Multi-technique characterization of Mars analogue samples: results from test campaigns 1-7

The characterization of Martian analogue samples requires robust, multi-disciplinary laboratory methodologies capable of resolving physical, mineralogical, and geochemical properties across a wide range of materials. In support of the European Space Agency (ESA) work to characterize terrestrial Mars analogue samples and provide data to the scientific community, the Norwegian Geotechnical Institute (NGI), in collaboration with Norwegian research partners, has developed and implemented a comprehensive testing framework for Mars analogue materials. This framework targets rock and soil analogues, as well as the FS-120 reference material, a porous fused silica previously used as an organic check material in studies related to the Sample Analysis at Mars (SAM) instrument on the Curiosity rover, and integrates standardized techniques commonly used in geotechnical engineering and planetary science. This study presents the results of test campaigns 1–7, focusing on the systematic materials characterization of six Mars analogue materials and the FS-120 reference material. The objective is to evaluate the applicability, complementarity, and limitations of a broad suite of laboratory techniques for constraining the physical properties, mineralogy, and geochemistry of analogue materials relevant to Mars sample science and curation. Each analogue sample was subjected to a standardized yet adaptable testing workflow including: (i) classification and index testing (e.g., particle size distribution, bulk and grain density), (ii) mineralogical and geochemical analyses (XRD, XRF, ICP-OES, ICP-MS, TOC), and (iii) microstructural and imaging techniques (SEM, optical microscopy, micro- and nano-CT, photogrammetry). For selected samples, strength and mechanical behaviour were additionally assessed through uniaxial compression and tensile strength tests. The analytical programme was designed to provide both qualitative and quantitative datasets while allowing flexibility depending on sample type and scientific priorities. The six natural analogue samples exhibit significant variability in mineralogical composition, grain size distribution, and microstructural characteristics, reflecting a range of potential Martian lithologies. Combined XRD and XRF/ICP datasets provide consistent identification of major phases and elemental composition, while CT and SEM analyses reveal complex pore structures and grain morphologies across scales. Mechanical testing highlights variability in strength and anisotropy, particularly in samples with sedimentary structures. For FS-120, this work extends previous mission-focused characterization into a more comprehensive open baseline dataset, supporting its use as a reference material alongside the natural analogues. The results demonstrate that a multi-technique characterization strategy is important to capture the complexity of Mars analogue materials and to support future Mars sample analysis missions. The workflows developed here provide a flexible approach that can be adapted to future analogue materials. Ongoing and future campaigns will expand the dataset. This work was carried out under ESA contract 4000145811/24/NL/PA.