Controlled (or closed) ecological life-support systems (acronym CELSS) are a self-supporting
life support system
A life-support system is the combination of equipment that allows survival in an environment or situation that would not support that life in its absence. It is generally applied to systems supporting human life in situations where the outsid ...
for
space stations
A space station is a spacecraft capable of supporting a human crew in orbit for an extended period of time, and is therefore a type of space habitat. It lacks major propulsion or landing systems. An orbital station or an orbital space station is ...
and colonies typically through controlled
closed ecological system
Closed ecological systems (CES) are ecosystems that do not rely on matter exchange with any part outside the system.
The term is most often used to describe small, manmade ecosystems. Such systems are scientifically interesting and can potential ...
s, such as the
BioHome
BioHome was a small facility created by NASA in the late 1980s that could support one person in a fully functional habitat. One of the influences on the project was the results from data obtained on the 1973 Skylab 3 (SL-3), where a total of 10 ...
,
BIOS-3
BIOS-3 is an experimental closed ecosystem at the Institute of Biophysics in Krasnoyarsk, Russia.
Its construction began in 1965, and was completed in 1972. BIOS-3 consists of a underground steel structure suitable for up to three persons, and ...
,
Biosphere 2
Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the univers ...
,
Mars Desert Research Station
The Mars Desert Research Station (MDRS) is the largest and longest-running Mars surface research facility in the world and is one of two simulated Mars analog habitats owned and operated by the Mars Society.
The MDRS station was built in the e ...
, and
Yuegong-1.
Original concept
CELSS was first pioneered by the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen national ...
during the famed "
Space Race
The Space Race was a 20th-century competition between two Cold War rivals, the United States and the Soviet Union, to achieve superior spaceflight capability. It had its origins in the ballistic missile-based nuclear arms race between the tw ...
" in the 1950s–60s. Originated by
Konstantin Tsiolkovsky
Konstantin Eduardovich Tsiolkovsky (russian: Константи́н Эдуа́рдович Циолко́вский , , p=kənstɐnʲˈtʲin ɪdʊˈardəvʲɪtɕ tsɨɐlˈkofskʲɪj , a=Ru-Konstantin Tsiolkovsky.oga; – 19 September 1935) ...
and furthered by
V.I. Vernadsky, the first forays into this science were the use of closed, unmanned ecosystems, expanding into the research facility known as the
BIOS-3
BIOS-3 is an experimental closed ecosystem at the Institute of Biophysics in Krasnoyarsk, Russia.
Its construction began in 1965, and was completed in 1972. BIOS-3 consists of a underground steel structure suitable for up to three persons, and ...
.
Then in 1965, manned experiments began in the
BIOS-3
BIOS-3 is an experimental closed ecosystem at the Institute of Biophysics in Krasnoyarsk, Russia.
Its construction began in 1965, and was completed in 1972. BIOS-3 consists of a underground steel structure suitable for up to three persons, and ...
.
Rationale
Human presence in space
Human presence in space is about humanity in space, particularly about all anthropogenic presence in space and human activity in space, that is in outer space and in a broader sense also on any extraterrestrial astronomical body.
Humans have ...
, thus far, has been limited to our own
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
–
Moon
The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...
system. Also, everything that
astronauts
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally r ...
would need in the way of life support (
air
The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing f ...
,
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
, and
food
Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inge ...
) has been brought with them. This may be economical for short missions of
spacecraft
A spacecraft is a vehicle or machine designed to fly in outer space. A type of artificial satellite, spacecraft are used for a variety of purposes, including communications, Earth observation, meteorology, navigation, space colonization, p ...
, 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
A generation ship, or generation starship, is a hypothetical type of interstellar ark starship that travels at sub-light speed. Since such a ship might require hundreds to thousands of years to reach nearby stars, the original occupants of a gene ...
) or a settlement.
