NASA’s most enduring Mars mission has provided an extraordinary side view of a colossal volcano towering above the Red Planet just before twilight. On May 2, as sunlight began to illuminate the Martian horizon, the Odyssey spacecraft recorded Arsia Mons, a majestic, long-extinct volcano, rising through a luminous band of greenish mist in the planet’s upper atmosphere. The 12-mile-high volcano — almost double the height of Mauna Loa in Hawaii — stands like a testament to the planet’s ancient history. The image from space is both visually stunning and scientifically informative.

“We selected Arsia Mons with the hope of witnessing the summit rise above the early morning mist,” stated Jonathon Hill, who oversees Odyssey’s camera operations at Arizona State University, “and it certainly delivered.”

Arsia Mons is located at the southern tip of a formidable trio of volcanoes known as the Tharsis Montes. To achieve this perspective, Odyssey performed a maneuver it wasn’t originally designed for. This orbiter, operational since 2001, typically directs its camera straight down to photograph the planet’s surface. However, in the past two years, scientists have begun tilting the spacecraft 90 degrees to observe the horizon. This change enables NASA to investigate how dust and ice clouds vary with the seasons.

Although the image remains an aerial perspective, the view resembles that of the horizon, akin to how astronauts glimpse Earth’s horizon from 250 miles above on the International Space Station. At that elevation, Earth does not consume their entire field of vision — there is sufficient distance and perspective to observe the planet’s curved edge meeting the void of space. Odyssey operates above Mars at a similar altitude.

The Tharsis region contains the largest volcanoes in the solar system. The absence of plate tectonics on the Red Planet enabled them to expand far beyond any volcanoes on Earth. Collectively, they dominate the Martian surface and are sometimes enveloped in clouds, particularly during the early morning hours. However, these clouds are unique — they are composed of water ice, distinct from the more prevalent carbon dioxide clouds on the planet. Arsia Mons is the cloudiest of the trio.

Researchers have recently investigated a specific, localized cloud formation that forms over the mountain, referred to as the Arsia Mons Elongated Cloud. This transient phenomenon stretches 1,100 miles across southern Mars, lasting only about three hours in the morning during spring before vanishing in the warm sunlight. It is generated by strong winds being pushed up the mountainside.

The cloudy veil evident in Odyssey’s latest image, according to NASA, is known as the aphelion cloud belt. This extensive seasonal system blankets the planet’s equator when Mars is at its furthest point from the sun.

This marks Odyssey’s fourth side image since 2023, and it is the first to depict a volcano emerging through the clouds. “We are observing some truly significant seasonal variations in these horizon images,” remarked Michael D. Smith, a NASA planetary scientist, in a statement. “It’s providing us with new insights into the evolution of Mars’ atmosphere over time.”