| How Might Mars Become a Home for Humans? |
Cover Note.
Before Christmas 1998, Professor Robert Haynes of York University, Ontario, passed away. Bob was best known for his work as a geneticist and for his co-discovery of DNA repair, but he was also, perhaps unusually for a scientist of such eminence, a pillar of the terraforming community
Bob seemed to take some pride in the fact that a new word, ecopoiesis, that he introduced into discussions has gained in currency since. Here’s how he described it : "Ecopoiesis is my neologism. The term refers to the fabrication of a sustainable ecosystem on a currently lifeless, sterile planet, thereby establishing a new arena in which biological evolution ultimately might proceed independent of further human husbandry… The expression ecopoiesis is derived from the Greek roots oikoV, an abode, house or dwelling place (from which we also derive ‘ecology’ and ‘economics’) and poihsiV, a fabrication or production (from which we derive ‘poesy’, as well as a variety of other biological terms such as biopoiesis, haematopoiesis, etc.)." Ecopoiesis is now used in the literature to describe the implantation of a pioneering, and hence microbial, ecosystem on a planet, either as an end in itself, or as an initial stage in a more lengthy process of terraforming. Ecopoiesis is a more modest aim, with less of the speculative extravagance associated with terraforming.
Within the bulk of his notes I identified at least one unpublished manuscript, an essay originally intended for an encyclopedia. It is re-printed here with Jane Haynes’ permission.
HOW MIGHT MARS BECOME A HOME FOR HUMANS? (c. 1993)
Robert H. Haynes, York University, Toronto, Canada.
People can live in inhospitable places in two distinct ways, by changing the local environment, or by carrying a suitable ‘environment’ with them. Desert irrigation for agricultural development is an example of the first, while the life-support systems of lunar landing modules, or orbiting space stations, exemplify the second mode of survival. The latter devices cannot be inhabited indefinitely; for lengthy stays the crews sooner or later become dependent on resupply missions from Earth. Recently, the President of the United States called for the establishment of bases for astronauts on the moon and Mars. The first human outposts in space will, of necessity, be of the second kind, even though some local resources may be exploited by their occupants. Human settlements on other planets can become fully and permanently independent of Earth only of these distant environments are transformed to provide Earth-like living conditions and a local agriculture. The realistic possibilities for this latter type of planetary engineering, carried out on a global scale, are assessed briefly in this essay.
Life is a planetary phenomenon, but Earth is the only living planet in the solar system. Plants and animals are mutually dependent products of Earth’s global ecosystem – the biosphere. All are intricately coupled with each other, and with land, oceans and air by the recycling of water, carbon, oxygen, nitrogen and other inorganic materials needed to maintain life. Humans also are component parts of this complex, ever-changing but to some extent self-regulating, biochemical system. We are exotic products of a planetary engine originally set in motion, and continuously fuelled, by energy from the sun.
On other planets, high and low extremes of atmospheric temperatures and pressures, lack of free oxygen and liquid water, high concentrations of toxic gases, and deadly radiation levels variously preclude the existence of life. Though presently barren, Mars, nonetheless, is a biocompatible planet. Its unalterable physical characteristics (e.g. size, density, gravity, orbit, rotation rate, incident sunlight) and its possible chemical resources are remarkably consistent with life. Indeed, it was the hope that organisms might be found on Mars that made life-detection the top priority for NASA’s Viking missions in 1976. However, all of the ingenious biological experiments carried out by the two robotic landers gave negative results.
The Viking data did reveal that environmental conditions on Mars are more severe than ever had been imagined. At the two ‘temperate zone’ landing sites, local temperatures exhibited wide daily variation averaging 60 degrees below zero celsius. The atmospheric pressure was found to be very low, just over six millibars, which is less than one hundredth of that at Earth’s surface. This thin atmosphere consists of 95% carbon dioxide and 3% nitrogen, with only trace amounts of water vapour, oxygen and other gases. There is no protective ozone layer to shield the planet from the ultraviolet radiation emitted by the sun. Most surprising was the absence from the soil of any detectable organic molecules, the building blocks of life. Even though such materials arrive on Mars in meteorites, they are subsequently destroyed, at least on the surface of the planet. Thus, any organisms which might arrive there unprotected today would be freeze-dried, chemically degraded, and soon reduced to dust. It would not be possible to ‘seed’ Mars just by sprinkling bacteria over its surface.
Despite its presently hostile environment, Mars did once possess a great northern ocean and substantial quantities of flowing water, together with a thick, mostly carbon dioxide, atmosphere. These conditions may have persisted long enough for early stages of chemical and cellular evolution to have occurred. It is largely for these reasons that some scientists have begun to consider whether Mars might ultimately be returned, by human intervention, to a habitable state. A major uncertainty in these discussions is whether there remains on Mars today adequate amounts of carbon dioxide, water and nitrogen to allow such a planetary-scale transformation. If most of Mars’ original endowment of these materials has been lost to space, then the regeneration of a habitable state would be impossible.
