The European Space Agency (ESA) is repurposing its fleet of spacecraft around Mars and the Sun to track 3I/ATLAS, a rare interstellar comet, as it slips out of view from Earth during a three-month solar conjunction.
Astronomers say the object—only the third known interstellar visitor to our Solar System—will remain invisible to ground telescopes from late September until December 2025, making spacecraft observations critical.
