Results from Rosetta fly-by analyses indicated abundant O₂, H₂O, N₂, CO CH₄, and Ar.

Early results from Rosetta's probe Philae’s of Comet 67P/Churyumov­-Gerasimenko were published July 30, 2015 in a special edition of the journal Science.

Samples collected during the first touchdown revealed a suite of 16 aliphatic organic compounds comprising numerous carbon and nitrogen-rich compounds, including four compounds – methyl isocyanate, acetone, propionaldehyde and acetamide – that have never before been detected in comets before. A bio-available form of Phosporous (phosphorous monoxide) was also detected by Rosetta.

Heated by the Sun on Sep 14 2014 releases gases. The gases detected included – water vapor, carbon monoxide and carbon dioxide, along with smaller amounts of carbon-bearing organic compounds, including formaldehyde, which plays a key role in the prebiotic synthesis of amino acids, sugars and nucleobases: the ingredients for life. Formaldehyde is implicated in the formation of ribose, which ultimately features in molecules like DNA.The existence of such complex molecules in a comet, a relic of the early Solar System, imply that chemical processes at work during that time could have played a key role in fostering the formation of prebiotic material. Molecules detected include long-chain, aromatic, and oxygenated hydrocarbons, as well as sulfur compounds, glycine, and cyanamide and glycoaldehyde, which in Earth research laboratories  have been used to make nucleotides.

Bernard Marty, a geochemist at the U. of Lorraine in France studied measurements made by the ESA's Rosetta spacecraft, which orbited Comet 67P (Churyumov-Gerasimenko). They analyzed xenon-isotope data that Rosetta gathered during a series of low-altitude orbits of Comet 67P between May 14 and May 31, 2016. Rosetta's observations revealed that 67P is deficient in heavy xenon (more neurons). The Xenon isotope analyses supported the suggestion that less than 1% or today's surface water on Earth was likely delivered by comets and 67P.  On Sep 30, 2016 Rosetta free fell to the surface of 67P.