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

Deep space exploration has reached a new milestone with the release of high-resolution images of the interstellar comet 3I/ATLAS, captured by the Chinese probe Tianwen-1. The operation, successfully conducted in the orbit of Marte in October 2025, represents the first time that an object from outside Sistema Solar has been imaged with such a level of detail from the vicinity of another planet, offering a unique perspective for science.

The recordings were carried out at a distance of approximately 30 million kilometers from the celestial body, a maneuver that required meticulous planning and unprecedented technical precision on the part of Administração Espacial Nacional of China (CNSA). The images obtained provide crucial data for the global scientific community, which can now analyze in more depth the composition and trajectory of rare cosmic visitors.

The passage of comet 3I/ATLAS close to Planeta Vermelho mobilized a collaborative effort between different space agencies. Essa cooperation was essential to cross-reference data and obtain a more complete understanding of the nature of this object, consolidating a significant advance for planetary science and modern astronomy.

A visitor from another star system

Comet 3I/ATLAS is the third object with a confirmed origin outside our Sistema Solar, following the detections of ‘Oumuamua in 2017 and 2I/Borisov in 2019. Sua trajectory, described as a sharp hyperbolic orbit, is the main evidence that it does not belong to our system and is just passing through our cosmic backyard. With an estimated diameter of 5.6 kilometers and traveling at a speed of 58 kilometers per second, its analysis offers a unique opportunity to study materials formed in the protoplanetary disk of another star, providing valuable clues about the formation of other planetary systems in Via Láctea.

Unlike its predecessors, the 3I/ATLAS observation from Marte allowed a different perspective, free from certain atmospheric distortions from Terra and with a privileged viewing angle during its approach to Sol. Cientistas around the world seek to understand whether the chemical composition of these objects varies significantly, which could indicate the diversity of “ingredients” for the formation of planets in other parts of the galaxy. Detailed analysis of its coma and tail helps model conditions in its home star system, such as the temperature and density of the gas cloud where it formed billions of years ago.

The technical details of the unprecedented capture

The high-resolution camera HiRIC (High Resolution Imaging Camera), on board Tianwen-1, was the central instrument for the successful observation. Originalmente designed to map the surface of Marte in unprecedented detail, the mission engineering team adapted its use for a completely different challenge: tracking a small, faintly glowing, ultra-high-speed target in vast space. Para To overcome the challenge of capturing such a fast-moving object without generating blurry images, extensive simulations were carried out on the ground, ensuring that the equipment was perfectly calibrated for the task.

The strategy adopted was to use extremely short exposure times, optimizing light capture and ensuring the necessary sharpness for scientific analysis. The raw data was transmitted to the control center at Pequim, where a specialized processing system assembled the image sequences, revealing the comet in never-before-seen detail. The maneuver demonstrates the versatility and capacity of the probe’s instruments, which went beyond their primary objectives.

What the images reveal about 3I/ATLAS

The photographs released by CNSA clearly show the rocky and frozen core of 3I/ATLAS, which is the heart of the comet. The Este nucleus is surrounded by a coma, a cloud of gas and dust that forms when the heat from the Sol sublimates the ice on the comet’s surface, transforming it directly into gas. The coma reached a diameter of thousands of kilometers, indicating very intense cometary activity, greater than that observed in many comets from our own Sistema Solar. The tail, formed by particles ejected by solar radiation pressure, extended approximately 56,000 kilometers and was positioned in the opposite direction to Sol during observations, a classic behavior of active comets. Análises Preliminary spectral data, based on collected data, suggest the presence of water ice and carbon dioxide. Também weaker signals of carbon monoxide were detected, a composition that points to a formation in a very cold region of its home star system. The reddish glow observed in the core is attributed to the presence of dust rich in complex organic compounds. Além Furthermore, scientists analyze a non-gravitational acceleration, a slight deviation in the trajectory that cannot be explained by gravity alone, indicating additional forces caused by the ejection of gases from its surface.

An international scientific collaboration

The passage of 3I/ATLAS through Marte was not observed only through China.

Agência Espacial Europeia (ESA) used its Mars Express and ExoMars Trace Gas Orbiter probes to analyze gaseous emissions from the comet’s coma.

These observations provided a complementary perspective to the Chinese data, allowing a more three-dimensional view of the object’s activity and chemical composition.

NASA also actively participated in the effort, directing Mars Reconnaissance Orbiter (MRO) to capture images with its powerful HiRISE instrument, while the MAVEN probe collected spectrometric data to enrich the information set.

The journey of mission Tianwen-1 to date

Launched in July 2020, the Tianwen-1 mission represents a milestone for the Chinese space program, being the country’s first mission, Marte, which included an orbiter, a lander and a rover.

The probe successfully entered Martian orbit in February 2021. In May of the same year, the Zhurong rover landed on the vast plain of Utopia Planitia, where it operated for approximately one Earth year, exceeding initial expectations.

During its surface mission, the rover collected geological data, analyzed the composition of the soil and atmosphere, and sent back detailed images of the terrain, contributing significantly to the understanding of the geological history of Marte.

Planning and execution of the maneuver

The Tianwen-1 mission team began planning to observe the comet in September 2025, as soon as orbital predictions became accurate enough.

The calculations took into account the object’s high speed and low luminosity to determine the ideal observation windows, ensuring that the probe was in the correct position and the instruments were properly calibrated for recording.

Next steps for Chinese exploration

The success of the 3I/ATLAS observations serves as an important validation of the technologies and methods that will be used in future Chinese missions. The experience gained strengthens the Sistema Solar smaller bodies exploration program, one of the CNSA’s focuses for the next decade, consolidating the country’s position as a power in space exploration.

The Tianwen-2 mission, launched in May 2025, is the next big step. Seu objective is to collect samples from an asteroid close to Terra and, subsequently, study a comet from the main belt. The successful tracking of 3I/ATLAS confirms the ability of China to conduct complex operations in deep space, paving the way for even more ambitious explorations in the future.