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Abstract: Ground based experiments, conducted in advanced space environment simulation facilities, complement the exo/astrobiological experiments in Low Earth Orbit (LEO). For example, the in-orbit ESA-facility EXPOSE on the International Space Station ISS can only accommodate a limited number of experiments for exposure to the space parameters high vacuum, intense radiation of galactic and solar origin and microgravity. Ground based experiments in carefully equipped and monitored simulation facilities allow necessary experiment preparation and additional investigation of a much wider variety of samples. In the ESA accepted experiment SSIOUX, ESA-RA-LS-01-PREP, an international consortium of 14 prime investigators will expose organic compounds and a wide range of microorganisms, from bacterial spores to complex microbial communities, to simulated space environment parameters in pursuit of exobiological questions on their resistance to space environment and the origin and distribution of life. The experiments will be conducted in the Planetary and Space Simulation Facilities of the Institute of Aerospace Medicine at DLR in Köln, Germany, where the simulated space parameters vacuum with controlled residual composition, ionizing radiation, polychromatic UV radiation and selected UV ranges from vacuum-UV to UVA, VIS and IR or individual monochromatic UV wavelengths, and temperature control at the sample site are provided individually or in selected combinations in 9 facilities of varying sizes. Parameters are constantly measured and data are available in real time online during the exposure. Experiments in these facilities discriminate between the effects of individual space parameters and selected combinations. In addition, they serve as ground experiments defining interesting and suitable biological samples for future space experiments and compliment the data of executed space experiments and those in progress. As 1×g controls, they also enable the identification of microgravity effects when compared to the space experiments. Here, the SSIOUX consortium and their experiments will be presented as well as the ground based Planetary and Space Simulation Facilities at DLR. The results of the SSIOUX experiments will be directly comparable and are designed to lead to further understanding of adaptation and evolution of life. [Copyright &y& Elsevier]

The survivability of resistant terrestrial microbes, bacterial spores of Bacillus subtilis, was investigated in the BIOPAN facility of the European Space Agency onboard of Russian Earth-orbiting FOTON satellites (BIOPAN I -III missions). The spores were exposed to different subsets of the extreme environmental parameters in space (vacuum, extraterrestrial solar UV, shielding by protecting materials like artificial meteorites). The results of the three space experiments confirmed the deleterious effects of extraterrestrial solar UV radiation which, in contrast to the UV radiation reaching the surface of the Earth, also contains the very energy-rich, short wavelength UVB and UVC radiation. Thin layers of clay, rock or meteorite material were shown to be only successful in UV-shielding, if they are in direct contact with the spores. On Mars the UV radiation climate is similar to that of the early Earth before the development of a protective ozone layer in the atmosphere by the appearance of the first aerobic photosynthetic bacteria. The interference of Martian soil components and the intense and nearly unfiltered Martian solar UV radiation with spores of B. subtilis will be tested with a new BIOPAN experiment, MARSTOX. Different types of Mars soil analogues will be used to determine on one hand their potential toxicity alone or in combination with solar UV (phototoxicity) and on the other hand their UV protection capability. Two sets of samples will be placed under different cut-off filters used to simulate the UV radiation climate of Mars and Earth. After exposure in space the survival of and mutation induction in the spores will be analyzed at the DLR, together with parallel samples from the corresponding ground control experiment performed in the laboratory. This experiment will provide new insights into the principal limits of life and its adaptation to environmental extremes on Earth or other planets which and will also have implications for the potential for the evolution and distribution of life. [Copyright &y& Elsevier]

In the 21st century, an increasing number of astronauts will visit the International Space Station (ISS) for prolonged times. Therefore it is of utmost importance to provide necessary basic knowledge concerning risks to their health and their ability to work on the station and during extravehicular activities (EVA) in free space. It is the aim of one experiment of the German project TRIPLE-LUX (to be flown on the ISS) to provide an estimation of health risk resulting from exposure of the astronauts to the radiation in space inside the station as well as during extravehicular activities on one hand, and of exposure of astronauts to unavoidable or as yet unknown ISS-environmental genotoxic substances on the other. The project will (i) provide increased knowledge of the biological action of space radiation and enzymatic repair of DNA damage, (ii) uncover cellular mechanisms of synergistic interaction of microgravity and space radiation and (iii) examine the space craft milieu with highly specific biosensors. For these investigations, the bacterial biosensor SOS-LUX-LAC-FLUORO-Toxicity-test will be used, combining the SOS-LUX-Test invented at DLR Germany (Patent) with the commercially available LAC-FLUORO-Test. The SOS-LUX-Test comprises genetically modified bacteria transformed with the pBR322-derived plasmid pPLS-1. This plasmid carries the promoterless lux operon of Photobacterium leiognathi as a reporter element under control of the DNA-damage dependent SOS promoter of ColD as sensor element. This system reacts to radiation and other agents that induce DNA damages with a dose dependent measurable emission of bioluminescence of the transformed bacteria. The analogous LAC-FLUORO-Test has been developed for the detection of cellular responses to cytotoxins. It is based on the constitutive expression of green fluorescent protein (GFP) mediated by the bacterial protein expression vector pGFPuv (Clontech, Palo Alto, USA). In response to cytotoxic agents, this system reacts with a dose-dependent reduction of GFP-fluorescence. Currently, a fully automated miniaturized hardware system for the bacterial set up, which includes measurements of luminescence and fluorescence or absorption and the image analysis based evaluation is under development. During the first mission of the SOS-LUX-LAC-FLUORO-Toxicity-Test on the ISS, a standardized, DNA-damaging radiation source still to be determined will be used as a genotoxic inducer. A panel of recombinant Salmonella typhimurium strains carrying either the SOS-LUX plasmid or the fluorescence-mediating lac-GFPuv plasmid will be used to determine in parallel on one microplate the genotoxic and the cytotoxic action of the applied radiation in combination with microgravity. Either in addition to or in place of the fluorometric measurements of the cytotoxic agents, photometric measurements will simultaneously monitor cell growth, giving additional data on survival of the cells. The obtained data will be available on line during the TRIPLE-LUX mission time. Though it is the main goal during the TRIPLE-LUX mission to measure the radiation effect in microgravity, the SOS-LUX-LAC-FLUORO-Toxicity-test in principle is also applicable as a biomonitor for the detection and measurement of genotoxic substances in air or in the (recycled) water system on the ISS or on earth in general. [Copyright &y& Elsevier]

