East Meridiani Planum’s karst geomorphology and biosignature preservation potential: a multi-criteria landing site analysis

IntroductionFuture Mars astrobiology missions require landing sites that balance scientific potential for biosignature detection with engineering safety. This study addresses the need for systematic identification of optimal sites targeting ancient aqueous environments distinct from previously explored terrains.MethodsA multi-criteria GIS-based analysis was conducted to evaluate five candidate landing sites (Aram Chaos, East Meridiani Planum, Ottumwa Crater, East Margaritifer Terra, and Nili Fossae) using global and regional datasets including MOLA topography, MOCAAS mineralogy, HiRISE imagery, and thermal inertia measurements. Sites were assessed against engineering constraints (latitude ±30°, elevation <−0.5 km, slopes <15°, thermal inertia >100 J m−2 K−1 s0.5) and scientific criteria (diversity, context, habitability, and biosignature preservation potential).ResultsEast Meridiani Planum emerged as the top-ranked candidate. The site features unique evaporite karst geomorphology (ridges, dolines, salt pans), extensive hydrous sulfate and Fe/Mg phyllosilicate deposits, and favorable engineering parameters (elevation: −1.1 km; thermal inertia: 200–450 J m−2 K−1 s0.5; slopes <5°). The proposed 25 km × 20 km landing ellipse at 0.74°N, 4.44°E provides access to the Noachian-age (∼3.7 Ga) Upper Etched Unit, offering a distinct paleoenvironment from the Hesperian hematite plains explored by the Opportunity rover.DiscussionThis site offers exceptional potential for investigating Mars' hydrological evolution and detecting preserved organic molecules. The dual mineralogy—neutral-pH smectite clays favorable for molecular preservation and acidic sulfate evaporites conducive to morphological biosignature preservation—enables testing of multiple biosignature hypotheses. The combination of high scientific value, minimal aeolian cover, and flat topography makes East Meridiani Planum an optimal target for future astrobiology missions seeking evidence of ancient Martian habitability.