Interstellar comet 3I/ATLAS: Now it's the space probes' turn

The interstellar comet 3I/ATLAS has passed Mars, and because the celestial body cannot currently be observed from Earth, various space probes and other research equipment are now on the job. This is according to communications from the space agencies ESA and NASA, which summarize the upcoming observation campaigns. On 3 October, for example, the ESA orbiters Mars Express and TGO were to set their sights on the interstellar comet, while the US space agency even planned to observe it with the two rovers Perseverance and Curiosity. The closest approach of 3I/ATLAS to the sun (perihelion) will then follow at the end of the month, which will include observations by ESA's Jupiter probe Juice.

In total, observations with more than a dozen missions are planned, and the ESA assures that it intends to make the most of its equipment. According to NASA, it is planning observations with the Hubble, James Webb, and TESS space telescopes, as well as numerous other probes. However, the US space agency has not announced when exactly these will take place. It is also unclear what impact the US government's current budget freeze will have on the organization's work and the planned observations by 3I/ATLAS. The space missions are currently particularly important for this because the interstellar comet is behind the sun from the Earth's perspective and therefore cannot be observed from here.

Of particular interest for research

3I/ATLAS was discovered at the beginning of July with the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile, hence its name. The interstellar comet is only the third ever visitor to our solar system to be discovered during its passage. Researchers have been calling for observations with the probes distributed throughout the solar system for some time, and now it is clear that their call has been heard. The passage of the interstellar comet through the solar system could now also serve as an opportunity to prepare a mission that could visit a similar celestial body in the future. That would certainly be possible.

The interstellar comet probably comes from the outskirts of the Milky Way—the so-called thick disk—and is probably much older than the Earth, the sun, and the entire solar system. Initial analyses revealed this back in July. One of the indications of this is its speed, as 3I/ATLAS races through the solar system much faster than the other two interstellar visitors, 1I/ʻOumuamua and 2I/Borisov. Among other things, those responsible hope that the observations will provide insights into the composition of the celestial body, as it will lose a particularly large amount of material, especially close to the sun, which makes up the ever-growing tail and can therefore be analyzed.

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(mho)