Shalbatana Vallis stretches roughly 1,300 kilometers, about the length of Italy, connecting the heavily cratered highland region of Xanthe Terra to the lowland Chryse Planitia.
Scientists are especially interested in regions like Shalbatana Vallis because they preserve evidence that Mars was once far warmer and wetter than it is today.
An earlier Mars Express video, captured in October 2025, had already observed the full length of the Shalbatana Vallis channel from beginning to end.
Outflow channels like Shalbatana Vallis are commonly accompanied by scattered rock mounds and raised blocks of this kind.
The spacecraft originally included a lander, Beagle 2, alongside the Mars Express orbiter itself.
Shalbatana Vallis stretches roughly 1,300 kilometers, about the length of Italy, connecting the heavily cratered highland region of Xanthe Terra to the lowland Chryse Planitia. The images, released by the European Space Agency (ESA) on May 13, focus specifically on a northern segment of this channel, delivering what scientists describe as exquisite high-resolution detail on one of Mars’s most geologically complex surface features.
Scientists are especially interested in regions like Shalbatana Vallis because they preserve evidence that Mars was once far warmer and wetter than it is today. The channel empties toward Chryse Planitia, one of the lowest regions on Mars, where some researchers have proposed an ancient ocean may once have existed.
A Valley Carved by Catastrophic Groundwater
According to ESA, enormous quantities of groundwater are believed to have burst onto the Martian surface around 3.5 billion years ago, rapidly cutting a winding path through solid rock. The result is a main channel roughly 10 kilometers wide and 500 meters deep. The sheer scale of those dimensions reflects the violence of the events that produced them.
This image shows part of Shalbatana Vallis, a large channel near Mars’s equator, in wider context – © NASA/USGS; ESA/DLR/FU Berlin
Researchers believe that, over time, the once-deep valley has gradually filled in with sediments and other material. The precise composition of everything that accumulated cannot be fully pinpointed, but some clues exist. Dark blue-black deposits scattered through the valley are thought to be volcanic ash redistributed across the surface by Martian winds, a detail visible in the new HRSC imagery.
An earlier Mars Express video, captured in October 2025, had already observed the full length of the Shalbatana Vallis channel from beginning to end. This new release goes further, zooming in tightly on a northern segment to reveal higher-resolution detail on the chaotic terrain and associated geological features that previous imaging had not fully resolved.
Volcanic Activity, Lava Flows, and Wrinkle Ridges
The new imagery reveals layers of Mars’s complex geological past across the region. According to the space agency, volcanic activity has over time flooded portions of the area with lava, smoothing ancient features before cooling and contracting into what geologists call wrinkle ridges. A few isolated sections of earlier surface have managed to survive this process, now jutting up as scattered hilltops and mesas within the channel.
Remnants of impact craters in the area now lie partially obscured by later burial, long-term wear, and even a covering of material ejected during the initial impact. Alongside those craters, the images capture what planetary scientists call chaotic terrain, fractured, jumbled blocks of rock thought to have formed when underground ice melted and caused the surface above to collapse. In Shalbatana Vallis, a section of this chaotic terrain appears near the same blue-black deposit identified as likely volcanic ash.
As reported by The Debrief, Mars Express has previously captured such features in the regions of Pyrrhae Regio, Iani Chaos, Ariadnes Colles, Aram Chaos, and Hydraotes Chaos, suggesting these formations are a recurring signature of Mars’s volatile past rather than isolated anomalies. Outflow channels like Shalbatana Vallis are commonly accompanied by scattered rock mounds and raised blocks of this kind.
This view was generated from the digital terrain model and the nadir and colour channels of the High Resolution Stereo Camera on ESA’s Mars Express. It shows a bird’s-eye view of part of Shalbatana Vallis, a large channel near Mars’s equator – © ESA/DLR/FU Berlin
Two Decades in Orbit, With Years Still Ahead
Mars Express has been circling the Red Planet since its 2003 launch, carrying a suite of eight onboard scientific instruments. The spacecraft originally included a lander, Beagle 2, alongside the Mars Express orbiter itself.
Over more than two decades, its High Resolution Stereo Camera has mapped the Martian surface in color and in three dimensions at resolutions not previously achieved, playing a major role in uncovering evidence of Mars’s watery past, mapping minerals formed in water, studying buried ice deposits, and contributing to findings suggesting possible liquid water beneath the planet’s southern polar ice cap.
The mission also lies near Chryse Planitia, likely an ancient ocean based on its status as one of the lowest points on the Martian surface and the many outflow channels leading into it. The region sits at a geological crossroads, with relatively smooth northern lowlands on one side and heavily cratered southern highlands on the other, a landscape that encapsulates billions of years of planetary history in a single frame.
This colour-coded topographic image shows part of Shalbatana Vallis, a large channel near Mars’s equator – © ESA/DLR/FU Berlin
Software updates carried out last year are expected to keep Mars Express operational through 2034, meaning the orbiter could still be sending back data ahead of any potential crewed landings on the Red Planet, a prospect that gives these images a significance reaching well beyond pure scientific curiosity.
