Cometary dust particles rain on Earth. However, they can only be found in collections performed in the cleanest regions of the Earth (the stratosphere and Antarctica). From Antarctic snow at the vicinity of the French-Italian Concordia Antarctic base, we recovered large (> 50-100 µm) particles of very probable cometary origin, the Ultracarbonaceous Antarctic Micrometeorites (UCAMMs). UCAMMs are constituted of a dominant fraction of a solid macromolecular organic matter intimately mixed with a minor mineral component. The organic matter is structurally disorganized, shows large deuterium enrichments and exhibit an unusually large bulk nitrogen concentrations (up to 20 at%). Preliminary studies have shown that several types of organic matter co-exist in UCAMMs, with different nitrogen contents and mixed with different amounts of minerals. The minerals embedded in the organic matter have typical sizes around 50-100 nm. Both crystalline and amorphous minerals are present and exhibit a wide range of compositions. Some precursors of UCAMM organic matter (the most N-rich) could have been formed by galactic cosmic rays’ irradiation of nitrogen-rich ices at the surface of icy bodies in the outer regions of the protoplanetary disk. UCAMMs are remarkable particles as their subcomponents preserved records of early solar system formation and evolution. The association in UCAMMs of minerals (formed at high temperatures) among large amounts of organic matter (necessarily formed at lower temperatures) opens a new window on the study of the origin and formation mechanisms of matter originating from the outer regions of the solar system. This proposal focuses on the formation mechanism and evolution of cometary dust organics and their relation with the mineral components embedded within, following 3 main questions: 1. What is the origin of the subcomponents of cometary matter? "Inner and outer solar system…" 2. What are the variations of the composition of organics and their embedded minerals with heliocentric distance? 3. How did the different environments encountered (radiative interplanetary medium, terrestrial atmosphere, Antarctica) modify the cometary particles collected on Earth? This project proposes innovative analysis protocols of UCAMMs using state-of the-art analysis techniques to characterize both the organic matter, the minerals and their association. Experimental simulations of their evolution from interplanetary space to their collection in Antarctica will be performed on cometary organic analogues and on synthetic UCAMMs produced in the laboratory. The originality of the COMETOR proposal resides in four points: i) the availability in the laboratory of well-preserved cometary samples; ii) the analysis of these complex particles with a combination of complementary and state-of-the-art techniques – including infrared spectroscopy coupled with atomic force microscopy (AFMIR) that allows infrared analysis at the ~ 50-100 nm scale; iii) the production of analogues of cometary solids and the real-time observation of their evolution under irradiation thanks to the unique JANNuS platform, coupling a transmission electron microscope with two ion accelerators; iv) the search for soluble organic compounds (including amino acids) in UCAMMs with the very high mass resolution Orbitrap technique to probe the input of prebiotic molecules on the early Earth by cometary dust. The expected results will have implications in the fields of astrophysics, planetology-cosmochemistry and astrobiology. They will bring an original contribution to the understanding of the formation and evolution of solid matter in the outer regions of the protoplanetary disk, as well as important inputs for the interpretation of data from Rosetta and Stardust samples, from samples returned by future space missions such as Hayabusa 2, OSIRIS-Rex, and for the observations of protoplanetary disks by the future James Webb Space Telescope (JWST).