This past summer AIP’s Rebecca Charbonneau participated in a workshop in Fort Collins, Colorado, exploring the concept of “habitability.” To learn more about the workshop’s motivation and goals, she posed questions by email to its organizers, Patrick McCray, a historian at the University of California, Santa Barbara, and Matt Shindell, a curator at the Smithsonian’s National Air and Space Museum. This project has also received support through AIP’s grants-in-aid program.

Rebecca Charbonneau: You’ve been working together on both a co-authored article and a larger edited volume on the topic of habitability. How did this partnership start, and what drew each of you to the subject of habitability?

Patrick McCray: For me, the project started in 2023 when Matt and I realized that we both had a shared interest in the history of astrobiology and exoplanets. We were thinking about doing some sort of co-authored book together, and at some point Matt suggested the rubric of “habitability.” We realized right away that it was a capacious and intellectually stimulating concept that spoke to a lot of our interests, both in the history of astrobiology, but also the histories of science, technology, and the environment more broadly. Matt and I started to formulate a set of topics for a co-authored book but quickly realized that the project was outstripping our time and abilities to speak to each of these topics. We then decided that doing some sort of edited collection made more sense and it was around this point, given that we already had Antarctica on our shopping list, that we wanted to bring a specialist in that topic into the picture. That’s how we connected with Adrian Howkins who is an excellent historian on the history of the polar regions. This also opened up new vistas for thinking about concepts of habitability and human exceptionalism.

We were also very fortunate to receive a Catalyst Grant from the Canadian Institute for Advanced Research (CIFAR). This allowed us to fund the workshop that we held recently in June 2026, which brought together all of the authors who are contributing essays to the Limits to Life volume that we expect will come out at the end of 2027

Matt Shindell: For me, my interest in habitability goes back a little longer. I became the curator of planetary science at the National Air and Space Museum in 2015. Prior to this, I had been working on a project related to climate change and environmental assessments. I started thinking about the connection between our evolving understanding of the Earth and the dynamic systems that support its habitability, our search for life in our own solar system, and our search for Earth-like planets among the exoplanets. I didn’t know where I would go with this, but I felt like there was a way in which all of these things were connected, and the concept of habitability seemed to be a common thread that could be historically traced. I pursued this a bit in my book, For the Love of Mars: A Human History of the Red Planet, but I felt like there was a lot more to be said. Patrick and I started talking about it, and we thought it would be interesting to try to bring together scholars working on a variety of topics that approached habitability in different ways. What would happen if we brought them all together?

Charbonneau: The Limits to Life is organized around three themes—definition, human exceptionalism, and detection—and three scales, from the microbial to the planetary/civilizational. What made you want to bring together such a range of disciplines, institutions, and career stages in one volume? What do you hope readers, both inside and outside academia, take away from it?

McCray: As we put together the invitation list for people we wanted in the edited volume, we worked to make sure that we had diversity represented across a number of different axes. This included having people from different kinds of institutions, including museums, government agencies, and universities, as well as people who represent diversity in terms of where they are career-wise. So, we were very fortunate to recruit people who are tenured professors or established curators as well as people who are independent scholars, advanced graduate students, and postdocs.

We also have a nice diversity in terms of the research specialties and disciplinary backgrounds that contributors to the edited collection come from. This includes people who focus on environmental history as well as the histories of science and technology, of course. But we also have someone who specializes in rhetoric, an art historian, and an architectural historian. This was a wonderful thing when we met as a group as we had a plurality of opinions and ideas that really made this project be much greater than the sum of the parts.

As we initially formulated it, habitability pertained mainly to the places and infrastructures where scientific, social, and environmental concerns intersected. This term took on special relevance during the Cold War and the space race, where it described conditions for maintaining human life in outer space and its analogs in other built environments. It was also linked to Earth and environmental science, as well as the environmental movement, with regard to studying and sustaining life on Earth.

