Chinese probe Tianwen-1 records images of the interstellar comet 3I/ATLAS in orbit around Mars

In a remarkable feat for deep space exploration, the Chinese probe Tianwen-1, operating in the orbit of Marte, captured detailed images of comet 3I/ATLAS. Este celestial object is a rare visitor from outside our Sistema Solar, and its record represents a significant advance in the ability to monitor distant, dynamic bodies from orbital platforms on other planets.

The observation occurred in late 2025 and marks the first time an interstellar comet has been successfully imaged from Martian orbit. The event provided valuable data to the international scientific community, which is dedicated to understanding the composition and trajectory of objects formed in other star systems, offering a unique window into the formation processes of other worlds.

The images, released by Administração Espacial Nacional of China (CNSA), show the comet’s nucleus and gaseous coma with impressive clarity. The operation challenged the limits of Tianwen-1’s instruments, originally designed to map the surface of Marte, confirming its versatility for tracking high-speed targets in deep space.

An unprecedented orbital engineering maneuver

The capture of images of comet 3I/ATLAS by Tianwen-1 was an engineering feat that required meticulous and innovative planning. The probe’s high-resolution camera, known as HiRIC, was developed to photograph Martian topography with extreme precision, a fundamentally different task from tracking a small, faintly glowing, fast-moving object against the dark background of space. Para achieved the objective, the mission team at Terra needed to develop a new observation strategy from scratch. Isso involved completely recalibrating the probe’s targeting systems and performing precise orbital maneuvers to align the equipment with the comet’s predicted trajectory. Foram performed exhaustive simulations to determine the ideal exposure times, which needed to be short enough to avoid blur caused by the relative motion between the probe and the comet, but long enough to capture the faint light reflected by its nucleus and coma. The thermal stability of the instruments was also a critical factor, requiring adjustments to ensure that the lenses and sensors operated in their optimal temperature range during the observation window, which lasted just a few minutes. The raw data was transmitted to the control center at Pequim, where specialized algorithms processed the multiple exposures to create the sharp images that were later released.

The third messenger from another star system

Comet 3I/ATLAS is the third confirmed interstellar visitor to be detected by astronomers, following the passes of ‘Oumuamua in 2017 and 2I/Borisov in 2019.

Its discovery was made in July 2025 by the ATLAS telescope system (Asteroid Terrestrial-impact

Confirmation of its extrasolar origin came quickly from the analysis of its trajectory, described as hyperbolic. Esta is a clear mathematical signature that indicates an origin external to our planetary system.

Unlike the elliptical orbits of local comets and asteroids, a hyperbolic trajectory means the object has enough speed to escape the gravitational pull of Sol, allowing it to continue its journey through interstellar space after its brief passage through our cosmic neighborhood.

Initial clues about the comet’s composition

The spectral data and initial images collected by Tianwen-1 already offer important indications about the nature of 3I/ATLAS. The photographs show a dense, well-defined core, which is likely composed of a mixture of rock and different types of ice. Analysis of the light reflected by its surface points to the presence of reddish organic dust, a common feature in celestial bodies formed in cold regions far from their host star. The presence of these organic compounds is of great interest to astrobiologists, as they are the building blocks of life as we know it.

Additionally, spectrometers aboard other missions have detected signatures of water ice and carbon dioxide sublimating from the surface, along with traces of carbon monoxide, confirming their typical cometary activity. Detailed analysis of these ejected gases and dust, which form the comet’s coma and tail, can reveal the chemical composition of the protoplanetary disk where it formed billions of years ago, providing a direct glimpse into conditions existing in another star system.

International effort in the orbit of Marte

The 3I/ATLAS observation was not an isolated initiative by the Chinese space agency.

The presence of an international fleet of probes in Marte’s orbit enabled a coordinated observation campaign, which significantly expanded the quantity and quality of data collected about the object.

Agência Espacial Europeia (ESA) and NASA also directed their orbiters to study the gaseous composition of the comet’s coma and attempt to obtain even higher resolution images of its nucleus.

On the surface, the Perseverance and Curiosity rovers were programmed to attempt to locate and observe the comet in the Martian sky, contributing a unique perspective from the ground of Planeta Vermelho.

Chinese mission versatility proven

For the Tianwen-1 team, the comet tracking operation served as a rigorous test of the probe’s capabilities beyond its primary mission of studying Marte.

The success of the maneuver demonstrated the flexibility and robustness of the orbiter’s navigation and attitude control systems, qualifying it for future opportunity observation tasks that may arise.

Next steps for China space exploration

Launched in July 2020, the Tianwen-1 mission represents a milestone in the history of Chinese space exploration. The probe reached the orbit of Marte in February 2021 and successfully landed the Zhurong rover in May of the same year.

The experience gained from the 3I/ATLAS observation is considered extremely valuable for future China missions, especially Tianwen-2. Lançada in 2025, this new mission has the ambitious objective of collecting samples from an asteroid and studying a comet. The protocols developed to observe the interstellar visitor will be directly applied to these new and complex deep space exploration missions.

Continuous Mapping of the Red Planet

Currently, the Tianwen-1 orbiter continues its mapping work, expanding scientific knowledge about Planeta Vermelho while remaining alert to new scientific observation opportunities, now with proven capabilities for tracking distant objects.