Should humans be allowed to colonise outer space?

Should we protect space because doing so will benefit humans, or is there some intrinsic value in preserving places beyond our own planet?

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     – Immanuel Kant

Philosophers have written many books discussing Kant’s conviction that there is a moral law within us that gives rise to a feeling of awe or respect when we reflect upon it. They have had much less to say about his belief that reflecting on the stars above also generates such feelings. Yet in April the first image of a black hole brought to mind that aspect of Kant’s famous quote.

The more we reflect upon the understanding of the universe achieved by contemporary science, the more our admiration and awe increases. The image of the black hole is a reminder of Einstein’s work that implied the existence of such objects a century ago. At the same time, what we now know about the vastness of the universe continues to challenge our comprehension.

On 10 April even those with a limited understanding of physics were stunned by the picture of a black hole with a diameter about 3 million times that of the Earth, and some 55 million light-years distant from us.

Like Kant’s reverence for the starry heavens that came from simply looking up on a clear night, the picture of the black hole forces us to contemplate our place in the universe. The image of the black hole was similar to the famous “Earthrise” photograph taken by William Anders during the 1968 Apollo 8 mission. That picture, showing the Earth rising over the surface of the moon, has been called “the most influential environmental photograph ever taken.” It allowed us to see our planet as a sphere in space, surrounded by nothingness, a perspective that was unseen until we ventured into orbit.

In 1990, before the black hole and after Earthrise, the Voyager 1 space probe photographed the Earth from so far away that it appears, in astronomer Carl Sagan’s words, as “a pale blue dot.” “That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives”, Sagan described. Does that mean that everything that matters exists on the Earth?

In the same week that earth marveled at the picture of the black hole, a private Israeli lunar probe, Beresheet, experienced a technical glitch and crashed onto the surface of the moon. Its venture into space returns us to the moral law in Kant’s famous quote, and raises ethical issues about humans’ exploration and use of the universe beyond their own planet. Are the starry heavens now open for everyone to colonise, for whatever they wish, if they have the means to do so? And what about all the objects we have sent into orbit?

There is already a vast quantity of debris circling the planet. Space Surveillance Networks are tracking 22,300 entities, and the European Space Agency estimates that there are about 900,000 objects larger than 1cm and 129 million larger than 1mm. In 2007, a single event – China’s deliberate destruction of one of its own satellites in order to test an anti-satellite rocket – added 3,400 new trackable entities, and two years later another 2,300 were created by the accidental collision of two satellites.

At low orbit levels where most of the debris is, we can predict that the more objects there are, the more collisions there will be, and the more collisions there are, the more debris there will be, creating a vicious spiral that will eventually make frequently used orbits dangerous places to occupy. The debris could also be a hazard for traffic between Earth and the Moon, or Earth and Mars, which some think could increase significantly in decades to come.

The European Space Agency is concerned about space debris because “modern life depends on the uninterrupted availability of space infrastructures” that are being destroyed by collisions with debris. There is also a risk to people on the ground from re-entering space entities. These concerns are reason enough to avoid the creation of more space debris, and they also suggest that removing some of the junk that is already in orbit, even if it is not easy, is a moral imperative.

The risks that space debris pose imply there is something wrong with littering the atmosphere. In debates about environmental ethics it is common to distinguish between those who think that protecting the environment is important only because of the benefits it brings to humans and those who think that the preservation of wilderness is important for its own sake. A similar distinction can be applied to the extraterrestrial environment. Should we protect it because doing so will benefit humans? Or is there some intrinsic value in preserving places beyond our own planet as they were prior to human contact with them?

In a recent article, André Galli and Andreas Losch discuss the implications of extending the idea of sustainable development to space. One way of doing this that fits within an anthropocentric ethical framework is to recognise that a time may come when humanity is able to survive only because it has expanded beyond the Earth. That thought lies behind both Elon Musk’s SpaceX venture, which aims at colonising Mars, and Jeff Bezos’ Blue Origin, which envisages a day when Earth’s resources will be insufficient to sustain humanity and we will need to draw on the Moon or other objects in space.

But what if our foray into space posed a threat to life – possibly even sentient life – outside our orbit? The biological contamination of extraterrestrial environments may be of greater concern than littering space with pieces of metal or plastic. After all, Europeans have a terrible record of contaminating the parts of the world they colonised, introducing not only diseases, but also plants and animals that have forever changed the ecology of previously isolated regions such as Australia and New Zealand. Are we about to repeat the same mistakes when we explore space?

The Industrial Revolution and everything that has followed it, including our growing population, has undoubtedly damaged ecosystems around the world and polluted the atmosphere. Indeed, the electricity that we are using to write these words has made the nights less dark and dimmed the stars. For Kant, the heavens above us must have looked even more impressive.

Still, technological advances have made our lives much more comfortable. Ultimately, the awe we experience when confronted with the immensity of the universe is not in itself a compelling ethical argument against leaving our traces in those parts of space we are able to reach.

There are, however, many good reasons why, even without attributing value to the stars themselves, we should strive to avoid treating our corner of space as nothing more than a quarry, a rubbish dump, and a lawless frontier. Here the idea of sustainable development is key.

We can start with concern for our own safety and the sustainability of our environment. We can extend this by recognising that we should not discount the interests of future generations, who seem likely to travel at least to our nearer planets. Nor can we exclude the possibility of other sentient or intelligent life outside our orbit. And if we fail to respect the extraordinary and still mysterious universe in which we live, then perhaps one day our descendants, or these other forms of life, will regret that failing, as we now regret the damage we have done to Earth.

Agata Sagan has studied astronomy, human ecology, and bioethics. She is now an independent researcher living in Warsaw, and is not, as far as she knows, related to Carl Sagan.   

Peter Singer is professor of bioethics at Princeton University and laureate professor at the University of Melbourne. His books include Practical Ethics and The Life You Can Save.
