The survival of some

microorganisms A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

exposed to outer space has been studied using both simulated facilities and

low Earth orbit A low Earth orbit (LEO) is an geocentric orbit, orbit around Earth with a orbital period, period of 128 minutes or less (making at least 11.25 orbits per day) and an orbital eccentricity, eccentricity less than 0.25. Most of the artificial object ...

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. is a gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus '' Escherichia'' that is commonly fo ...

'', ''

Staphylococcus ''Staphylococcus'', from Ancient Greek σταφυλή (''staphulḗ''), meaning "bunch of grapes", and (''kókkos''), meaning "kernel" or " Kermes", is a genus of Gram-positive bacteria in the family Staphylococcaceae from the order Bacillale ...

'', and '' Enterobacter aerogenes'' 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 () is an organism that is able to live (or in some cases thrive) in extreme environments, i.e., environments with conditions approaching or stretching the limits of what known life can adapt to, such as extreme temperature, pres ...

. 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 federal government of the United States, US federal government responsible for the United States ...

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 is a Syntrophy, syntrophic Microbial consortium, community of microorganisms in which cell (biology), cells cell adhesion, stick to each other and often also to a surface. These adherent cells become embedded within a slimy ext ...

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 those of ocean water (3.5%, i.e. ). Specific microbial species can thrive i ...

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 or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combination of low tempe ...

, acidic sites, cold and dry polar regions and

permafrost Permafrost () is soil or underwater sediment which continuously remains below for two years or more; the oldest permafrost has been continuously frozen for around 700,000 years. Whilst the shallowest permafrost has a vertical extent of below ...

. 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), or their survival on

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

for understanding the likelihood of past or present life on that planet. Because of their ubiquity and resistance to spacecraft decontamination, bacterial

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s 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 mak ...

Table

References

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

Table

See also

References