The evolution of the solar system and the origin of life remain some of the most intriguing questions for humankind. Addressing these questions experimentally is challenging due to the difficulty of mimicking environmental conditions representative for Early Earth and/or space conditions in general in ground-based laboratories. Performing experiments directly in space offers the great chance to overcome some of these obstacles and to possibly find answers to these questions. Exposure platforms in Low Earth Orbit (LEO) with the possibility for long-duration solar exposure are ideal for investigating the effects of solar and cosmic radiation on various biological and non-biological samples. Up to now, the Exobiology and space science research community has successfully made use of the International Space Station (ISS) via the EXPOSE facility to expose samples to the space environment with subsequent analyses after return to Earth. The emerging small and nanosatellite market represents another opportunity for astrobiology research as proven by the robotic O/OREOS mission, where samples were monitored in-situ , i.e. in Earth orbit. In this framework, the European Space Agency is developing a novel Exobiology facility outside the ISS. The new platform, which can host up to four different experiments, will combine the advantages of the ISS (long-term exposure, sample return capability) with near-real-time in-situ monitoring of the chemical/biological evolution in space. In particular, ultraviolet–visible (UV–Vis) and infrared (IR) spectroscopy were considered as key non-invasive methods to analyse the samples in situ. Changes in the absorption spectra of the samples developing over time will reveal the chemical consequences of exposure to solar radiation. Simultaneously, spectroscopy provides information on the growth rate or metabolic activities of biological cultures. The first quartet of experiments to be performed on-board consists of IceCold, OREOcube and Exocube (dual payload consisting of ExocubeChem and ExocubeBio). To prepare for the development of the Exobiology facility, ground units of the UV–Vis and IR spectrometers were studied, manufactured and tested as precursors of the flight units. The activity led to a modular in-situ spectroscopy platform able to perform different measurements (e.g. absorbance, optical density, fluorescence measurements) at the same time on different samples. We describe here the main features of the ground model platform, the verification steps, results and approach followed in the customization of commercial–off-the-shelf (COTS) modules to make them suitable for the space environment. The environmental tests included random and shock vibration, thermal vacuum cycles in the range −20 °C to +40 °C and irradiation of the components with a total dose of 1800 rad (18 Gy). The results of the test campaign consolidated the selection of the optical devices for the Exobiology Facility. The spectroscopic performance of the optical layout was tested and benchmarked in comparison with state-of-the-art laboratory equipment and calibration standards showing good correlation. This includes spectra of samples sets relevant for the flight experiments and a performance comparison between the SPECTROModule ground model and state-of-the-art laboratory spectrometers. Considering the large number of samples and different types of optical measurements planned on-board the ISS, the main outcome was the implementation of an LED-photodiode layout for the optical density and fluorescence measurements of IceCold (42 samples) and ExocubeBio (111 samples); while the UV–Vis spectrometer will be mainly focused on the change of the absorption spectra of the 48 samples of OREOcube.The ExocubeChem samples (in total 48) will be analysed by infrared spectroscopy. The ground platform supports the establishment of analogue research capabilities able to address the long-term objectives beyond the current application. • Biological samples shall be exposed to solar and cosmic radiation. • UV/VIS and IR spectroscopy are used for in-situ measurements in space. • Commercial off-the shelf (COTS) spectrometers were tested and verified for use in space. • A scientific test campaign proved the predicted results. • SPECTROmodule is the precursor mission of the Exobiology facility accommodated outside the International Space Station. [ABSTRACT FROM AUTHOR]

Abstract: The objective of the LICHENS space experiment within the BIOPAN facility of ESA on board of the Russian Foton satellite is to test the limits of life in the hostile environment of space, and the effects of selected parameters, such as space vacuum and specific wavelength bands of extraterrestrial UV-radiation, on the viability of lichens. In preparation of this space experiment, pre-flight verification tests were performed with the lichen system Rhizocarpon geographicum on its natural granite substrate using the Planetary and Space Simulation Facilities at the DLR in Cologne, Germany. The test parameters (high temperature, UV-radiation, vacuum) were adjusted to the conditions expected to be experienced during the 15days long space mission of LICHENS. After exposure, the maximum quantum yield of photosynthetic activity was determined as a measure of survivability of the lichen. The lichen R. geographicum was capable to fully recover from exposures to vacuum (up to 3×10−6 hPa for 1 week), to the full spectrum of UV-radiation (>200nm for up to 20h giving a final fluence of 10.89×106 J/m2), as well as to a combined treatment with both simulated space parameters. It was less resistant to heating: after 1 week at 40°C the photosynthetic activity was reduced by about 20%. The results demonstrate the high resistance of the R. geographicum-granite ecosystem to simulated space conditions and justify its use in the LICHENS space experiment. It might even be capable of coping with the intense influx of extraterrestrial solar UV-radiation, which so far no biological system was able to withstand. [Copyright &y& Elsevier]