[Paper Review] OSIRIS-REx Sample Analysis Plan -- Revision 3.0

D. S. Lauretta, H. C. Connolly+3 more|arXiv (Cornell University)|Aug 22, 2023

Astro and Planetary SciencePhysics and Astronomy3 citations

TL;DR

This paper outlines the comprehensive analysis strategy for the OSIRIS-REx mission's returned sample from asteroid Bennu, detailing a hypothesis-driven, coordinated approach using advanced analytical techniques to determine the asteroid's presolar history, formation age, organic content, space weathering effects, and regolith energy balance. The plan ensures systematic sample handling, data integration via a micro-geographic information system, and readiness testing to maximize scientific return from the returned material.

ABSTRACT

The Origins, Spectral Interpretation, Resource Identification, and Security Regolith Explorer (OSIRIS-REx) spacecraft arrived at its target, near-Earth asteroid 101955 Bennu, in December 2018. After one year of operating in proximity, the team selected a primary site for sample collection. In October 2020, the spacecraft descended to the surface of Bennu and collected a sample. The spacecraft departed Bennu in May 2021 and will return the sample to Earth in September 2023. The analysis of the returned sample will produce key data to determine the history of this B-type asteroid and that of its components and precursor objects. The main goal of the OSIRIS-REx Sample Analysis Plan is to provide a framework for the Sample Analysis Team to meet the Level 1 mission requirement to analyze the returned sample to determine presolar history, formation age, nebular and parent-body alteration history, relation to known meteorites, organic history, space weathering, resurfacing history, and energy balance in the regolith of Bennu. To achieve this goal, this plan establishes a hypothesis-driven framework for coordinated sample analyses, defines the analytical instrumentation and techniques to be applied to the returned sample, provides guidance on the analysis strategy for baseline, overguide, and threshold amounts of returned sample, including a rare or unique lithology, describes the data storage, management, retrieval, and archiving system, establishes a protocol for the implementation of a micro-geographical information system to facilitate co-registration and coordinated analysis of sample science data, outlines the plans for Sample Analysis Readiness Testing, and provides guidance for the transfer of samples from curation to the Sample Analysis Team.

Motivation & Objective

• To determine the presolar history and formation age of asteroid Bennu and its components through coordinated sample analysis.
• To investigate nebular and parent-body alteration processes that modified the asteroid's materials.
• To assess the relationship between Bennu's composition and known meteorite classes.
• To characterize the organic inventory and its evolution on the asteroid surface.
• To evaluate space weathering and resurfacing processes affecting the regolith through micro-scale analysis.

Proposed method

• A hypothesis-driven framework guides all sample analyses, ensuring alignment with mission-level science objectives.
• A suite of analytical instruments, including electron microscopes, mass spectrometers, and X-ray diffraction systems, is specified for detailed mineralogical and chemical characterization.
• The plan defines baseline, overguide, and threshold sample amounts to optimize analysis under varying sample return conditions.
• A micro-geographic information system (micro-GIS) is implemented to co-register and coordinate spatially referenced sample data across multiple analytical platforms.
• Data management protocols ensure secure storage, retrieval, and long-term archiving of all analytical results.
• Sample Analysis Readiness Testing is conducted to validate procedures and instrument readiness prior to actual sample processing.

Experimental results

Research questions

• RQ1 What is the presolar history and formation age of the materials in the Bennu sample?
• RQ2 To what extent were the materials altered by nebular processes or parent-body aqueous and thermal metamorphism?
• RQ3 How do the mineralogical and organic compositions of the sample compare to known meteorite groups?
• RQ4 What is the nature and distribution of organic compounds, and what do they reveal about prebiotic chemistry?
• RQ5 What evidence exists for space weathering and resurfacing on Bennu’s surface, and how do these processes affect regolith properties?

Key findings

• The sample analysis framework enables systematic, hypothesis-driven investigation of Bennu’s composition and history across multiple scientific domains.
• The use of a micro-geographic information system allows for precise co-registration of analytical data across different instruments and sample locations.
• The plan ensures readiness for sample analysis through pre-flight testing and validation of analytical protocols.
• The defined sample allocation strategy (baseline, overguide, threshold) optimizes scientific return under varying sample mass conditions.
• The data management and archiving system ensures long-term accessibility and integrity of all analytical results.
• The plan supports a coordinated, multi-instrument approach to fully characterize the returned sample’s mineralogical, chemical, and organic properties.