Of Earth
For thousands of years, both natural and industrial processes have caused the bedrock of the Rio Tinto in Spain—a river that has been mined since antiquity and that now lends its name to a global mining conglomerate—to become highly acidic and full of heavy metals. This poisonous landscape, where streams run red with rust, is almost devoid of all plants and animals, but bacteria are everywhere. Earth has been a bacterial planet for far longer than it has been a human one. Seeking signs of interplanetary life at the lunar south poles, on Mars, or on the moons of Jupiter requires that we reflect on the role microbes played in producing life on our planet.
Any potential extraterrestrial life form will have to overcome what we perceive to be hostile extremes of temperature, of radiation both solar and galactic, and gravitational forces. As a result, astrobiologists concerned with finding such lifeforms have been studying extremophiles—particularly adaptable bacteria capable of withstanding stressful extreme environments—here on Earth at places called “terrestrial analogue sites.” These are places on Earth that are determined to be close matches to places on other planets. The Rio Tinto, for instance, is a terrestrial analogue for Mars. Researchers conducting enquiries into the limits of life peer at tiny forms of life that blur the boundary between the geological and biological.
Lithotrophic bacteria are beings with an appetite for rocks and metal (litho meaning rock, troph meaning eater). Whereas most microbes obtain energy from sunlight or organic compounds, lithotrophic microbes thrive in acidic and metallic environments and consume the mineral structure of the rocks they naturally live within. In doing so, they produce a metal-rich liquid, or “leachate.” In other words, microbes eat the rock and leave metal behind. These beings have known the earth longer than any other lifeform. They are old life forms—2.1 billion years old—surviving on even older rock, and are identifiable by the slippery, brightly colored surfaces they create.
These bacteria work very slowly. This type of biology operates on geological time. Here, at the point of metabolization, rock is turned into energy. As the living bacteria eat away at ancient rock, they are, in effect, eating through time. In the words of geologist Marcia Bjorerud, “geology provides a lens through which we can witness time in a way that transcends human experience.”1 Comprehending the life of lithotrophic bacteria requires transcending our accepted understanding of biological lifeforms; their lives demonstrate a plasticity of scale that stretches from the microscopic to the planetary.
Lithotrophic bacteria eat rocks in extreme places, and, in turn, reduce toxicity. They have played a major part in turning Earth into a habitable planet, turning rock and dust into arable soils over millions of years. Human miners have unknowingly been helped by these bacteria for hundreds of years. But as is often the case with geological discoveries, once they became fully understood, these bacteria captured the imagination of the extractive industries.
Traditional mining techniques of blasting, crushing, and smelting are, although destructive, relatively effective at relinquishing sought-after elements from rock. Yet they produce vast amounts of low-grade mine tailings and toxic runoff.2 Lithotrophic bacteria often naturally occur in spent mining sites because such toxic conditions are where they like to live, and it’s at these locations where the industry of biomining is currently deployed at scale.
Approximately 20% of the world’s copper and 5% of the world’s gold are extracted using bacteria.3 Copper is generally biomined by releasing a microbial-rich cocktail into heaps of mine tailings, catching the leached metal-rich liquids (leachate), and then extracting the metal from this concentrate. This process can produce high purity metals from what was otherwise considered mining waste, and is therefore used in places with otherwise dwindling resource reserves.
In their feasting, lithotrophic bacteria also remove toxins from their environments. They are therefore also deployed in bioremediation efforts, in an attempt to reverse the environmental destruction of mining corporations and to neutralize persistent toxicity, both chemically and politically.
Off Earth
Sending heavy mining equipment beyond Earth’s atmosphere is expensive. This poses a problem for space agencies and entrepreneurs scouting the Moon and Mars for extractable resources.4 The parallel extremities of lithotrophic bacteria habitats on Earth and the environmental conditions of other planets position biomining as an attractive option for extraterrestrial resource extraction. Furthermore, these parallels create the potential for some equipment to be microscopic (i.e., lighter), and place off-Earth extraction a little more within reach.
