The photobiological/photochemical processes in the simulated radiation climate of planets (early Earth, Mars, role of ozone in protecting the biosphere against harmful UV radiation) as well as the probabilities and limitations for life to be distributed beyond its planet of origin (spores in artificial meteorites, intrinsic and extrinsic protection mechanisms) are studied in the space experiment SPORES as part of the international DLR-coordinated consortium ROSE (Responses of Organisms to Space Environment). The experiments will be performed in the ESA-EXPOSE facility to be mounted as external payload on the ISS. A pre-flight ROSE experiment verification and test program (ESA-EVT 1 - 4) was performed in the space simulation facilities for defining the environmental constraints and limits (e.g. temperature, period of insolation, UV wavelength ranges) during the mission, for the assessment of the compatibility of the different experiments housed in the same container and for the preparation of a detailed experiment sequence and pre-mission simulation test procedure.
In the space experiment MARSTOX (Martian soil, solar UV radiation and spores: protection and toxicity) flown in the ESA facility BIOPAN on FOTON M-2 in Mai/June 2005 toxicity and phototoxicity as well as protection against UV radiation by Martian soil simulants was investigated with spores of the bacterium Bacillus subtilis as a model system for highly resistant terrestrial life forms.