Photo: Imagens 3D do cometa 3I ATLAS – Photo: jhonny marcell oportus/ shutterstock.com
Space exploration reached a new milestone in October 2025, when the Chinese probe Tianwen-1, operating in the orbit of Marte, captured high-resolution images of comet 3I/ATLAS. Este event represents the first time that an interstellar object is observed and photographed from another planet, consolidating a significant advance for planetary science and astronomy.
The recording was carried out at an approximate distance of 30 million kilometers from the celestial body, a feat that required high-precision maneuvers and meticulous planning on the part of Administração Espacial Nacional of China (CNSA). The images provide crucial data for the global scientific community, which studies the composition and trajectory of visitors from outside our Sistema Solar.
The passage of comet 3I/ATLAS close to Planeta Vermelho mobilized several space agencies, which directed their equipment to collect as much information as possible. International collaboration was essential to cross-reference data and obtain a more complete understanding of the nature of this rare cosmic object.
A visitor from another solar 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. Chile. The comet’s trajectory, described as a sharp hyperbolic orbit, is the main evidence that it does not belong to our system and is just passing through. About 5.6 kilometers wide 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 clues about the formation of other planetary systems in Via Láctea.
Technical details of the 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 detail, the mission engineering team adapted its use to track a small, dimly glowing, fast-moving target in vast space.
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To overcome the challenge of capturing such a fast-moving object without generating blurry images, extensive simulations were carried out. The strategy adopted was to use extremely short exposure times, optimizing light capture and ensuring the necessary sharpness. The raw data was transmitted to the control center at Pequim, where a specialized processing system assembled the image sequences.
What the images reveal about 3I/ATLAS
The photographs released by CNSA clearly show the rocky and frozen core of 3I/ATLAS. 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.
The coma reached a diameter of thousands of kilometers, indicating very intense cometary activity. The tail, formed by particles ejected by solar radiation pressure, grew to about 56,000 kilometers and was positioned in the opposite direction to Sol during observations.
Preliminary spectral analyses, based on the data collected, 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 organic compounds. Além In addition, 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, providing a complementary perspective to the Chinese data. The collaboration allowed us to obtain a more three-dimensional view of the object’s activity, combining different observation angles to refine models of its composition and structure.
NASA also actively participated in the effort, directing Mars Reconnaissance Orbiter (MRO) to capture images with its powerful HiRISE instrument. On the surface, rovers like Perseverance have attempted to detect the comet from the Martian soil, a considerable technical challenge. NASA’s Hope probe and NASA’s MAVEN collected spectrometric data, enriching the set of information and helping to refine estimates about the orientation of its rotation axis and the forces acting on it.
The journey of mission Tianwen-1 so far
Launched in July 2020, the Tianwen-1 mission represents a milestone for the Chinese space program, being the country’s first mission, Marte. The probe successfully entered Martian orbit in February 2021, carrying an orbiter, a lander and the Zhurong rover.
In May 2021, the Zhurong rover landed on the vast plain of Utopia Planitia, where it operated for approximately one Earth year. Durante its mission on the surface, the rover collected geological data, analyzed the composition of the soil and atmosphere and sent back detailed images of the terrain, contributing to the understanding of the geological history of Marte. Enquanto that, the orbiter continues its work, mapping the planet and studying the Martian poles.
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 successful 3I/ATLAS observations serve as an important validation of the technologies and methods that will be employed 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.
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.