and one of quiet observation. The planet could well end up like Antarctica, protected from change and exploitation by stringent international treaties. If Mars is dead, and we’re alone, we must decide, for ourselves then, to protect Mars as our collective inheritance, to avoid the errors and faults that have placed our own planetary cradle in flux. To terraform ethically, if we terraform at all. To start again, on this newest frontier. To provide a real example of human flourishing.


  1. “In this scenario, what would become of these putative Martian microbes? They are adapted to a desiccated world. Radically altering Mars’s environment would prove destructive to them. Do we have a moral obligation to microbes? I would argue that we do. If there is independent life on Mars, then Mars is its inheritance – not ours.”

    Think of that the next time you overcome a common cold, or take antibiotics to cure a more serious infection or actually eat… anything. Practicality has to enter into the “ethical” consideration at some point. Not colonizing Mars when the ability to do so exists, because of microbes, is a far greater ethical failure.


    1. Mars should be a fresh start, there’s no reason to repeat the errors of colonialism, but do microbes really deserve to be ethical objects you suggest they are? Calling for a grace period for accurate scientific appraisal is all well and good, but what could possibly prevent humans from settling Mars if all that lives there are subterranean microbiota? Would it be correct to call this colonisation in a sociological context, if the colonized have no claim to sentience?

      Mars could be, as you say, a future example of human flourishing. Why disbar this outcome over things you admit we murder without a second thought here on Earth?



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