Rare Interstellar Comet 3I/ATLAS Spotted from Mars — NASA Shares New Images

NASA this week released new images of the interstellar visitor 3I/ATLAS, offering scientists fresh views of a rare object that originated beyond our solar system. First identified in July as the third confirmed interstellar object, 3I/ATLAS transformed from a frozen nucleus into an active, bright comet as it plunged toward the Sun.

Public updates from the agency were paused for more than a month during a U.S. government shutdown, a lull that allowed speculation to flourish online. With communications restored, NASA made it clear at a recent briefing that the object is a comet, not technology of extraterrestrial origin.

“We think the universe is a magical place,” said NASA Associate Administrator Amit Kshatriya. “We want very much to find signs of life in the universe. 3I/ATLAS is a comet.”

Several weeks before reaching perihelion on October 30, 3I/ATLAS passed within roughly 19 million miles of Mars. That flyby put the comet in view of three Mars missions that were not designed as stargazers: the Perseverance rover, the Mars Atmosphere and Volatile Evolution (MAVEN) orbiter, and the Mars Reconnaissance Orbiter (MRO).

Perseverance captured the comet as a faint, fuzzy smudge in one camera — an impressive feat for a surface rover but limited in scientific detail. MAVEN, using an ultraviolet filter, recorded a broad, puffy coma, revealing the cloud of gas and dust released as sunlight vaporized the comet’s ices. MAVEN’s UV data can help identify molecules being emitted and thus constrain the comet’s composition.

“All of these observations are very, very difficult,” said Tom Statler, lead scientist for solar system small bodies at NASA headquarters.

MRO contributed a high-resolution monochrome image that highlights the comet’s expansive coma and a diffuse dust tail. Meanwhile, the European Space Agency’s ExoMars Trace Gas Orbiter tracked 3I/ATLAS in October, providing additional positional measurements that helped refine its trajectory.

Two other NASA spacecraft — Psyche and Lucy — also spotted the comet in September, further improving orbital predictions. Observing 3I/ATLAS from multiple platforms allowed teams to map its path through the solar system with increased precision, making follow-up observations easier to coordinate.

A particular challenge for Earth-based observers was timing: from our vantage point the comet reached its most active phase nearly behind the Sun. Fortunately, three solar-observing missions — PUNCH, STEREO and the joint ESA–NASA SOHO — were able to monitor the comet as it swung around perihelion. The intense sublimation near the Sun produced a hazy, firework-like burst that those instruments detected despite the Sun’s glare.

3I/ATLAS is now traveling back out of the solar system, but astronomers still expect to study it as it fades. The James Webb Space Telescope may be among the last observatories able to follow the visitor. “I’m really excited about tracking it to the very end,” said Nicky Fox, NASA’s Associate Administrator for the Science Mission Directorate.

Why this matters

Interstellar objects like 3I/ATLAS provide a rare opportunity to sample material formed around other stars. Multi-platform observations — from Mars orbiters and rovers to deep-space probes and solar observatories — give researchers complementary data on the comet’s structure, composition and behavior, offering new clues about the makeup and history of distant planetary systems.