The aim of CELSS is to create a regenerative environment that can support and maintain
human
Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...
life via
agricultural
Agriculture or farming is the practice of cultivating Plant, plants and livestock. Agriculture was the key development in the rise of Sedentism, sedentary human civilization, whereby farming of Domestication, domesticated species created food ...
means.
Components of CELSS
Air revitalization
In non-CELSS environments, air replenishment and processing typically consists of stored
air tanks and
scrubbers. 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, which come from the
synthetic materials used in the construction of habitats. Therefore, the issue of how
air quality
Air pollution is the contamination of air due to the presence of substances in the atmosphere that are harmful to the health of humans and other living beings, or cause damage to the climate or to materials. There are many different types ...
is maintained requires attention; in experiments, it was found that the plants also removed
volatile organic compounds
Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature
Colloquially, "room temperature" is a range of air temperatures that most people prefer for indoor settings. It feels comfortable to a ...
offgassed
Outgassing (sometimes called offgassing, particularly when in reference to indoor air quality) is the release of a gas that was dissolved, trapped, frozen, or absorbed in some material. Outgassing can include sublimation and evaporation (which ...
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
A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, s ...
plants, which create
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
in
photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
(aided by the waste-byproduct of human
respiration
Respiration may refer to:
Biology
* Cellular respiration, the process in which nutrients are converted into useful energy in a cell
** Anaerobic respiration, cellular respiration without oxygen
** Maintenance respiration, the amount of cellul ...
, ). 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
Consumables (also known as consumable goods, non-durable goods, or soft goods) are goods that are intended to be consumed. People have, for example, always consumed food and water. Consumables are in contrast to durable goods. Disposable products ...
they require prior to launch. Typically, hard-food consumables were
freeze dried
Freeze drying, also known as lyophilization or cryodesiccation, is a low temperature dehydration process that involves freezing the product and lowering pressure, removing the ice by sublimation. This is in contrast to dehydration by most conve ...
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
Condensate may refer to:
* The liquid phase produced by the condensation of steam or any other gas
* The product of a chemical condensation reaction, other than water
* Natural-gas condensate, in the natural gas industry
* ''Condensate'' (album) ...
in the air (a byproduct of
air conditioning
Air conditioning, often abbreviated as A/C or AC, is the process of removing heat from an enclosed space to achieve a more comfortable interior environment (sometimes referred to as 'comfort cooling') and in some cases also strictly controlling ...
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.
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 waste
Human waste (or human excreta) refers to the waste products of the human digestive system, menses, and human metabolism including urine and faeces. As part of a sanitation system that is in place, human waste is collected, transported, treated a ...
s and, if possible, integrating the processed products back into the ecology. For instance,
urine
Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excretion, excreted from the body through the urethra.
Cel ...
was processed into water, which was safe for use in
toilet
A toilet is a piece of sanitary hardware that collects human urine and feces, and sometimes toilet paper, usually for disposal. Flush toilets use water, while dry or non-flush toilets do not. They can be designed for a sitting position popu ...
s 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 plant
Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes to distinguish them from algae and other microphytes. A macrophyte is a plant that ...
s (or, more specifically, their
root system
In mathematics, a root system is a configuration of vectors in a Euclidean space satisfying certain geometrical properties. The concept is fundamental in the theory of Lie groups and Lie algebras, especially the classification and representati ...
s), the larger the aquatic plants grow.
In tests, such as those done in the
BioHome
BioHome was a small facility created by NASA in the late 1980s that could support one person in a fully functional habitat. One of the influences on the project was the results from data obtained on the 1973 Skylab 3 (SL-3), where a total of 10 ...
, the plants also made viable
compost
Compost is a mixture of ingredients used as plant fertilizer and to improve soil's physical, chemical and biological properties. It is commonly prepared by decomposing plant, food waste, recycling organic materials and manure. The resulting m ...
as a
growth medium
A growth medium or culture medium is a solid, liquid, or semi-solid designed to support the growth of a population of microorganisms or cells via the process of cell proliferation or small plants like the moss ''Physcomitrella patens''. Differen ...
