Exobiology Radiation Assembly (ERA) was an experiment that investigated the biological effects of space radiation. An
astrobiology mission developed by the
European Space Agency (ESA), it took place aboard the
European Retrievable Carrier (EURECA), an unmanned 4.5 tonne satellite with a payload of 15 experiments.[1]
Spores of different strains of Bacillus subtilis and the Escherichia coliplasmidpUC19 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 laclocus (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.[2][3]
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.
The decrease in the microorganisms' viability could be correlated with the increase in
DNA damage.
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.[2]
^Horneck, G; Eschweiler, U; Reitz, G; Wehner, J; Willimek, R; Strauch, K (1995). "Biological responses to space: Results of the experiment 'Exobiological Unit' of ERA on EURECA I". Advances in Space Research. 16 (8): 105–18.
Bibcode:
1995AdSpR..16..105H.
doi:
10.1016/0273-1177(95)00279-N.
PMID11542695.