Views of Interstellar Comet 3I/ATLAS | NASA Mars Spacecraft: MRO & MAVEN

Views of Interstellar Comet 3I/ATLAS | NASA Mars Spacecraft: MRO & MAVEN

The High Resolution Imaging Science Experiment (HiRISE) camera aboard NASA's Mars Reconnaissance Orbiter (MRO) captured this image of interstellar comet 3I/ATLAS on October 5, 2025. At the time it was imaged, the comet was about 0.2 astronomical units (19 million miles or 30 million kilometers) from the spacecraft. 

An ultraviolet image composite of the hydrogen atoms surrounding comet 3I/ATLAS, the third interstellar object ever detected by astronomers as it passes through our solar system. This image was taken on September 28, 2025—just days before the comet's closest approach to Mars—by an instrument on NASA's MAVEN spacecraft that has been studying Mars since 2014. The instrument, the Imaging Ultraviolet Spectrograph, takes pictures in the ultraviolet part of the spectrum to reveal the chemical composition of objects. The image shows hydrogen emitted from multiple 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). Hydrogen emission from the comet is confined to the location of the comet in the sky. This is why it is small and round instead of extended.

NASA is in the middle of an unprecedented solar system-wide observation campaign, turning its spacecraft and space telescopes to follow comet 3I/ATLAS, the third known interstellar object to pass through our solar system. Twelve NASA assets have captured and processed imagery of the comet since it was first discovered on July 1, 2025, and several others will have opportunities to capture more images as the comet continues to pass through our solar system. 

By observing the comet from so many locations, NASA has an opportunity to learn about the ways that 3I/ATLAS differs from our solar system’s home-grown comets and give scientists a new window into how the compositions of other systems may differ from our own.

Observations from Mars
The closest imagery of the comet was taken by NASA’s spacecraft at Mars. Earlier this fall, 3I/ATLAS passed by Mars from a distance of 19 million miles, where it was observed by three NASA spacecraft. The Mars Reconnaissance Orbiter (MRO) captured one of the closest images of the comet, while the Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter obtained ultraviolet images that will help scientists understand the comet’s make-up. Meanwhile, the Perseverance rover grabbed a faint glimpse from the surface of Mars.

Sun watchers’ view
NASA has heliophysics missions with the unique ability to observe areas of the sky near the Sun. This allowed them to track comet 3I/ATLAS as it passed behind our Sun as seen from Earth, making observations with ground-based telescopes impossible. NASA’s Solar Terrestrial Relations Observatory (STEREO) captured images from Sept. 11 to Oct. 2, 2025, and the European Space Agency (ESA) and NASA mission Solar and Heliospheric Observatory (SOHO) observed the comet from Oct. 15 to 26. Images from NASA’s Polarimeter to Unify the Corona and Heliosphere (PUNCH) mission, launched earlier this year, reveal the comet’s tail during observations from Sept. 20 to Oct. 3.
Despite previously observing and discovering thousands of comets, this is the first time NASA’s heliophysics missions have purposefully observed an object originating in another solar system.

The NASA-funded Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope in Chile discovered 3I/ATLAS on July 1, 2025. Later that month it was viewed by NASA’s Hubble Space Telescope. In August, both NASA’s James Webb Telescope and Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer (SPHEREx) captured imagery. 

Comet 3I/ATLAS will fly closest to Earth about Friday, Dec. 19, 2025, at 170 million miles. This is almost twice the distance between the Earth and Sun. NASA spacecraft will continue to observe the comet as it makes its journey through the solar system, passing the orbit of Jupiter in spring 2026. 

For more information on NASA’s comet 3I/ATLAS observations, visit:
https://go.nasa.gov/3I-ATLAS

https://science.nasa.gov/solar-system/comets/3i-atlas/

Credit: NASA/JPL-Caltech/University of Zrizona
Release Date: Nov. 19, 2025

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