The survival of some microorganisms exposed to

outer space Outer space, commonly shortened to space, is the expanse that exists beyond Earth and its atmosphere and between celestial bodies. Outer space is not completely empty—it is a near-perfect vacuum containing a low density of particles, pred ...

has been studied using both simulated facilities and

low Earth orbit A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, with an altitude never mor ...

exposures. Bacteria were some of the first organisms investigated, when in 1960 a Russian satellite carried ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Esc ...

'', '' Staphylococcus'', and ''

Enterobacter aerogenes ''Klebsiella aerogenes'', previously known as ''Enterobacter aerogenes,'' is a Gram-negative, oxidase negative, catalase positive, citrate positive, indole negative, rod-shaped bacterium. The bacterium is approximately 1-3 microns in length, an ...

'' into orbit. Many kinds of microorganisms have been selected for exposure experiments since, as listed in the table below. Experiments of the adaption of microbes in space have yielded unpredictable results. While sometimes the microorganism may weaken, they can also increase in their disease-causing potency. It is possible to classify these microorganisms into two groups, the human-borne and the

extremophiles An extremophile (from Latin ' meaning "extreme" and Greek ' () meaning "love") is an organism that is able to live (or in some cases thrive) in extreme environments, i.e. environments that make survival challenging such as due to extreme tempe ...

. Studying the human-borne microorganisms is significant for human welfare and future crewed missions in space, whilst the extremophiles are vital for studying the physiological requirements of survival in space.

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the US federal government responsible for the civil List of government space agencies, space program ...

has pointed out that normal adults have ten times as many microbial cells as human cells in their bodies.NASA – Spaceflight Alters Bacterial Social Networks (2013)
/ref> They are also nearly everywhere in the environment and, although normally invisible, can form slimy

biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

s. Extremophiles have adapted to live in some of the most extreme environments on Earth. This includes

hypersaline lake A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial species can thrive in hi ...

s, arid regions,

deep sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...

, acidic sites, cold and dry polar regions and permafrost. The existence of extremophiles has led to the speculation that microorganisms could survive the harsh conditions of extraterrestrial environments and be used as model organisms to understand the fate of biological systems in these environments. The focus of many experiments has been to investigate the possible survival of organisms inside rocks (

lithopanspermia Panspermia () is the hypothesis, first proposed in the 5th century BCE by the Greek philosopher Anaxagoras, that life exists throughout the Universe, distributed by space dust, meteoroids, asteroids, comets, and planetoids, as well as by spacecr ...

), or their survival on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...

for understanding the likelihood of past or present life on that planet. Because of their ubiquity and resistance to spacecraft decontamination, bacterial spores are considered likely potential forward contaminants on robotic missions to

. Measuring the resistance of such organisms to space conditions can be applied to develop adequate decontamination procedures. Research and testing of microorganisms in outer space could eventually be applied for directed panspermia or

terraforming Terraforming or terraformation ("Earth-shaping") is the hypothetical process of deliberately modifying the atmosphere, temperature, surface topography or ecology of a planet, moon, or other body to be similar to the environment of Earth to make ...

Table

References

{{DEFAULTSORT:Microorganisms tested in outer space Astrobiology Astrobiology space missions Biology-related lists Lists of bacteria Extremophiles Life in space Medical lists Microbiology Science-related lists Space medicine Space science experiments +

Table

See also

References