Review of meteorite irradiation tests to support next C-type asteroid missions

ABSTRACT Effect of space weathering of airless asteroids could be better understood by artificial irradiation tests on meteorites in laboratories. This work surveys the infrared and Raman analysis based interpretation of simulated charged particle irradiation tests in order to better understand near-future observational possibilities of asteroid visiting missions and also to support the planning of next missions and directions of detector improvement. Recent works properly targeted different meteors and meteor relevant minerals, evaluating bulk meteorite spectra, during the irradiation tests. He+, (Ne+, Kr+), and Ar+ ions were used with fluxes characteristic for inner planetary system solar wind, considering 1–10 million yr exposure durations. Although main meteorite minerals were irradiated and analysed, one missing aspect is that only bulk analysis have been done, not minerals separately in their original embedded context. Some Earth based mineral references were also analysed; however, they might not necessarily behave similar to the same type of reference minerals and irradiation effect is poorly known for feldspar, troilite, and magnetite. Darkening should be also further analysed for separate minerals too, together with the record of peak shape and position changes. Infrared ATR analysis might still provide such data in the future using the recently emerged technology, as well as Raman analysis – however for flyby missions’ infrared is the useful method while Raman can be used only at in situ missions. The overview including the tables to support the identification of specific missing information related gaps in our current knowledge and directions for future research.