Figure 8.

The COmetary Sampling And Composition (COSAC) instrument deployed on Rosetta's Philae lander was a high‐resolution multipass time‐of‐flight mass spectrometer (TOFMS) that centered on a linear reflectron, with the electron ionization (EI) source (to the right as depicted) and a multi‐sphere‐plate secondary electron multiplier (to the left) on opposite ends, supporting a mass resolving power of m/Δm = 2000 (FWHM). The Engineering Test Unit (ETU) and Flight Model (FM), shown above, conform to the same design with the exception of the electrical harnessing. Image courtesy of Fred Goesmann (principal investigator of COSAC)