B. Marty, K. Altwegg, M. Rubin and the ROSINA team The potential contribution of comets to terrestrial volatiles is a long-standing problem that was central in the definition of the ESA Rosetta mission exploring Comet 67P/Churyumov-Gerasimenko (67P/C-G). The Rosina mass spectrometer on board of the spacecraft analyzed volatiles emitted by the comet during 2 years. Among them, noble gases are key tracers for the origin(s) and processing of volatile elements in the nascent solar system and in planetary atmospheres. The analysis of argon and xenon in Comet 67P/C-G permits for the first time to set stringent constraints on the origins of volatiles including carbon on Earth.