PROJECTS: BIOSPHERE

makezine.com/10/biosphere

Beyond Spaceship Earth

At least 5kg of food, water, and oxygen must be lifted into space for every person-day spent on the International Space Station, relates NASA’s Mark Kliss. For human habitation on the Moon, Mars, or elsewhere — stays of hundreds or thousands of days — that adds up to an unworkable ball and chain.

That’s why Kliss and others are trying to replicate the closed-system sustainability of Spaceship Earth. Academics have long built “closed ecosystem” models for streams or lakes to investigate subjects like carbon cycling and population dynamics. For potential space travel, the conditions are far more constrained. Species may be mixed in ways never seen in nature, but must include the target species, humans.

American and Russian space scientists have been working on the problem since the 1960s. Early Russian tests were brutally simple: one guy climbed into a cask with little more than a light and a bucket of photosynthetic algae, to stumble out 24 hours later, alive and stinking. Progress has been slow, and no bioregenerative systems have yet been used in space for human life support.

Research has followed two paths. Space agencies have focused on highly engineered systems that include just a few well-understood species and fully account for their chemical products and needs.

118 Make: Volume 10

“Econaut” Jane Poynter working within Biosphere 2.

Projects like Biosphere 2 (and the TSSM project here), however, take a more top-down approach. Thousands of species were imported to Biosphere 2’s fantastic glass structure in the Arizona desert, and assembled into new forests, farms, and “oceans.” By the time eight jump-suited “econauts” were sealed in, in 1991, it was a publicity juggernaut.

Over the next two years — the duration of a Mars expedition — the econauts met the recycling challenge, surviving very largely on regenerated air, food, and water. But their elaborate menagerie suffered a hard shakeout. Oxygen declined to dangerously low levels, and food became scarce. Extinctions were rampant and, critically, included all the pollinating species.

Life in Biosphere 2, that questing ecological utopia, wasn’t sustainable. When ecosystems are sealed off, it’s Escape from New York. Systems must balance locally, and an ecological shakeout ensues. The community that emerges may be strange and new, or as dismal as pond scum. Even with our TSSM, you can follow the same recipe to bottle up more than one tabletop biosphere, and things will evolve in different directions.

As Kliss philosophizes, closed ecosystems tread a fine line between symbiosis and mutual parasitism. Will the inhabitants help each other survive, or eat each other alive?

Resources at makezine.com/10/biosphere

Photograph courtesy of Roy L. Walford Living Trust