Unpublished photographs of the interstellar comet 3I/ATLAS are recorded by the Tianwen-1 probe on Mars

A historic moment for astronomy was consolidated in October 2026, when Administração Espacial Nacional of China (CNSA) confirmed that its probe Tianwen-1, on a mission in the orbit of Marte, successfully obtained the first images of an interstellar comet from another planet. The object, cataloged as 3I/ATLAS, was photographed from a distance of approximately 30 million kilometers, a feat that not only demonstrates the advanced technological capabilities of the Chinese mission, but also opens a new frontier for the study of celestial bodies that originate outside our Sistema Solar. The complex operation required detailed planning and high-precision maneuvers so that the probe’s camera could track the small and fast cosmic visitor, providing invaluable data for the international scientific community.

Capturing the images represents a significant advance in planetary science, as it allows the analysis of an object coming from another star system from a completely new observation point. The information collected by Tianwen-1 is crucial for unraveling the composition and dynamics of comets traveling across the galaxy.

The event also mobilized global collaboration, with other space agencies directing their own instruments at Marte to observe 3I/ATLAS. Esse joint effort aims to build a detailed profile of the comet, taking advantage of the rare opportunity of its passage through our planetary system.

A visitor from another solar system

Comet 3I/ATLAS is only the third confirmed interstellar object to be detected by astronomers, following observations of ‘Oumuamua in 2017 and 2I/Borisov in 2019. Via Láctea. With an estimated diameter of 5.6 kilometers and an impressive speed of 58 kilometers per second, its passage offers a unique window of opportunity to examine materials that were formed in the protoplanetary disk of a distant star. Analysis of their chemical and physical composition could reveal information about planet formation processes elsewhere in the galaxy, allowing scientists to compare the “building blocks” of alien worlds with those of our own Sistema Solar and enhance understanding of the diversity of planetary systems that may exist in the universe.

The technical challenge of capturing in Marte

Responsibility for capturing the images fell to the high-resolution camera HiRIC (High Resolution Imaging Camera), one of the main instruments on board the Tianwen-1 orbiter. Although Embora was designed primarily to map the topography and geology of the surface of Marte in unprecedented detail, the CNSA engineering team adapted its functionality for a completely different task: tracking a small, dimly glowing, ultra-high-speed target against the dark background of space. Essa recalibration was a notable challenge, requiring the development of new tracking software and the implementation of extremely complex command sequences to ensure that the camera could focus and follow the comet with the necessary precision throughout the observation window.

Overcoming the difficulty of photographing such a fast object without the images becoming blurred was a priority. Para this, the team carried out extensive simulations on land, testing different capture strategies. The solution adopted involved the use of very short exposure times, combined with a predictive tracking system that continuously adjusted the orientation of the probe. The raw data was transmitted to the mission control center at Pequim, where image processing algorithms were applied to assemble the sequences, correct optical distortions and highlight details of the comet’s structure, such as its nucleus and the coma of gas and dust surrounding it.

The first revelations of the images

The photographs released by the Chinese space agency show with remarkable clarity the core of 3I/ATLAS, a mass composed of rock and ice.

This nucleus appears surrounded by a coma, a diffuse cloud of gas and dust that forms when solar heat vaporizes the ice on the comet’s surface.

The comet’s tail, made up of dust particles and ions pushed by radiation and the solar wind, stretched tens of thousands of kilometers.

Initial spectral analyses, conducted based on visual and other sensor data, indicate the presence of water ice, carbon dioxide and carbon monoxide, suggesting that the comet formed in an extremely cold region of its home star system.

Global effort in observing the comet

The passage of 3I/ATLAS close to Marte was an event that attracted the attention of multiple space agencies, transforming the observation into an international collaborative effort.

Agência Espacial Europeia (ESA) contributed its orbiting probes, Mars Express and ExoMars Trace Gas Orbiter, which used their spectrometers to analyze the composition of gases released by the comet’s coma.

NASA also actively participated, redirecting its Mars Reconnaissance Orbiter (MRO) to try to capture images with the powerful HiRISE camera and instructing rovers on the surface, like Perseverance, to look for the comet in the Martian sky.

The trajectory of the Tianwen-1 mission

Launched in July 2020, Tianwen-1 is China’s first independent interplanetary mission and a milestone in its ambitious space program. The probe successfully entered the orbit of Marte in February 2021.

The mission is made up of an orbiter, which continues to map the planet, a lander and the Zhurong rover, which explored the Utopia Planitia region for about an Earth year, collecting valuable data on the local geology and atmosphere.

The precision behind the orbital maneuver

Planning for the 3I/ATLAS observation began in September 2026, as soon as the comet’s orbital calculations reached a sufficient degree of precision to guarantee the success of the operation. The CNSA team calculated the ideal observation windows, taking into account the object’s speed, its luminosity and the position of the Tianwen-1 probe to maximize the quality of the data collected.

Future ambitions of the Chinese space program

The successful observation of comet 3I/ATLAS serves as an important validation of the navigation and instrument control technologies that will be essential for future deep space exploration missions planned by China.

The next major project in this field is the mission