text: With the experiments onboard of the EXPOSE facilities, various aspects of astrobiology were investigated that could not be sufficiently approached by use of laboratory facilities on ground. The chemical set of experiments is designed to reach a better understanding of the role of interstellar, cometary and planetary chemistry in the origin of life. Comets and meteorites are interpreted as exogenous sources of prebiotic molecules on the early Earth. All data achieved from the astrobiological experiments on both EXPOSE missions will add to the understanding of the origin and evolution of life on Earth and on the possibility of its distribution in space or origin elsewhere.
  Data obtained from the studies on complex organics of cometary interest will support the interpretation of in-situ data obtained from the Rosetta mission after landing on Comet 67P/Churyumov–Gerasimenko in 2014, and samples analyzed by the Curiosity and ExoMars rovers on Mars. Finally the chemical experiments will contribute to the understanding of the chemical processes on Saturn's moon Titan and possible analogies to the prebiotic chemistry on the early Earth.
  The biology experiments used the full extraterrestrial spectrum of solar UV radiation and suitable cut-off filters to study both, the role of the ozone layer in protecting our biosphere and the likelihood of resistant terrestrial microorganisms (extremophiles)  to survive in outer space. The latter studies will provide experimental data to the lithopanspermia hypothesis, and they will provide basic data to planetary protection issues. To get better insight into the habitability of Mars, one set of samples was exposed to simulated Martian conditions (UV-radiation climate, pressure, atmosphere), with and without a protective cover of simulated Martian soil. The biological test samples selected are hardy representatives of various branches of life.