Preliminary studies have shown that if the surface crust and polar caps of Mars still possess sufficient and accessible quantities of carbon dioxide, water and nitrogen, and if acceptable planetary engineering techniques can be devised to initiate planetary warming and release these volatile materials from their geological reservoirs, then Mars could support a stable and much thicker carbon dioxide/nitrogen atmosphere than it does at present. This atmosphere would be warm and moist, and water would flow again in the dried up river beds. The average temperature at the surface would rise to about 15 degrees celsius and the atmospheric pressure would be roughly twice that on Earth. Appropriately selected, or genetically engineered, anaerobic microorganisms, and eventually some plants, could grow under these conditions. If future exploration reveals that the necessary volatiles are indeed available then a new home for life might someday be created on our sister planet.
The creation of a self-sustaining ecosystem, or biosphere, on a lifeless planet is called ecopoiesis, a new word which means ‘the making of an abode for life’. On Mars, as was the case on Earth, the earliest biosphere would most likely have to consist of localized microbial ecosystems growing and developing under anaerobic conditions. Obviously, this would not provide an environment in which animals or humans could survive outdoors. All oxygen-dependent organisms transported to Mars would have to remain enclosed in life-support modules or appropriate protective gear. The word ‘terraformation’ is used to describe the formation of specifically Earth-like, aerobic conditions on planets. Such a salubrious environment is only one of many possible long-term and not necessarily inevitable, outcomes of ecopoiesis. If we consider the spontaneous development of Earth’s biosphere as a model for what might be achieved by design on Mars, terraformation would have to be initiated subsequently to ecopoiesis. If we restrict our speculations to plausible, near-term technologies, the time periods required to carry out ecopoiesis and terraformation on Mars are very different. If suitable volatile inventories exist, the thick, warm atmosphere described above might be generated in as little as 200 years. However approximately 100,000 years would be required if an oxygen atmosphere was to be produced as efficiently as it was on Earth, that is, by microbial and green plant photosynthesis. However, it remains possible that presently unimagined, futuristic technologies could be developed to shorten these time estimates considerably.
For many people, including some leading scientists, talk of humanly initiated ecopoiesis and terraformation sounds more like science fiction than any justifiable program in space research. The obstacles posed by present conditions on Mars, quite apart from the costs entailed, seem almost insurmountable. In addition, the prospect of ecopoiesis, as a long-range objective for civilian space agencies, raises many unresolved philosophical, political and even legal questions. For example, do humans have any right to ‘play God’ on another planet?
Migration and the colonization of initially in hospitable environments has been one of the most astonishing historical features of biological evolution. The first living cells were formed at least 3.8 billion years ago, presumably in the darker reaches of the primeval, anerobic seas. At that time much of Earth’s surface environment, and certainly its land areas, would have been extremely hostile, if not downright lethal, to most of the organisms which flourish here today. However, in an amazing biotic diaspora, microrganisms, followed by plants and animals, migrated from marine to fresh water environments and then onto the initially barren land. None of this would have been possible were it not for the evolutionary development, by living cells, of the ‘technology’ of photosynthesis. Essentially all of the free oxygen (and the resulting ozone shield) in Earth’s atmosphere was, and is, generated by photosynthesis. Even though oxygen is poisonous to most anaerobic organisms, its accumulation in the atmosphere created the conditions necessary for the flowering of aerobic life as we know it today.
The slow, chancy processes of genetic variation, natural selection and species diversification have made possible the dispersal of nonhuman life across the globe. In contrast the migration and dispersal of Homo sapiens has not entailed any significant biological evolution, and certainly no speciation, ever since the emergence of ‘modern’ humans with linguistic and tool making capabilities about 100,000 years ago. Rather, it has been the amazingly rapid and efficient processes of social and technological evolution which have facilitated the propagation of our species, across every continent, and most recently into space.
In 1969 astronauts first set foot on the moon. If all goes well, others are scheduled to arrive on Mars in 2019. Against this background it is not just an idle dream to imagine that people might yet "slip the surly bonds of Earth" to pioneer new habitats in the sky. Further exploration of Mars may well reveal that ecopoiesis is feasible on that planet. Such a discovery would provide future generations with a tremendous challenge in life and an exhilarating vision of the role of humankind as a participant in creation. Perhaps however, there are also deep psychological and biological reasons for seeking to enliven Mars: such a vast enterprise would surely be consistent with the Promethean myths of many cultural traditions and the proliferative imperative that animates life itself.