Nasa coordinates an unprecedented operation with 12 space assets to monitor comet 3I/ATLAS, the third interstellar object confirmed in the solar system. The celestial body was discovered on July 1, 2025 by the ATLAS telescope, at Chile, and has already passed close to Marte and Sol. The campaign allows you to compare characteristics of the comet with objects born in the solar system.
Observations began shortly after the discovery and continue as the comet follows a hyperbolic trajectory. The minimum approach to Terra occurs on December 19, 2025, at approximately 170 million kilometers. The object will leave the solar system after crossing Júpiter’s orbit in spring 2026.
- Closest images were taken by spacecraft in Marte
- Heliographic missions recorded passage close to Sol
- Probes transiting asteroids contributed trajectory data
Observations carried out on Marte
Three Nasa assets orbiting Marte recorded the comet in September and October. The Mars Reconnaissance Orbiter probe (MRO) produced one of the most detailed images of the nucleus.
The MAVEN mission captured ultraviolet data to analyze the chemical composition. The Perseverance rover managed to record a faint luminous point from the Martian surface.
Vision of solar missions
The missions dedicated to studying Sol were able to observe the comet even when it was behind the star, invisible from Terra. The STEREO observatory recorded images between September 11th and October 2nd.
The SOHO mission followed the object from October 15th to 26th. The recently launched PUNCH mission revealed details of the tail between September 20 and October 3, marking the first time heliographic missions have intentionally observed an interstellar object.
Contributions from transit probes
The Psyche probe, on its way to the metallic asteroid of the same name, carried out four observations on September 8 and 9, 53 million kilometers away. Os data helps refine the comet’s orbit.
The Lucy mission captured a series of images on September 16, 386 million kilometers away. The composition of the images highlights the object’s coma and tail.
Records with space telescopes
Telescópio Espacial Hubble obtained images in July 2025. In August, Telescópio James Webb and the SPHEREx observatory also recorded the comet.
These spectral data complement chemical composition observations. The combination of multiple instruments allows detailed analysis of extrasolar origin.
Next steps of the campaign
Nasa maintains continuous monitoring with assets positioned in different regions of the solar system. Terra’s minimum distance in December will still allow new high-resolution images.
The data collected will be used for comparative studies between comets from the solar system and objects formed in other stellar systems. The operation represents the largest mobilization ever carried out for a single interstellar object.
The diversity of observation points offers a three-dimensional view of the comet’s trajectory and evolution. Cientistas hopes to identify variations in the release of gases and dust along the route.
