COSIMA at Comet 67P/Churyumov-Gerasimenko After Perihelion
Abstract:COSIMA (the COmetary Secondary Ion Mass Analyser) is one of the three scientific in-situ dust instruments onboard the Rosetta spacecraft . Rosetta has been orbiting comet 67P/Churyumov-Gerasimenko since August of 2014. COSIMA is collecting cometary dust particles in the inner coma by exposing metal targets. It then images the targets periodically with COSISCOPE, a microscope/camera, in search of the captured particles. A variety of particle morphologies are seen. A sample particle is shown in Figure 1.
Some of the identified cometary particles are further investigated by SIMS (Secondary Ion Mass Spectrometry). The high resolution mass spectra show the presence of positive or negative ions of elements, organic molecules and molecular fragments originating from the selected grain surface. Changes in dust characteristics with time will be discussed.
 Kissel et al. (2007), Sp. Sci. Rev. 128, 823-867.  Schulz et al. (2015), Nature, 518, 216-218.