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 investig ...

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 (1205 ...

(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 Inte ...

'' 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'' 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'', cells of '' Deinococcus radiodurans'',

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 the ...

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; how ...

DNA, proteins, purple membranes, amino acids, urea) 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, microorganisms 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 s ...

to outer space 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 own ...

and vacuum.

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, f ...

s of different strains of '' Bacillus subtilis'' and the '' Escherichia coli''

pUC19 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 in the ''his'' (''B. subtilis'') or ''

lac Lac is the resinous secretion of a number of species of lac insects, of which the most commonly cultivated is ''Kerria lacca''. Cultivation begins when a farmer gets a stick that contains eggs ready to hatch and ties it to the tree to be infes ...

'' locus (pUC19), induction of DNA strand breaks, efficiency of DNA repair 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. *Spores embedded in artificial meteorites ( clays and simulated Martian soil) did not survive. *Vacuum treatment lead to an increase of

mutation frequency Mutation frequency and mutation rates are highly correlated to each other. Mutation frequencies test are cost effective in laboratories however; these two concepts provide vital information in reference to accounting for the emergence of mutations ...

in spores, but not in

DNA. *Extraterrestrial solar ultraviolet radiation was

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

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 wa ...

confirmed the results of previous space experiments of a synergistic action of

space 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 dis ...

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