Exobiology Radiation Assembly (ERA) was an experiment that investigated the biological effects of space radiation. An

astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investi ...

mission developed by the

European Space Agency , owners = , headquarters = Paris, Île-de-France, France , coordinates = , spaceport = Guiana Space Centre , seal = File:ESA emblem seal.png , seal_size = 130px , image = Views in the Main Control Room (120 ...

(ESA), it took place aboard the

European Retrievable Carrier The European Retrievable Carrier (EURECA) was an unmanned 4.5-tonne satellite with 15 experiments. It was a European Space Agency (ESA) mission and the acronym was derived from Archimedes' bathtub revelation " Eureka!". It was built by the Germa ...

(EURECA), an unmanned 4.5 tonne satellite with a payload of 15 experiments. It was launched 31 July 1992 by the

STS-46 STS-46 was a NASA Space Shuttle mission using and was launched on July 31, 1992, and landed on August 8, 1992. Crew Backup crew Crew seating arrangements Mission highlights The mission's primary objectives were the deployment of ...

- ''

Space Shuttle Atlantis Space Shuttle ''Atlantis'' (Orbiter Vehicle designation: OV‑104) is a Space Shuttle orbiter vehicle which belongs to NASA, the spaceflight and space exploration agency of the United States. ''Atlantis'' was manufactured by the Rockwell ...

'' and put into orbit at an altitude of 508 km. It was retrieved on 1 July 1993 by

STS-57 STS-57 was a NASA Space Shuttle-Spacehab mission of that launched 21 June 1993 from Kennedy Space Center, Florida. Crew Spacewalk * '' Low and Wisoff '' – EVA 1 * EVA 1 Start: 25 June 1993 * EVA 1 End: 25 June 1993 * Duration: 5 hours ...

- ''

Space Shuttle Endeavour Space Shuttle ''Endeavour'' ( Orbiter Vehicle Designation: OV-105) is a retired orbiter from NASA's Space Shuttle program and the fifth and final operational Shuttle built. It embarked on its first mission, STS-49, in May 1992 and its 25th an ...

'' and returned to Earth for further analysis.

Objectives

The experiment's goal was to study the response of dehydrated and metabolically dormant microorganisms (spores of ''

Bacillus subtilis ''Bacillus subtilis'', known also as the hay bacillus or grass bacillus, is a Gram-positive, catalase-positive bacterium, found in soil and the gastrointestinal tract of ruminants, humans and marine sponges. As a member of the genus '' Baci ...

'', cells of ''

Deinococcus radiodurans ''Deinococcus radiodurans'' is an extremophilic bacterium and one of the most radiation-resistant organisms known. It can survive cold, dehydration, vacuum, and acid, and therefore is known as a polyextremophile. It has been listed as the wor ...

'',

conidia A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non-motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due to th ...

l spores of '' Aspergillus species'') and cellular constituents (

plasmid A plasmid is a small, extrachromosomal DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently. They are most commonly found as small circular, double-stranded DNA molecules in bacteria; howev ...

DNA,

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...

s, purple membranes,

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha ...

urea Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid. Urea serves an important ...

) to the extremely dehydrating conditions of outer space, in some cases in combination with irradiation by solar UV light.

Results

ERA provided information on the long-exposure of

invertebrates Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism'' from the el, ὀργανισμός, ''organismós'', "organism"). It is usually written as a single word but is sometimes hyphenated (''micro-organism''), especially in olde ...

s and

organic molecules In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The ...

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 ...

conditions, such as ultraviolet (UV) radiation,

cosmic radiation Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our ow ...

and

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often di ...

Spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, ...

s of different strains of ''

'' and the ''

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 ...

pUC19 pUC19 is one of a series of plasmid cloning vectors created by Joachim Messing and co-workers. The designation "pUC" is derived from the classical "p" prefix (denoting "plasmid") and the abbreviation for the University of California, where early w ...

were exposed to selected conditions of space (space vacuum and/or defined wavebands and intensities of solar ultraviolet radiation). After the approximately 11-month mission, the organisms' responses were studied in terms of survival,

mutagenesis Mutagenesis () is a process by which the genetic information of an organism is changed by the production of a mutation. It may occur spontaneously in nature, or as a result of exposure to mutagens. It can also be achieved experimentally using l ...

in the ''his'' (''B. subtilis'') or '' lac''

locus Locus (plural loci) is Latin for "place". It may refer to: Entertainment * Locus (comics), a Marvel Comics mutant villainess, a member of the Mutant Liberation Front * ''Locus'' (magazine), science fiction and fantasy magazine ** ''Locus Award ...

(pUC19), induction of DNA strand breaks, efficiency of

DNA repair DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA da ...

systems, and the role of external protective agents. The data were compared with those of a simultaneously running ground control experiment. *When spores were exposed to the vacuum of space, but shielded from solar radiation, their survivability was substantially increased if they were exposed in multilayers and/or in the presence of

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, usi ...

. *Spores embedded in artificial meteorites (

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay part ...

s and simulated

Martian soil Martian soil is the fine regolith (a blanket of unconsolidated, loose, heterogeneous superficial deposits covering solid rock) found on the surface of Mars. Its properties can differ significantly from those of terrestrial soil, including its to ...

) did not survive. *Vacuum treatment lead to an increase of mutation frequency in spores, but not in

DNA. *Extraterrestrial solar

ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...

radiation was

mutagen In genetics, a mutagen is a physical or chemical agent that permanently changes genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can cause cancer i ...

ic, inducing strand breakage in the DNA and substantially reducing survival. *Action

spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...

confirmed the results of previous space experiments of a synergistic action of space vacuum and solar UV radiation with DNA being the critical target. *The decrease in the microorganisms' viability could be correlated with the increase in

DNA damage DNA repair is a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as radiation can cause DNA da ...

. *The purple membranes, amino acids and urea were not measurably affected by the dehydrating condition of open space, if sheltered from solar radiation. Plasmid DNA, however, showed a significant amount of strand breakage.

References

External links

* {{ESA projects Astrobiology space missions European Space Agency Space science experiments Space exposure experiments Space-flown life Space hardware returned to Earth intact

Objectives

Results

See also

References

External links