OSIRIS-REx: Chemical and structural analysis of asteroidal material returned from C-type asteroid Bennu.

这一建议是我们在日本宇宙航空研究开发机构隼鸟2号使命任务框架内对来自Ryugu的小行星样本进行的非常成功的研究的后续行动。小行星样本研究的延伸是在样本返回使命OSIRIS-REx（起源、光谱解释、资源识别、安全、风化层探测器）（美国航天局）中进行的，其使命目标是调查碳质C级近地小行星Bennu。在拟议的项目中，我们将在矿物学和岩石学工作组（MAPWG）初步调查小组的OSIRIS-REx使命框架内开展工作，应用同步辐射XRF和TEM分析。OSIRIS-REx使命的两个最主要的目标是：1）“返回和分析原始碳质小行星风化层的样本，其数量足以研究其组成矿物和有机物质的性质、历史和分布”;和2）“绘制全球性质，化学，对一颗原始碳质小行星的地质学和矿物学进行研究，以确定其地质和动力学历史的特征，并为送回的样品提供背景资料”。目标是获得关于类地行星与小天体种群之间关系、地球起源以及地球有机物质和水的来源的新的基本信息。自太阳系形成以来，碳质小行星被认为变化最小，可能会让我们深入了解这些物质是在最早的行星形成时期存在于类地行星区域，还是在后期的轰击阶段被送到地球。样本材料于2020年直接从小行星Bennu的表面收集，目前正在OSIRIS-REx航天器上带回地球，预计将于2023年9月24日抵达。抵达后，这些直接收获的小行星材料将被运送到约翰逊航天中心（JSC）的OSIRIS-REx管理设施，称重，分类和管理。然后，将把其中一些材料分发给主要调查组，这是一个由专家小组组成的国际跨学科小组，供进行有针对性的具体分析。作为OSIRIS-REx使命的指定专家团队之一，我们将参与该项目的初始分析阶段，并将成为首批接收部分Bennu材料的团队之一。在我们对Bennu材料的调查中，我们将获得化学，矿物学和岩石学数据，这些数据将有助于解释Bennu的含水，热和冲击历史，并应用两种独立的分析方法，即同步加速器-XRF和TEM。

This proposal is a follow-up of our very successful study of asteroidal samples from Ryugu in the framework of JAXAs Hayabusa2 mission. The elongation of the study of asteroidal samples is embedded within the sample return mission OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer) (NASA), whose mission target is the investigation of the carbonaceous C-class near-Earth asteroid Bennu. In the proposed project we will work in the framework of the OSIRIS-REx mission in the mineralogy and petrology working group (MAPWG) preliminary investigation team applying synchrotron radiation XRF and TEM analyses. The two most primary objectives of the OSIRIS-REx mission are: 1) to “return and analyze a sample of pristine carbonaceous asteroid regolith in an amount sufficient to study the nature, history, and distribution of its constituent minerals and organic material”; and 2) to “map the global properties, chemistry, and mineralogy of a primitive carbonaceous asteroid to characterize its geologic and dynamic history and provide context for the returned samples”. The goal is to acquire new and fundamental information about the relationship between the terrestrial planets and the small-body populations, the origins of the Earth and the source of the Earth’s organic materials and water. Thought to be minimally altered since the formation of the Solar System, carbonaceous asteroids may provide insight into whether these materials were present in the terrestrial planet region during the earliest planet formation era, or delivered to the Earth by a late phase of bombardment. Sample material was directly collected from the asteroid Bennu´s surface in 2020 and is currently being carried back to Earth on board the OSIRIS-REx spacecraft, due to arrive on the 24th September 2023. Upon arrival, this directly harvested asteroidal material will be transported to the OSIRIS-REx curation facility at the Johnson Space Centre (JSC), weighed, sorted and curated. Some of the material will then be distributed to the primary investigating teams, an international and interdisciplinary group of expert subteams, for specific targeted analysis. As one of the designated expert teams of the OSIRIS-REx mission, we will be involved in the initial analysis stage of the project and will be one of the first teams to receive some of the Bennu material. In our investigation of the Bennu material, we will obtain chemical, mineralogical and petrological data that will help decipher the hydrous, thermal and shock history of Bennu, with the application of two separate analytical methods, namely synchrotron-XRF and TEM.