EXPOSE has several objectives, specific to each experiments, but all linked to the exobiology domain. The two French experiments Process and Amino are detailed below.
Their objective is to better understand the nature and evolution of organic matter presents in extraterrestrial environments and their potential exobiological implications.
The solar ultraviolet radiation is the main factor of chemical evolution in the Solar System. Numerous experimental programmes on ground are dedicated to the study of solid and gaseous phase molecule photochemistry. Nonetheless, the validity of such works and their extrapolation to extraterrestrial environments can be questionned as long as they have not been confronted to similar experiments in space, with exposition to the extended solar spectrum, most particularly in the short wavelength domain (difficult to reproduce in laboratory).
This project is more particularly devoted to the study of interesting molecules either from comets (in the framework of the preparation of the interpretation of ROSETTA mission results), or about Titan chemistry (CASSINI-HUYGENS mission), or organic chemistry in Martian environment (future Martian rover missions).
The photochemical behaviour of organic molecules in the laboratory is compared to the "ground truth" that these experiments are supposed to represent: the direct exposition to the solar radiation during the experiments realised in orbit around the Earth. The final objective is to improve the experiments in the laboratory and to obtain quantitative measurements of selected molecules photolysis (notably photolysis products and cross sections).
At the end of the exposition period, EXPOSE-E will be brought back to the ground by the space shuttle in august 2009. During 2011, EXPOSE-R sample carriers will be brought back on Earth by a Soyouz spacecraft then transfered to the MUSC in Köln (Germany). Then, the samples will be distributed to the scientists for analyses.
For PROCESS and AMINO experiments, the sample analyses after return on Earth will be realised by infrared spectroscopy through the cells windows (opened or scealed), then by gas chromatography or HPLC. A direct mass spectrometry analysis of the target molecules is also systematically realised during the ground irradiations.
EXPOSE-E Process experiment and EXPOSE-R Amino experiment have been prepared by the LISA(Laboratoire Inter-universitaire des Systèmes Atmosphériques), the LATMOS (Laboratoire Atmosphères, Milieux, Observations Spatiales), the CBM Centre de Biophysique Moleculaire d'Orleans) and the ANBioPhy (Laboratoire Acides Nucleiques et BioPhotonique), with CNES support.
EXPOSE-R2 PSS experiment (Photochemistry on the Space Station) was created in close partnership associating chemists, biochemists, planetologists, nuclear physicists and material experts from CNRS observatories and laboratories and the following Universities : LISA , CBM , IBMM (Institut des Biomolécules Max Mousseron - université de Montpellier), LATMOS, LAB (Laboratoire d’Astrophysique de Bordeaux),LMEE (Laboratoire de microbiologie des environnements extrêmes), UBO (Université de Bretagne Occidentale/IFREMER), the Leiden Institute of Chemistry - Astrobiology Laboratory and the Catane observatory as well as an AMES NASA team.