# Controlled ecological life-support system > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Controlled_ecological_life-support_system > Markdown URL: https://mediated.wiki/source/Controlled_ecological_life-support_system.md > Source: https://en.wikipedia.org/wiki/Controlled_ecological_life-support_system > Source revision: 1309410641 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) Technology on Space Stations & Closed Ecosystems This article includes a list of general references, but it lacks sufficient corresponding inline citations. Please help to improve this article by introducing more precise citations. (September 2010) (Learn how and when to remove this message) **Controlled** (or **closed**) **ecological life-support systems** (acronym **CELSS**) are self-supporting [life-support systems](/source/Life-support_system) for [space stations](/source/Space_stations) and colonies typically through controlled [closed ecological systems](/source/Closed_ecological_system), such as the [BioHome](/source/BioHome), [BIOS-3](/source/BIOS-3), [Biosphere 2](/source/Biosphere_2), [Mars Desert Research Station](/source/Mars_Desert_Research_Station), and [Yuegong-1](/source/Yuegong-1). ## Original concept CELSS was first pioneered by the [Soviet Union](/source/Soviet_Union) during the famed "[Space Race](/source/Space_Race)" in the 1950s–60s. Originated by [Konstantin Tsiolkovsky](/source/Konstantin_Tsiolkovsky) and furthered by [V.I. Vernadsky](/source/Vladimir_Vernadsky), the first forays into this science were the use of closed, uncrewed ecosystems, expanding into the research facility known as the [BIOS-3](/source/BIOS-3). Then in 1965, crewed experiments began in the [BIOS-3](/source/BIOS-3). ## Rationale [Human presence in space](/source/Human_presence_in_space), thus far, has been limited to the [Earth](/source/Earth)–[Moon](/source/Moon) system. Also, everything that [astronauts](/source/Astronauts) would need in the way of life support ([air](/source/Air), [water](/source/Water), and [food](/source/Food)) has been brought with them. This may be feasible for short missions of [spacecraft](/source/Spacecraft), but it is not the most viable solution when dealing with the life-support systems of a long-term craft (such as a [generation ship](/source/Generation_ship)) or a settlement. The aim of CELSS is to create a regenerative environment that can support and maintain [human](/source/Human) life via [agricultural](/source/Agricultural) means. ## Components of CELSS ### Air revitalization In non-CELSS environments, air replenishment and [CO2](/source/Carbon_dioxide) processing typically consists of stored [air tanks](/source/Oxygen_tank) and [CO2 scrubbers](/source/Carbon_dioxide_scrubber). The drawback to this method lies in the fact that upon depletion the tanks would have to be refilled; the scrubbers would also require replacement after they become ineffective. There is also the issue of processing [toxic fumes](/source/Outgassing), which come from the [synthetic](/source/Chemical_synthesis) materials used in the construction of habitats. Therefore, the issue of how [air quality](/source/Air_quality) is maintained requires attention; in experiments, it was found that the plants also removed [volatile organic compounds](/source/Volatile_organic_compounds) [offgassed](/source/Offgassed) by synthetic materials used thus far to build and maintain all man-made habitats. In CELSS, air is initially supplied by external supply, but is maintained by the use of [foliage](/source/Foliage) plants, which create [oxygen](/source/Oxygen) in [photosynthesis](/source/Photosynthesis) (aided by the waste-byproduct of human [respiration](/source/Respiration_(physiology)), CO2). Eventually, the main goal of a CELSS environment is to have foliage plants take over the complete and total production of oxygen needs; this would make the system a *closed*, instead of *controlled*, system. ### Food / consumables production As with all present forays into space, crews have had to store all [consumables](/source/Consumables) they require prior to launch. Typically, hard-food consumables were [freeze dried](/source/Freeze_dried) so that the craft's weight could be reduced. Of course, in a self-sustaining ecosystem, a place for crops to grow would be set aside, allowing foods to be grown and cultivated. The larger the group of people, the more crops would have to be grown. As for water, experiments have shown that it would be derived from [condensate](/source/Condensation) in the air (a byproduct of [air conditioning](/source/Air_conditioning) and vapors), as well as excess moisture from plants. It would then have to be filtered by some means, either by nature or by machine.