NASA’s 2001 Mars Odyssey spacecraft has captured an unprecedented panoramic view of one of the Red Planet’s colossal volcanoes—Arsia Mons—rising above a blanket of clouds just before Martian dawn. This marks the first time a Martian volcano has been photographed on the planet's horizon, offering a perspective of Mars akin to how astronauts aboard the International Space Station observe Earth.
Arsia Mons, an ancient Martian volcano, was captured before dawn on May 2, 2025, by NASA’s 2001 Mars Odyssey orbiter while the spacecraft was studying the Red Planet’s atmosphere, which appears here as a greenish haze Credit: NASA/JPL-Caltech/ASU
The image, taken on May 2, shows the southernmost of the Tharsis Montes—a towering trio of Martian volcanoes—poking through a canopy of early morning water-ice clouds. Arsia Mons, the focus of the new panorama, rises to a staggering 12 miles (20 kilometers), making it nearly twice the height of Earth’s Mauna Loa, the largest volcano on our planet.
"This is exactly the kind of image we were hoping for," said Jonathon Hill, operations lead for Odyssey’s Thermal Emission Imaging System (THEMIS) at Arizona State University. “We picked Arsia Mons hoping we would see the summit poke above the early morning clouds. And it didn’t disappoint.”
Launched in 2001, Odyssey holds the title of the longest-operating mission orbiting another planet. While its main mission has long been to study the Martian surface, a shift in 2023 enabled the spacecraft to pursue a new line of observation: capturing high-altitude images of the Martian horizon.
To acquire these rare vistas, Odyssey performs a 90-degree rotation while in orbit, allowing its downward-facing THEMIS camera to instead gaze out toward the horizon. This maneuver, while technically challenging, allows scientists to examine layers of dust and water-ice clouds and track their seasonal evolution.
“We're seeing some really significant seasonal differences in these horizon images,” said Michael D. Smith, planetary scientist at NASA’s Goddard Space Flight Center in Maryland. “It’s giving us new clues to how Mars’ atmosphere evolves over time.”
Clouds, Seasons, and Future Exploration
Understanding the behavior of Mars’ atmosphere—especially its cloud patterns and dust activity—is critical for future exploration, including robotic and human missions. The timing of this latest image coincides with aphelion, the period when Mars is farthest from the Sun. During this season, a vast aphelion cloud belt forms along the equator, and Arsia Mons, often the cloudiest of the Tharsis volcanoes, becomes shrouded in thick fog formed by rising and cooling air along its slopes.
The THEMIS camera plays a key role beyond imaging weather patterns. Its infrared capabilities allow scientists to detect hidden subsurface water ice—a resource that could be vital for the first astronauts to land on Mars. THEMIS can also observe Mars’ two tiny moons, Phobos and Deimos, shedding light on their composition and origins.
This new image of Arsia Mons emerging from a sea of clouds offers more than just a spectacular view—it offers insight into Mars’ dynamic weather, towering geology, and seasonal shifts. It also highlights the enduring capability of the Odyssey mission, which after nearly 25 years in orbit, continues to push the boundaries of Martian exploration.
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