by the European Space Agency that launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko Rosetta was a space probe built by the European Space Agency that launched on 2 March 2004. Along with Philae, its lander module, Rosetta performed a detailed study of comet 67P/Churyumov–Gerasimenko (67P). During its journey to the comet, the spacecraft performed flybys of Earth, Mars, and the asteroids 21 Lutetia and 2867 Šteins. It was launched as the third cornerstone mission of the ESA's Hori The Philae lander's COSAC instrument detected organic molecules in the comet's atmosphere as it descended to its surface. Measurements by the COSAC and Ptolemy instruments on the Philae's lander revealed sixteen organic compounds, four of which were seen for the first time on a comet, including acetamide, acetone, methyl…

In 2014, the Rosetta space probe delivered its lander module Philae to the nucleus of comet 67P/Churyumov-Gerasimenko. After a non-nominal landing, instruments onboard Philae had very limited time and energy to operate. After the initial touchdown (supposed to be the only one) on the surface of the comet, COSAC, a Gas Chromatograph coupled to a Mass Spectrometer (GC-MS) embarked on Philae, took an automated mass spectrometric measurement. This data was produced during the bounce, and revealed a clear signal with intensity and diversity far greater than what was seen in the several blanks taken until this point. This signal was shown to come from excavated material from the surface which, at the moment of impact, entered the mass spectrometer’s chamber through its exhaust port located underneath Philae’s body. This data therefore represents the first ever sampling of a cometary nucleus. The core of this limited dataset is a single mass spectrum containing a mixture of unknown volatile molecules coming from the nucleus of the comet. The COSAC team published a deconvolution of this mass spectrum in 2015, identifying 16 organic molecules [1]. We revisited this dataset and applied a newly developed deconvolution method tailored for this specific and unusual problem [2]. We reduce the “clearly identified” pool of molecules to 12, including 3 new molecules never detected before on a comet (Figure 1 and 2).Once at rest on the comet, using the very last of Phil