ROSINA, (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) is an instrument designed to determine the gas properties and composition of the atmosphere and ionosphere of comet 67P.
The instrument consists of two mass spectrometers, one of which has two modes in order to analyse both gases and ions from the comet. A third section of the instrument consists of a pressure sensor designed to measure the rate of gas flow and the gas density in specific regions around the comet. This also serves the purpose of protecting the other orbiter instruments by giving advance warning if the pressure rises too high for them to operate correctly.
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