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International audience; INTRODUCTION: Organic compounds in asteroids and comets contain information about the early history of the Solar System. They could also have delivered organic material to early Earth. The Hayabusa2 spacecraft visited the carbonaceous asteroid Ryugu and collected samples of its surface materials, which were brought to Earth in December 2020. RATIONALE: We investigated the macromolecular organic matter in the Ryugu samples, measuring its elemental, isotopic, and functional group compositions along with its small-scale structures and morphologies. Analytical methods used included spectro-microscopies, electron microscopy, and isotopic microscopy. We examined intact Ryugu grains and insoluble carbonaceous residues isolated by acid treatment of the Ryugu samples. RESULTS: Organic matter is abundant in the Ryugu grains, distributed as submicrometersized organic grains and as organic matter dispersed in matrix. The Ryugu organic matter consists of aromatic carbons, aliphatic carbons, ketones, and carboxyls. The functional group

Introduction: On December 6, 2020, the Hayabusa2 mission successfully returned to Earth ~ 5.4 g of samples collected at the surface of the C-type asteroid Ruygu [1,2]. Its surface was first sampled on February 22, 2019, then on July 12, 2019, close to a 10-meter large artificial crater, so as to possibly access sub-surface material [3]. The collected samples are now kept at the Extraterrestrial Samples Curation Center of JAXA at ISAS in Sagamihara, Japan, for a first round of preliminary analyses, with the objective to characterize in a non-destructive manner both the bulk samples and a few hundreds of grains extracted from them [4]. In particular, the objective is 1) to support their further detailed characterization by the international initial analysis teams, which will start their activity in July 2021, and 2) to catalog the grains, accessible to the international community through AO selection, starting mid-2022. The preliminary characterization of these samples is being conducted with a visible microscope with four color filters, a FTIR spectrometer operating in the 1-5 µm range and MicrOmega, a hyperspectral NIR microscope developed at Institut d'Astrophysique Spatiale (Université Paris-Saclay/CNRS, Orsay, France), operating in the near-infrared range (0.99-3.65 µm) [5]. It is noteworthy that never before have the preliminary analyses of returned extraterrestrial samples included the characterization by a NIR hyperspectral microscope. Results: Preliminary outcomes of the analyses performed with MicrOmega will be presented at the conference. In particular, the question of the representativity of the samples collected by the Hayabusa2 spacecraft will be addressed thanks to the comparison of the spectra obtained by MicrOmega and the NIRS3 remote sensing IR spectrometer [6] which performed a spectral characterization (1.8-3.2 µm) of Ryugu's surface, including the sites of the samples' collection [7,8]. A preliminary analysis of the spatial compositional heterogeneity will be presented. Specific signatures, detected in grains typically present in References: [1] Binzel R. P. et al. (2002), Physical Properties of Near-Earth Objects. pp. 255-271, [2] Vilas F. (2008) The Astronomical Journal 135 (4), 1101-1105, [3] Morota et al. (2020) Science 368, Issue 6491, pp. 654-659, [4] Yada T. et al., in preparation, [5] Bibring J.-P. et al. (2017) Astrobiology 17, Issue 6-7, pp.621-626, [6] Iwata T. et al. (2017) Space Science Reviews 208 (1-4), 317-337, [7] Kitazato K. et al. (2019) Science 364 (6437), 272-275, [8] Kitazato K. et al. (2020) Nature Astronomy, Volume 5, p. 246-250.

Since December 2010, a new French Law on Space Operations (LSO) must be complied with by any entity related to space activities. It imposes, for instance, that any satellite operator shall demonstrate his capability to control the space vehicle, whatever the mission phase from the launch up to its End Of Life (EOL). The French Space Agency (CNES) is currently operating several remote sensing satellites (the last one called PLEIADES 1A), among a larger fleet of satellites. In that context, CNES has decided to perform several specific studies in order to define satellite disposal operation plans in any situation. The typical scenario of EOL operations consists in implementing five phases : disposal orbital manoeuvres, fluidic passivation, electrical passivation, transmitter disconnection and EOL orbit computation. One shall point out that these satellites (except PLEIADES 1A and 1B) were not originally designed to conform with the constraints imposed by the LSO. Thus, detailed analysis were conducted to identify the on-board and the on-ground improvements, as well as the operations chronology, without compromising in any way the security in the conduct of the operations. Depending on the context (nominal, contingency or emergency case) and the satellite subsystems status, different scenarios have been defined and compared in terms of strategy of disposal orbital manoeuvres, on-board and on-ground software upgrades, cumbersome operations, complexity, feedback... This paper addresses this tradeoff, and moreover, it focuses on two main points : 1) the on-board software upgrades (monitoring parameters, Failure Detection Isolation Recovery strategy, chronology and constraints of modifications upload) and the equipment that must be switched off or for which configuration parameters must be tuned, 2) the different disposal orbit manoeuvre strategies : several Orbit Control Manoeuvres (OCM), one or two OCMs followed by an infinite-duration thrust, or an unique infinite-duration thrust. In conclusion, the generic principles applied in these studies could be considered as guidelines for any other satellite platform EOL operations.