FRACTURE MAPPING AND DIRECTIONAL ANALYSIS AT ESA’S ROSALIND FRANKLIN LANDING SITE, OXIA PLANUM, MARS

The European Space Agency's ExoMars program will send the Rosalind Franklin rover to Oxia Planum on Mars in 2028. The primary aim of this mission is to search for indications of past and present life on the Red Planet. The presence of fractured rocks at the landing site is of particular interest to the astrobiological goal of the mission, as fractures may serve as pathways for fluid circulation and thus are important scientific targets. Our research focuses on mapping the fractures distribution and evaluating the statistical characteristics of these fractures, investigating their possible origin from various processes.

We first mapped the spatial distribution of fractures within the designated 115 by 15 km landing area of the Rosalind Franklin rover. For this preliminary analysis, we employed a grid mapping method with a scale of 1:5000, utilising basemap imagery from the High-Resolution Imaging Science Experiment (HiRISE). Based on this mapping product, we evenly positioned 50 measurement stations across the landing site, where most of the area was clear from other features outside fractures. At each measurement station, we traced all visible fractures at a large scale, and extracted their directional statistics using the R high-level computer language.

The results from all the measurement stations reveal an isotropic orientation of the fractures combined with a consistent east-west (E-W) trend. The E-W evidence from the statistical analysis is not readily apparent to the naked eye and remains consistent throughout the entire landing area.

Our results indicate that the fracturing observed at the Rosalind Franklin landing site can be attributed to at least two geological processes. The isotropic component of the fractures may have been generated by processes such as impacts, desiccation (drying out), thermoclastism (thermal stress fracturing), or hydrofracturing (fracturing due to fluid activity). Meanwhile, the E-W trend suggests the involvement of tectonic activity or oriented heat wave.

This first specific investigation of the fractures at the Rosalind Franklin landing site aims to contribute to the broader understanding of the geological history of Oxia Planum. It emphasises the need to unravel the complex geological narrative from multiple perspectives, consolidating and expanding upon previous studies conducted in this intriguing area.