Mars orbiter captures first-ever photo of volcano above clouds, taller than any on Earth

A NASA spacecraft that has been circling Mars for more than two decades has spotted something it never has before in well over 100,000 orbits of the Red Planet.

On a morning horizon in May, the Odyssey orbiter caught a stunning glimpse of one of the planet's largest volcanoes peeking above a canopy of clouds. Known as Arsia Mons, the volcano dwarfs Earth’s tallest volcanoes.

Odyssey snapped photos of the volcano in May, which NASA released in June in a blog post.

Scientists at the U.S. space agency say the images provide far more than just a striking never-before-seen view of the Martian geography. Studying the features detailed in Odyssey's photos could help NASA prepare for crewed missions to Mars by better understanding the planet's weather and atmosphere.

Here's a look at what Odyssey captured and what to know about the volcano, Arsia Mons.

Mars orbiter spots volcano peeking above clouds

A panorama shot captured by Odyssey shows one of Mars' tallest volcanoes poking through clouds just before dawn.

The image marks the first time a Martian volcano can be seen on the planet's horizon, offering what NASA says is a view akin to what astronauts on the International Space Station have of Earth.

Odyssey’s camera, called the Thermal Emission Imaging System, or THEMIS, is built to study the Martian surface.

The camera is equipped to view Mars in both visible and infrared light, the second of which allows scientists to identify subsurface areas that contain water ice. Such a resource would be an invaluable source of not only water but a means to produce oxygen and fuel for crewed spacecraft when the first astronauts land on Mars.

Odyssey rotated 90 degrees while orbiting Mars so its camera had the correct angle to capture the shot, which, by revealing the horizon, allows scientists to observe seasonal changes on the Red Planet. Understanding the planet's weather, including its dust storms, also could help the space agency plan for human spaceflights, according to NASA.

What is the Arsia Mons volcano?

The volcano Odyssey spotted is known as Arsia Mons, one of three that forms the Tharsis Montes, or Tharsis Mountains. Though clouds composed of carbon dioxide are common on Mars, the Martian mountain range is instead often surrounded by water ice clouds, especially in the morning, NASA says.

Odyssey’s latest horizon image, captured May 2, indicates Arsia Mons stands 12 miles high. That's roughly twice as tall as Earth’s largest volcano, Mauna Loa in Hawaii, which rises 6 miles above the seafloor.

The southernmost of the Tharsis volcanoes, Arsia Mons is also the cloudiest of the three. The clouds, which form when air expands as it flows up the sides of the mountain and rapidly cools, are especially thick when Mars is farthest from the sun.

The band of clouds that forms across the planet’s equator at this time of year, called the aphelion cloud belt, is on prominent display in Odyssey’s new panorama.

“We picked Arsia Mons hoping we would see the summit poke above the early morning clouds," Jonathon Hill, a researcher at Arizona State University who is the operations lead for THEMIS, said in a statement. "And it didn’t disappoint.”

What is the Martian Odyssey orbiter?

Launched in 2001, Odyssey is the longest-running mission orbiting any planet besides Earth.

The orbiter is also one of two spacecrafts orbiting Mars under threat of being axed under President Donald Trump's budget proposal for NASA.

Managed by NASA’s Jet Propulsion Laboratory in California, Odyssey completed its primary science mission from February 2002 through August 2004. Since then, the orbiter has set out to study Martian clouds, fog and frost while mapping the surface to pave the way for crewed landings.

The newest panorama, NASA said, represents the kind of science the orbiter began pursuing in 2023, when it captured the first of its now four high-altitude images of the Martian horizon.

Eric Lagatta is the Space Connect reporter for the Paste BN Network. Reach him at elagatta@gannett.com