Comet ATLAS: New Activity Spotted by JUICE Probe

Juice Probe Captures First Images of Active Comet 3I/ATLAS

A surprising early glimpse of comet 3I/ATLAS has been captured by the European Space Agency’s Jupiter Icy Moons Explorer (Juice), revealing a vibrant and active celestial body even at a distance of 66 million kilometers. The probe utilized both its scientific instruments and its navigation camera to gather initial data on the comet’s composition and behavior.

The initial observations, made during November 2025, offer a tantalizing preview of the detailed data expected in February 2026. Scientists were eager to assess the comet’s condition, prompting a partial download of an image from the Navigation Camera (NavCam) – a tool primarily designed for spacecraft navigation upon arrival at Jupiter in 2031, not high-resolution scientific imaging.

Did you know? – Comet 3I/ATLAS was discovered in early 2023 and is expected to become a naked-eye object in late 2025 and early 2026, offering a rare viewing chance.

Unexpected Activity Revealed

The downloaded image, though limited in resolution, immediately revealed a comet brimming with activity. “The very clearly visible comet, surrounded by signs of activity, surprised them,” a member of the Juice team stated. The image showcases the coma, a glowing halo of gas surrounding the comet’s nucleus, and hints at the presence of two distinct tails.

The most prominent feature is the plasma tail, composed of electrically charged gas, extending upwards from the comet. A fainter dust tail, made up of tiny solid particles, appears to stretch towards the lower left of the frame. These features indicate a comet in a highly active state, likely due to its recent close approach to the Sun.

Closest Approach and data Collection

Juice took the initial image on November 2, 2025, just two days before its closest approach to 3I/ATLAS on November 4.Why did Juice observe 3I/ATLAS? The observation was an opportunistic event, allowing scientists to test and calibrate the probe’s instruments during its journey to Jupiter. The probe employed five scientific instruments during the observation period: JANUS, MAJIS, UVS, SWI, and PEP. Who was involved? The European Space Agency (ESA) and the juice mission team. What did Juice capture? Images and data revealing the comet’s active state, including its coma and tails. Data from these instruments – including high-resolution images from JANUS, spectrometry data from MAJIS and UVS, composition data from SWI, and particle data from PEP – is anticipated to arrive on Earth on February 18 and 20, 2026.

The delay in data transmission is due to current operational constraints. Juice is utilizing its main high-gain antenna as a heat shield against the sun, forcing it to rely on a smaller, medium-gain antenna for data transmission, resulting in a significantly slower data rate.

Pro tip: – Comets display tails as they approach the Sun. The solar wind and radiation pressure push dust and ionized gases away from the comet’s nucleus, creating these visible features.

Active State Despite Distance

Despite being farther from 3I/ATLAS than previous observations by Mars orbiters in October, juice benefited from observing the comet shortly after its closest approach to the Sun. This timing allowed the probe to capture the comet during a period of heightened activity. Scientists anticipate the forthcoming data will provide even clearer evidence of this activity. How did the observation end? Juice completed its observation period on November 4, 2025, after its closest approach, and is now transmitting the collected data back to Earth, expected to arrive in February 2026.

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