Abstract EANA2026-48

The ExoMars Rosalind Franklin (RF) rover, set to launch in 2028, is equipped with a payload of instruments designed to facilitate the search for signs of ancient microbial life at the Martian surface and sub-surface to a depth of 2 m [1]. The landing site, Oxia Planum, shows remote sensing evidence for aqueous activity in the Noachian, and contains a phyllosilicate-bearing clay unit with high organic preservation potential, making it a compelling location for the detection of potential Martian biosignatures [2]. Analysis by the Perseverence rover of the Bright Angel formation in the Neretva Vallis river channel—another ancient aqueous environment that may have similar geological characteristics to Oxia Planum at the sub-meter scale—has determined that organic carbon present in outcrops has undergone post-depositional redox reactions to produce millimiter-scale reaction fronts and nodules that are visible in rover data and similar to terrestrial ‘reduction spots’ [3]. 

Analysis with ExoMars Rosalind Franklin emulators has been performed on 6 samples that are terrestrial examples of rocks bearing similar ‘reduction spots’, sourced from three localities (Budleigh Salterton, Dingwall and Stoer, UK), to evaluate whether RF could detect similar nodules and reaction fronts as observed at Jezero Crater if present at Oxia Planum. The Panoramic Camera (PanCam) instrument on board Rosalind Franklin is equipped with two wide-angle cameras (WACs) and a high-resolution camera (HRC) designed to perform geological characterisation of the landing site and aid in target selection for further analysis. The WACs provide stereographic multispectral images of science targets with 11 geological filters, encompassing a spectral range of 440–1000 nm [4], and will be used in tandem with Enfys, a linear variable filter spectrometer with spectral range of 0.9–2.5 µm, to perform geochemical analysis on outcrops to determine their suitability as drill target locations [5]. The Close-Up Imager (CLUPI) instrument [6] provides complementary high-resolution imagery of science targets, revealing texture, colour and rock microstructure to aid in geological characterisation. 

This study confirms that PanCam WAC and HRC can detect, both visually and spectrally, cm- to mm-scale ‘reduction spots’ on samples measured from a nominal operation distance of >2 m. Across the Budleigh Salterton and Dingwall samples, PanCam WAC multispectral images discriminate between reaction fronts and the host rock, whilst across all samples HRC images visualise the presence and characteristics of both reaction fronts and cores. Planned analyses with Enfys-representative spectrometers aims to confirm whether cores can be spectrally discriminated from reaction fronts and host rock composition, and complimentary imaging is scheduled to be collected with the CLUPI enhanced engineering model (EM+) to further assess the capabilities of the RF payload to detect small-scale features that may be considered as potential biosignatures. 

[1] Vago J. L. et al. (2017) Astrobiology, Vol. 17, No. 6–7 [2] Quantin-Nataf C. et al. (2021) Astrobiology, Vol. 21, No. 3 [3] Hurowitz, J. A., et al. (2025) Nature 645.8080, pp. 332-340. [4] Coates A. J. et al. (2017) Astrobiology, Vol. 17, No. 6–7 [5] Boyd, A. M., et al. (2025) Next-Generation Spectroscopic Technologies XVII. Vol. 13449 pp. 26-42 [6] Josset J. L. et al. (2017) Astrobiology, Vol. 17, No. 6-7