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
Entropy is a scientific concept, as well as a measurable physical property, that is most commonly associated with a state of disorder, randomness, or uncertainty. The term and the concept are used in diverse fields, from classical thermodynam ...
of a closed system can only
increase with time. But if the otherwise closed system is allowed to accept high-temperature
radiant energy
Radiant may refer to:
Computers, software, and video games
* Radiant (software), a content management system
* GtkRadiant, a level editor created by id Software for their games
* Radiant AI, a technology developed by Bethesda Softworks for '' ...
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
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
itself.
Controlled systems, by contrast, depend on certain external interactions such as periodic
maintenance
Maintenance may refer to:
Biological science
* Maintenance of an organism
* Maintenance respiration
Non-technical maintenance
* Alimony, also called ''maintenance'' in British English
* Champerty and maintenance, two related legal doct ...
. An example of such a system is the
ISS
The International Space Station (ISS) is the largest modular space station currently in low Earth orbit. It is a multinational collaborative project involving five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (J ...
.
Notable CELSS projects
*
BioHome
BioHome was a small facility created by NASA in the late 1980s that could support one person in a fully functional habitat. One of the influences on the project was the results from data obtained on the 1973 Skylab 3 (SL-3), where a total of 10 ...
*
Biosphere 2
Biosphere 2 is an American Earth system science research facility located in Oracle, Arizona. Its mission is to serve as a center for research, outreach, teaching, and lifelong learning about Earth, its living systems, and its place in the univers ...
*
BIOS-3
BIOS-3 is an experimental closed ecosystem at the Institute of Biophysics in Krasnoyarsk, Russia.
Its construction began in 1965, and was completed in 1972. BIOS-3 consists of a underground steel structure suitable for up to three persons, and ...
* Biosphere J
* Controlled Environment Systems Research Facility
*
Biotron (disambiguation) Biotron may refer to:
* Biotron, a controlled ecological life-support system used for studying a living organism's response to specific environmental conditions or to produce uniform organisms for use in experiments
* Space Environment Simulation ...
*
Biotron Experimental Climate Change Research FacilityBiotron Experimental Climate Change Research Facility
University of Western Ontario
Other types of regenerative ecological systems
*Bioregenerative life support system
Bioregenerative life support systems (BLSS) are artificial ecosystems consisting of many complex symbiotic relationships among higher plants, animals, and microorganisms. As the most advanced life support technology, BLSS can provide a habitati ...
(acronym: BLSS)
*Environmental Control and Life Support System
A life-support system is the combination of equipment that allows survival in an environment or situation that would not support that life in its absence. It is generally applied to systems supporting human life in situations where the outsid ...
(acronym
An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...
ECLSS)
* Engineered Closed/Controlled EcoSystem (acronym
An acronym is a word or name formed from the initial components of a longer name or phrase. Acronyms are usually formed from the initial letters of words, as in ''NATO'' (''North Atlantic Treaty Organization''), but sometimes use syllables, as ...
ECCES)
*Spome
A spome is any hypothetical system closed with respect to matter and open with respect to energy capable of sustaining human life indefinitely. The term was coined in 1966 by Isaac Asimov in a paper entitled "There’s No Place Like Spome", publi ...
See also
* Life support system
A life-support system is the combination of equipment that allows survival in an environment or situation that would not support that life in its absence. It is generally applied to systems supporting human life in situations where the outsid ...
* Closed ecological system
Closed ecological systems (CES) are ecosystems that do not rely on matter exchange with any part outside the system.
The term is most often used to describe small, manmade ecosystems. Such systems are scientifically interesting and can potential ...
* Arcology
Arcology, a portmanteau of "architecture" and "ecology",. is a field of creating architectural design principles for very densely populated and ecologically low-impact human habitats.
The term was coined in 1969 by architect Paolo Soleri, who be ...
References
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{{Authority control
Ecological experiments
Systems ecology
Spacecraft life support systems