The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) is one of the main instruments of the ambitious Rosetta mission. As the comet draws close to the sun, it will release numerous particles and gases, creating an “atmosphere” made of materiel that is relatively unaltered since the dawn of our solar system. The role of ROSINA is to sample and analyze this material. ROSINA consists of three instruments: two mass spectrometers, the Double Focusing Mass Spectrometer (DFMS) and the Reflectron Time of Flight Spectrometer (RTOF), and a pressure sensor, the Comet Pressure Sensor (COPS). Together, those instruments provide Rosetta with unprecedented range and resolution for the analysis of the molecules in the comet’s tail, including different organic species.