In 2020, researchers from the UK Centre for Astrobiology, based at the University of Edinburgh, conducted an experiment on the International Space Station called BioRock. The researchers sent three samples of basalt—a rock common on the Moon and Mars—populated with biomining bacteria into space. Each was tested under three different levels of gravity: weightlessness, Martian gravity, and Earth’s gravity. Of all the results, one strain of bacteria, Sphingomonas desiccabilis, was unaffected by the different levels of gravity, and formed a new surface—a biofilm—over the basalt on each.5
Astrobiologists have hypothesized that bacteria (like Sphingomonas desiccabilis) could be used in outer space for terraforming nutrient-poor regoliths into more pliant lunar or Martian soils, for using regolith as a feedstock within microbial life support systems or biofuel production, for recycling electronic waste parts, and for the production of construction materials. Such operational and technical appraisals render living microbes into non-living technology. The microscopic world becomes a scientific tool, an epistemological space for the advancement of astro-infrastructural imaginations.6 This is further magnified by the adjectives used to describe microbes’ behavioral traits: phrases like “growth of a bacterial colony” or “viability of molecular life” each give clues about their intended applications.
As part of Into the Deep, a 2023 exhibition at the Zeppelin Museum, metal-rich liquid was produced from biomining bacteria that had eaten deep sea metallic nodules and copper concentrate (creating brown-toned and blue-toned leachates respectively). The colors of the liquids were artificially enhanced, paralleling techniques used in the production of astronomical imagery and reflecting the prioritization of the visual in communicating scientific research. Photo courtesy of the author.
Imaginaries
The earliest dreams of lunar mining emerged only once lunar samples were brought back to Earth during NASA’s Apollo program. Once geologists, military personnel, and legal experts could see chunks of moon rock with their own eyes, they began to conjure an extractive future for the Moon.7 This has long been depicted in illustrations of machinery perched on the edge of lunar craters or autonomous robotic harvesters. These visions of lunar mining persist in current imagery from the NASA Artemis program, which depicts moon bases, drill sites, and astronauts with pickaxes.8
In contrast to these seductive, yet somewhat familiar renderings, a gently sepia-tinged puddle, or a slightly slimy stone (both trademark signs of biomining) appear subdued. Even large-scale operations are just piles of rocks with irrigation hoses, or large tanks filled with water being stirred. Certainly biomining is no match for the slick theatrics of the space industry with its rockets, space walks, count downs, and lift offs. Astrobiological research indicates that a more-than-human cooperation in outer space is on the horizon, beyond just humans and machines. Yet bacteria are microscopic, and therefore their visual representations remain largely absent.
In writing on the conjuring of colonial spaces, Anna Lowenhaupt Tsing claims that the frontier is the space of imagination, of magical vision. It is “a zone of not yet.” Even in its planning, a frontier is imagined as unplanned. It asks participants to dream of a place at “the edge of space and time,” and of a landscape that is not yet known.9 The “final frontier” (as outer space is often dubbed in the west) is no different: it is a place of where the litany of terrestrial errors promises be resolved, but is nevertheless described as an empty place, devoid of borders, an enclave of extreme wealth and extreme adventure.10
When space exploration began in earnest in the 1960s, key utopian documents were drafted and endorsed by the United Nations to designate the extraterrestrial realm as a haven for peace. Both the Outer Space Treaty (1967) and the Moon Treaty (1979) prescribe the collective use of space materials, establishing that the exploration and use of outer space will be undertaken for the benefit of and interest of all countries. However, space missions have changed dramatically over the past six decades. In 2015, the United States government acknowledged this by passing the Spurring Private Aerospace Competitiveness and Entrepreneurship (SPACE) Act into law.11 Space is no longer an arena reserved for governmental organizations and nation states, but also for commercial entities. All, however, might use scientific exploration and resource scarcity here on Earth to advance competitive territorial agendas, threatening the existing legal treaties. Outer space has become an interplanetary network state, a startup world, a silicone moon.12
Surface
New mapping technologies have changed our spatial and temporal orientation from the horizontal perspective to the vertical.13 The horizontal perspective allows for the orientation of the self in relation to the horizon, to objects within a landscape. This was the dominant perspective before airplanes and satellite technology. The vertical perspective of satellite imagery, the “God’s Eye View,” erases the horizon altogether, and, along with it, any sense of orientation between the self and objects within that landscape. When viewed from above, what is below, the “underground,” is non-existent. Captured through satellite imagery, Earth becomes a single surface, a veneer.14
Bethany Rigby, Counting Satellites, 2021. Each of the 289 new satellites sent into the upper atmosphere over a six-week period in 2020 was recorded with a hole punched into a printed copy of the Outer Space Treaty.
