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Artist's concept of NASA's MAVEN spacrcraft in orbit around Mars. (Credit: NASA/GSFC)

This summer, scientists spotted an incredibly rare visitor to Earth’s solar system—a comet, now known as 3I/ATLAS, that entered our solar system from the galaxy beyond and is zipping past the sun at a speed of about 137,000 miles per hour.

Now, a team of researchers from the ������ý���� has gotten an unprecedented opportunity to observe this visitor from interstellar space.

The team captured images of 3I/ATLAS over 10 days in September and October using NASA’s (MAVEN) spacecraft, which is now orbiting Mars. The observations were part of a to capture images of the comet from a fleet of spacecraft spread across the solar system.

Image of the comet 3I/ATLAS taken by MAVEN in October 2025. (Credit: NASA/Goddard/LASP/CU ������ý����)

Map of 3I/ATLAS's trajectory through the solar system. (Credit: NASA)

“This is the biggest and brightest object from outside our solar system that’s ever been observed,” said Shannon Curry, a planetary scientist at the (LASP) at CU ������ý���� who leads the MAVEN mission. “The idea that we could be observing it at this level of detail is really incredible.”

She’s not alone in her excitement: 3I/ATLAS is only the third comet or similar icy body researchers have ever seen flying through solar system from interstellar space.

The comet, which scientists estimate could measure as much as 3.5 miles across, will make its closest brush with Earth on Dec. 19. It will pass within 167 million miles of our planet—too far to see with the naked eye.

NASA , along with data from other spacecraft, in November. The MAVEN team is still analyzing these data, but they may yield a treasure trove of information about 3I/ATLAS, including some of the main ingredients that make up the comet.

“It comes from somewhere else, and that’s why we’re so excited about it,” said Nicky Fox, associate administrator for NASA’s Science Mission Directorate, in a Nov. 19 media event. “It’s only the third time that we’ve been able to identify and track something coming from outside our own solar system.”

A view from Mars

Curry noted that MAVEN was never designed to observe objects like comets.

The spacecraft launched in 2014 to study the upper atmosphere of Mars. But in fall 2025, it was in the right time and place to see 3I/ATLAS.

On Oct. 3, the comet passed Mars at a distance of roughly 18.6 million miles. At the time, Earth was on the other side of the sun from Mars, blocking our planet’s view of 3I/ATLAS.

A team at Lockheed Martin in Colorado, which operates MAVEN, positioned the spacecraft so that it was pointing in the comet’s direction. The researchers then began collecting images using an instrument called the Imaging Ultraviolet Spectrometer (IUVS), designed by a team from LASP.

“Our engineering teams enjoy a challenge, and our spacecraft are incredibly versatile, allowing us to support science far beyond the spacecrafts’ initial mission profiles,” said Sandy Freund, mission operations manager for Deep Space Exploration at Lockheed Martin.

Image taken by MAVEN of 3I/ATLAS showing hydrogen emitted from different sources: the comet (dim spot on the far left), hydrogen from Mars (bright emission on the right), and hydrogen flowing through our solar system between the planets (dim emission in the middle). (Credit: NASA/Goddard/LASP/CU ������ý����)

A comet from beyond

The resulting images show a bright object pummeling through space surrounded by a haze of gas and dust—almost like a fuzzy dandelion ball in space.

They may not look like much on the surface, but these pixels carry a wealth of information about the comet.

Image taken of 3I/ATLAS by the Hubble Space Telescope in July 2025. (Credit: NASA, ESA, David Jewitt/UCLA; Image Processing: Joseph DePasquale/STScI)

“There was a lot of adrenaline when the data came down and we saw what we’d captured,” said Justin Deighan, a research scientist at LASP and deputy principal investigator for MAVEN. “Every measurement we can make of this comet is precious and helps to open up new understanding of interstellar objects.”

Curry explained that 3I/ATLAS is made up mostly of ice. As the comet flies through the solar system, radiation from the sun cooks off some of that ice. In the process, 3I/ATLAS emits water through hydrogen and oxygen in various forms into space.

These elements become part of the comet’s coma, or the wide halo of wispy gases and dust that surround its body.

MAVEN’s images will allow scientists to identify many of the ingredients in that halo—bringing researchers as close as they can to traveling to 3I/ATLAS and seeing what it’s made of. It’s the only spacecraft capable of measuring how fast the comet is losing water to space, Curry said.

She added that, despite speculation among some people that 3I/ATLAS could be an alien spacecraft, data from multiple NASA instruments show that it’s clearly a comet.

“Everything about this object tells us it’s a comet,” she said. “There’s nothing to indicate that its trajectory, size and evolution could be produced in any other way.”

Curry sees the new observations as a testament to the MAVEN scientists and engineers and the spacecraft itself—which has been collecting invaluable scientific information at Mars since 2014

“You the MAVEN team show up to do science and can still produce exciting and groundbreaking results no matter what the challenges are,” she said. “That demonstrates the inherent value of an observatory like MAVEN.”

The MAVEN mission is part of NASA’s Mars Exploration Program portfolio. MAVEN’s principal investigator is based at the Laboratory for Atmospheric and Space Physics (LASP) at the ������ý����, which is also responsible for managing science operations and public outreach and communications. NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the MAVEN mission. Lockheed Martin Space built the spacecraft and is responsible for mission operations. NASA’s Jet Propulsion Laboratory in Southern California provides navigation and Deep Space Network support.