ESA's ExoMars Orbiter Detects Hydrogen Chloride, Hinting at Dormant Volcanic Activity on Mars

The European Space Agency's ExoMars Trace Gas Orbiter has detected atmospheric hydrogen chloride above the northern flanks of Alba Mons, a large shield volcano on Mars. These findings suggest a possible source of volcanic gas emissions beneath the Martian surface, indicating that Mars may still retain some degree of magmatic activity. The results were published in Science Advances on November 4, 2026.

Context

The ExoMars Trace Gas Orbiter, launched by the European Space Agency, aims to study trace gases in the Martian atmosphere. Alba Mons is one of the largest shield volcanoes on Mars, and its geological features have been of interest to scientists. Previous missions have suggested that Mars is geologically inactive, making this new evidence significant.

Why it matters

The detection of hydrogen chloride on Mars suggests that the planet may still have active geological processes. This finding could reshape our understanding of Mars' volcanic history and its potential for past or present habitability. Understanding volcanic activity on Mars is crucial for future exploration and potential colonization efforts.

Implications

If Mars is indeed experiencing volcanic activity, it could impact future exploration missions and the search for life. This may lead to renewed interest in Mars as a target for human exploration. Additionally, understanding Mars' geological processes could provide insights into similar processes on Earth and other celestial bodies.

What to watch

Researchers will continue to analyze data from the ExoMars orbiter to further investigate the implications of this hydrogen chloride detection. Upcoming missions may target areas near Alba Mons to gather more detailed information. The scientific community will watch for additional findings that could confirm or refute ongoing volcanic activity.