Thursday, December 18, 2008

Living in a Pocket Biosphere

Mstislav, our most dedicated gardener now that Sledge rarely emerges from the Attic, has been tinkering with the carbon-dioxide balance, a dangerous but crucial sport. At six or seven hundred parts per million, the air in here is dreadful but sustains life. Regular jiggering of organic functions is needed to keep the ratio from ballooning to something deadly. To make a long story short, after an alarmingly high reading Mstislav discovered a mound of rotting mangrove fronds under a seemingly healthy hillock of wheatgrass—a camouflaged nightmare of poison-leaching compost. Endgame for us could be that simple, that foolish.
~ "Lostronaut" by Jonathan Lethem
Half of the oxygen in the air we breathe is produced by phytoplankton, tiny plants living in Earth's oceans. The plant life is crucial to maintaining the proper balance of gases in Earth's biosphere. It's only natural, then, that NASA has been trying to develop efficient bioregenerative life support systems that incorporate plants and bacteria for long term space settlements and space stations.

It's not an easy problem, though, either scientifically or politically, as NASA scientists pointed out back in 1997.
"If the current [funding] level is maintained, I would not expect to see a functional ground-based regenerative system for 10-15 years, or a space-rated system for 15-20 years," Finger said. "If a long-duration manned mission becomes a reality, then I would expect the budget to increase significantly for all aspects of life support research."

In addition to the reality of funding, doubts about the reliability of biological systems remain fixed in many people’s minds. Can a closed system recycle waste material quickly enough to renew vital resources? Will the reduced gravity environment of space affect the biological system in ways we cannot assess on Earth? What back-up life support must lunar or planetary colonies have if a plant-based system should fail? Above all, is the concept truly feasible?

"The challenges of designing a working bioregenerative life support system are gargantuan," Morris admitted. He noted that investigators will need to find ways to make such a system extraordinarily compact and energy-efficient. Physicochemical back-up systems add a slew of weight and energy requirements.

Browsing through the NASA web site, it doesn't look like there has been too much progress in the past ten years. The International Space Station (ISS) has a Plant Research Unit is being used to study the effects of microgravity on plant growth and reproduction . It's important research to determine the best plant strains and growth conditions for low gravity environments, but it's just one of the first steps in developing a self-sustaining environment. Science not Fiction has more about NASA's plant research.

But science fiction steps in where science has yet to go. Jonathan Letham's short story "Lostronaut", published in the November 17th issue of The New Yorker, is set on a space station orbiting Earth. The Chinese have planted mines below the station's orbit, preventing the astronauts from leaving the station or supplies from being delivered. They are completely dependent on the the slowly deteriorating systems, including the plant beds that provide them with oxygen and absorb excess carbon dioxide. Letham doesn't provide a lot of scientific details, but does give us a moving story of memory and love and death and life.

Read Jonathan Lethem's "Lostronaut"

For more technical information about plant research on the International Space Station, see "Factors Affecting the Utilization of the International Space Station for Research in the Biological and Physical Sciences" (2003)

Top Image: 39-inch closed glass Ecosphere in the Rose Center for Earth and Space, American Museum of Natural History. The sphere is a closed ecosystem containing small shrimp, bacteria and algae in salt water. Credit: me.

Bottom Image: Corn growing under red LED grow lights, which would be efficient for growing plants in space. Source: NASA.


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3 comments:

Sean Craven said...

Mangrove? Wheat?

Here's my take on the whole biosphere thing. When I read about Biosphere II, my initial thought on reading the list of plants and animals and environments they were using was that this wasn't a serious experiment -- it was an attempt to create a gum-drop and rainbow fantasy land filled with beauty and wonder and hugs and cuddles.

When the word 'mangrove' came in here, I saw the same kind of design going on. Of course those poor astronauts are doomed -- remember what happened to the crew of Biosphere II and they had the option of using Earth's atmosphere in case of emergency.

I'll have to read the story, though. Lethem's one of the good ones.

The idea that a biosphere should use the entire Earth or even one particular terrestrial environment as a model is just whacky. There are too many unknown and under-examined factors in play for this to work well.

If I were to create a biosphere actually intended to sustain life I'd put almost all my effort into micro-organisms and work my way up, adding macro-organisms on the basis of practical use.

Here's an instructional video on making a desktop biosphere -- this seems like a more reasonable approach.

http://www.youtube.com/watch?v=s_WWG9rTUyI

Ford said...

Then again, you could see Biosphere II as as experiment to test the hypothesis that, given enough biodiversity, a self-regulating biosphere compatible with humans will emerge automatically. It's just that the hypothesis turned out to be wrong.

Thomas said...

To paraphrase Herbert, ecology is simply the free play of energy within a self ordering system.

It's been fairly well established that life, once established, will creep and cling to just about every environment and that life does much to soften environments and allow for the evolution or importation of more life.

The question is not whether we can create a self-sustaining biosphere but rather can we engineer an environment that will sustain us.