OSIRIS-REx Sample Site Selection Data Bundle Overview ===================================================== The OSIRIS-REx mission, launched in September 2016, aimed to collect and return a pristine sample from the near-Earth asteroid Bennu. Bennu is a primitive, carbon-rich body believed to hold clues about the early Solar System and the origins of life. The spacecraft arrived at Bennu in December 2018 and returned the sample to Earth in September 2023. The OSIRIS-REx Sample Site Selection archive is a group of data products produced for the OSIRIS-REx Sample Site Selection Team at various points during the Bennu Encounter that were used to select the final sampling site for the mission. These products were produced with the best available data at the time of production, but may not be the best and final science products. These catalogs are included in the overall OSIRIS-REx archive as historical documents for mission context. Scientific analysis should use archival data products found in the instrument and derived data product bundles. For more information about the documents contained on this bundle and the OSIRIS-REx sample site selection at Bennu, see Lauretta et al. 2021. OSIRIS-REx Sample Site Selection Timeline at Bennu ================================================== - Dec 2018: Arrival at Bennu; initial observations reveal unexpected, rugged, boulder-rich surface. - Dec 3, 2018: Preliminary Survey begins to determine Bennu’s mass and shape. - Feb 2019: Detailed Survey - Baseball Diamond flybys redesigned to improve global mapping. - Apr 2019: Equatorial Stations phase begins. - Jun 2019: Orbit B operations provide high-resolution laser altimetry and surface imaging. - Aug 2019: Orbit C begins; reduced operations while monitoring particle ejections. - Oct 2019: Recon A flybys of four candidate sites: Nightingale, Osprey, Kingfisher, Sandpiper. - Late 2019: Site selection board evaluates Recon A data; Nightingale selected as primary site due to high sampleability and science value. - Early 2020: Recon B and C sorties executed to gather high-resolution data for NFT guidance and sampleability assessment. - Apr 14, 2020: Checkpoint rehearsal tests initial descent and NFT guidance. - Aug 11, 2020: Matchpoint rehearsal tests hazard map and descent accuracy. - Oct 20, 2020: Successful sample collection at Nightingale using TAGSAM. - Oct 28, 2020: Sample safely stowed in SRC. OSIRIS-REx Sample Site Selection Bundle Contents ================================================ This bundle contains the following collections: document_final collection: Contains .pdf map catalogs of Bennu Nightingale sample site. This is the primary OSIRIS-REx sample site. Each catalog features geospatial maps with comparative visualizations across all candidate sites. These catalogs are decisional products, and as such are historical documents. document_final_four collection: Contains .pdf map catalogs of Bennu Nightingale, Osprey, Sandpiper, and Kingfisher potential sample sites. Each catalog features geospatial maps with comparative visualizations across all candidate sites as well as an overviewmap.The catalog encompasses PolyCam-derived imagery, shadow mapping, surface texture analysis, boulder distribution, reflectance imagery, and false color composite visualizations for each site. These catalogs are decisional products, and as such are historical documents. document_final_eight collection: Contains .pdf map catalogs of the final eight potential sample sites. Each catalog features geospatial maps with comparative visualizations across all candidate sites as well as an overviewmap.The catalog encompasses PolyCam-derived imagery, shadow mapping, surface texture analysis, boulder distribution, reflectance imagery, and false color composite visualizations for each site. These catalogs are decisional products, and as such are historical documents. This bundle was created by the OSIRIS-REx Science Team in collaboration with the OSIRIS-REx Science Operations and Processing Center (SPOC) and archived by the Small Bodies Node of the Planetary Data System. References ========== Lauretta, D. S., Enos, H. L., Polit, A. T., Roper, H. L., and Wolner, C. W. V. Chapter 8 – OSIRIS-REx at Bennu: Overcoming challenges to collect a sample of the early Solar System. In Sample Return Missions, Elsevier, 2021, p.163–194. https://doi.org/10.1016/B978-0-12-818330-4.00008-2. Glossary ======== Checkpoint rehearsal: The trial run of the initial steps of the sample collection sequence Baseball Diamond: The mission subphase before Equitorial Stations subphase. This observation sequence prioritized Bennu global mapping requirements. This subphase was a part of the Detailed Survey phase. Equatorial Stations: A mission subphase from in late April 2019. The station sequence prioritized the observations needed to inform sample-site selection. This subphase was a part of the Detailed Survey phase. Matchpoint rehearsal: The matchpoint rehearsal was a real-time test of the hazard map software designed to keep the spacecraft from contacting an unsafearea of the surface. NFT: Natural Feature Tracking. One of the two independent autonomous guidance systems the spacecraft was equipped with. This guidance system was used for the final closure with the asteroid surface. OSIRIS-REx: Origins, Spectral Interpretation, Resource Identification, Security, Regolith Explorer. PolyCam: The OSIRIS-REx Camera Suite (OCAMS) comprises three cameras used for navigation, surface mapping, and documenting sample collection. The PolyCam instrument is used for target acquisition and preliminary surface mapping with resolution of less than 25cm. The MapCam instrument is used for mapping at multiple phase angles through one panchromatic and four color filters. The MapCam filter set is similar to the filter set used in the Eight Color Asteroid Survey (ECAS) ground-based data set. The SamCam was used to document and provide context for the sample collection at asteroid (101955) Bennu. ROI: Region of interest (area under consideration as a potential sample site). Sortie: A maneuver in which the spacecraft departs orbit to fly over a specific site and inserts back into orbit at the conclusion of the observation. SRC: Sample Return Capsule. Target Variability: The distance between the desired sampling touchdown location and slightly different target touchdown locations based on safety if the chosen spot. Candidate sample sites were chosen first based on the potential for adequate regolith. Target variability allows for slight variability in the touchdown location to increase the ability to deliver the spacecraft safely to the surface. W-bs: Color ratio map using the equation w/(v/2+x/2).