[*[citation needed](https://en.wikipedia.org/wiki/Wikipedia:Citation_needed)*] ### Waste-water treatment Early space-flight had travelers either ejecting their wastes into space or storing it for a return trip. CELSS studied means of breaking down [human wastes](/source/Human_waste) and, if possible, integrating the processed products back into the ecology. For instance, [urine](/source/Urine) was processed into water, which was safe for use in [toilets](/source/Toilet) and watering plants. Wastewater treatment makes use of plants, particularly aquatic, to process the wastewater. It has been shown that the more waste is treated by the [aquatic plants](/source/Aquatic_plant) (or, more specifically, their [root systems](/source/Root_system)), the larger the aquatic plants grow. In tests, such as those done in the [BioHome](/source/BioHome), the plants also made viable [compost](/source/Compost) as a [growth medium](/source/Growth_medium) for crops. ## Closed versus controlled Closed systems are totally self-reliant, recycling everything indefinitely with no external interaction. The life of such a system is limited, as the [entropy](/source/Entropy) of a closed system can only [increase with time](/source/Second_law_of_thermodynamics). But if the otherwise closed system is allowed to accept high-temperature [radiant energy](/source/Radiant_energy) from an external source (e.g., sunlight) and to reject low-temperature waste heat to deep space, it can continue indefinitely. An example of such a system is the [Earth](/source/Earth) itself. Controlled systems, by contrast, depend on certain external interactions such as periodic [maintenance](/source/Maintenance%2C_repair_and_operations). An example of such a system is the [ISS](/source/ISS). ## Notable CELSS projects See also: [Category:Controlled ecological life support systems](https://en.wikipedia.org/wiki/Category:Controlled_ecological_life_support_systems) - [BioHome](/source/BioHome) - [Biosphere 2](/source/Biosphere_2) - [BIOS-3](/source/BIOS-3) - Biosphere J[1] - Controlled Environment Systems Research Facility[2] - [Biotron (disambiguation)](/source/Biotron_(disambiguation)) - [Biotron Experimental Climate Change Research Facility](/source/Biotron_(Western_University))[3] - [ALS-NSCORT](https://docs.lib.purdue.edu/alsnscort/) - Advanced Life Support - NASA Specialized Center of Research and Training ## Other types of regenerative ecological systems - [Bioregenerative life support system](/source/Bioregenerative_life_support_system) (acronym: BLSS) - [Environmental Control and Life Support System](/source/Environmental_Control_and_Life_Support_System) ([acronym](/source/Acronym) ECLSS) - [Engineered Closed/Controlled EcoSystem](https://en.wikipedia.org/w/index.php?title=Engineered_Closed/Controlled_EcoSystem&action=edit&redlink=1) ([acronym](/source/Acronym) ECCES) - [Spome](/source/Spome) ## See also - [Life-support system](/source/Life-support_system) - [Closed ecological system](/source/Closed_ecological_system) - [Arcology](/source/Arcology) ## References 1. **[^](#cite_ref-1)** [Biosphere J](http://www.ecotechnics.edu/1996.html) [Archived](https://web.archive.org/web/20060912163253/http://www.ecotechnics.edu/1996.html) 2006-09-12 at the [Wayback Machine](/source/Wayback_Machine) 1. **[^](#cite_ref-2)** [Controlled Environment Systems Research Facility](http://www.ces.uoguelph.ca), University of Guelph 1. **[^](#cite_ref-3)** [Biotron Experimental Climate Change Research Facility](http://www.biotron.uwo.ca), University of Western Ontario - Borthwick, Lindsey (2008). ["OnEarth Magazine » Biologists Dig Deeper"](http://www.onearth.org/article/biologists-dig-deeper). - Prado, Mark (2002). ["Ecological Issues and CELSS"](http://www.permanent.com/s-celss.htm). *PERMANENT Project*. Retrieved April 19, 2006. - Prado, Mark (2002). ["Russian CELSS Studies"](http://www.permanent.com/s-bios3.htm). *PERMANENT Project*. Retrieved April 19, 2006. - Fitch, Cris (2003). ["Biospheres, Controlled Ecosystems, and Life Support Systems"](https://web.archive.org/web/20061021195859/http://www.orbit6.com:80/celss/celss.htm). *Orbit 6*. Archived from [the original](http://www.orbit6.com:80/celss/celss.htm) on 2006-10-21. Retrieved April 19, 2006. - ["Functions of a CELSS"](https://web.archive.org/web/20061107170038/http://library.thinkquest.org/12145/lifes3.htm). *Mars Academy*. Archived from [the original](http://library.thinkquest.org/12145/lifes3.htm) on November 7, 2006. Retrieved April 19, 2006. 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