Closed Ecological Life Support Systems

From Gaia Wiki
Jump to: navigation, search
An interior view of Biosphere 2.
"There is about [human-built] biospheres an air of evolutionary inevitability.... From an evolutionary perspective what we are witnessing with Biosphere 2 is the budding, the first tentative reproducing of planet Earth as a biological identity.... Whereas before we have reproduction of cells and the multicellular collections of cells in the form of individual protoctists, fungi, plants and animals, with the advent of biospheres we now see the first reproduction of ecosystem enclaves as discrete, semi-independent units. This represents something new not only in the limited realm of greenhouses and human technology but also in the larger domain of Earth history."
- Lynn Margulis and Dorion Sagan, Gaia and Biospheres, 1987, as quoted in Jane Poynter, The Human Experiment: Two Years and Twenty Minutes Inside Biosphere 2, 2006

Closed Ecological Life Support Systems (CELSS) are generally described as systems in which living organisms provide for the needs of humans living in small airtight environments, conceived as one option for maintaining air, water, and food supplies for space colonies. However, defined more generally as materially closed environments in which life maintains the conditions for its own existence, the concept has clear Gaian implications as well. In that sense, Gaia herself is a giant CELSS, which is why the most famous CELSS experiment was named Biosphere 2. (Note that as described by geophysiology, a CELSS is materially closed but must accept energy input from outside in order to achieve long-term sustainability.) Creating a fully self-sustaining CELSS would arguably be an act of ecopoeisis, differing only in scale from a planetary terraforming project.

List of CELSS projects


  • BIOS-3, a small habitat at the Institute of Biophysics in Krasnoyarsk, Russia, with tests starting in 1972 with three occupants staying inside for up to 180 days.
  • CEBAS, an acronym for Closed Equilibrated Biological Aquatic System, a German aquarium experiment on the International Space Station
  • MELiSSA, an acronym for Micro-Ecological Life Support System Alternative, based in Spain.
  • Lunar Palace 1, a.k.a. the Integrative Experimental Facility for Permanent Astrobase Life-support Artificial Closed Ecosystem (PALACE) Research, a Chinese habitat whose initial mission supported three people for 105 days.


  • Biosphere 2, a massive greenhouse near Tucson, Arizona, built by Space Biosphere Ventures and Decisions Investment, which supported eight human occupants for two years beginning in 1991.