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
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
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