With space exploration broadly construed, our focus became one of considering habitability as a place (such as the idea of a “habitable zone” used by astrobiologists) as well as a condition, while questioning where humans fit in these conceptualizations. A whole suite of questions and topics soon emerged from our discussions such as: architectures of space settlements, whether on Mars or free-floating in space; astrobiological research where non-human life such as microbes and the idea of a “habitable zone” are central; and questions about how habitability, as seen in the context of space exploration, shapes how we think about how it is applied to the terrestrial context. This latter point seems especially salient if one considers the converse—inhabitability, especially at a time when there are human forces active on our planet which seem directed toward making it less habitable.

In the end, we came to see that, whether one is speaking of an exoplanet or a science-oriented built environment on Earth, habitability is not an innate quality of a place. Rather it is a social and scientific construction with varying interpretations and definitions for different professional disciplines. In other words, an astrobiologist thinks of habitability differently than an architect or an ecologist. And, just as importantly, habitability, for historians, is a dynamic term with a set of meanings which have changed and varied considerably in different times and in different national and cultural contexts. To paraphrase Claude Lévi-Strauss, habitability is good to think with. We hope other historians will agree and see our collection of essays about habitability as an invitation to engage with the ideas our authors present and the general concept itself.

Shindell: One thing we’ve found is that habitability is an unstable concept over time and between disciplines. It is defined in very different ways depending on what work it’s being asked to do—describe an ideal space station, an undersea habitat, a strategy for searching for life, a theoretical approach to thinking about the preconditions of life, etc. And yet, there is a connection between all of the definitions in that they are all talking about the relationship between life and the universe, and they are all reflections of a relationship between life and place (and perhaps also time). They also (almost) all relate to stories people are telling about our future in the universe—on this planet and beyond.

Charbonneau: You recently gathered contributors in Fort Collins to work through the collection’s essays together. What was it like putting so many different approaches to habitability in the same room, and did anything from those conversations change your thinking about your own essay or about the volume as a whole?

Shindell: The two days we spent together in Fort Collins were very intellectually stimulating. We had all read drafts of each other’s chapters, and we devoted every hour of that workshop to talking through each chapter and looking for the ways in which they could better engage with each other. And I was happy to see that the commonalities were already there, even between chapters that had little to do with each other, in ways that became evident during our discussions. I had never participated in anything of this type before (although I have contributed a few chapters to other volumes) and I think the result will be an edited volume that feels holistic, like it is greater than the sum of its parts. And we all did come away with some pretty specific recommendations for improving our chapters and making the existing connections stronger.

Charbonneau: Your proposal points out that ideas like a “Planet B” or Elon Musk’s “Occupy Mars” slogan are, in a sense, just the latest versions of much older narratives about habitability and the frontier. Does grounding today’s techno-futurist visions of space colonization in this longer history change how we should read them? What would you want someone following the private space race to take from the book?

Shindell: The future has a history. That’s something obvious to historians who have engaged with any science or technology that presents a vision of the future. Spaceflight is one area where visions of the future have always moved from background to foreground (or vice versa) in the conceptualization and development of plans and technologies, as well as selling these to policymakers and the public. And of course the frontier was at one point a future vision, and one connected to exploration and expansion in ways that are repeated in contemporary (and past) discussions of space exploration and occupation. Then the frontier became (in reality or rhetorically) a thing of the past. It became something that had been lost. A nostalgic and idealized vision of the frontier and its importance in American history came to occupy discussions of the importance of spaceflight and its ability to open up new frontiers. This has never really gone away, but it is definitely seeing a resurgence today in the ways some actors are talking about the Moon and Mars. What does that mean? I’m not entirely sure. But it does pop up in discussions of habitability, especially among those who want to make uninhabitable spaces habitable and carve out new spaces to colonize.

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Rebecca Charbonneau
American Institute of Physics
rcharbonneau@aip.org

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