The ORGANIC experiment on EXPOSE-R on the ISS: Flight sample preparation and ground control spectroscopy Original Research Article

In March of 2009, the ORGANIC experiment integrated into the European multi-user facility EXPOSE-R, containing experiments dedicated to Astrobiology, was mounted through Extra Vehicular Activity (EVA) externally on the International Space Station (ISS). The experiment exposed organic samples of astronomical interest for a duration of 97 weeks (∼22 months) to the space environment. The samples that were returned to Earth in spring 2011, received a total UV radiation dose during their exposure including direct solar irradiation of >2500 h, exceeding the limits of laboratory simulations. We report flight sample preparation and pre-flight ultraviolet–visible (UV–Vis) characterization of the ORGANIC samples, which include 11 polycyclic aromatic hydrocarbons (PAHs) and three fullerenes. The corresponding time-dependent ground control monitoring experiments for ORGANIC measured over ∼19 months are presented and the results anticipated upon return of the samples are discussed. We present the first UV–Vis spectrum of solid circobiphenyl (C38H16). Further, we present the first published UV–Vis spectra of diphenanthro[9,10-b′,10′-d]thiophene (C28H16S), dinaphtho[8,1,2-abc,2′,1′,8′-klm]coronene (C36H16), tetrabenzo[de,no,st,c′d′]heptacene (C42H22), and dibenzo[jk,a′b′]octacene (C40H22) in solid phase and in solution. The results of the ORGANIC experiment are expected to enhance our knowledge of the evolution and degradation of large carbon-containing molecules in space environments.