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Colonizing Mars

National space agencies and private corporations have declared plans to send humans to the red planet, with longer-term planets of settlement and resource extraction likely to follow. Such actions may conflict with the Outer Space Treaty of 1967, which currently prohibits any sovereign claims in space.

In a recent Space Policy paper written by Sara Bruhns and myself, titled “A pragmatic approach to sovereignty on Mars,” we develop a practical approach toward allowing the settlement of space and use of its resources through a “bounded first possession” model with a required planetary park system. We suggest that exclusive economic claims could be made without establishing sovereignty on Mars, and we propose a model for management and conflict resolution on Mars that build upon lessons from history. We also recommend revisions to the Outer Space Treaty to resolve the current ambiguity of how nations, corporations, and individuals can use the resources of space.

Planets in the habitable zone of low-mass, cool stars are expected to be in synchronous rotation, where one side of the planet always faces the host star (the substellar point) and the other side experiences perpetual night (the anti-stellar point). Previous studies using three-dimensional climate models have shown that slowly rotating plants orbiting these low-mass stars should develop thick water clouds form at substellar point, at the point at which the star is directly overhead, which should increase the reflectivity, and thus stabilize the planet against increased warming at the inner edge of the habitable zone.

However these studies did not use self-consistent orbital and rotational periods for synchronously rotating planets placed at different distances from the host star, which are a requirement from Kepler’s laws of motion. We address this issue in a new study led by Dr. Ravi Kopparapu, on which I am a co-author, titled “The inner edge of the habitable zone for synchronously rotating planets around low-mass stars using general circulation models.” In this study, we use correct relations between orbital and rotational periods to show that the inner edge of the habitable zone around low mass, cool stars is not as close as the estimates from previous studies. We also discuss how the stellar composition, or ‘metallicity,’ can affect the orbital distance of the habitable zone.

I am pleased to announce that the first volume of the Blue Marble Space Short Story Collection is now available! This volume, titled Tales From Spaceship Earth, includes stories from six different scientists at the Blue Marble Space Institute of Science and is the first in an ongoing series of science-informed fiction.

This collection of stories reflects an intersection of each author’s knowledge of science and vision of the future. These unique perspectives range from the near-term evolution of the space station program, to the beginnings of martian colonies, to the ultimate end of life on Earth–all of which grapple with critical issues of our transformation into a spacefaring society.

This book is available from Amazon as in both paperback and Kindle formats. Proceeds from this collection directly support the research of BMSIS scientists.

Earth’s climate is vulnerable to potential climate catastrophes that could threaten the longevity of civilization. Continued increases in greenhouse gas forcing could lead to the collapse of major ice sheets, which would cause catastrophic sea level rise and could cause the oceanic thermohaline circulation to halt. Further warming could cause the heat stress index to exceed survival limits, inducing hyperthermia in humans and other mammals. Even more extreme warming could shift Earth into a runaway greenhouse regime that would lead to the loss of all oceans, and the end of all life.

Geoengineering refers to the large-scale use of technology to alter Earth’s global climate, and geoengineering has been suggested as a way to ameliorate contemporary climate change. Addressing these immediate climate challenges through a combined strategy of adaptation, mitigation, and (if needed) geoengineering is a critical issue facing us today. Whether or not we decide to engage in geoengineering today, we must still devise a long-term strategy to address our changing climate.

But in the longer-term, could we also use geoengineering techniques to increase the size of the polar ice caps? In a paper published in a special issue of the journal Futures, I raise the question, “Should we geoengineer larger ice caps?” By doing so, the global average temperature of Earth could be lowered from its current state to a new stable regime with much larger ice caps. Earth has experienced shifts in ice coverage in its past, and a prolonged program of geoengineering–say, lasting a thousand years or more–could allow us to permanently shift the energy balance of Earth. More ice at the poles increases the amount of sunlight reflected back to space, leading to cooler temperatures.

Of course, the unfortunate side effects of this idea would be mass migration of populations near the poles, shifts in global agricultural zones, and a required commitment of millenia in order to avoid undesired side-effects. Human civilization today probably lacks the fortitude to embark on such a long-term goal. Nevertheless, thinking about the long-term management of our planetary system helps us realize that we have already entered the epoch of the Anthropocene. Our civilization itself is fundamentally intertwined with our global climate, and we should allow humility, rather than hubris, guide decisions to control our environment.

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