The interplanetary station Europa Clipper, en route to Jupiter’s moon, may pass through the ion tail of the interstellar comet 3I/ATLAS at the end of October or the beginning of November 2025. If the spacecraft manages to detect particles from this tail, it would mark the first confirmed encounter with an object from another star system.

Features of the 3I/ATLAS Comet Tail

Although the visible part of the 3I/ATLAS comet’s tail appears short, in reality, its material stretches across hundreds of millions of kilometers. The main components of the tail are water, carbon monoxide, carbon dioxide, and carbon disulfide.

Studying the tail’s composition, particularly the ratio of regular hydrogen to deuterium in the water, will allow scientists to compare 3I/ATLAS with comets from our Solar System and gain new insights into its origin. Researchers from Finland and the Netherlands note that this opportunity may arise in the near future.

Opportunities for Research

Scientists have calculated that two interplanetary probes—Europa Clipper and Hera—could pass through the 3I/ATLAS tail. The Hera probe is heading to the binary asteroid system Didymos-Dimorphos to observe the aftermath of the DART spacecraft impact, which in 2022 was directed at Dimorphos to test asteroid deflection technology.

Hera does not carry instruments for collecting data on cometary material, but Europa Clipper is equipped to measure magnetic field characteristics and analyze particles. If the probe enters the comet’s tail, it will be able to detect ions—molecules and atoms from which solar radiation has stripped electrons.

Comet and Probe Trajectories

Comet 3I/ATLAS was discovered near Jupiter and has already crossed Mars’s orbit, now approaching perihelion, which it will reach on October 29, 2025, at a distance of 203 million kilometers from the Sun. At that time, Europa Clipper will be about twice as far from the Sun, but only eight million kilometers from the central axis of the comet’s ion tail. The tail’s particles will be dispersed over even greater distances sideways.

According to calculations, the spacecraft may pass through 3I/ATLAS material between October 30 and November 6, 2025. If this occurs, it will be the first confirmed contact with an object from another star system.

Previous Possible Encounters

In 2014, the object CNEOS 08.01.2014 fell into the Pacific Ocean; its speed and trajectory also suggested an interstellar origin. In 2023, an expedition was sent to the impact site, and spherical particles of solidified melt with an unusual composition were recovered from the ocean floor. However, the scientific community remains divided on the interstellar origin of this object due to uncertainties in determining its exact impact location.