X‐ray computed tomography study of terrestrial analog cores in preparation for Mars sample return

Abstract Mars Sample Return (MSR) is expected to transform planetary science by providing unprecedented access to pristine Martian material. Initial characterization in the sample receiving facility (SRF) will rely on nondestructive techniques such as X‐ray computed tomography (XCT) to document the condition, distribution, and internal features of sealed core samples. To test XCT protocols in advance of MSR, we analyzed terrestrial analog cores collected during the Pilbara Sample Return campaign in Western Australia. Sedimentary and regolith samples were scanned at both whole‐core and fragment scales to evaluate scan times, optimal energy conditions, and resolution limits. Our results demonstrate that XCT offers critical insights into fragment size distributions, internal banding, porosity, and fracture networks before sample opening, information that is essential for subsampling and preserving astrobiologically relevant textures. Integration with Raman spectroscopy, optical microscopy, and EPMA confirmed that XCT reliably identifies high‐attenuation (high‐μ) phases (e.g., oxides, sulfides) but cannot distinguish between common silicates, underscoring the need for multi‐modal characterization. We also demonstrate how XCT data sets can be used to track sample mass, restore fragment orientation, and potentially reconstruct stratigraphic context. Updated sample mass estimates indicate that the MSR collection is sufficient to meet community science objectives, with required masses (12–15 g per core) well below expected returns. These results highlight XCT as a cornerstone of SRF pre‐basic characterization, providing both immediate triage value and a foundation for long‐term digital curation.