DEUTSCH

Experiments on the origin, evolution and distribution of Life on Expose-E and Expose-R (2008).
A new area in research on the origin, evolution and distribution of life has started for Radiation- and Astrobiologists with the launch of the two ESA exposure facilities Expose-E on EuTEF (European Technology Exposure Facility) in February 2008 and Expose-R in November 2008. EXPOSE-E is operative since February 17th, accommodated on the starboard cone of the European Columbus module; EXPOSE-R will start its operational phase after the attachment to the URM-D platform on the Russian Zvezda module end of 2008.
While Expose-E was carried to the ISS installed on the EuTEF platform with 8 other space instruments in the Cargo bay of the Space Shuttle STS-122 Atlantis together with the SOLAR platform and the Columbus module, Expose-R was launched from Baikonur on a Russian Progress-Transporter 31-P to the ISS. Both facilities expose a variety of biological, organic chemical and dosimetric samples to the harsh environment of space for more than one year. While the reactions of the chemical compounds triggered by these space conditions will be analysed after the return of the samples, the exposed organisms will be investigated on their survivability and the underlying mechanisms. During the missions, UV- and ionizing radiation as well as temperature of the sample trays are measured on both EXPOSES. Data are used for Mission parallel Ground Simulation Experiments performed at DLR. Six of the total of 16 Experiments on both Exposes are performed under the leadership of German research institutes, most by the Institute of Aerospace Medicine at DLR Cologne.
 
 
Expose-E

Together with the European Columbus module, two ESA-Instruments were launched to the ISS under the coordination of the DLR in Cologne and the operational support by MUSC: EXPOSE-E in February 2008 and EXPOSE-R in November 2008. The European Exposure Facility EXPOSE-E was accommodated outside of the Columbus module on the European Technology Exposure Facility EuTEF together as one of 9 instruments. The samples of the 8 international biological, organic chemical and dosimetric experiments are exposed in 4 compartments each in 3 trays to the extreme and hostile space environment. Organic chemical compounds and resistant species ranging from bacteria, bacterial spores and Achaea to fungi, lichens and plant seeds are exposed more than one year to the vacuum, temperature oscillations and extraterrestrial radiation of Low Earth Orbit (LEO). While the majority of the experiments on both EXPOSES are interested in the effect of the space conditions, one tray of EXOSE-E simulates Martian conditions with respect to inner tray atmosphere (mostly CO2) at low pressure of 6 mbar, and UV radiation attenuated by optical filter combinations. Parallel to the EXPOSE-E mission, identical samples in a similar hardware are exposed to environmental conditions simulated as close as possible according to the temperature and UV-data obtained from the experiment on the ISS and linked via MUSC to the Planetary and Space Simulation Facilities at DLR In Köln-Porz.

    In addition, the data from ISS are made available for all 8 international research groups participating on Expose-E (Telemetriedaten EXPOSE-E). For Expose-R, temperature and instrument status data are available from the beginning of the operational phase. After approximately 6 months, UV-data will be retrieved from a physically returned data carrier and made available to the respective Scientists. As for EXPOSE-E, a mission parallel ground simulation program utilizing the environmental data from EXPOSE-R on ISS, will be performed at DLR/MUSC.

At the end of the missions, EXPOSE-E on EuTEF will be brought back form ISS by Space Shuttle, in Autumn 2009 after approximately 1.5 years of exposure, and the 3 trays with the scientific sample of EXPOSE-R by a Soyuz capsule after approximately 1 year exposure in May 2010. Samples will be de-integrated and distributed to the individual science groups for analysis in their respective laboratories.

From the reactions of the organic molecules and the survivability of the organisms that were exposed to the harsh space conditions, as well as from the analysis of the space-condition induced damage, valuable information increasing our knowledge about the origin, evolution and distribution of life are expected. Results will support the aim of planetary protection: the efforts to not contaminate other celestial bodies like Mars with organisms travelling as stowaways on future missions from Earth to the planet of interest. Especially resistant organisms that might be able to survive the transfer to Mars and the environmental conditions on Mars need to be detected, their survivability assessed and corresponding precautions to be taken.

While on EXOSE-E more than 400 samples are exposed, more than 1200 samples are accommodated on EXPOSE-R, partly in three layers. Experiments on both EXOSES are complemented by the passive dosimeters distributed between and below the biological samples and the active R3D instruments.

   

Passive Dosimetry on both EXPOSES are performed in the experiment DOSIS on EXPOSE-E and as part of the biological SPORES experiment of EXPOSE-R by the department of Radiation Biology of the Institute of Aerospace Medicine at DLR, as are the biological experiments SPORES itself on EXPOSE-R and ADAPT and PROTECT on EXPOSE-E. Both PIs, Dr. Gerda Horneck (SPORES and PROTECT) and Dr. Petra Rettberg (ADAPT) from DLR at Cologne are supported by international consortia of scientists, that are waiting for the return of their space-travelling organisms to their laboratories. The same is true for the passive dosimetry experiments of PI Dr. Guenther Reitz, also from DLR in Cologne.

In addition, DLR/MUSC operationally supports both EXPOSE facilities, for EXPOSE-E as Facility Support Center, and coordinates and performs both mission parallel Ground Reference experiments. Expertise and the technical Planetary and Space Simulation Facilities were built up in the last decades, when previous astrobiological and biophysical space experiments were prepared and missions simulated, and adapted for the requirements of the current missions. In 2009, the two parallel EXPOSE missions will be simulated in parallel on Ground, to complement scientific data from the space experiments.