Obtaining an image of an interstellar object, a body that is not gravitationally bound to the Sun, is already exceptional. But doing so from a spacecraft in Mars orbit poses enormous challenges: the object is tens of millions of kilometers away, it is extremely faint (up to 100,000 times dimmer than the probe’s usual targets) and moves at high speed.
Well, that is precisely what Tianwen-1 has achieved, which has been orbiting Mars since 2021. The Chinese probe has managed to capture images of the interstellar comet 3I/ATLAS during its close pass to the red planet. According to the China National Space Administration (CNSA), The observation represents a technical and scientific milestone in the exploration of the solar system.
The image was taken as 3I/ATLAS approached Mars. Tianwen-1 High Resolution Camera (HiRIC) managed to detect a bright point surrounded by a diffuse cloud of gas and dustthe typical “comma” of comets, which confirms visible activity even at such a distance.
The image was taken about 28 million kilometers away, which surpasses the record held until now by the ExoMars Trace Gas Orbiter (TGO) probe of the European Space Agency during its close flyby of the planet Mars: 30 million km.
The presence of a coma suggests that 3I/ATLAS is releasing volatile material as it approaches the Sunwhich puts it in the category of an active comet, not just an inert asteroid.
At the same time, the resolution allows more refined estimates of their size, activity and dynamic behavior. Some sources mention that the coma could extend several thousand kilometers.
Viewing the object from a platform outside Earth (this is key) reduces many of the atmospheric interferences and opens a new window to study interstellar objects from another perspective.
But obtaining this image was not so simple. For example, the camera on board the probe was intended to observe well-lit surfaces on Mars, not diffuse, distant objects. To this we must add that the ship and the object were moving, which implied precise tracking, proper exposure and image stabilization. The dim luminosity of the object forced the use of longer exposure times, with greater risk of blurring or loss of the objective.
These preliminary images feed a trove of data that scientists will use to analyze the composition, trajectory, activity and origin of 3I/ATLAS. As this interstellar visitor moves away from the Sun and into deep space again, images like this constitute a kind of “portrait” of an object perhaps “billionaire” in age traveling through other star systemsbefore getting here.
And although we cannot yet touch it or bring samples (a future mission may leave that door open) the view from Mars already reminds us how vast and diverse the universe can be. This image of Tianwen-1 is not only a technical achievement: It is an invitation to think that, in some distant corner of the cosmos, there is another star system that this visitor spit out… and that we see it, we photograph it, and now we study it.