Interstellar comet 3I/ATLAS grows a pronounced tail as telescopes and ESA spacecraft mobilise

• High-resolution Hubble and Webb observations deliver improved measurements of 3I/ATLAS’s nucleus and expanding tail, refining activity, composition and trajectory datasets that underpin mission planning and scientific analysis (see Hubble’s sharpest images).
• ESA’s plan to repoint Mars Express, ExoMars Trace Gas Orbiter and JUICE converts existing interplanetary spacecraft into coordinated observers, offering unique vantage points for remote sensing as the comet approaches Mars (see European orbiters preparing coordinated observations).
• A global ground-based campaign in Hawaii, Chile and Australia provides continuous monitoring of rapid activity changes during the comet’s sunward passage, improving temporal coverage for follow-up studies (see Hubble’s first images of 3I/ATLAS).

Hubble’s sharpest images

European orbiters preparing coordinated observations

Hubble’s first images of 3I/ATLAS