Interstellar Comet 3I/ATLAS Approaches Mars, Observed by Spacecraft
Comet 3I/ATLAS, the third known interstellar object, is nearing Mars, with spacecraft from NASA and the European Space Agency set to observe its passage.
Comet 3I/ATLAS, the third confirmed interstellar object to traverse our solar system, is approaching Mars, providing a unique observation opportunity for spacecraft. Discovered on July 1, 2025, by the ATLAS survey, the comet is traveling at approximately 193,000 mph (310,000 kph) and will pass within 18 million miles (29 million kilometers) of Mars on October 3.
The European Space Agency's Mars orbiters, including Mars Express and the ExoMars Trace Gas Orbiter, are preparing to capture images and data of the comet during its closest approach. NASA's Mars Reconnaissance Orbiter and rovers are also set to observe the event. These observations aim to enhance understanding of interstellar objects and their compositions.
Comet 3I/ATLAS poses no threat to Earth or Mars. It is expected to reach its closest point to the Sun on October 29, 2025, at a distance of 1.36 astronomical units. The comet will make its closest approach to Earth in December, passing within 167 million miles (269 million kilometers). Observations by the Hubble Space Telescope estimate the comet's nucleus to be between 1,444 feet (440 meters) and 3.5 miles (5.6 kilometers) in diameter.