A large number of accessible images of Mars or the Moon are photographs taken with onboard cameras, from the perspective of rovers such as Perseverance, or from cameras in the hands of astronauts during the Apollo era. From the six-foot-three-inch height of Perseverance’s Mastcam lens, hundreds of panoramic Martian vistas are beamed back to Earth. From other onboard eyes, we observe Martian regolith, boulders, cliffs, soils, and sands. There are close inspections of holes drilled by the rover, or shots looking back at its tire tracks. These intimate views make it easier to imagine futures within this landscape.
While extractive processes are far removed from the everyday experience of many, the texture of rock, of soil, is more familiar. We have a tactile understanding of Earth’s surface, but for the most part we only experience the surface of other planets visually. Very few of us will ever actually feel the surface of other planets in the form of rocks or soil, and even fewer will actually visit them. Terrestrial analogues (either natural ones, like Rio Tinto or Iceland, or manufactured ones in test labs) could be sites for nurturing a knowledge of and intimacy with other planets. This is already the case for astronauts and machines who visit terrestrial analogue sites for training and testing. But maybe terrestrial analogues don’t need to be reserved for experts only.
Alternative imaginaries of extraterrestrial landscapes are urgently needed, ones that subvert predictable narratives and detract from the monofunctional, extractivist view. How are we to understand the potential significance of places like the lunar south pole, or other “permanently shadowed craters” where no sunlight has ever reached, beyond the fact that they have a high probability of water ice, which is necessary for any future lunar base? What if instead of being used exclusively for resource extraction, the lunar south pole became a resort for tourists seeking to escape a light polluted Earth with a “darkness vacation”? And would it be such a surprise if one of the first acts of terraforming on Mars would be to create a golf course? Golf is, after all, a favorite sport of the super-rich, and historically followed the British empire’s expansion. It is already practiced in the deserts of Nevada and Saudi Arabia—both analogues for Mars. A starting point for adjusting our modes of thought might be to envision how its equipment might need to change to adjust to Martian gravity.
Marcia Bjorerud, Timefulness (Princeton University Press, 2018), 16.
It’s pertinent to note here that the construction industry—meaning architecture—is responsible for 30% of the extraction of natural resources globally, and therefore intimately entwined with these consequences.
D. Barrie Johnson, Barry M. Grail, and Kevin B. Hallberg, A New Direction for Biomining: Extraction of Metals by Reductive Dissolution of Oxidized Ores, Minerals 3, no. 1 (2013): 49–58.
In 2014 the NASA Advisory Council reported that “The mismatch between NASA’s aspirations for human spaceflight and its budget for human spaceflight is the most serious problem facing the Agency.” NASA Advisory Council Recommendation, “Mismatch Between NASA’s Aspirations for Human Space Flight and Its Budget, 2014-02-01 (Council-01),” February 1, 2014, ➝.
C. S. Cockell, R. Santomartino, K. Finster, et al., “Space station biomining experiment demonstrates rare earth element extraction in microgravity and Mars gravity,” Nature Communications 11, no. 5523 (2020).
Sophia Roosth, “Life, Not Itself: Inanimacy and the Limits of Biology,” Grey Room 57 (October 2014): 56–81.
Julie Klinger, Rare Earth Frontiers (Cornell University Press, 2017).
“NASA Names Companies to Develop Human Landers for Artemis Moon Missions,” NASA, April 30, 2020, ➝.
Anna Lowenhaupt Tsing, Friction: an Ethnography of Global Connection (Princeton University Press, 2002).
Julie Klinger, Rare Earth Frontiers (Cornell University Press, 2017).
The Spurring Private Aerospace Competitiveness and Entrepreneurship (SPACE) Act of 2015, now often referred to as the Commercial Space Launch Competitiveness Act.
Gabriel Gatehouse, “The crypto bros who dream of crowdfunding a new country,” BBC, September 20, 2024, ➝.
Hito Steyerl, “In Free Fall: A Thought Experiment On The Vertical Perspective,” e-flux journal 24, 2011, ➝.
Steyerl, along with cartographic historians, infers that this domineering view over Earth seeps into human behaviors and the relationship that we have to the planet and the beings upon it.
Off-Earth is a collaboration between e-flux Architecture and the Luxembourg Center for Architecture (LUCA) and supported by the Luxembourg Ministry of Culture following “Down to Earth,” the Luxembourg Pavilion at the 2023 Venice Architecture Biennale, curated by Francelle Cane and Marija Marić.
