Meridiani Planum Archives

Opportunity's landing site - Challenger Memorial Station, NASA Larger image

One Way To Land Astrobiology Droids On Mars

by Keith CowingSeptember 14, 2026September 14, 2026

[NASA]. This image taken by the panoramic camera onboard the Mars Exploration Rover Opportunity shows the rover’s now-empty lander, the Challenger Memorial Station, at Meridiani Planum, Mars. The image was […]

(A) Sampling location at the origin of Río Tinto, Spain (modified from García-Moyano et al., 2007). (B) The iron microbialites (white arrow) grew horizontally on a northeast-facing wall. (C) -- [GSA Bulletin]

Analog Studies

Iron Microbialites From An Acidic Martian Analog (Río Tinto, Spain)—Implications For Finding Life On Mars

by Keith CowingJuly 17, 2026July 17, 2026

[GSA Bulletin] The search for life on Mars requires identifying suitable biosignatures detectable by rover missions or in returned samples. To support the progressing astrobiological exploration of Mars, we investigated […]

(Left) Predicted concretion diameter for different nucleation density scaling exponents α. For α ≤ 1, diffusion controls at the Mars dust grain size and predictions match observations (green band). For α ≥ 1.5, nucleation dominates even at 3 µm, predicting concretions well below the observed range, ruled out by the data. (Right) Crossover grain size as a function of α (log scale). Green region: diffusion-limited zone (crossover above Mars dust at 3 µm). Pink region: nucleation-limited zone. The graincontact derivation (dotted line, α = 1) sits within the diffusion-limited zone, consistent with observations. -- astro-ph.EP

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Mars, Status Report

Martian Concretion Sizes Predicted From Two Independently Constrained Inputs: Atmospheric Dust Grain Size And Obliquity-forced Wetting Duration

by Keith CowingMarch 13, 2026March 13, 2026

Diagenetic concretions have been identified at multiple widely separated sites on Mars, including Meridiani Planum (Opportunity), Gale crater (Curiosity), and Jezero crater (Perseverance).

This image from NASA’s Mars Perseverance rover, a fusion-processed SuperCam Remote Micro Imager (RMI) mosaic, shows part of the “St. Pauls Bay” target, acquired from the lower Witch Hazel Hill area of the Jezero crater rim. The image reveals hundreds of strange, spherical-shaped objects comprising the rock. Perseverance acquired this image on March 11, 2025, or sol 1442 — Martian day 1,442 of the Mars 2020 mission. NASA/JPL-Caltech/LANL/CNES/IRAP. Larger image

Astrogeology, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Fossils & Paleontology, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Press Release

Mars Perseverance Examines A Rock With Hundreds Of Millimeter-sized Spheres

by Keith CowingMarch 25, 2025March 25, 2025

Last week the Perseverance Science Team were astonished by a strange rock comprised of hundreds of millimeter-sized spheres and the team are now working hard to understand their origin.

active sand dunes in Meridiani Planum’s Endeavour crater

Astrogeology, Icy Worlds, Mars, Status Report

Aeolian Dune Sediment Flux Heterogeneity in Meridiani Planum, Mars

by Keith CowingJanuary 17, 2025January 17, 2025

It is now known unambiguously that wind-driven bedform activity is occurring on the surface of Mars today, including early detections of active sand dunes in Meridiani Planum’s Endeavour crater.