European orbiter detects hints of volcanic activity on Mars - SPACE & DEFENSE

New observations from the ExoMars Trace Gas Orbiter (TGO) have provided evidence that Mars may still be releasing volcanic gases, suggesting the planet could retain enough internal heat to support at least dormant volcanism.

The European Space Agency said researchers detected hydrogen chloride in the martian atmosphere above volcanic fissures on the flanks of the Alba Mons volcano during early summer in Mars’ northern hemisphere. The gas had previously been reported by TGO in 2021 and is commonly associated on Earth with emissions from magmatic vents.

An international research team led by Alexander Trokhimovskiy linked the hydrogen chloride detections to potential hot magma beneath the surface. Co-lead author Daniel Mège, a professor at the Space Research Centre of the Polish Academy of Sciences, said the findings indicate “Mars has retained enough internal heat to support volcanic activity until recently, and possibly still does”.

The team’s analysis combined atmospheric measurements with geological observations. ESA said the hydrogen chloride detections were strongly localised in both place and time, occurring just after winter frosts were thought to sublimate. The data were collected by infrared spectrometers in TGO’s Atmospheric Chemistry Suite.

High-resolution images of the Alba Mons region from TGO’s CaSSIS camera also showed fresh, narrow fissures—some hundreds of metres long—alongside surface colour changes. Researchers suggested these fissures could act as channels for gas release, blocked by ice during winter and opening as temperatures rise in early summer.

While Mars hosts the largest volcanoes in the Solar System, direct evidence of current eruptions has not been observed. ESA noted that some volcanoes appear to have been active within the last few million years, and marsquakes detected by seismometers point to continued internal activity.

Researchers also pointed to broader implications for Mars’ past climate and potential habitability. ESA said magmatic gases may have been more abundant in earlier periods, possibly contributing to a thicker atmosphere and warmer conditions. The team suggested that if magma interacts with groundwater, it could create warm subsurface environments that may be more favourable for life.

“Looking for martian life in the seeping fissures of the Alba Mons region would make a lot of sense,” Mège said, arguing that hydrothermal systems could provide energy and shelter for microorganisms.

ESA’s ExoMars Trace Gas Orbiter project scientist Colin Wilson said the results “may prove to be TGO’s greatest success yet”. The research paper, titled “Enigmatic HCl detections as a potential signature of igneous activity on Mars,” was published in Science Advances on 4 November 2026.