CaSSIS Archives

This graphic describes a possible new chemistry cycle on Mars following the discovery of hydrogen chloride in the atmosphere by the ESA-Roscosmos ExoMars Trace Gas Orbiter. -- ESA

ExoMars Trace Gas Orbiter Detects Hints Of Volcanic Activity On Mars

by Keith CowingNovember 5, 2026November 5, 2026

[ESA] New evidence from gas seeping above volcanic rifts suggests Mars is not geologically dead deep inside, but merely sleeping.

Moment 0 maps of the transitions of CH3OH at 282213.3 MHz (Eup = 341 K, Aij = 9 × 10−7 s−1) and 281000.1 MHz (Eup = 191 K, Aij = 4 × 10−5 s−1), 13CH3OH at 283207.3 MHz (two transitions with Eup = 95 and 110 K, Aij = 7 × 10−5 s−1), CH18 3 OH at 309979.3 MHz (Eup = 77 K, Aij = 3 × 10−4 s−1 ), CH3OD at 291412.8 MHz (Eup = 161 K, Aij = 1 × 10−4 s−1 ), CH2DOH at 279335.7 MHz (Eup = 132 K, Aij = 3 × 10−5 s−1 ), CHD2OH at 296460.6 MHz (Eup = 108 K, Aij = 7 × 10−5 s−1 ), and CD3OH at 305957.8 MHz (Eup = 163 K, Aij = 2 × 10−4 s−1 ). The integration was done between -9 and 0 km s−1. The continuum peak (C) and the blueshifted (B) and the redshifted (R) positions are indicated with crosses. The directions of the blueshifted and redshifted outflows are indicated with cyan and orange arrows, respectively. The 0,0 position is the continuum peak position. [astro-ph.GA]

Astrochemistry

Complex Organic Molecules in Protostars with ALMA Spectral Surveys (COMPASS) III. CH3OH isotopic fractionation in the low-mass protostar BHR71-IRS1

by Keith CowingNovember 2, 2026November 2, 2026

[astro-ph.GA]. [Abridged] Methanol is a complex organic molecule detected in both ice and gas toward star-forming regions. Due to its high abundance, its rarer isotopologues, including the deuterated ones, are […]

This is a false colour image – the blue tones of this image do not represent the real colour of the crater floor. The tonalities are stretched to bring out information about mineral diversity, and include information from the infrared, which is invisible to the human eye. -- ESA -- Larger image

Mars

An Interesting Crater In Valles Marineris

by Keith CowingAugust 12, 2026August 12, 2026

[ESA] Along the equator of Mars, CaSSIS spotted a couple of interesting craters in Ganges Chasma, a mineralogically diverse canyon in the far-eastern portion of Valles Marineris.

ID: ESP_076844_2550 date: 18 December 2022 altitude: 316 km -- NASA/JPL-Caltech/University of Arizona Larger image

Analog Studies, Arctic / Antarctic / Alpine, Biogeochemical Cycles & Geobiology, Desert Worlds, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Status Report

Translucent Ice On Martian Dunes

by Keith CowingApril 21, 2026April 21, 2026

Coordinating with the CaSSIS instrument on the ExoMars Trace Gas Orbiter, we acquired an image at this site for seasonal monitoring.

A Tributary channels identified in the northward facing promontory of the Southeast Coprates Chasma and Strahler orders characterizing the geometry of the channel networks in the various drainage basins. B Topographic cross-section drawn from elevation data that is extracted from the DEM along the red line across the promontory. The downward arrows indicate the depth of the local bedrock incision. SFD = scarp-fronted deposit. -- NPJ

Astrogeology, Atmospheres, Climate, Weather, Biogeochemical Cycles & Geobiology, Biosignatures & Paleobiology, Desert Worlds, Habitable Zones, Icy Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Press Release, Water/Hycean Worlds & Oceanography

Mars Was Half Covered By An Ocean

by Keith CowingJanuary 15, 2026January 15, 2026

Using images from cameras on Mars orbiters, an international research team led by the University of Bern has discovered structures on Mars that are very similar to classic river deltas […]

When a meteoroid shook the edge of Apollinaris Mons on Mars, it triggered streaks that carved a hundred new scratches on the surface. The European Space Agency’s ExoMars Trace Gas Orbiter captured these dust avalanches on the slopes the night before Christmas in 2023. -- ESA

Mars, Status Report

Origins Of Streak Features On Mars

by Keith CowingNovember 6, 2025November 6, 2025

This image from the Colour and Stereo Surface Imaging System (CaSSIS) onboard the European orbiter also shows the faint cluster of impact craters in the discoloured region at the base […]

Image of a dust devil, whirlwind of dust that is blown across Mars’ surface. Credit CC BY SA 3.0 IGO ESA/TGO/CaSSIS for CaSSIS

Atmospheres, Climate, Weather, Desert Worlds, Imaging & Spectroscopy, Mapping, Geodesy, Cartography, Bathymetry, Mars, Press Release

Raging Winds On Mars

by Keith CowingOctober 9, 2025October 9, 2025

Despite the very thin Martian atmosphere, there are also winds on Mars that are central to the climate and the distribution of dust.

ExoMars TGO image of comet 3I/ATLAS -- ESA

Astrochemistry, Astrogeology, Biochemistry & Organic Chemistry, Biophysics, Biosignatures & Paleobiology, Comets and Asteroids, Icy Worlds, Imaging & Spectroscopy, Interstellar, Press Release

ExoMars And Mars Express Observe Interstellar Comet 3I/ATLAS

by Keith CowingOctober 7, 2025October 7, 2025

Between 1 and 7 October, ESA’s ExoMars Trace Gas Orbiter (TGO) and Mars Express spacecraft turned their eyes towards interstellar comet 3I/ATLAS, as it passed close to Mars.

Slices from the edge of Mars reveal a layered atmosphere of delicate complexity. A European spacecraft has captured a luminous mille-feuille of dust enveloping the Red Planet in unprecedented detail. (larger image)

Atmospheres, Climate, Weather, Imaging & Spectroscopy, Mars, Press Release

Mars’ Atmospheric Mille-feuille

by Keith CowingSeptember 24, 2025

ESA’s ExoMars Trace Gas Orbiter keeps gathering information from its orbit around Mars to understand its ancient past and potential habitability. The spacecraft was cruising over the southern highlands of […]