NASA’s TESS Captures First Images of Rare Interstellar Comet 3I/ATLAS

NASA's Transiting Exoplanet Survey Satellite TESS operates as an exoplanet-hunting telescope that captured its first images of interstellar comet 3I/ATLAS during January 2026. The third known interstellar object, which this rare visitor represents, first appeared to scientists when the NASA-funded ATLAS telescope detected it in July 2025. NASA and MIT researchers currently examine the data to investigate the comet's rotational behaviour and its active periods. The initial results show that 3I/ATLAS operates like a known solar system comet, which rotates every 15 hours.

TESS Observations

According to NASA, the TESS spacecraft collected dozens of images of comet 3I/ATLAS during a special January 15–22 observing run. Using data from Jan. 15 and Jan. 18–19, MIT research scientist Daniel Muthukrishna compiled a 28-hour video showing 3I/ATLAS as a bright, fast-moving dot with a faint tail. NASA notes that astronomers will use these data to study the comet's activity and rotation. Because TESS constantly monitors large sky regions, it even recorded 3I/ATLAS back in May 2025 – two months before astronomers first identified the comet.

A Familiar Comet

Further observations have also confirmed that 3I/ATLAS spins like a normal comet. In December 2025, scientists from the Two-Meter Telescope at the Teide Observatory in Spain observed a faint gas and dust jet emanating from 3I/ATLAS that wobbled as the comet rotated. This wobble indicated a rotation period of 14 to 17 hours. The scientists observed that the comet's behaviour is surprisingly normal: 3I/ATLAS was found to be an “extraordinarily normal interstellar comet,” complete with sunlight-powered jets. NASA explains that the study of 3I/ATLAS, its orbit, size, and gas emission, may provide information on the composition of distant star systems.